1.
Which molecule is paired with its correct role in protein synthesis?
Correct Answer
D. TRNA - transfers amino acids
Explanation
tRNA, or transfer RNA, is responsible for transferring amino acids to the ribosome during protein synthesis. It recognizes the specific codons on the mRNA molecule and brings the corresponding amino acid to the ribosome, where it is added to the growing protein chain. This process ensures that the correct sequence of amino acids is incorporated into the protein, based on the instructions encoded in the mRNA molecule. Therefore, tRNA is correctly paired with its role in protein synthesis.
2.
Which cellular process converts solar energy into chemical energy?
Correct Answer
C. pHotosynthesis
Explanation
Photosynthesis is the cellular process that converts solar energy into chemical energy. During photosynthesis, plants use sunlight, carbon dioxide, and water to produce glucose and oxygen. The energy from sunlight is captured by chlorophyll in the plant's cells and converted into chemical energy, which is stored in the form of glucose. This process is essential for the survival of plants and is responsible for the production of oxygen in the atmosphere.
3.
Which best explains why a bacterial cell is classified as a prokaryote?
Correct Answer
B. The absence of a nucleus
Explanation
A bacterial cell is classified as a prokaryote because it lacks a nucleus. Prokaryotes are characterized by the absence of a membrane-bound nucleus, which means that their genetic material is not enclosed within a distinct nucleus. Instead, the DNA is present in the cytoplasm of the cell. This distinguishes them from eukaryotes, which have a membrane-bound nucleus. The absence of a nucleus in bacterial cells allows for a simpler and more streamlined structure, enabling them to carry out essential functions efficiently.
4.
In certain species of roses, white roses and red roses are incompletely dominant to each other. When a red rose and a white rose are crossed, a pink rose is produced. What is the probability of producing a white rose when a red rose is crossed with a pink rose?
Correct Answer
D. 0%
Explanation
When a red rose is crossed with a pink rose, the pink rose is a result of incomplete dominance between red and white roses. This means that the pink rose carries both the red and white alleles. Since the white allele is not present in the pink rose, there is no probability of producing a white rose when a red rose is crossed with a pink rose. Therefore, the probability of producing a white rose in this scenario is 0%.
5.
Proteins are synthesized in which numbered organelle?
Correct Answer
C. 3
Explanation
Proteins are synthesized in organelle number 3.
6.
The diagram below shows the feeding relationship for four coral reef organisms.
Humans sometimes kill giant tritons in order to collect their attractive spiral shells.
If humans kill most of the giant tritons in the coral reef, the coral population will most likely
Correct Answer
D. Decrease due to an increase in the crown-of-thorns sea star population.
Explanation
If humans kill most of the giant tritons, there will be an increase in the population of crown-of-thorns sea stars. Crown-of-thorns sea stars are known to eat coral, so an increase in their population will lead to an increase in coral predation. This will result in a decrease in the coral population.
7.
In the late 1800s, Christiaan Eijkman studied a disease called beriberi, which is caused by a vitamin deficiency. A disease similar to beriberi occured in chickens that were fed polished rice, which is rice that has the bran layer removed. Chickens that ate unpolished rice did not get the disease.
Eijkman convinced officials of a prison experiencing an outbreak of the disease to start feeding the prisoners unpolished rice. The rate of beriberi decreased dramatically. Which procedure would best convince other scientists who questioned his results?
Correct Answer
B. Provide the same number of prisoners with polished rice as with unpolished rice.
Explanation
To convince other scientists who questioned his results, providing the same number of prisoners with polished rice as with unpolished rice would be the best procedure. This would allow for a controlled experiment where the only variable being tested is the type of rice being consumed. By comparing the rates of beriberi in both groups of prisoners, Eijkman can demonstrate a clear cause-and-effect relationship between polished rice consumption and the disease. This would provide stronger evidence for his hypothesis and help convince other scientists of the validity of his findings.
8.
What is the primary function of DNA in organisms?
Correct Answer
B. Stores genetic information
Explanation
DNA serves as the primary function of storing genetic information in organisms. It contains the instructions necessary for the development, functioning, and reproduction of all living organisms. DNA molecules are made up of nucleotides that form a double helix structure, and the sequence of these nucleotides determines the genetic code. This genetic information is passed on from parents to offspring and is responsible for the inheritance of traits and characteristics. DNA is essential for protein synthesis, cell division, and the overall functioning of an organism.
9.
The roots of some plant species have a special coating to help resist rotting in exteremly wet weather. In which environment is it most beneficial for plants to have rot-resistant roots?
Correct Answer
C. C
Explanation
Plants with rot-resistant roots would benefit the most in environment C, which is extremely wet. The special coating on the roots helps protect them from rotting in such conditions, allowing the plant to continue absorbing nutrients and water from the soil. This adaptation is advantageous in environments where there is a high moisture content, as it helps the plant survive and thrive despite the wet conditions.
10.
An ecologist performed a study to determine how the rate of photosynthetic activity in a lake changed from month to month. The results of the study are shown in the graph below.
Which conclusion is best supported by the evidence?
Correct Answer
C. The rate of pHotosynthesis was greatest during the months of May through July.
Explanation
The graph clearly shows that the rate of photosynthesis is highest during the months of May through July. This conclusion is supported by the upward trend in the graph during these months, indicating an increase in photosynthetic activity. Additionally, the graph shows a decline in photosynthetic activity after July, further supporting the conclusion that the rate of photosynthesis was greatest during the months of May through July.
11.
Which piece of equipment is best for measuring the change in the mass of potato slices after placing them in different concentrations of salt water?
Correct Answer
D. Triple beam balance
Explanation
A triple beam balance is the best piece of equipment for measuring the change in the mass of potato slices after placing them in different concentrations of salt water. A triple beam balance is a precise instrument used to measure the mass of an object. By using this balance, we can accurately measure the change in mass of the potato slices before and after they are placed in different concentrations of salt water. The other options, such as a beaker, metric ruler, and graduated cylinder, are not suitable for measuring mass and would not provide accurate results in this experiment.
12.
Students conducted an investigation using Biuret reagent to determine the presence of proteins in different foods. The results are shown in the table below.
According to the data, which foods tested by the students contained proteins?
Correct Answer
D. Cottage cheese and yogurt
Explanation
Based on the results shown in the table, the foods tested by the students that contained proteins are cottage cheese and yogurt. The presence of proteins in these foods was likely confirmed by a positive reaction with the Biuret reagent, which is commonly used to detect the presence of proteins.
13.
Which best describes how enzymes function in the body?
Correct Answer
B. Enzymes lower the activation energy of reactions.
Explanation
Enzymes are biological catalysts that speed up chemical reactions in the body. They do this by lowering the activation energy required for the reaction to occur. By lowering the activation energy, enzymes make it easier for the reactant molecules to reach the transition state and form products. This allows the reactions to occur more quickly and efficiently. Unlike other options, enzymes are not converted into products, can catalyze multiple reactions, and are not destroyed after one use.
14.
The graph represents the relationship between an oraganism's oxygen consumption and body mass.
Which statement is supported by the information shown in the graph?
Correct Answer
C. As the body mass of an organism increases, oxygen consumption decreases.
Explanation
The graph shows a negative correlation between body mass and oxygen consumption. As the body mass of an organism increases, the oxygen consumption decreases. This can be observed by the downward sloping trend of the graph. Therefore, the statement "As the body mass of an organism increases, oxygen consumption decreases" is supported by the information shown in the graph.
15.
An energy pyramid is shown below.
Which best explains why an pyramid is used to represent energy flow within an ecosystem?
Correct Answer
B. Available energy decreases when moving up an energy pyramid.
Explanation
An energy pyramid is used to represent energy flow within an ecosystem because available energy decreases when moving up the pyramid. This is because energy is lost as it is transferred from one trophic level to the next. The organisms at the lower trophic levels, such as producers, have access to more energy compared to those at higher trophic levels, such as consumers. This decrease in available energy is due to inefficiencies in energy transfer, such as energy being used for metabolism, heat loss, and waste production. Therefore, an energy pyramid visually represents this decrease in available energy as you move up the trophic levels.
16.
Which molecules store and transmit genetic information?
Correct Answer
C. Nucleic Acids
Explanation
Nucleic acids are the molecules that store and transmit genetic information. This is because they contain the genetic code in the form of DNA or RNA. DNA carries the instructions for building and maintaining an organism, while RNA helps in the synthesis of proteins based on these instructions. Lipids, proteins, and carbohydrates do not have the ability to store or transmit genetic information.
17.
A student notices that the lettuce in a salad wilts soon after salt is added. Wilting most likely occurs because the lettuce cells
Correct Answer
C. Release water in the presence of salt.
Explanation
When salt is added to the lettuce, it creates a hypertonic solution, meaning that the concentration of solutes outside the lettuce cells is higher than inside the cells. This causes water to move out of the cells through osmosis, resulting in the lettuce wilting. Therefore, the lettuce cells release water in the presence of salt.
18.
The pedigree chart below shows the transmission of genetic traits over several generations.
How is this trait inherited?
Correct Answer
C. Sex-linked recessive
Explanation
The trait in the pedigree chart is inherited as a sex-linked recessive trait. This means that the gene responsible for the trait is located on the sex chromosome, specifically the X chromosome. In this case, the trait is more commonly seen in males because they only have one X chromosome, while females have two. If a male inherits the recessive allele on his X chromosome, he will express the trait. Females, on the other hand, need to inherit the recessive allele on both of their X chromosomes to express the trait.
19.
A diagram showing the evolution of eight bird species is shown below.
The differences in the species are most likely a result of
Correct Answer
D. Available food sources.
Explanation
The diagram showing the evolution of eight bird species suggests that the differences in the species are most likely a result of available food sources. This is because the availability of food sources plays a crucial role in the survival and adaptation of bird species. Birds with different beak shapes and sizes may have evolved to exploit different food sources, leading to the diversification of species over time. The diagram likely illustrates how the availability of food sources influenced the evolution and divergence of these bird species.
20.
In active transport, carrier proteins
Correct Answer
D. Move substances from low concentration to high concentration through the use of energy.
21.
An isolated population of termites lives in a forest surrounded by mountains. These termites feed on dead wood, grasses, and seeds. This food is broken down by species of microorganism that lives inside the intestines of the termites. Without the microorganisms, these termites cannot obtain the nutrients they need to survive. One winter, a virus causes most of these microogranisms to die.
As a result of the microorganism's absence, these termites will most likely
Correct Answer
B. Decrease to a level near extinction.
Explanation
The termites rely on the microorganisms in their intestines to break down their food and obtain the necessary nutrients for survival. Without these microorganisms, the termites will not be able to properly digest their food and obtain the nutrients they need. As a result, their ability to survive will be greatly compromised, leading to a decrease in their population size. If the population size continues to decrease, it may eventually reach a level near extinction. Therefore, the most likely outcome in this situation is that the termites will decrease to a level near extinction.
22.
A researcher is studying the damage that predators cause to wings of butterflies. Which tools are best to use to determine the percentage of butterflies with damaged wings?
Correct Answer
C. Catch net and hand lens
Explanation
To determine the percentage of butterflies with damaged wings, the researcher would need to physically catch the butterflies using a catch net. Once caught, the researcher can then use a hand lens to carefully examine each butterfly's wings and determine if they are damaged or not. Therefore, the best tools to use for this purpose would be a catch net and hand lens. A triple beam balance is used to measure weight, a microscope is used to examine small objects in detail, and a graduated cylinder is used to measure liquid volume, none of which are relevant for determining wing damage in butterflies.
23.
Diagrams of a bent pinky finger and a straight pinky finger are shown below. The allele for having a bent pinky finger is dominant to the allele for having a straight pinky finger.
If two people who are both heterzygous for the trait of a bent pinky finger have a child, what is the percent proabability that the child will have straight pinky fingers?
Correct Answer
B. 25%
Explanation
When two people are heterozygous for a trait, it means that they have one dominant allele and one recessive allele for that trait. In this case, the allele for a bent pinky finger is dominant, while the allele for a straight pinky finger is recessive.
When these two heterozygous individuals have a child, there is a 25% chance that the child will inherit two recessive alleles for the trait, resulting in straight pinky fingers. This is because each parent can pass on either the dominant or the recessive allele, resulting in four possible combinations of alleles for the child: BB, Bb, bB, or bb. Only one of these combinations (bb) represents the child having two recessive alleles and therefore straight pinky fingers.
24.
Which best describes the role of enzymes in a chemical reaction?
Correct Answer
C. Increase the reaction rate
Explanation
Enzymes are biological catalysts that increase the rate of chemical reactions by lowering the activation energy required for the reaction to occur. They do not absorb or release energy, but rather facilitate the conversion of reactants into products by providing an alternative reaction pathway with a lower energy barrier. This allows the reaction to proceed more quickly and efficiently. Therefore, the best description of the role of enzymes in a chemical reaction is to increase the reaction rate.
25.
Which best describes how meiosis contributes to genetic variation?
Correct Answer
B. Produces a new individual different from either parent
Explanation
Meiosis is a type of cell division that occurs in reproductive cells to produce gametes (sperm and eggs). During meiosis, genetic material is shuffled and recombined, resulting in new combinations of genes. This process contributes to genetic variation by creating offspring that are genetically distinct from their parents. Through meiosis, new combinations of alleles are formed, leading to increased genetic diversity within a population. Therefore, the answer "produces a new individual different from either parent" accurately describes how meiosis contributes to genetic variation.
26.
A food web is diagrammed below.
What would most likely happen if the rabbit population decreased as a result of another predator being introduced to the food web?
Correct Answer
A. The fox population would decrease.
Explanation
If the rabbit population decreases, it means there is less prey available for the foxes. As a result, the fox population would decrease because they would have less food to eat. The other options are unlikely because they do not directly depend on the rabbit population for their survival or growth.
27.
Which human activity will have the most positive effect on the global environment?
Correct Answer
C. Reducing air pollution across countries by enforcing stricter emissions laws
Explanation
Enforcing stricter emissions laws to reduce air pollution across countries will have the most positive effect on the global environment. This action will help in reducing the release of harmful pollutants into the atmosphere, which can have detrimental effects on both human health and the environment. By implementing stricter emissions laws, countries can ensure that industries and vehicles are adhering to regulations that limit their pollution levels. This will lead to cleaner air, improved air quality, and a reduction in the negative impacts of air pollution on climate change, ecosystems, and biodiversity.
28.
The following diagram represents a food pyramid.
Which trophic level has the greatest total amount of energy to transfer to the next level?
Correct Answer
A. Grain
Explanation
The trophic level with the greatest total amount of energy to transfer to the next level is the base of the food pyramid, which consists of producers such as plants. Plants have the highest amount of energy available as they convert sunlight into food through photosynthesis. Therefore, the correct answer is Grain.
29.
Some microorganisms, such as yeast, produce energy in oxygen-free environments through the process of
Correct Answer
D. Anerobic respiration
Explanation
Some microorganisms, like yeast, are capable of producing energy in the absence of oxygen through a process called anaerobic respiration. During anaerobic respiration, these microorganisms break down glucose or other organic molecules to release energy in the absence of oxygen. This process is less efficient than aerobic respiration, which occurs in the presence of oxygen, but allows these microorganisms to survive and produce energy in oxygen-free environments.
30.
Which is an organelle that performs cellular respiration and is paired with its correct functions?
Correct Answer
C. Mitochondrion - converts energy found in glucose into energy for use by the cell
Explanation
The correct answer is mitochondrion - converts energy found in glucose into energy for use by the cell. Mitochondria are organelles that are responsible for cellular respiration, which is the process of converting glucose and oxygen into ATP, the main energy source for the cell. Through a series of biochemical reactions, mitochondria break down glucose molecules and produce ATP molecules, which can be used by the cell for various energy-requiring processes. This conversion of glucose energy into usable cellular energy is crucial for the survival and functioning of the cell.
31.
Which biomolecule contains nitrogenous bases?
Correct Answer
C. Nucleic acid
Explanation
Nucleic acids are the biomolecules that contain nitrogenous bases. These bases, namely adenine, guanine, cytosine, and thymine (or uracil in RNA), are the building blocks of DNA and RNA. These nitrogenous bases are responsible for storing and transmitting genetic information. Lipids, proteins, and carbohydrates do not contain nitrogenous bases and have different functions in the body.
32.
Generic drugs are copies that are the same as brand-name drugs in dosage, safety, strength, quality, and performance. Many people prefer drugs because they cost much less than their brand-name counterparts. Which best explains why pharmaceutical companies are able to sell generic drugs at a much lower cost than the brand-name drugs?
Correct Answer
A. Generic drugs do not have the initial costs of production and advertising.
Explanation
Pharmaceutical companies are able to sell generic drugs at a much lower cost than brand-name drugs because generic drugs do not have the initial costs of production and advertising. Brand-name drugs require significant investment in research and development, clinical trials, and marketing campaigns, which increases their overall cost. In contrast, generic drugs can be produced once the patent for the brand-name drug expires, eliminating the need for extensive research and advertising expenses. This allows pharmaceutical companies to offer generic drugs at a lower price while still maintaining the same quality, safety, and effectiveness as the brand-name drugs.
33.
Which statement best describes the primary function of DNA replication?
Correct Answer
A. To ensure daughter cells have a complete copy of the DNA
Explanation
The primary function of DNA replication is to ensure that daughter cells have a complete copy of the DNA. During replication, the DNA molecule unwinds and separates into two strands, and each strand serves as a template for the synthesis of a new complementary strand. This process ensures that each daughter cell receives an identical copy of the genetic information, allowing for accurate transmission of genetic material from one generation to the next.
34.
Which best describes the interaction between DNA and RNA during protein synthesis?
Correct Answer
C. RNA carries the code from DNA in the nucleus to the ribosome for protein synthesis.
Explanation
During protein synthesis, RNA carries the genetic code from DNA in the nucleus to the ribosome, where it is translated into a protein. DNA does not directly translate the code, but instead acts as a template for RNA synthesis. The correct answer accurately describes the interaction between DNA and RNA during protein synthesis.
35.
An ion must cross the cell membrane through active transport instead of passive transport when the ion is
Correct Answer
C. Going against the concentration gradient.
Explanation
When an ion is going against the concentration gradient, it means that it is moving from an area of lower concentration to an area of higher concentration. This requires the input of energy, which is provided by active transport. Active transport is necessary in this case because passive transport, which relies on the natural movement of molecules from high to low concentration, would not be able to move the ion against the concentration gradient. Therefore, the ion must cross the cell membrane through active transport in order to move against the concentration gradient.