1.
Which statement describes an activity of a decomposer?
Correct Answer
A. A mushroom digests and absorbs nutrients from organic matter.
Explanation
DECOMPOSERS break down dead things and RECYCLE NUTRIENTS back into the soil. Two types of decomposers are fungi and bacteria, and a mushroom is a type of fungus.
2.
The calcium concentration in the root cells of certain plants is higher than in the surrounding soil. Calcium may continue to enter the root cells of the plant by the process of
Correct Answer
C. Active transport
Explanation
DIFFUSION involves the MOVEMENT of particles from HIGH TO LOW CONCENTRATION. Since the calcium is higher inside the root, it cannot enter the root by DIFFUSION, but rather active transport.
3.
Homeostasis is maintained in a single-celled organism by the interaction of:
Correct Answer
D. Organelles
Explanation
ORGANELLES maintain HOMEOSTASIS in SINGLE-CELLED ORGANISMS. The MEMBRANE allows exchange of materials and the CYTOPLASM allows movement of materials within the cell.
4.
Within which structure of an animal cell does DNA replication take place?
Correct Answer
C. Nucleus
Explanation
Since the DNA never leaves the NUCLEUS, all activities involving DNA take place in the NUCLEUS.
5.
The shape of a protein is originally determined by the:
Correct Answer
C. Arrangement of amino acids in the protein
Explanation
Depending on the amino acids included in the protein, the shape will be different. The function is based on the shape.
6.
Plant cells can synthesize energy-rich organic molecules, and later break them down to extract that energy for performing life processes. These activities require direct interaction between the
Correct Answer
C. Chloroplasts and mitochondria
Explanation
Plant cells can synthesize energy-rich organic molecules and later break them down with the direct interaction between the chloroplasts and mitochondria. The chloroplasts are responsible for photosynthesis, producing organic molecules, and the mitochondria are involved in cellular respiration, extracting energy from those molecules for various life processes.
7.
Selective breeding has been used for thousands of years to:
Correct Answer
D. Produce new varieties of domestic animals
Explanation
SELECTIVE BREEDING deals with producing DOMESTIC ANIMALS (horses, pigs, cows, dogs, cats, etc.) as well as AGRICULTURAL PLANTS (corn, wheat, etc.) that can be used by humans.
8.
A deletion of a DNA segment alters a gene in a single skin cell of an individual. Which statement best describes a result of this mutation?
Correct Answer
A. Any cell produced from this skin cell will have the same mutation.
Explanation
Only skin cells that were reproduced through MITOSIS will have the same DNA (and, as a result, the same mutation).
9.
Some goats have been genetically modified with a human gene that codes for a blood anticlotting factor. The anticlotting factor can then be extracted from the goat milk and used during surgery. To produce these genetically modified goats, scientists most likely:
Correct Answer
C. Inserted the human gene into the egg cells of goats
Explanation
GENETIC ENGINEERING...a gene is inserted into another organism that will produce a desired hormone (or other substance). In order for this gene to be successfully passed along to the offspring, it must be placed into a gamete (sperm or egg).
10.
Which characteristic is necessary for natural selection to occur in a species?
Correct Answer
B. Variation
Explanation
VARIATION is necessary for NATURAL SELECTION because the individuals born with beneficial adaptations will survive and pass along the traits to their offspring.
11.
Researchers use a variety of techniques to learn more about the function of a specific gene in an organism. In one type of experiment, called a loss-of-function experiment, the gene being investigated is eliminated. In a gain-of-function experiment, extra copies of the gene being investigated are inserted. The cell process most directly affected in both experiments is
Correct Answer
A. Protein synthesis
Explanation
This question is confusing, but two of these things deal with going from large to small (breakdown) and the protein synthesis is something that is going from small to large (synthesis). You can be pretty safe in general if you identify the "odd man out."
12.
Plants are green because they contain the protein chlorophyll. A bucket was left on the lawn for one week. When the bucket was removed, the grass under the bucket had turned from green to a yellowish white color. This change is due to the interaction between the grass and
Correct Answer
B. The amount of sunlight, an abiotic factor
Explanation
Notice the keywords in the answers? BIOIC (living) and ABIOTIC (non-living) were only used correctly in one answer: SUNLIGHT is ABIOTIC!!
13.
Which statement describes a function of the human male reproductive system?
Correct Answer
A. It produces gametes in testes.
Explanation
The testes are responsible for producing male gametes, which are sperm cells. Sperm cells are essential for fertilization when they combine with female gametes (egg cells) to form a zygote, which eventually develops into an embryo. The other options refer to functions associated with the female reproductive system, such as providing support for embryo development and supplying nutrient materials through a placenta.
14.
Exposure to toxins during early stages of pregnancy is more likely to cause birth defects than exposure in late pregnancy because
Correct Answer
A. Essential organs form during early development
Explanation
EARLY PREGNANCY = DIFFERENTIATION. Essential organs (heart, nerves, etc.) are forming during these stages.
15.
Although a liver cell and a muscle cell in a human developed from the same single cell, their appearance and functions are different. This is because the liver cell
Correct Answer
B. Expresses different genes than the muscle cell
Explanation
All cells in an individual organism have the same DNA, which means they have the same genes as well. The reason we have different types of cells and organs is because only certain genes are expressed in each cell.
16.
Sexual reproduction in a species usually results in
Correct Answer
C. Recombination of genes
Explanation
SEXUAL REPRODUCTION involves MEIOSIS, which re-combines chromosomes...this allows organisms that perform sexual reproduction more possibilities for variation.
17.
As water flows downhill, its energy can be used to generate electricity. Later, this water may evaporate, fall as rain, and be used again to generate electricity in the same way. This explains why electricity generated with water is considered
Correct Answer
B. A renewable form of energy
Explanation
The water is recycled in nature so it will always be present. It is considered RENEWABLE.
18.
Scientists have found that although plants require light to carry on photosynthesis, very high levels of sunlight can kill some plants. This illustrates that many biochemical processes may occur
Correct Answer
B. Within a specific range of conditions
Explanation
Every organism in nature survives within a specific range of conditions. HOMEOSTASIS is the balance that is maintained within this range of conditions.
19.
A relationship between a consumer and producer is best illustrated by a
Correct Answer
D. Deer eating grass
Explanation
PRODUCER: plant.
CONSUMER: animal...though DECOMPOSERS are also CONSUMERS, so think about the question when you encounter these types in the future.
20.
The evolutionary pathways of several species are represented in the diagram below.
Which species was best adapted for survival in changing environmental conditions?
Correct Answer
B. E
Explanation
E appears in the pathway on 3 different occasions, while the other three appear only one time each.
21.
The diagram below represents a microscopic view of blood.
Cell A protects the body by producing specific chemicals in response to pathogens. Cell A is
Correct Answer
D. A white blood cell
Explanation
White blood cells are found in the bloodstream and fights pathogens.
22.
The diagram below represents a change in guard cells that open and close pores in a plant.
This change directly helps to
Correct Answer
C. Regulate water loss
Explanation
The guard cells open to release excess water AND exchange CO2 and O2 with the environment. They help to maintain homeostasis.
23.
Which statement represents a characteristic of an ecosystem that is not likely to sustain itself?
Correct Answer
C. There are more consumers than producers.
Explanation
Three of these options are good things and one of these things is a bad thing. If there are MORE CONSUMERS THAN PRODUCERS, there won't be enough food to go around...in other words, if an ecosystem had hundreds of deer but very little grass, the deer would die out.
24.
Which statement best explains why different plant species are found at different water depths as represented in the diagram below?
Correct Answer
B. In any particular environment, the growth and survival of organisms is affected by pHysical conditions.
Explanation
Some plants can tolerate deep water, while some tolerate shallow water, and yet others tolerate land...all physical conditions.
25.
Some people see the benefit of wind energy as a clean alternative to fossil fuels for energy production. Others believe it is dangerous for migratory birds. These opinions best illustrate that decisions about alternate energy sources
Correct Answer
B. Must be made by weighing the risks and costs against the benefits
Explanation
Considering both sides of the spectrum is called TRADE OFF...you compare the good things with the bad things.
26.
One way humans can promote the survival of organisms in an ecosystem is to
Correct Answer
D. Learn about the interactions of populations
Explanation
If you understand how organisms interact within a population, there is a better chance we can do more to help them to survive.
27.
Environmentalists are hoping to protect endangered organisms by calling for a reduction in the use of pesticides, because loss of these organisms would
Correct Answer
C. Reduce biodiversity in various ecosystems
Explanation
PESTICIDES kill organisms and can harm others that come into contact with affected organisms...If too many organisms die, the BIODIVERSITY will be reduced.
28.
Which farming practice causes the least harm to the environment?
Correct Answer
A. Using natural predators to reduce insect numbers
Explanation
When farmers plant the same crop over and over again, the nutrients are not recycled into the soil...PESTICIDES cause harm to the plants and animals, so using NATURAL predators eliminates any possibility of an exotic species taking over an ecosystem.
29.
Some bacteria are unable to survive unless a certain nutrient is present in their food supply. After exposure to ultraviolet radiation, some of these bacteria are able to synthesize this nutrient. This change is most likely due to
Correct Answer
C. An alteration in a gene
Explanation
Radiation causes mutation. Some mutations are good, some are bad. In this case, it was a good mutation.
30.
Which action by humans could improve the quality of the air?
Correct Answer
B. Buying cars that get more miles per gallon of gasoline
Explanation
Buying cars that get more miles per gallon of gasoline could improve the quality of the air. This action reduces the amount of fuel consumed and decreases the emissions of pollutants and greenhouse gases, leading to cleaner air.
31.
Base your answer to this question on the information below and on your knowledge of biology.
Euglena are single-celled organisms that live in ponds. All euglena have chloroplasts and can make their own food. They can also take in food from the environment. The diagram below represents a euglena.
An experiment was set up to determine the effect of nitrates, a pollutant, on the number of chloroplasts present in euglena. Five tanks were set up, each with euglena and a different concentration of nitrate solution: 0%, 0.5%, 1.0%, 1.5%, and 2.0%.
The tanks were placed in a sunny location where each tank received the same amount of light.
Which statement is a possible hypothesis for this experiment that could be supported by the results of this experiment?
Correct Answer
B. If the nitrate concentration is increased, then the euglena will have a lower average number of chloroplasts.
Explanation
Nitrates are pollutants and that will harm the euglena. Since euglenas have chloroplasts, they may be destroyed by pollutants, due to a chance of mutation.
32.
Base your answer to this question on the information below and on your knowledge of biology.
Euglena are single-celled organisms that live in ponds. All euglena have chloroplasts and can make their own food. They can also take in food from the environment. The diagram below represents a euglena.
An experiment was set up to determine the effect of nitrates, a pollutant, on the number of chloroplasts present in euglena. Five tanks were set up, each with euglena and a different concentration of nitrate solution: 0%, 0.5%, 1.0%, 1.5%, and 2.0%.
The tanks were placed in a sunny location where each tank received the same amount of light.
Which statement correctly identifies a variable in this experiment?
Correct Answer
A. The independent variable is the concentration of nitrate solution used.
Explanation
IF we change nitrates, THEN the chloroplasts will be affected.
IF = INDEPENDENT...the number of nitrates used.
33.
Base your answer to this question on the information below and on your knowledge of biology.
Euglena are single-celled organisms that live in ponds. All euglena have chloroplasts and can make their own food. They can also take in food from the environment. The diagram below represents a euglena.
An experiment was set up to determine the effect of nitrates, a pollutant, on the number of chloroplasts present in euglena. Five tanks were set up, each with euglena and a different concentration of nitrate solution: 0%, 0.5%, 1.0%, 1.5%, and 2.0%.
The tanks were placed in a sunny location where each tank received the same amount of light.
Euglena can be classified as both
Correct Answer
D. An autotropH and a heterotropH
Explanation
Autotrophs make their own food and heterotrophs consume other organisms...EUGLENA do both.
34.
Two methods of reproduction are represented in the diagram below.
How does the DNA in the offspring produced by these methods compare to the DNA in the original organism?
Correct Answer
B. The DNA in the offspring is genetically identical to that of the original organism in both methods.
Explanation
The sheep are CLONED through GENETIC ENGINEERING, while the single-celled organism are CLONED through MITOSIS...in both situations, the DNA is identical to the parent.
35.
Puppies are often given medicine to eliminate roundworms from their intestines. These worms consume some of the food the puppies have digested. The worms and the puppies represent a relationship known as
Correct Answer
C. Parasite-host
Explanation
PARASITE is something that feeds on another organism, causing it harm while the HOST is the organism that is harmed.
36.
The diagram below represents cells and hormones present in the human body.
Which statement correctly describes an interaction between the hormones and the cells?
Correct Answer
C. Specific reactions carried out by cell 1 are regulated by hormone C.
Explanation
The connections are as follows: CELL 1 interacts with HORMONE C, while CELL 2 interacts with HORMONE A.
37.
In the diagram below, which letter indicates the part of the cell that carries out a function most similar to a function of the human excretory system?
Correct Answer
B. B
Explanation
EXCRETORY system REMOVES WASTE from the body...MEMBRANES REMOVE WASTE from the cell...they have similar functions.
38.
In a DNA sample, 15% of the bases are thymine (T). What percentage of the bases in this sample are adenine (A)?
Correct Answer
A. 15%
Explanation
This one is a bit tricky: If there is 15% T, there must be 15% A as well. That leaves 70% for BOTH C and G...each C and G must be 35%.
15 + 15 + 35 + 35 = 100%
39.
The graph below shows the results of an action of the enzyme catalase on a piece of meat. Evidence of enzyme activity is indicated by bubbles of oxygen.
Which statement best summarizes the activity of catalase shown in the graph?
Correct Answer
C. The enzyme works better at 35°C than at either temperature extreme.
Explanation
According to the graph, the enzyme functions better in the middle range, which is around 35°C.
40.
Which process is represented in the diagram below?
Correct Answer
D. Ecological succession
Explanation
This diagram represents what is happening following a forest fire. Although it is not diagrammed like other examples, it still shows ECOLOGICAL SUCCESSION.
41.
Base your answer to this question on the diagram below and on your knowledge of biology. The diagram represents various levels of interaction between organisms in a prairie ecosystem.
If the amount of carbon dioxide in the atmosphere were to decrease, which organism in the diagram would be one of the first affected by this change?
Correct Answer
B. Wheat
Explanation
Wheat uses CARBON DIOXIDE during the process of PHOTOSYNTHESIS, and would therefore be affected first.
42.
Base your answer to this question on the diagram below and on your knowledge of biology. The diagram represents various levels of interaction between organisms in a prairie ecosystem.
Which statement best describes a function of the molds, bacteria, and yeasts in this ecosystem?
Correct Answer
C. They break down dead organisms, releasing raw materials to the environment.
Explanation
DECOMPOSERS RECYCLE nutrients in the environment.
43.
The diagram below represents the measurement of a biological specimen.
What is the approximate length of the specimen in millimeters?
Correct Answer
A. 25 mm
Explanation
The organism starts out at 1 cm (which is 10 mm) and ends at 3.5 cm (which is 35 mm)...the difference is 2.5 cm (which is 25 mm).