Biology EOC Practice Questions (Practice Mode)

1. The presence of what cellular structure distinguishes a plant cell from an animal cell?

Cell membrane

Chloroplast

Mitochondrion

Nucleus

Animal Cells do NOT have = chloroplasts, cell walls, & large central vacuoles
Both Animal Cells & Plant Cells are Eukaryotes = nucleus & membrane bound organelles

Explanation

Animal Cells do NOT have = chloroplasts, cell walls, & large central vacuoles
Both Animal Cells & Plant Cells are Eukaryotes = nucleus & membrane bound organelles

2. In addition to the reproductive system, which body system is most directly essential to the production of gametes and offspring?

Circulatory

Endocrine

Immune

Nervous

Endocrine system produces hormones that are needed to produce gametes (ex: testosterone & estrogen).

Explanation

Endocrine system produces hormones that are needed to produce gametes (ex: testosterone & estrogen).

3. During what phase of meiosis does nondisjunction occur?

Metaphase I

Anaphase I

Prophase II

Metaphase II

Nondisjunction = can occur when chromosomes SEPARATE (anaphase I or II)

Explanation

Nondisjunction = can occur when chromosomes SEPARATE (anaphase I or II)

4. Lions and tigers both belong to genus Panthera., Cheetahs belong to the genus Achinonyx. Scientists group these 3 types of cats together at the next taxonomic level. What is the most specific taxonomic level that lions, cheetahs, and tigers share?

Class

Family

Kingdom

Order

Kingdom -> Phylum -> Class -> Order -> FAMILY -> Genus -> Species

Explanation

Kingdom -> Phylum -> Class -> Order -> FAMILY -> Genus -> Species

5. Which group(s) contain organsims that can be classified as primary producers?

Monerans only

Protists only

Monerans and protists

Viruses and monerans

In addition to plants, algae (protists) and some bacteria (monerans) are autotrophs (a.k.a. producers).

Explanation

In addition to plants, algae (protists) and some bacteria (monerans) are autotrophs (a.k.a. producers).

6. Hummingbirds transfer pollen from one flower to another while feeding. What plant structure contains the pollen?

Carpel

Petal

Sepal

Stamen

Pistil = female part which produces the ovum
Stamen = male part which produces the sperm contained in pollen

Explanation

Pistil = female part which produces the ovum
Stamen = male part which produces the sperm contained in pollen

7. The graph represents the average fastest speed of 5 animals recorded in one study. Based on the graph, which species is approximately 1/3 as fast as the cheetah?

Elephant

Kangaroo

Lion

Snake

25 is 1/3 of 75 so 25 (elephant speed) is approximately 1/3 of 70 (cheetah speed)

Explanation

25 is 1/3 of 75 so 25 (elephant speed) is approximately 1/3 of 70 (cheetah speed)

8. These diagrams represent different stages of animal cell division. From start to finish, what is the correct order of the stages?

2, 4, 3, 1

2, 3, 4, 1

3, 2, 1, 4

3, 1, 2, 4

Prophase (chromosomes condense & nuclear membrane disappears)
Metaphase (chromosomes line up in the MIDDLE)
Anaphase (chromosomes are pulled APART)
Telophase (2 nuclear membranes form & cytokinesis occurs

Explanation

Prophase (chromosomes condense & nuclear membrane disappears)
Metaphase (chromosomes line up in the MIDDLE)
Anaphase (chromosomes are pulled APART)
Telophase (2 nuclear membranes form & cytokinesis occurs

9. This molecule is an example of which substance?

Amino acid

Carbohydrate

Fatty Acid

Nucleotide

Amino acids are the building blocks of proteins. They are made of a central Carbon & Hydrogen, an Amino group (-NH2), a Carboxyl group (-COOH), and an R group (variable)

Explanation

Amino acids are the building blocks of proteins. They are made of a central Carbon & Hydrogen, an Amino group (-NH2), a Carboxyl group (-COOH), and an R group (variable)

10. This graph illustrates 4 different chemical reactions. Which reaction has the fastest initial reaction rate?

Reaction I

Reaction II

Reaction III

Reaction IV

Reaction 1 (black circles) has the steepest rate of increase (slope) at the beginning of the experiment.

Explanation

Reaction 1 (black circles) has the steepest rate of increase (slope) at the beginning of the experiment.

11. A scientist found that the results of an experiment did not support her hypothesis. If she is following proper scientific procedure, what should she do next?

Discard those results and repeat the experiment.

Accept the hypothesis and exclude data that does not fit.

Reject the hypothesis and assume it is incorrect.

Create a new hypothesis and a new experiment to test it.

If the data does not support the hypothesis, it should be rejected. A new experiment should be designed to test a revised hypothesis.
f the data does support the hypothesis, it should be accepted but the experiment should be repeated to ensure accuracy. The experimental design, results, & conclusion should be published so that other scientists can confirm the work.

Explanation

If the data does not support the hypothesis, it should be rejected. A new experiment should be designed to test a revised hypothesis.
f the data does support the hypothesis, it should be accepted but the experiment should be repeated to ensure accuracy. The experimental design, results, & conclusion should be published so that other scientists can confirm the work.

12. After learning about viruses in Biology class, Sam decides to have his cat vaccinated against feline leukemia virus. According to cell theory, are viruses, such as feline leukemia, considered living things?

Yes, because they can reproduce.

Yes, because they are composed of cells.

No, because they cannot adapt to their environment.

No, because they are not composed of cells.

Cell theory = ALL living things are made of cells
Viruses are made of proteins & nucleic acids but they are NOT cells (no cell membrane, cytoplasm, or ribosomes)

Explanation

Cell theory = ALL living things are made of cells
Viruses are made of proteins & nucleic acids but they are NOT cells (no cell membrane, cytoplasm, or ribosomes)

13. Which group(s) contain organsims that can be classified as primary producers?

Monerans only

Protists only

Monerans and protists

Viruses and monerans

In addition to plants, algae (protists) and some bacteria (monerans) are autotrophs (a.k.a. producers).

Explanation

In addition to plants, algae (protists) and some bacteria (monerans) are autotrophs (a.k.a. producers).

14. A researcher counted the number of eggs a single fruit fly laid in 24 hrs for 5 days and recorded the findings in this table. What is the average number of eggs laid per day over the 5 days?

5

10

25

50

add number of eggs from each day (50) and divide by the number of days (5)
50 / 5 = 10

Explanation

add number of eggs from each day (50) and divide by the number of days (5)
50 / 5 = 10

15. Lazzaro Spallanzani and Louis Pasteur both performed experiments hoping to disprove spontaneous generation. What conditions existed in Pasteur's experiment that did not exist in Spallanzani's?

Air could enter the flasks, but no microorganisms could enter.

No air could enter the flasks, but microorganisms could enter.

Neither air nor microorganisms could enter the flasks.

Both air and microorganisms could enter the flasks.

Spallanzani = straight necked flasks
Pasteur = S-shaped flasks that allowed air in but trapped dust in the neck

Explanation

Spallanzani = straight necked flasks
Pasteur = S-shaped flasks that allowed air in but trapped dust in the neck

16. Which solution has the greatest concentration of hydroxide ions (OH-)?

Urine (pH 6.0)

Rainwater (pH 5.5)

Tomato juice (pH 2.0)

Gastric juice (pH 2.0)

When a solution becomes more acidic, the concentration of H+ ions increases (by a factor of 10).
When a solution becomes more of a base, the concentration of OH- ions increases (by a factor of 10).

Explanation

When a solution becomes more acidic, the concentration of H+ ions increases (by a factor of 10).
When a solution becomes more of a base, the concentration of OH- ions increases (by a factor of 10).

17. A flagellated protozoan lives within the intestines of a termite and helps it digest wood. What type of relationship most likely exists between the protozoan and the termite?

Competitive

Mutualistic

Parasitic

Predatory

Mutualism = both benefit
Commensalism = one benefits & the other is unaffected
Parasitisim = one benefits & the other is harmed

Explanation

Mutualism = both benefit
Commensalism = one benefits & the other is unaffected
Parasitisim = one benefits & the other is harmed

18. When a new volcanic island forms, the pioneer species is the first species to successfully inhabit the island. Which organism is the most likely candidate for a pioneer species?

A seagull hatched from an egg laid on the island

A palm tree grown from a coconut that washed onto shore

Lichen spores deposited on rocks by the wind

Insect larvae carried on a piece of driftwood

Lichen can live on bare rock so they are a pioneer species for Primary Succession
Primary Succession = bare rock, no soil
Secondary Succession = bare soil, no plants

Explanation

Lichen can live on bare rock so they are a pioneer species for Primary Succession
Primary Succession = bare rock, no soil
Secondary Succession = bare soil, no plants

19. What characteristic of early autotrophs gave them an advantage over early heterotrophs?

They ate heterotrophs.

They produced spores.

They made their own food.

They reproduced asexually.

autotroph = means it makes its own food (producers)
heterotroph = consumers

Explanation

autotroph = means it makes its own food (producers)
heterotroph = consumers

20. What is the RNA sequence for a section of protein composed of Val-Glu-Ser?

GUA-GCC-AGU

GUA-GGG-AGC

GUG-GAC-GGU

GUG-GAG-AGC

Valine could be any GU_ codon (GUG)
Glutamine could be GAG or GAA
Serine could be AGU, AGC, or any UC_ codon

Explanation

Valine could be any GU_ codon (GUG)
Glutamine could be GAG or GAA
Serine could be AGU, AGC, or any UC_ codon

21. If a football field in the taiga is abandoned, which group of organisms will most likely be part of the resulting climax community?

Apple tree, deer, and wolf

Cactus, snake, and hawk

Grass, mouse, and coyote

Pine tree, moose, and bear

Taiga = coniferous forest (most of Canada is part of the Taiga)

Explanation

Taiga = coniferous forest (most of Canada is part of the Taiga)

22. In the following food chain, assuming that the producer contains 180,000 J of energy, how much energy would be able to be transferred to the tertiary consumer? Plant --> Mouse --> Snake --> Owl --> Fungus

180 J

18,000 J

1,800 J

18 J

10% of energy is stored & transferred to the next trophic level (move the decimal place)
90% is used or lost as heat

Explanation

10% of energy is stored & transferred to the next trophic level (move the decimal place)
90% is used or lost as heat

23. Dr. Hansen performs an experiment testing the effectiveness of different cough syrups. Identify the independent variable in the experiment.

Type of cough syrup

Flavor of the cough syrup

Number of people taking each cough syrup

Number of days people take each cough syrup

Independent variable = the cause that is purposely changed in the experiment (different cough syrups)
Dependent variable = the effect that is measured in the experiment (effectiveness/# of days sick)

Explanation

Independent variable = the cause that is purposely changed in the experiment (different cough syrups)
Dependent variable = the effect that is measured in the experiment (effectiveness/# of days sick)

24. The graph provides information about the size of 1 rabbit population over 30 generations. What most likely happened shortly after the 10th generation to cause the change in population between Points A and B?

A fatal disease infected the rabbits.

Area farmers set traps for coyotes.

The average temperature decreased by 0.5 oC.

The average monthly rainfall increased by 0.25 in.

The only answer choice above that would cause the rabbit population to decrease would be a disease. The temperature & rainfall changes are not drastic, therefore not significant. The coyotes are predators, so killing coyotes would cause the rabbit population to increase

Explanation

The only answer choice above that would cause the rabbit population to decrease would be a disease. The temperature & rainfall changes are not drastic, therefore not significant. The coyotes are predators, so killing coyotes would cause the rabbit population to increase

25. Cosmetics often contain glycerol (C₃H₈O₃), which has three identical functional groups. Which type of bond holds these functional groups together?

Covalent

Hydrogen

Intermolecular

Ionic

Glycerol is Organic because it contains Carbon (C3H8O3). Carbon ALWAYS forms Covalent bonds.

Explanation

Glycerol is Organic because it contains Carbon (C3H8O3). Carbon ALWAYS forms Covalent bonds.

26. Adrenoleukodystrophy (ALD) is a sex-linked recessive trait that affects the nervous system. In one family, the father, mother, daughter, and elder son do not have ALD, while the younger son has ALD. Who must be a carrier of the ALD allele?

Father

Mother

Daughter

Elder son

If it is Sex-Linked it is on the X-chromosome. That means that females can be carriers (heterozygous) but males can NOT be carriers. (Females = XX Males = XY)
In order for the disorder to be passed to the younger son, he had to inherit that allele from mom because that is where the X chromosome came from. (He inherited the Y from dad)
SO, mother is the carrier.

Explanation

If it is Sex-Linked it is on the X-chromosome. That means that females can be carriers (heterozygous) but males can NOT be carriers. (Females = XX Males = XY)
In order for the disorder to be passed to the younger son, he had to inherit that allele from mom because that is where the X chromosome came from. (He inherited the Y from dad)
SO, mother is the carrier.

27. Plant cells contain both a cell wall and a cell membrane. What is the composition of the cell wall and where is it located in relation to the cell membrane?

Cellulose, inside the cell membrane

Cellulose, outside the cell membrane

Glucose, inside the cell membrane

Glucose, outside the cell membrane

Plant cells have cell walls made of cellulose
Cell Walls are ALWAYS outside of the cell membrane

Explanation

Plant cells have cell walls made of cellulose
Cell Walls are ALWAYS outside of the cell membrane

28. Keisha passes a local dairy farm that has many brown cows, but only a few white cows. A dominant allele produces brown hair in cows and a recessive allele produces white hair. Which characteristic of any brown cow can Keisha identify?

The genotype of both of the cow's parents.

The genotype of the cow's hair color.

The phenotype of both of the cow's parents.

The phenotype of the cow's hair color.

Phenotype = physical characteristic (observable)
Genotype can only be determined through tracing traits through generations (pedigree or punnett squares)

Explanation

Phenotype = physical characteristic (observable)
Genotype can only be determined through tracing traits through generations (pedigree or punnett squares)

29. What is the purpose of mitosis?

To produce 2 cells, each with 1 complete set of chromosomes

To produce 2 cells, each with half the normal number of chromosomes

To produce 4 cells, each with 1 complete set of chromosomes

To produce 4 cells, each with half the normal number of chromosomes

Mitosis produces 2 identical diploid body cells
Diploid = a complete set of chromosomes (2 alleles for every gene)

Explanation

Mitosis produces 2 identical diploid body cells
Diploid = a complete set of chromosomes (2 alleles for every gene)

30. What is the purpose of meiosis?

To produce 2 cells, each with 1 complete set of chromosomes

To produce 2 cells, each with half the normal number of chromosomes

To produce 4 cells, each with 1 complete set of chromosomes

To produce 4 cells, each with half the normal number of chromosomes

Meiosis produces 4 genetically different haploid sex cells (gametes)
haploid = half the number of chromosomes (1 allele for every gene)

Explanation

Meiosis produces 4 genetically different haploid sex cells (gametes)
haploid = half the number of chromosomes (1 allele for every gene)

31. What trait of an ATP molecule enables it to store energy for use by cells?

Its small size

Its solubility in water

Its ability to form hydrogen bonds

Its phosphate-phosphate bond

Energy is stored in chemical bonds. Energy is released when a phosphate group is removed from ATP (bond is broken). Energy is stored when a phosphate group is added to ADP (bond is formed).

Explanation

Energy is stored in chemical bonds. Energy is released when a phosphate group is removed from ATP (bond is broken). Energy is stored when a phosphate group is added to ADP (bond is formed).

32. Which is the LEAST likely trait of an organic molecule?

The molecules may exist as isomers.

The backbone is linear, cyclic, or branched.

Ionic bonds are present between the atoms.

Functional groups, such as alcohols, are present.

Organic compounds contain Carbon. Carbon ALWAYS form covalent bonds.

Explanation

Organic compounds contain Carbon. Carbon ALWAYS form covalent bonds.

33. What key factor distinguishes organic compounds from inorganic compounds?

Organic compounds contain carbon.

Organic compounds contain hydrogen.

Organic compounds provide energy for cells.

Organic compounds are the building blocks of cells.

Organic compounds ALWAYS contain carbon. Inorganic compounds do NOT contain carbon.

Explanation

Organic compounds ALWAYS contain carbon. Inorganic compounds do NOT contain carbon.

34. Alkaptonuria is a genetic disorder of protein metabolism. The disorder is determined by 2 alleles at 1 locus. What is the genotype for Individual 1 in the diagram?

AA or Aa

AA

Aa

If both parents have the same phenotype (black), the only way you can get offspring that have a different phenotype from BOTH of their parents (white) is if the parents both CARRY the recessive allele but it is not expressed because they also have the dominant allele. This means they are heterozygous

Explanation

If both parents have the same phenotype (black), the only way you can get offspring that have a different phenotype from BOTH of their parents (white) is if the parents both CARRY the recessive allele but it is not expressed because they also have the dominant allele. This means they are heterozygous

35. Cystic fibrosis is a genetic disease in which mucus accumulates in the lungs and digestive system of affected individuals. Males and females must inherit 2 alleles with this mutation to have the disease. What is the mode of inheritance of cystic fibrosis?

Autosomal dominant

Autosomal recessive

Sex-linked dominant

Sex-linked recessive

Autosomal = NOT on sex chromosomes (X or Y) so the chance of males and females getting it would be the same
Recessive = MUST have 2 alleles for the disorder in order for it to be expressed
Dominant = would have disorder if heterozygous (2 different alleles)

Explanation

Autosomal = NOT on sex chromosomes (X or Y) so the chance of males and females getting it would be the same
Recessive = MUST have 2 alleles for the disorder in order for it to be expressed
Dominant = would have disorder if heterozygous (2 different alleles)

36. DNA and RNA have many structural similarities. Which structure in DNA and RNA is similar?

Purine bases

Pyrimidine bases

Type of sugar

Attached proteins

SAME Purines = G & A (both DNA & RNA have these)
Different Sugars = DNA (deoxyribose) & RNA (ribose
Different Pyrimidines = C (both DNA & RNA have cytosine), T (only in DNA), & U (only in RNA)

Explanation

SAME Purines = G & A (both DNA & RNA have these)
Different Sugars = DNA (deoxyribose) & RNA (ribose
Different Pyrimidines = C (both DNA & RNA have cytosine), T (only in DNA), & U (only in RNA)

37. A scientist studies the effects that barnyard grass, a weed, has on the growth of rice, other weeds, and insects. The barnyard grass and other weeds, rice, and insects make up whihc level of biological organization?

Population

Community

Ecosystem

Biome

Community = more than 1 species of organism in the same area OR all biotic factors in an area

Explanation

Community = more than 1 species of organism in the same area OR all biotic factors in an area

38. Ella told her sister the sun would set at 6:30 p.m. and there would be a full moon on Thursday night. Under which basic assumption of science is she operating?

Nature is orderly.

Knowledge is superior to ignorance.

Nothing is self-evident.

All phenomena have natural causes.

The assumption that Ella is operating under is that nature is orderly. This means that she believes that there is a predictable pattern and regularity in the natural world, such as the timing of the sunset and the occurrence of a full moon. This assumption is a fundamental principle of science, as it allows scientists to make predictions and understand the world based on consistent patterns and laws.

Explanation

The assumption that Ella is operating under is that nature is orderly. This means that she believes that there is a predictable pattern and regularity in the natural world, such as the timing of the sunset and the occurrence of a full moon. This assumption is a fundamental principle of science, as it allows scientists to make predictions and understand the world based on consistent patterns and laws.

39. Persons A and B have similar mRNA sequences with the exception of 1 nucleotide. Person A: AUGGUUACUAAGGGCUGA Person B: AUGGUUACUGAGGGCUGA The genetic code chart to determine how this difference affects the sequence of amino acids in the resulting protein.

Lys in Person A is replaced with Glu in Person B.

Phe in Person A is replaced with Leu in Person B.

Persons A and B have identical amino acid sequences.

A stop codon is generated in Person B and not in Person A.

Person A: AUGGUUACUaagGGCUGA
Person B: AUGGUUACUgagGGCUGA
AAG = Lysine
GAG = Glutamine

Explanation

Person A: AUGGUUACUaagGGCUGA
Person B: AUGGUUACUgagGGCUGA
AAG = Lysine
GAG = Glutamine

40. Which process generates most of the ATP produced during cellular respiration?

Electron transport chain

Fermentation

Glycolysis

Krebs cycle

ETC produces the MOST ATP
Glycolysis produces 2 ATP (net gain)
Fermentation produces 0 ATP
Krebs Cycle produces 2 ATP
Electron Transport Chain produces 32 ATP

Explanation

ETC produces the MOST ATP
Glycolysis produces 2 ATP (net gain)
Fermentation produces 0 ATP
Krebs Cycle produces 2 ATP
Electron Transport Chain produces 32 ATP

41. How do enzymes speed up chemical reactions?

By reducing activation energy

By reducing energy produced by the reaction

By increasing activation energy

By increasing energy produced by the reaction

Enzymes lower the amount of activation energy needed which speeds up the rate of the reaction.
Enzymes are like coupons for the cost (activation energy) of the reaction.

Explanation

Enzymes lower the amount of activation energy needed which speeds up the rate of the reaction.
Enzymes are like coupons for the cost (activation energy) of the reaction.

42. What combine with sugar and a phosphate group to form a nucleotide?

Amino acid

Deoxyribose

Glycerol

Nitrogenous base

Nucleotide = monomer of nucleic acids (DNA or RNA)
Made of = Pentose Sugar (deoxyribose or ribose), 1 phosphate group, and a Nitrogen base (G, C, A, T or U)

Explanation

Nucleotide = monomer of nucleic acids (DNA or RNA)
Made of = Pentose Sugar (deoxyribose or ribose), 1 phosphate group, and a Nitrogen base (G, C, A, T or U)

43. What process of natural selection favors the extreme phenotypes of a trait and eliminates intermediate phenotypes?

Directional selection

Disruptive selection

Random selection

Stabilizing selection

Disruptive = intermediates die out
Stabilizing = extremes die out
Directional = one phenotype preferred

Explanation

Disruptive = intermediates die out
Stabilizing = extremes die out
Directional = one phenotype preferred

44. In pea plants, purple flowers are dominant to white flowers and tall stems are dominant to short stems. If two heterozygotes for both height and flower color are crossed, what is the probability of having short stemmed pea plants with purple flowers?

9/16

1/4

3/16

1/16

PpTt x PpTt (factor using foil or window method)
set up dyhibrid punett square (16 blocks)
Phenotypic ratio should be:
9 = Purple & Tall
3 = Purple & Short
3 = White & Tall
1 = White & Short

Explanation

PpTt x PpTt (factor using foil or window method)
set up dyhibrid punett square (16 blocks)
Phenotypic ratio should be:
9 = Purple & Tall
3 = Purple & Short
3 = White & Tall
1 = White & Short

45. Which criterion is NOT necessarily true of a trait that has evolved through natural selection?

It is heritable.

It varies among individuals.

It increases individuals' life spans.

It influences individuals' reproductive success.

Natural Selection = makes organism better able to leave offspring in next generation NOT necessarily a longer life

Explanation

Natural Selection = makes organism better able to leave offspring in next generation NOT necessarily a longer life

46. After Harrison adds a chemical to cells growing in a test tube, proteins accumulate in the cells' endoplasmic reticula. The chemical prevents movement of proteins from the endoplasmic reticulum to which organelle?

Golgi apparatus

Lysosome

Mitochondrion

Ribosome

After being modified by the Rough ER, proteins are SUPPOSED to go to the Golgi Apparatus to be packaged & shipped out of the cell through Exocytosis.

Explanation

After being modified by the Rough ER, proteins are SUPPOSED to go to the Golgi Apparatus to be packaged & shipped out of the cell through Exocytosis.

47. Despite the diversity of nature, most organisms contain the same 4 DNA bases. This table shows the DNA composition of 3 organisms as reported in a classic 1950s experiment. Based on this study, what did scientists conclude about the DNA composition of all organisms?

A, G, T, and C occur in equal percentages.

A and G occur in equal percentages, and T and C occur in equal percentages.

A and T occur in equal percentages, and G and C occur in equal percentages.

A and C occur in equal percentages, and T and G occur in equal percentages.

In DNA, A bonds to T & G bonds to C
SO there would be the SAME amount of A as T & the SAME amount of G as C

Explanation

In DNA, A bonds to T & G bonds to C
SO there would be the SAME amount of A as T & the SAME amount of G as C

48. Red blood cells have a salt content of 0.9%. When a microbiologist places red blood cells in pure water, osmosis occurs. What net movement of a substance occurs in this instance of osmosis?

Water molecules move out of the cells.

Water molecules move into the cells.

Salt ions move out of the cells.

Salt ions move into the cells.

Pure water is ALWAYS hypotonic to cells SO water will move in to the cell causing the cell to swell.
Osmosis = water moves from where there is a lot of water to where there is a little water
Hypotonic = more water, less solutes
Hypertonic = less water, more solutes

Explanation

Pure water is ALWAYS hypotonic to cells SO water will move in to the cell causing the cell to swell.
Osmosis = water moves from where there is a lot of water to where there is a little water
Hypotonic = more water, less solutes
Hypertonic = less water, more solutes

49. Thylakoid membranes within chloroplasts contain chlorophyll. The Calvin cycle occurs in the stroma of the chloroplasts. How are the processes occurring within the Calvin cycle and the thylakoid membrane connected?

The Calvin cycle uses high-energy molecules formed within the thylakoid membrane to convert carbon dioxide into sugar molecules.

The Calvin cycle uses sugar molecules formed within the thylakoid membrane to generate high-energy molecules.

The processes in the thylakoid membrane use sugar molecules formed during the Calvin cycle to generate high-energy molecules.

Light Dependent Reactions of photosynthesis occur in the thylakoid membranes because the chlorophyll absorbs the light energy & it is converted into energy molecules (ATP & electron carriers) to be used during the Calvin Cycle to make glucose.
Light Dependent = uses light energy to split water to make oxygen; stores chemical energy
Calvin Cycle = uses chemical energy to combine CO2 & Hydrogens to make glucose

Explanation

Light Dependent Reactions of photosynthesis occur in the thylakoid membranes because the chlorophyll absorbs the light energy & it is converted into energy molecules (ATP & electron carriers) to be used during the Calvin Cycle to make glucose.
Light Dependent = uses light energy to split water to make oxygen; stores chemical energy
Calvin Cycle = uses chemical energy to combine CO2 & Hydrogens to make glucose

50. Megan examines a liver cell and observes an organelle with many smooth-sided channels. Which activity would identify this organelle as the Golgi apparatus?

Digestion of macromolecules and old organelles

Detoxification of poisonous molecules within the cell

Harvesting of energy from organic molecules to make ATP

Processing and packaging of cellular materials prior to export

The Golgi apparatus packages proteins in vesicles (small membranes) which then fuse with the cell membrane for exocytosis (export).

Explanation

The Golgi apparatus packages proteins in vesicles (small membranes) which then fuse with the cell membrane for exocytosis (export).

51. According to fossil evidence, whales evolved from 4-legged ancestors. The modern baleen whale has forelimbs, but inspection of its skeleton reveals only tiny vestigial hind limbs. What is the best explanation for this loss of hind limbs in the baleen whale?

The hind limbs adapted into flippers to help the whale swim faster.

Random chance and genetic drift led to the reduction in size of hind limbs.

Whales with shorter hind limbs swam faster than those with longer hind limbs.

Some whales lost longer hind limbs to predators and passed that trait to their offspring.

Vestigial structures are structures that have been minimized over time & no longer have a useful function.
Natural Selection would cause each generation to have slightly shorter hind limbs because the ones with longer hind limbs would DIE because they are not as adapted to the environment SO they would not be able to pass those genes on to the next generation.

Explanation

Vestigial structures are structures that have been minimized over time & no longer have a useful function.
Natural Selection would cause each generation to have slightly shorter hind limbs because the ones with longer hind limbs would DIE because they are not as adapted to the environment SO they would not be able to pass those genes on to the next generation.

52. What accounts for genetic biodiversity existing in modern multicellular organisms?

Mutations in gametes are passed to offspring.

Protein mutations cause DNA changes, creating new species.

Genetic mutations form when similar species mate and reproduce.

Somatic cell DNA mutations create new phenotypes in the population.

During Meiosis, homologous chromosomes pair up & crossing over occurs. This increases genetic diversity.

Explanation

During Meiosis, homologous chromosomes pair up & crossing over occurs. This increases genetic diversity.

53. Which sequence is in order from the simplest level of organization to the most complex?

Muscle, erythrocyte, lipid, mitochondrion, carbon

Carbon, lipid, erythrocyte, mitochondrion, muscle

Muscle, mitochondrion, lipid, erythrocyte, carbon

Carbon, lipid, mitochondrion, erythrocyte, muscle

Atom -> molecule -> organelle -> cell -> tissue
examples = carbon -> lipid -> mitochondria -> erythrocyte -> muscle

Explanation

Atom -> molecule -> organelle -> cell -> tissue
examples = carbon -> lipid -> mitochondria -> erythrocyte -> muscle

54. Two black guinea pigs bred and produced 3 black offspring and 2 albino offspring. Assuming no mutations, which guinea pigs must be heterozygous?

All 3 black offspring

Both albino offspring

Both parents

If both parents have the same phenotype (black), the only way you can get offspring that have a different phenotype from BOTH of their parents (white) is if the parents both CARRY the recessive allele but it is not expressed because they also have the dominant allele. This means they are heterozygous

Explanation

If both parents have the same phenotype (black), the only way you can get offspring that have a different phenotype from BOTH of their parents (white) is if the parents both CARRY the recessive allele but it is not expressed because they also have the dominant allele. This means they are heterozygous

55. The diagram shows a cell membrane composed of a phospholipid bilayer with a channel protein. Each X represents the same type of molecule inside or outside the cell. Facilitated diffusion moves these molecules across the cell membrane. In what direction do these molecules move and through which structure?

Into the cell through the channel protein

Into the cell through the phospholipid bilayer

Out of the cell through the channel protein

Out of the cell through the phospholipid bilayer

facilitated diffusion is PASSIVE so molecules will move from high concentration (crowded) to low concentration (uncrowded) so they will be moving inside the cell.
Facilitated diffusion requires a protein channel or carrier protein because large/polar molecules cannot pass through the lipid bilayer.

Explanation

facilitated diffusion is PASSIVE so molecules will move from high concentration (crowded) to low concentration (uncrowded) so they will be moving inside the cell.
Facilitated diffusion requires a protein channel or carrier protein because large/polar molecules cannot pass through the lipid bilayer.

56. Jenna's favorite breakfast food, papaya, contains significant amounts of the enzyme papain (a protease). What substances does papain help digest?

Carbohydrates

Fatty acids

Nucleic acids

Proteins

ase = enzyme
PROTEase = enzyme that affects PROTEins

Explanation

ase = enzyme
PROTEase = enzyme that affects PROTEins

57. A Paramecium lives in an environment that is hypotonic to its cytoplasm. How does the Paramecium maintain homeostasis under these conditions?

It expels excess water using contractile vacuoles.

It expels excess sodium using the sodium-potassium pump.

It absorbs additional water through osmosis.

It absorbs additional sodium through facilitated diffusion.

Hypotonic solution = the cell will swell because water is moving from the solution (a lot of water) to the cell (little water)
Paramecia have contractile vacuoles, which are specialized organelles that collect the extra water from the cytoplasm and force it out of the cell.

Explanation

Hypotonic solution = the cell will swell because water is moving from the solution (a lot of water) to the cell (little water)
Paramecia have contractile vacuoles, which are specialized organelles that collect the extra water from the cytoplasm and force it out of the cell.

58. Chan wants to determine how much the mass of fungus growing on a nutrient agar plate changes over an 8 hr period. What is the most appropriate unit of measure for him to use?

Kilogram

Kilometer

Milligram

Millimeter

A gram is a measurement of mass. Kilograms are used for very large things (1000 grams). Milligrams are used for very small things (0.001 gram)

Explanation

A gram is a measurement of mass. Kilograms are used for very large things (1000 grams). Milligrams are used for very small things (0.001 gram)

59. Scientists collected data on the height and weight of individuals in a population. They recorded their results in this scatterplot. What is the most accurate conclusion regarding the relationship between height and weight?

Tall individuals are always heavier than short individuals.

There is no relationship between height and weight.

There is a negative relationship between height and weight.

There is a positive relationship between height and weight.

In general, the line of best fit shows us that as weight increases, height increases. That is a positive relationship.
If it was a negative relationship, one factor would be increasing & the other would be decreasing.
If it was random, there would be no discernable pattern in the data.

Explanation

In general, the line of best fit shows us that as weight increases, height increases. That is a positive relationship.
If it was a negative relationship, one factor would be increasing & the other would be decreasing.
If it was random, there would be no discernable pattern in the data.

60. When the pH in a stomach increases from 2 to 4, how does the hydrogen ion concentration change?

It increases by a factor of 2.

It increases by a factor of 100.

It decreases by a factor of 2.

It decreases by a factor of 100.

When a solution becomes more acidic, the concentration of H+ ions increases (by a factor of 10) & the OH- ions decrease.
When a solution becomes more of a base, the concentration of OH- ions increases (by a factor of 10) & the H+ ions decrease.
Move 2 steps up on pH scale = move decimal 2 places to the left (divide by 100)

Explanation

When a solution becomes more acidic, the concentration of H+ ions increases (by a factor of 10) & the OH- ions decrease.
When a solution becomes more of a base, the concentration of OH- ions increases (by a factor of 10) & the H+ ions decrease.
Move 2 steps up on pH scale = move decimal 2 places to the left (divide by 100)

61. Naomi adds cyclohexamide to cells grown in a test tube. Within minutes, she identifies short incomplete segments of proteins in the cells. On which organelle does cyclohexamide act?

Endoplasmic reticulum

Golgi apparatus

Nucleus

Ribosome

If INCOMPLETE PROTEINS are being produced, that means the chemical (cyclohexamide) is affecting whatever produces the proteins.
Proteins are made by the ribosome.

Explanation

If INCOMPLETE PROTEINS are being produced, that means the chemical (cyclohexamide) is affecting whatever produces the proteins.
Proteins are made by the ribosome.

62. During aerobic cellular respiration, where do ATP molecules form?

Cytoplasm only

Mitochondrial matrix only

Mitochondrial matrix and inner mitochondrial membrane only

Cytoplasm, mitochondrial matrix, and outer mitochondrial membrane

Glycolysis occurs in the cytoplasm but is considered anaerobic (it can happen even if O2 is not present)
Krebs cycle (produces 2 ATP) occurs in the matrix (fluid filled space) of the mitochondria
Electron Transport Chain (produces 32 ATP) occurs in the inner mitochondrial membrane
Nothing happens in the outer mitochondrial membrane

Explanation

Glycolysis occurs in the cytoplasm but is considered anaerobic (it can happen even if O2 is not present)
Krebs cycle (produces 2 ATP) occurs in the matrix (fluid filled space) of the mitochondria
Electron Transport Chain (produces 32 ATP) occurs in the inner mitochondrial membrane
Nothing happens in the outer mitochondrial membrane

63. What process of natural selection favors the intermediate phenotypes of a trait and eliminates extreme phenotypes?

Directional selection

Disruptive selection

Random selection

Stabilizing selection

Disruptive = intermediates die out
Stabilizing = extremes die out
Directional = one phenotype preferred

Explanation

Disruptive = intermediates die out
Stabilizing = extremes die out
Directional = one phenotype preferred

64. What is the best definition of a scientific theory?

An explanation of how and why a natural phenomenon behaves the way it does

A description of an invariable relationship that exists in nature

A speculation or guess about how nature works

An unproven fact

Scientific theories are well tested with lots of data to support them. It is not just a hypothesis!

Explanation

Scientific theories are well tested with lots of data to support them. It is not just a hypothesis!

65. Sunee and Jamila grow 2 distinct strains of E. coli bacteria following appropriate lab procedures. In Experiment 1, they use a new culture of Strain X and a 30-day old culture of Strain Y. In Experiment 2, they use a new culture of Strain Y and a 30-day old culture of Strain X. Sunee and Jamila measure the number of bacterial colonies and record the data in these graphs. What is the most accurate conclusion about the growth rate of the bacteria?

Strain X grows faster than Strain Y regardless of the culture's age.

Strain Y grows faster that Strain X regardless of the culture's age.

The 30-day old culture grows faster regardless of the strain.

The new culture grows faster regardless of the strain.

The most accurate conclusion about the growth rate of the bacteria is that the 30-day old culture grows faster regardless of the strain. This can be inferred from the information provided in the question, where in both experiments, the 30-day old culture consistently resulted in a higher number of bacterial colonies compared to the new culture. This indicates that the older culture has a higher growth rate, regardless of the specific strain used.

Explanation

The most accurate conclusion about the growth rate of the bacteria is that the 30-day old culture grows faster regardless of the strain. This can be inferred from the information provided in the question, where in both experiments, the 30-day old culture consistently resulted in a higher number of bacterial colonies compared to the new culture. This indicates that the older culture has a higher growth rate, regardless of the specific strain used.

66. Paul and Simon want to determine who is more fit. They decide to run in place for 5 minutes and then measure their blood pressures to see whose returns to notrmal most quickly. They record the data in this table. Paul told Simon that the heart pumps more blood during exercise than at rest. How do the experiment's results support Paul's statement?

Exercise increases only the pulse.

Exercise increases only the systolic pressure.

Exercise increases both the systolic and diastolic pressure.

Exercise increases both the pulse and the systolic pressure.

Systolic blood pressure & pulse both increase significantly during exercise, but the diastolic basically stays close to the same value.

Explanation

Systolic blood pressure & pulse both increase significantly during exercise, but the diastolic basically stays close to the same value.

67. Which experimental design would provide scientists with the best data for investigating which type of feed yields the greatest gain in lean muscle mass in cattle?

Only change 1 independent variable (type of food) with multiple trials & measure the dependent variable (weight gain/muscle mass); type of cow & amount of food should be constant

Explanation

Only change 1 independent variable (type of food) with multiple trials & measure the dependent variable (weight gain/muscle mass); type of cow & amount of food should be constant

68. In humans, pigmented skin is dominant to non-pigmented skin (albinism). What is the genotype of an individual with albinism?

Carrier

Heterozygous

Homozygous dominant

Homozygous recessive

An individual with albinism has a genotype of homozygous recessive. This means that both of their alleles for the pigmentation gene are recessive, resulting in the absence of pigmentation in their skin.

Explanation

An individual with albinism has a genotype of homozygous recessive. This means that both of their alleles for the pigmentation gene are recessive, resulting in the absence of pigmentation in their skin.

69. In a classic study of population growth, G.F. Gause obtained data on growth rates of 2 species of Paramecium, a common ciliate protozoan. The 2 species grew in separate cultures. The graph shows his results. According to these data, which is the most accurate comparison of the 2 species' growth rates.

Both show exponential growth, but P. caudatum has a higher rate of increase.

Both show logistic growth, but P. caudatum has a higher rate of increase.

P. caudatum shows exponential growth, but P. bursaria shows logistic growth.

P. bursaria shows exponential growth, but P. caudatum shows logistic growth.

Logistic = levels off (shows carrying capacity)
Exponential = grows at a constant rate of increase (never levels off)

Explanation

Logistic = levels off (shows carrying capacity)
Exponential = grows at a constant rate of increase (never levels off)

70. Shown below is a growth curve for Paramecium grown in a 1.0 L flask containing pond water at 20^oC. The pond water is continually filtered to remove waste products, and nutrients are added at a constant rate. How could the experiment be modified to determine whether the temperature influences the population size of Paramecium?

Repeat the procedures described using 1 flask, and increase the temperature to 25oC for Days 10-15.

Repeat the procedures described using 1 flask, and vary the temperature randomly during the entire incubation time.

Repeat the procedures described using 2 flasks; incubate 1 flask at 15oC and the other at 25oC.

Repeat the procedures described using 2 flasks; incubate both flasks at 20oC.

Change 1 independent variable (temperature) and measure the dependent variable (population size)

Explanation

Change 1 independent variable (temperature) and measure the dependent variable (population size)

71. A scientist places a cell in a solution, and over time the cell gains mass and swells. What is the most likely explanation for the cell's gain in mass?

The solution is hypertonic to the cell.

The solution is hypotonic to the cell.

The solution and the cell have equal concentrations of solutes.

The solution and the cell have equal concentrations of water.

Cells swell in a hypotonic solution because of osmosis. They shrink in a hypertonic solution because they are loosing water.

Explanation

Cells swell in a hypotonic solution because of osmosis. They shrink in a hypertonic solution because they are loosing water.

72. The areobic and anaerobic pathways of cellular respiration REQUIRE which products of glycolysis?

NADPH and ATP

Pyruvate and ATP

Pyruvate and NADH

ATP , pyruvate, and NADH

Glycolysis produces ATP, pyruvate, & NADH (an electron carrier) BUT that is not what the question is asking.
It says what do the next steps REQUIRE.
Fermentation & Krebs cycle must have Pyruvate
ETC must have NADH
ATP is NOT USED (required) for the next steps

Explanation

Glycolysis produces ATP, pyruvate, & NADH (an electron carrier) BUT that is not what the question is asking.
It says what do the next steps REQUIRE.
Fermentation & Krebs cycle must have Pyruvate
ETC must have NADH
ATP is NOT USED (required) for the next steps

73. The genotype of F1 individuals from a dihybrid cross is AaBb x AaBB. What is the expected ratio of AaBb individuals in the F2 generation?

8/16

4/16

2/16

1/16

must factor alleles & then set up a dihybrid punnett square (16 block)
you get 4 that are heterozygous for both traits

Explanation

must factor alleles & then set up a dihybrid punnett square (16 block)
you get 4 that are heterozygous for both traits

74. What occurs during metaphase I of meiosis?

Centromeres of replicated chromosomes line up along the cell’s equator.

Centromeres divide as sister chromatids move toward opposite poles of the cell.

Homologous chromosome pairs line up along the cell’s equator.

Homologous chromosomes move toward opposite poles of the cell.

Metaphase I = homologous chromosomes are pulled to the middle of the cell

Explanation

Metaphase I = homologous chromosomes are pulled to the middle of the cell

75. As part of an experiment, a student adds 10 mL of 5% hydrochloric acid solution to 100 mL of a non-buffered, colorless solution of sugar. What is the most likely result?

The concentration of hydroxide ions (OH-) will increase.

The concentration of hydrogen ions (H+) will increase.

The pH will not change.

The pH will increase.

When a solution becomes more acidic, the concentration of H+ ions increases (by a factor of 10).
When a solution becomes more of a base, the concentration of OH- ions increases (by a factor of 10).

Explanation

When a solution becomes more acidic, the concentration of H+ ions increases (by a factor of 10).
When a solution becomes more of a base, the concentration of OH- ions increases (by a factor of 10).

76. When comparing 2 populations of animals, which statement most likely indicates that they are the same species?

They produce fertile offspring.

They inhabit the same general area.

Their outward appearance is similar.

They consume the same type of diet.

biological definition of species = must be able to mate & produce FERTILE offspring (can basically have grandkids)

Explanation

biological definition of species = must be able to mate & produce FERTILE offspring (can basically have grandkids)

77. The presence of which structure indicates that cells are NOT photosynthetic bacteria?

Cell wall

Chloroplast

DNA

Ribosome

Bacteria = prokaryotes
Prokaryotes NEVER have a nucleus or membrane-bound organelles (organelles with membranes around them)
Chloroplasts have membranes around them AND are ONLY found in plant cells

Explanation

Bacteria = prokaryotes
Prokaryotes NEVER have a nucleus or membrane-bound organelles (organelles with membranes around them)
Chloroplasts have membranes around them AND are ONLY found in plant cells

78. Most male crickets produce a mating song by rubbing together their curved wings. In a certain geographic area, parasitic flies detected male crickets singing and deposited their larvae into them, which killed the crickets. Eighteen generations later, the number of males with flat wings has increased to 90%. The flat-winged crickets do not sing, but are still able to mate with females, and parasitic flies cannot detect them. Which type of selection is occurring in this cricket population?

Artificial

Directional

Disruptive

Stabilizing

Disruptive = intermediates die out
Stabilizing = extremes die out
Directional = one phenotype preferred

Explanation

Disruptive = intermediates die out
Stabilizing = extremes die out
Directional = one phenotype preferred

79. A student wants to determine whether temperature affects the rate at which mold grows on bread. The student puts one piece of bread inside a Petri dish, closes the lid, and places the Petri dish in the refrigerator. Which treatment would be the best comparison for this experiment?

Placing another piece of bread in an open Petri dish in the same refrigerator

Placing another piece of bread in a closed Petri dish in the same refrigerator

Placing another piece of bread in an open Petri dish on the countertop

Placing another piece of bread in a closed Petri dish on the countertop

The best comparison for the experiment would be placing another piece of bread in a closed Petri dish on the countertop. This is because the student wants to determine whether temperature affects the rate of mold growth on bread. By placing another piece of bread in a closed Petri dish on the countertop, the student can compare the mold growth in the refrigerator (low temperature) to the mold growth on the countertop (room temperature). This will allow the student to observe the difference in mold growth rates under different temperature conditions.

Explanation

The best comparison for the experiment would be placing another piece of bread in a closed Petri dish on the countertop. This is because the student wants to determine whether temperature affects the rate of mold growth on bread. By placing another piece of bread in a closed Petri dish on the countertop, the student can compare the mold growth in the refrigerator (low temperature) to the mold growth on the countertop (room temperature). This will allow the student to observe the difference in mold growth rates under different temperature conditions.

80. Jeanine inherited 2 alleles for round eye shape and has round eye shape. Her brother inherited 1 allele for round eye shape and 1 allele for almond eye shape and has almond eye shape. What type of trait is round eye shape?

Co-dominant

Dominant

Recessive

Sex-linked

Codominant would mean that one eye was almond and the other eye was round
Incomplete dominant would be eyes were intermediate (oval) between the 2 phenotypes
Dominant means that it would overpower the other allele and be expressed in the heterozygote (brother)
Recessive = you must have 2 recessive alleles
Boys cannot be heterozygous for sex linked traits because they only have 1 allele (on the X not Y)

Explanation

Codominant would mean that one eye was almond and the other eye was round
Incomplete dominant would be eyes were intermediate (oval) between the 2 phenotypes
Dominant means that it would overpower the other allele and be expressed in the heterozygote (brother)
Recessive = you must have 2 recessive alleles
Boys cannot be heterozygous for sex linked traits because they only have 1 allele (on the X not Y)

81. Which example best illustrates the process of natural selection?

Giraffe necks varied in length, and all offspring had an equal chance of survival.

Giraffe necks varied in length, and the shorter-necked giraffes were at a disadvantage.

Giraffes with short necks migrated to locations best suited for their neck lengths.

Giraffes stretched their necks to reach for food, and resulting offspring had longer necks.

natural selection = change in allele frequencies over generations of time because certain alleles are more advantageous (longer neck)

Explanation

natural selection = change in allele frequencies over generations of time because certain alleles are more advantageous (longer neck)

82. In pea plants, purple flowers are dominant to white flowers and tall stems are dominant to short stems. If two heterozygotes for both height and flower color are crossed, what is the probability of having tall stemmed pea plants with purple flowers?

9/16

1/4

3/16

1/16

PpTt x PpTt (factor using foil or window method)
set up dyhibrid punett square (16 blocks)
Phenotypic ratio should be:
9 = Purple & Tall
3 = Purple & Short
3 = White & Tall
1 = White & Short

Explanation

PpTt x PpTt (factor using foil or window method)
set up dyhibrid punett square (16 blocks)
Phenotypic ratio should be:
9 = Purple & Tall
3 = Purple & Short
3 = White & Tall
1 = White & Short

83. Carbon-14 is a radioactive isotope used to determine the age of ancient objects composed of organic matter. Carbon-12 and carbon-13 are other isotopes of carbon. The number of what subatomic particles varies among these carbon isotopes?

Electrons

Neutrons

Photons

Protons

Isotopes have the same number of protons (atomic number) but they have different numbers of neutrons. This changes the atomic mass.

Explanation

Isotopes have the same number of protons (atomic number) but they have different numbers of neutrons. This changes the atomic mass.

84. Lydia works in a flower shop after school. She notices that the hydrangeas in Container 1 have pink blossoms, while the hydrangeas in Container 2 have blue blossoms. She makes sure they all recieve the same amount of light and water. Her boss tells her that the flowers were all grown from the same seed variety. Lydia discovers, after testing the soil, that although the same type of soil was used, the soil in Container 1 has a pH of 6.0, and the soil in Container 2 has a pH of 5.0. Lydia most likely conducted her investigation to answer what question about hydrangeas?

How does the chemistry of the soil affect the color of hydrangea blossoms?

What role do genetic factors play in hydrangea color?

Do varying degrees of light affect hydrangea color?

What type of soil will produce a hydrangea with both pink and blue blossoms?

Because she is changing the pH and measuring the color of the flowers; her question should reflect that.

Explanation

Because she is changing the pH and measuring the color of the flowers; her question should reflect that.

85. Ming is having trouble sleeping and decides to participate in a study to determine whether a certain medication helps people sleep. There are 30 volunteers, each of whom is assigned to 1 of 2 groups. Volunteers in group 1 are given the medication, and volunters in group 2 are given a placebo (a pill with no medication). Which step is important in order to ensure scientifically valid results?

Assigning the subjects to groups at random

Assigning all of the subjects with sleeping problems to the placebo group

Telling subjects if they are receiving the medicine or the placebo

Ensuring that the researchers can determine which subjects are getting the medicine

Assigning the subjects to groups at random is important in order to ensure scientifically valid results because it helps to eliminate bias and ensure that the groups are comparable. Random assignment helps to distribute the potential confounding variables equally among the groups, making the comparison between the medication group and the placebo group more reliable. This increases the internal validity of the study and allows for more accurate conclusions to be drawn about the effectiveness of the medication in helping people sleep.

Explanation

Assigning the subjects to groups at random is important in order to ensure scientifically valid results because it helps to eliminate bias and ensure that the groups are comparable. Random assignment helps to distribute the potential confounding variables equally among the groups, making the comparison between the medication group and the placebo group more reliable. This increases the internal validity of the study and allows for more accurate conclusions to be drawn about the effectiveness of the medication in helping people sleep.

86. Edison studies the effects of temperature on starch digestion in a test tube. He adds 2 g of starch and 1 mL of enzyme suspension to a test tube and incubates it at 25^oC for 20 min. To accurately test the effects of temperature, Edison should begin a second test with 2 g of starch in a test tube and continue with which set of conditions?

1 mL of enzyme suspension incubated at 25oC for 10 min

1 mL of enzyme suspension incubated at 37oC for 20 min

2 mL of enzyme suspension incubated at 25oC for 20 min

2 mL of enzyme suspension incubated at 37oC for 10 min

In order to accurately test the effects of temperature on starch digestion, Edison should begin a second test with the same amount of starch (2 g) but vary the temperature and enzyme concentration. The given answer suggests using 1 mL of enzyme suspension, which keeps the enzyme concentration constant, but increasing the temperature to 37oC. This allows Edison to compare the effects of different temperatures on starch digestion while keeping other factors constant. The longer incubation time of 20 minutes ensures sufficient time for the reaction to occur.

Explanation

In order to accurately test the effects of temperature on starch digestion, Edison should begin a second test with the same amount of starch (2 g) but vary the temperature and enzyme concentration. The given answer suggests using 1 mL of enzyme suspension, which keeps the enzyme concentration constant, but increasing the temperature to 37oC. This allows Edison to compare the effects of different temperatures on starch digestion while keeping other factors constant. The longer incubation time of 20 minutes ensures sufficient time for the reaction to occur.

87. Which example best illustrates Mendel's law of independent assortment?

Two short-haired cats produce a litter of 4 kittens including 1 long-haired and 3 shot-haired.

A color-blind man and a woman with normal vision produce a son with normal vision and a color-blind daughter.

A tall prurple-flowered pea plant and a short white-flowered pea plant are crossed, producing offspring including tall white-flowered pea plants.

A red-flowered snapdragon and a white-flowered snapdragon are crossed, producing offspring with pink flowers.

Independent assortment can only be shown if you are looking at 2 different TRAITS at the same time (dihybrid cross) BECAUSE independent assortment says that different genes will separate independently of one another

Explanation

Independent assortment can only be shown if you are looking at 2 different TRAITS at the same time (dihybrid cross) BECAUSE independent assortment says that different genes will separate independently of one another

88. Which event of meiosis reveals the mechanism for understanding Mendel's laws of segregation and independent assortment?

Chromosome number is reduced during telophase I so gametes have half the standard number of chromosomes.

The arrangement of homologous chromosomes during metaphase I varies from cell to cell.

Centromeres break apart during anaphase II so that sister chromatids can move to opposite poles of the cell.

DNA is replicated during interphase before chromosomes condense and become attached to kinetochores.

Homologous chromosomes pair up during Prophase I of Meioisis but how they line up on the spindle is RANDOM (during Metaphase I)

Explanation

Homologous chromosomes pair up during Prophase I of Meioisis but how they line up on the spindle is RANDOM (during Metaphase I)

89. While investigating yeast respiration, a researcher detects ethanol in the yeast culture. Which molecules does the yeast culture also contain?

Lactic acid and ATP

Oxygen and lactic acid

Carbon dioxide and ATP

Oxygen and carbon dioxide

Glycoiysis produces ATP and pyruvate
Fermentation breaks down pyruvate and produces NADH (an electron carrier) and harmful byproducts
Lactic Acid Fermentation (only happens in animal cells) produces lactic acid (which is why muscles hurt after anaerobic exercise)
Alcoholic fermentation (yeast & other fungi) produce ethanol & CO2 (which is why bread rises)

Explanation

Glycoiysis produces ATP and pyruvate
Fermentation breaks down pyruvate and produces NADH (an electron carrier) and harmful byproducts
Lactic Acid Fermentation (only happens in animal cells) produces lactic acid (which is why muscles hurt after anaerobic exercise)
Alcoholic fermentation (yeast & other fungi) produce ethanol & CO2 (which is why bread rises)

90. In humans, red-green color blindness is a recessive, sex-linked trait. The chromosomes and alleles associated with color blindness are represented in this chart. Which child could NOT be born to these parents; a female (X^BX^b) and a male (X^BY)?

Color-blind daughter

Color-blind son

Daughter with normal color vision

Son with normal color vision

DO THE PUNNETT SQUARE.
The only way to have a daughter with a sex linked recessive disorder is for the dad to have it and the mom has to be a carrier (or have the disorder herself). The daughter has to get the recessive X from mom and whatever X dad has. If he has the recessive disorder, all of his daughters will automatically be at least carriers because they inherit that X.

Explanation

DO THE PUNNETT SQUARE.
The only way to have a daughter with a sex linked recessive disorder is for the dad to have it and the mom has to be a carrier (or have the disorder herself). The daughter has to get the recessive X from mom and whatever X dad has. If he has the recessive disorder, all of his daughters will automatically be at least carriers because they inherit that X.

91. Horse skeleton fossils indicate that the size of horses increased over time. Which statement best explains this fossil record?

Smaller horses bred with larger horses, creating hybrids.

Smaller horses were infected by a fatal virus early in their history.

Larger horses consumed the food supply of the smaller horses.

Larger horses produced a slightly greater number of surviving offspring.

natural selection = change in allele frequencies over generations of time because certain alleles are more advantageous (larger horse)

Explanation

natural selection = change in allele frequencies over generations of time because certain alleles are more advantageous (larger horse)

92. A science teacher performs an experiment to measure the CO₂ uptake of the green algae Chlorella under light conditions. He prepares a suspension of Chlorella and places it in a growth chamber near a lamp. A student disrupts the experiment by turning off the lamp, creating dark conditions. Why is there a negative uptake (release) of CO₂under dark conditions?

CO2 production requires light.

Cellular respiration is taking place.

Chlorella is actively photosynthesizing.

Glucose production in the dark requires less CO2.

CO2 normally is absorbed (positive uptake) during cellular respiration. Plants go through photosynthesis to make glucose BUT it still must be broken down during cellular respiration in order to make ATP.
Plants would be producing CO2 during Cellular Respiration so it will be released (negative uptake).

Explanation

CO2 normally is absorbed (positive uptake) during cellular respiration. Plants go through photosynthesis to make glucose BUT it still must be broken down during cellular respiration in order to make ATP.
Plants would be producing CO2 during Cellular Respiration so it will be released (negative uptake).

93. Pepsin is a protein-digesting enzyme in the human stomach. Antacids cause the pH of the stomach to increase and protein digestion becomes less efficient. What occurs to reduce the efficiency of protein digestion?

Antacids break the covalent bonds within pepsin.

Pepsin dissolves antacids in the gastric juice.

The active site of pepsin changes shape.

The concentration of pepsin increases.

Enzymes & substrates must have complementary shapes so that they fit together at the active site. If you change environmental conditions (pH or temperature), it can change the shape of the active site (denature) so that the enzyme will not work anymore.

Explanation

Enzymes & substrates must have complementary shapes so that they fit together at the active site. If you change environmental conditions (pH or temperature), it can change the shape of the active site (denature) so that the enzyme will not work anymore.

94. Which functional group found in amino acids is absent from monosaccharides, polysaccharides, fatty acids, and glycerol?

-COOH

-NH2

-OH

-PO4

Nitrogen is only found in nucleic acids & proteins.
Carbohydrates (mono & polysaccharides) have Carbon, Hydrogen, & Osygen (1:2:1 ratio)
Lipids (fatty acids & glycerol) are mostly VERY long chains of Carbon & Hydrogen (sometimes called hydrocarbons)

Explanation

Nitrogen is only found in nucleic acids & proteins.
Carbohydrates (mono & polysaccharides) have Carbon, Hydrogen, & Osygen (1:2:1 ratio)
Lipids (fatty acids & glycerol) are mostly VERY long chains of Carbon & Hydrogen (sometimes called hydrocarbons)

95. The hydrolysis of which molecule provides energy for muscle contraction?

ATP

Glucose

Lactic acid

Oxygen

ATP is the energy molecule of the cell. Hydrolysis of ATP is when you break the bond between the last 2 phosphates, which releases energy.

Explanation

ATP is the energy molecule of the cell. Hydrolysis of ATP is when you break the bond between the last 2 phosphates, which releases energy.

96. How does the regulation of gene expression lead to cell specialization?

Enzymes degrade unnecessary DNA.

Methylation of some regions of DNA prevents transcription.

Mutations change certain RNA sequences.

Removal of exons from RNA prevents translation into protein.

methylation (adding a CH3 group) stops certain proteins from being made. This is why the cells in your eyes do not make insulin but the cells in your pancreas do

Explanation

methylation (adding a CH3 group) stops certain proteins from being made. This is why the cells in your eyes do not make insulin but the cells in your pancreas do

Biology EOC Practice Questions (Practice Mode)

1. The presence of what cellular structure distinguishes a plant cell from an animal cell?

2.

What first name or nickname would you like us to use?

2. In addition to the reproductive system, which body system is most directly essential to the production of gametes and offspring?

3. During what phase of meiosis does nondisjunction occur?

4. Lions and tigers both belong to genus Panthera., Cheetahs belong to the genus Achinonyx. Scientists group these 3 types of cats together at the next taxonomic level. What is the most specific taxonomic level that lions, cheetahs, and tigers share?

5. Which group(s) contain organsims that can be classified as primary producers?

6. Hummingbirds transfer pollen from one flower to another while feeding. What plant structure contains the pollen?

7. The graph represents the average fastest speed of 5 animals recorded in one study. Based on the graph, which species is approximately 1/3 as fast as the cheetah?

8. These diagrams represent different stages of animal cell division. From start to finish, what is the correct order of the stages?

9. This molecule is an example of which substance?

10. This graph illustrates 4 different chemical reactions. Which reaction has the fastest initial reaction rate?

11. A scientist found that the results of an experiment did not support her hypothesis. If she is following proper scientific procedure, what should she do next?

12. After learning about viruses in Biology class, Sam decides to have his cat vaccinated against feline leukemia virus. According to cell theory, are viruses, such as feline leukemia, considered living things?

13. Which group(s) contain organsims that can be classified as primary producers?

14. A researcher counted the number of eggs a single fruit fly laid in 24 hrs for 5 days and recorded the findings in this table. What is the average number of eggs laid per day over the 5 days?

15. Lazzaro Spallanzani and Louis Pasteur both performed experiments hoping to disprove spontaneous generation. What conditions existed in Pasteur's experiment that did not exist in Spallanzani's?

16. Which solution has the greatest concentration of hydroxide ions (OH-)?

17. A flagellated protozoan lives within the intestines of a termite and helps it digest wood. What type of relationship most likely exists between the protozoan and the termite?

18. When a new volcanic island forms, the pioneer species is the first species to successfully inhabit the island. Which organism is the most likely candidate for a pioneer species?

19. What characteristic of early autotrophs gave them an advantage over early heterotrophs?

20. What is the RNA sequence for a section of protein composed of Val-Glu-Ser?

21. If a football field in the taiga is abandoned, which group of organisms will most likely be part of the resulting climax community?

22. In the following food chain, assuming that the producer contains 180,000 J of energy, how much energy would be able to be transferred to the tertiary consumer? Plant --> Mouse --> Snake --> Owl --> Fungus

23. Dr. Hansen performs an experiment testing the effectiveness of different cough syrups. Identify the independent variable in the experiment.

24. The graph provides information about the size of 1 rabbit population over 30 generations. What most likely happened shortly after the 10th generation to cause the change in population between Points A and B?

25. Cosmetics often contain glycerol (C3H8O3), which has three identical functional groups. Which type of bond holds these functional groups together?

26. Adrenoleukodystrophy (ALD) is a sex-linked recessive trait that affects the nervous system. In one family, the father, mother, daughter, and elder son do not have ALD, while the younger son has ALD. Who must be a carrier of the ALD allele?

27. Plant cells contain both a cell wall and a cell membrane. What is the composition of the cell wall and where is it located in relation to the cell membrane?

28. Keisha passes a local dairy farm that has many brown cows, but only a few white cows. A dominant allele produces brown hair in cows and a recessive allele produces white hair. Which characteristic of any brown cow can Keisha identify?

29. What is the purpose of mitosis?

30. What is the purpose of meiosis?

31. What trait of an ATP molecule enables it to store energy for use by cells?

32. Which is the LEAST likely trait of an organic molecule?

33. What key factor distinguishes organic compounds from inorganic compounds?

34. Alkaptonuria is a genetic disorder of protein metabolism. The disorder is determined by 2 alleles at 1 locus. What is the genotype for Individual 1 in the diagram?

35. Cystic fibrosis is a genetic disease in which mucus accumulates in the lungs and digestive system of affected individuals. Males and females must inherit 2 alleles with this mutation to have the disease. What is the mode of inheritance of cystic fibrosis?

36. DNA and RNA have many structural similarities. Which structure in DNA and RNA is similar?

37. A scientist studies the effects that barnyard grass, a weed, has on the growth of rice, other weeds, and insects. The barnyard grass and other weeds, rice, and insects make up whihc level of biological organization?

38. Ella told her sister the sun would set at 6:30 p.m. and there would be a full moon on Thursday night. Under which basic assumption of science is she operating?

39. Persons A and B have similar mRNA sequences with the exception of 1 nucleotide. Person A: AUGGUUACUAAGGGCUGA Person B: AUGGUUACUGAGGGCUGA The genetic code chart to determine how this difference affects the sequence of amino acids in the resulting protein.

40. Which process generates most of the ATP produced during cellular respiration?

41. How do enzymes speed up chemical reactions?

42. What combine with sugar and a phosphate group to form a nucleotide?

43. What process of natural selection favors the extreme phenotypes of a trait and eliminates intermediate phenotypes?

44. In pea plants, purple flowers are dominant to white flowers and tall stems are dominant to short stems. If two heterozygotes for both height and flower color are crossed, what is the probability of having short stemmed pea plants with purple flowers?

45. Which criterion is NOT necessarily true of a trait that has evolved through natural selection?

46. After Harrison adds a chemical to cells growing in a test tube, proteins accumulate in the cells' endoplasmic reticula. The chemical prevents movement of proteins from the endoplasmic reticulum to which organelle?

47. Despite the diversity of nature, most organisms contain the same 4 DNA bases. This table shows the DNA composition of 3 organisms as reported in a classic 1950s experiment. Based on this study, what did scientists conclude about the DNA composition of all organisms?

48. Red blood cells have a salt content of 0.9%. When a microbiologist places red blood cells in pure water, osmosis occurs. What net movement of a substance occurs in this instance of osmosis?

49. Thylakoid membranes within chloroplasts contain chlorophyll. The Calvin cycle occurs in the stroma of the chloroplasts. How are the processes occurring within the Calvin cycle and the thylakoid membrane connected?

50. Megan examines a liver cell and observes an organelle with many smooth-sided channels. Which activity would identify this organelle as the Golgi apparatus?

51. According to fossil evidence, whales evolved from 4-legged ancestors. The modern baleen whale has forelimbs, but inspection of its skeleton reveals only tiny vestigial hind limbs. What is the best explanation for this loss of hind limbs in the baleen whale?

52. What accounts for genetic biodiversity existing in modern multicellular organisms?

53. Which sequence is in order from the simplest level of organization to the most complex?

54. Two black guinea pigs bred and produced 3 black offspring and 2 albino offspring. Assuming no mutations, which guinea pigs must be heterozygous?

56. Jenna's favorite breakfast food, papaya, contains significant amounts of the enzyme papain (a protease). What substances does papain help digest?

57. A Paramecium lives in an environment that is hypotonic to its cytoplasm. How does the Paramecium maintain homeostasis under these conditions?

58. Chan wants to determine how much the mass of fungus growing on a nutrient agar plate changes over an 8 hr period. What is the most appropriate unit of measure for him to use?

59. Scientists collected data on the height and weight of individuals in a population. They recorded their results in this scatterplot. What is the most accurate conclusion regarding the relationship between height and weight?

60. When the pH in a stomach increases from 2 to 4, how does the hydrogen ion concentration change?

61. Naomi adds cyclohexamide to cells grown in a test tube. Within minutes, she identifies short incomplete segments of proteins in the cells. On which organelle does cyclohexamide act?

62. During aerobic cellular respiration, where do ATP molecules form?

63. What process of natural selection favors the intermediate phenotypes of a trait and eliminates extreme phenotypes?

64. What is the best definition of a scientific theory?

67. Which experimental design would provide scientists with the best data for investigating which type of feed yields the greatest gain in lean muscle mass in cattle?

68. In humans, pigmented skin is dominant to non-pigmented skin (albinism). What is the genotype of an individual with albinism?

71. A scientist places a cell in a solution, and over time the cell gains mass and swells. What is the most likely explanation for the cell's gain in mass?

72. The areobic and anaerobic pathways of cellular respiration REQUIRE which products of glycolysis?

73. The genotype of F1 individuals from a dihybrid cross is AaBb x AaBB. What is the expected ratio of AaBb individuals in the F2 generation?

74. What occurs during metaphase I of meiosis?

75. As part of an experiment, a student adds 10 mL of 5% hydrochloric acid solution to 100 mL of a non-buffered, colorless solution of sugar. What is the most likely result?

76. When comparing 2 populations of animals, which statement most likely indicates that they are the same species?

77. The presence of which structure indicates that cells are NOT photosynthetic bacteria?

79. A student wants to determine whether temperature affects the rate at which mold grows on bread. The student puts one piece of bread inside a Petri dish, closes the lid, and places the Petri dish in the refrigerator. Which treatment would be the best comparison for this experiment?

80. Jeanine inherited 2 alleles for round eye shape and has round eye shape. Her brother inherited 1 allele for round eye shape and 1 allele for almond eye shape and has almond eye shape. What type of trait is round eye shape?

81. Which example best illustrates the process of natural selection?

82. In pea plants, purple flowers are dominant to white flowers and tall stems are dominant to short stems. If two heterozygotes for both height and flower color are crossed, what is the probability of having tall stemmed pea plants with purple flowers?

83. Carbon-14 is a radioactive isotope used to determine the age of ancient objects composed of organic matter. Carbon-12 and carbon-13 are other isotopes of carbon. The number of what subatomic particles varies among these carbon isotopes?

25. Cosmetics often contain glycerol (C₃H₈O₃), which has three identical functional groups. Which type of bond holds these functional groups together?

90. In humans, red-green color blindness is a recessive, sex-linked trait. The chromosomes and alleles associated with color blindness are represented in this chart. Which child could NOT be born to these parents; a female (X^BX^b) and a male (X^BY)?