EOC Practice Test #1

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Quizzes Created: 36 | Total Attempts: 35,085
Questions: 50 | Attempts: 148

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• 1.

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?

• A.

Kilogram

• B.

Kilometer

• C.

Milligram

• D.

Millimeter

C. Milligram
Explanation
The most appropriate unit of measure for Chan to use in determining the mass of fungus growing on a nutrient agar plate over an 8 hr period would be milligram. Milligram is a unit of mass that is commonly used for small measurements, making it suitable for measuring the mass of the fungus. Kilogram and kilometer are units of measure for distance and larger masses respectively, while millimeter is a unit of measure for length.

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• 2.

What is the best definition of a scientific theory?

• A.

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

• B.

A description of an invariable relationship that exists in nature

• C.

A speculation or guess about how nature works

• D.

An unproven fact

A. An explanation of how and why a natural phenomenon behaves teh way it does
Explanation
A scientific theory is the best definition because it provides an explanation for how and why a natural phenomenon behaves the way it does. It goes beyond just describing an invariable relationship or making a speculation or guess. It is also different from an unproven fact, as a scientific theory is supported by evidence and has undergone rigorous testing and scrutiny.

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• 3.

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?

• A.

Population

• B.

Community

• C.

Ecosystem

• D.

Biome

B. Community
Explanation
The scientist is studying the interactions between barnyard grass, other weeds, rice, and insects. These organisms are all living in the same area and are interacting with each other. Therefore, the correct answer is "Community," which refers to a group of different species living and interacting in the same location.

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• 4.

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?

• A.

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

• B.

What role do genetic factors play in hydrangea color?

• C.

Do varying degrees of light affect hydrangea color?

• D.

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

A. How does the chemistry of the soil affect the color of hydrangea blossoms?
Explanation
The correct answer is "How does the chemistry of the soil affect the color of hydrangea blossoms?" because Lydia conducted her investigation to understand the relationship between the pH of the soil and the color of the hydrangea blossoms. She noticed that hydrangeas in Container 1 with a pH of 6.0 had pink blossoms, while hydrangeas in Container 2 with a pH of 5.0 had blue blossoms. This suggests that the acidity of the soil, determined by its pH, affects the availability of certain pigments in the plant, resulting in different flower colors.

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• 5.

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?

• A.

Test 5 different types of cows with the same feed mixture and measure their weight gain at the end of a 6-week trial.

• B.

Test 5 similar groups of cows with 5 different feed mixtures and measure their weight gain at the end of a 6-week trial.

• C.

Test 5 similar groups of cows with the same feed mixture, give each group varying amounts of feed, and measure their weight gain at the end of a 6-week trial.

• D.

Test 5 different types of cows with 5 different feed mixtures, give each group varying amounts of feed, and measure their weight gain at the end of a 6-week trial.

B. Test 5 similar groups of cows with 5 different feed mixtures and measure their weight gain at the end of a 6-week trial.
Explanation
Testing 5 similar groups of cows with 5 different feed mixtures and measuring their weight gain at the end of a 6-week trial would provide scientists with the best data for investigating which type of feed yields the greatest gain in lean muscle mass in cattle. This design allows for a direct comparison between different feed mixtures, as each group of cows is exposed to a different feed. By using similar groups of cows, any variations in weight gain can be attributed to the different feed mixtures rather than other factors. This design also allows for a larger sample size, increasing the statistical power of the study.

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• 6.

Shown below is a growth curve for Paramecium grown in a 1.0 L flask containing pond water at 20oC. 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?

• A.

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

• B.

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

• C.

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

• D.

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

C. Repeat the procedures described using 2 flasks; incubate 1 flask at 15oC and the other at 25oC.
Explanation
To determine whether temperature influences the population size of Paramecium, it is necessary to compare the growth of Paramecium at different temperatures. By repeating the procedures described using 2 flasks and incubating one flask at 15oC and the other at 25oC, it allows for a direct comparison of the population sizes under different temperature conditions. This experimental setup controls for other variables and allows for a clear evaluation of the impact of temperature on the population size of Paramecium.

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• 7.

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?

• A.

Tall individuals are always heavier than short individuals.

• B.

There is no relationship between height and weight.

• C.

There is a negative relationship between height and weight.

• D.

There us a positive relationship between height and weight.

D. There us a positive relationship between height and weight.
Explanation
The scatterplot shows that as height increases, weight also tends to increase. This suggests a positive relationship between height and weight, indicating that taller individuals tend to be heavier. However, it is important to note that this conclusion is based on the data collected and may not apply universally to all individuals in the population.

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• 8.

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?

• A.

Exercise increases only the pulse.

• B.

Exercise increases only the systolic pressure.

• C.

Exercise increases both the systolic and diastolic pressure.

• D.

Exercise increases both the pulse and the systolic pressure.

D. Exercise increases both the pulse and the systolic pressure.
Explanation
The experiment's results support Paul's statement because they show that exercise increases both the pulse and the systolic pressure. This indicates that the heart is pumping more blood during exercise, as a higher pulse rate and systolic pressure are both indicators of increased blood flow.

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• 9.

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?

• A.

5

• B.

10

• C.

25

• D.

50

B. 10
Explanation
The average number of eggs laid per day over the 5 days can be calculated by adding up the total number of eggs laid over the 5 days and then dividing it by 5 (the number of days). In this case, the researcher recorded the number of eggs laid per day for 5 days and found that the total number of eggs laid was 50. Therefore, the average number of eggs laid per day is 10.

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• 10.

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?

• A.

Elephant

• B.

Kangaroo

• C.

Lion

• D.

Snake

A. Elephant
Explanation
Based on the graph, the elephant is approximately 1/3 as fast as the cheetah. This can be determined by comparing the speeds of the animals on the graph. The graph shows that the cheetah has the highest speed, and the elephant's speed is significantly lower, indicating that it is approximately 1/3 as fast as the cheetah.

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• 11.

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?

• A.

Nature is orderly.

• B.

Knowledge is superior to ignorance.

• C.

Nothing is self-evident.

• D.

All phenomena have natural causes.

A. Nature is orderly.
Explanation
The basic assumption of science that Ella is operating under is that nature is orderly. This means that there are consistent patterns and laws that govern the natural world, including the movement of celestial bodies like the sun and moon. Ella's statement about the sun setting at 6:30 p.m. and there being a full moon on Thursday night suggests that she believes in the predictability and regularity of natural phenomena.

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• 12.

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?

• A.

Assigning the subjects to groups at random

• B.

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

• C.

Telling subjects if they are receiving the medicine or the placebo

• D.

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

A. Assigning the subjects to groups at random
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 two groups are comparable. Random assignment helps to distribute potential confounding factors evenly across the groups, making it more likely that any differences observed between the groups are due to the medication and not other factors. This increases the internal validity of the study and allows for more accurate conclusions to be drawn.

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• 13.

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 25oC 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?

• A.

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

• B.

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

• C.

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

• D.

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

B. 1 mL of enzyme suspension incubated at 37oC for 20 min
Explanation
To accurately test the effects of temperature on starch digestion, Edison should begin a second test with the same amount of starch (2g) in a test tube. Since the first test was incubated at 25oC for 20 minutes, the second test should have a different temperature condition to observe the effects. Among the given options, the only one that meets this requirement is "1 mL of enzyme suspension incubated at 37oC for 20 min". This will allow Edison to compare the effects of different temperatures on starch digestion by keeping the enzyme suspension amount constant and changing only the temperature.

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• 14.

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?

• A.

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

• B.

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

• C.

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

• D.

The new culture grows faster regardless of the strain.

C. The 30-day old culture grows faster regardless of the strain.
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, when Strain Y is the 30-day old culture, it consistently shows a higher number of bacterial colonies compared to Strain X. This indicates that the 30-day old culture has a faster growth rate, regardless of the strain being used.

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• 15.

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?

• A.

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

• B.

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

• C.

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

• D.

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

D. Placing another piece of bread in a closed Petri dish on the countertop
Explanation
The best comparison for this experiment would be placing another piece of bread in a closed Petri dish on the countertop. This is because the student is testing the effect of temperature on mold growth, so it is important to have a control group that is exposed to the same conditions as the experimental group (bread in the refrigerator), but without the variable being tested (temperature). By placing the bread in a closed Petri dish on the countertop, it ensures that both the experimental and control groups are in the same environment, but only the experimental group is exposed to the colder temperature in the refrigerator.

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• 16.

What key factor distinguishes organic compounds from inorganic compounds?

• A.

Organic compounds contain carbon.

• B.

Organic compounds contain hydrogen.

• C.

Organic compounds provide energy for cells.

• D.

Organic compounds are the building blocks of cells.

A. Organic compounds contain carbon.
Explanation
The key factor that distinguishes organic compounds from inorganic compounds is the presence of carbon. Carbon is the fundamental element that is found in all organic compounds, while inorganic compounds do not contain carbon. Carbon forms the backbone of organic molecules, allowing for the vast diversity and complexity of organic compounds. This characteristic of carbon allows organic compounds to exhibit unique properties and participate in various chemical reactions that are essential for life processes.

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• 17.

The hydrolysis of which molecule provides energy for muscle contraction?

• A.

ATP

• B.

Glucose

• C.

Lactic acid

• D.

Oxygen

B. Glucose
Explanation
Glucose is the correct answer because during the process of muscle contraction, glucose is broken down through a series of chemical reactions in a process called glycolysis. This breakdown of glucose releases energy in the form of ATP (adenosine triphosphate), which is used as the primary source of energy for muscle contraction. Therefore, the hydrolysis of glucose provides the necessary energy for muscle contraction.

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• 18.

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

• A.

Digestion of macromolecules and old organelles

• B.

Detoxification of poisonous molecules within the cell

• C.

Harvesting of energy from organic molecules to make ATP

• D.

Processing and packaging of cellular materials prior to export

D. Processing and packaging of cellular materials prior to export
Explanation
The Golgi apparatus is responsible for processing and packaging cellular materials prior to export. It consists of smooth-sided channels or cisternae that modify, sort, and package proteins and lipids into vesicles for transport to their final destinations within or outside the cell. This activity is distinct from the other options provided, which are not directly related to the Golgi apparatus.

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• 19.

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

• A.

Electron transport chain

• B.

Fermentation

• C.

Glycolysis

• D.

Krebs cycle

A. Electron transport chain
Explanation
The electron transport chain is responsible for generating the majority of ATP during cellular respiration. This process occurs in the inner mitochondrial membrane and involves the transfer of electrons from electron carriers to oxygen. As the electrons pass through a series of protein complexes, energy is released and used to pump protons across the membrane. This creates an electrochemical gradient that drives the synthesis of ATP by ATP synthase. Overall, the electron transport chain is the final step in cellular respiration and produces the most ATP compared to glycolysis, fermentation, and the Krebs cycle.

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• 20.

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

• A.

Urine (pH 6.0)

• B.

Rainwater (pH 5.5)

• C.

Tomato juice (pH 2.0)

• D.

Gastric juice (pH 2.0)

A. Urine (pH 6.0)
Explanation
Urine has the greatest concentration of hydroxide ions (OH-) because it has a higher pH value of 6.0 compared to the other solutions. pH is a measure of the concentration of hydrogen ions (H+), and a higher pH indicates a lower concentration of H+ ions. Since hydroxide ions (OH-) are formed by the reaction of water with H+ ions, a higher pH means a lower concentration of H+ ions and therefore a higher concentration of OH- ions. Therefore, urine with a pH of 6.0 has a greater concentration of hydroxide ions compared to rainwater, tomato juice, and gastric juice with lower pH values.

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• 21.

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

• A.

-COOH

• B.

-NH2

• C.

-OH

• D.

-PO4

B. -NH2
Explanation
The functional group -NH2, also known as the amino group, is absent from monosaccharides, polysaccharides, fatty acids, and glycerol. Monosaccharides are simple sugars and do not contain an amino group. Polysaccharides are made up of multiple sugar units and also lack an amino group. Fatty acids, which are the building blocks of lipids, and glycerol, a component of triglycerides, do not have an amino group. The absence of -NH2 in these molecules distinguishes them from amino acids, which contain this functional group.

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• 22.

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

• A.

Carbohydrates

• B.

Fatty acids

• C.

Nucleic acids

• D.

Proteins

D. Proteins
Explanation
Papain is an enzyme found in papaya that belongs to the protease family. Proteases are responsible for breaking down proteins into smaller peptides and amino acids. Therefore, papain helps in the digestion of proteins.

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• 23.

How do enzymes speed up chemical reactions?

• A.

By reducing activation energy

• B.

By reducing energy produced by the reaction

• C.

By increasing activation energy

• D.

By increasing energy produced by the reaction

A. By reducing activation energy
Explanation
Enzymes speed up chemical reactions by reducing the activation energy required for the reaction to occur. Activation energy is the energy needed to start a chemical reaction. Enzymes lower this energy barrier by binding to the reactant molecules and bringing them closer together, making it easier for them to collide and react. This allows the reaction to proceed more rapidly, ultimately increasing the rate of the chemical reaction.

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• 24.

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

• A.

Cell wall

• B.

Chloroplast

• C.

DNA

• D.

Ribosome

B. Chloroplast
Explanation
The presence of chloroplast indicates that cells are photosynthetic bacteria. Chloroplasts are organelles found in plant cells and some bacteria that are responsible for photosynthesis, the process by which plants convert sunlight into energy. Therefore, if cells do not have chloroplasts, it indicates that they are not capable of photosynthesis and are not photosynthetic bacteria.

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• 25.

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?

• A.

Endoplasmic reticulum

• B.

Golgi apparatus

• C.

Nucleus

• D.

Ribosome

D. Ribosome
Explanation
Cyclohexamide acts on the ribosome. Ribosomes are responsible for protein synthesis in cells. By adding cyclohexamide, which is an inhibitor of protein synthesis, Naomi is able to observe the formation of short incomplete segments of proteins in the cells. This suggests that the ribosomes are being affected by the cyclohexamide, leading to the production of incomplete proteins.

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• 26.

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?

• A.

The solution is hypertonic to the cell.

• B.

The solution is hypotonic to the cell.

• C.

The solution and the cell have equal concentrations of solutes.

• D.

The solution and the cell have equal concentrations of water.

B. The solution is hypotonic to the cell.
Explanation
The most likely explanation for the cell's gain in mass is that the solution is hypotonic to the cell. In a hypotonic solution, the concentration of solutes is lower outside the cell compared to inside the cell. As a result, water moves into the cell by osmosis, causing it to swell and gain mass.

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• 27.

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?

• A.

Into the cell through the channel protein

• B.

Into the cell through the phospholipid bilayer

• C.

Out of the cell through the channel protein

• D.

Out of the cell through the phospholipid bilayer

A. Into the cell through the channel protein
Explanation
The molecules move into the cell through the channel protein. The diagram shows a cell membrane composed of a phospholipid bilayer with a channel protein. Facilitated diffusion is a process that allows molecules to pass through a cell membrane with the help of specific channel proteins. Therefore, the molecules in this case will move into the cell through the channel protein.

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• 28.

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

• A.

• B.

Pyruvate and ATP

• C.

• D.

Explanation
During glycolysis, glucose is broken down into pyruvate molecules. These pyruvate molecules are then used as substrates in both the aerobic and anaerobic pathways of cellular respiration. NADH is also produced during glycolysis as a result of the oxidation of NADH to NAD+. Both pyruvate and NADH are essential for the subsequent steps of cellular respiration to occur, making them the required products of glycolysis for both aerobic and anaerobic respiration. ATP is also produced during glycolysis, but it is not specifically required for the pathways to proceed.

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• 29.

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

• A.

Lactic acid and ATP

• B.

Oxygen and lactic acid

• C.

Carbon dioxide and ATP

• D.

Oxygen and carbon dioxide

C. Carbon dioxide and ATP
Explanation
During yeast respiration, glucose is broken down in the absence of oxygen, leading to the production of ethanol, carbon dioxide, and ATP. The presence of ethanol in the yeast culture indicates that glucose fermentation has occurred. Carbon dioxide is also produced as a byproduct of this process. ATP is generated through the breakdown of glucose and is used as a source of energy by the yeast cells. Therefore, the yeast culture contains carbon dioxide and ATP.

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• 30.

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

• A.

2, 4, 3, 1

• B.

2, 3, 4, 1

• C.

3, 2, 1, 4

• D.

3, 1, 2, 4

A. 2, 4, 3, 1
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

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• 31.

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

• A.

It increases by a factor of 2.

• B.

It increases by a factor of 100.

• C.

It decreases by a factor of 2.

• D.

It decreases by a factor of 100.

D. It decreases by a factor of 100.
Explanation
When the pH in the stomach increases from 2 to 4, it means that the solution becomes less acidic. pH is a logarithmic scale, so each unit represents a tenfold difference in acidity. Therefore, an increase of 2 units in pH corresponds to a decrease in hydrogen ion concentration by a factor of 100.

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• 32.

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?

• A.

Antacids break the covalent bonds within pepsin.

• B.

Pepsin dissolves antacids in the gastric juice.

• C.

The active site of pepsin changes shape.

• D.

The concentration of pepsin increases.

C. The active site of pepsin changes shape.
Explanation
When the pH of the stomach increases due to the use of antacids, the active site of pepsin, which is responsible for binding and breaking down proteins, undergoes a conformational change. This change in shape of the active site makes it less effective in binding to and digesting proteins, thus reducing the efficiency of protein digestion.

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• 33.

During aerobic cellular respiration, where do ATP molecules form?

• A.

Cytoplasm only

• B.

Mitochondrial matrix only

• C.

Mitochondrial matrix and inner mitochondrial membrane only

• D.

Cytoplasm, mitochondrial matrix, and outer mitochondrial membrane

C. Mitochondrial matrix and inner mitochondrial membrane only
Explanation
During aerobic cellular respiration, ATP molecules form in the mitochondrial matrix and inner mitochondrial membrane. This is because the mitochondrial matrix is where the Krebs cycle occurs, which produces high-energy molecules that are used to generate ATP through oxidative phosphorylation in the inner mitochondrial membrane. The cytoplasm does not directly produce ATP molecules during aerobic cellular respiration. The outer mitochondrial membrane is not directly involved in ATP production, as its main function is to separate the mitochondria from the rest of the cell.

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• 34.

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 CO2 under dark conditions?

• A.

CO2 production requires light.

• B.

Cellular respiration is taking place.

• C.

Chlorella is actively photosynthesizing.

• D.

Glucose production in the dark requires less CO2.

B. Cellular respiration is taking place.
Explanation
In dark conditions, Chlorella cannot perform photosynthesis due to the absence of light. As a result, it relies on cellular respiration to generate energy. During cellular respiration, CO2 is released as a byproduct. Therefore, under dark conditions, there is a negative uptake (release) of CO2 because Chlorella is actively undergoing cellular respiration.

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• 35.

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

• A.

Purine bases

• B.

Pyrimidine bases

• C.

Type of sugar

• D.

Attached proteins

A. Purine bases
Explanation
DNA and RNA both contain purine bases, which are a type of nitrogenous base. Purine bases include adenine (A) and guanine (G). These bases are responsible for the genetic information carried by DNA and RNA. Therefore, the structure of purine bases is similar in both DNA and RNA.

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• 36.

What occurs during metaphase I of meiosis?

• A.

Centromeres of replicated chromosomes line up along the cellâ€™s equator.

• B.

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

• C.

Homologous chromosome pairs line up along the cellâ€™s equator.

• D.

Homologous chromosomes move toward opposite poles of the cell.

C. Homologous chromosome pairs line up along the cellâ€™s equator.
Explanation
Metaphase I = homologous chromosomes are pulled to the middle of the cell

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• 37.

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

• A.

They produce fertile offspring.

• B.

They inhabit the same general area.

• C.

Their outward appearance is similar.

• D.

They consume the same type of diet.

A. They produce fertile offspring.
Explanation
The statement "They produce fertile offspring" most likely indicates that the two populations of animals are the same species. This is because the ability to produce fertile offspring is a key characteristic of a species. If two populations can successfully mate and produce offspring that can also reproduce, it suggests that they share enough genetic similarity to be considered the same species. The other statements, such as inhabiting the same area, having a similar appearance, or consuming the same type of diet, do not necessarily indicate that the populations are the same species.

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• 38.

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.

• A.

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

• B.

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

• C.

Persons A and B have identical amino acid sequences.

• D.

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

A. Lys in Person A is replaced with Glu in Person B.
Explanation
The given answer correctly states that the difference in the mRNA sequences between Person A and Person B results in a replacement of Lysine (Lys) with Glutamic acid (Glu) in the resulting protein. This is because the codon for Lysine (AAA) in Person A's mRNA sequence is changed to the codon for Glutamic acid (GAG) in Person B's mRNA sequence due to the difference in a single nucleotide. Therefore, the amino acid sequence of the resulting protein is affected, leading to the replacement of Lysine with Glutamic acid.

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• 39.

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

• A.

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

• B.

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

• C.

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

• D.

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

C. A tall prurple-flowered pea plant and a short white-flowered pea plant are crossed, producing offspring including tall white-flowered pea plants.
Explanation
This example best illustrates Mendel's law of independent assortment because it shows the inheritance of two different traits (tallness and flower color) that are independently inherited. The fact that the offspring include tall white-flowered pea plants indicates that the genes for these traits are segregating independently, as predicted by Mendel's law.

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• 40.

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

• A.

• B.

Methylation of some regions of DNA prevents transcription.

• C.

Mutations change certain RNA sequences.

• D.

Removal of exons from RNA prevents translation into protein.

B. Methylation of some regions of DNA prevents transcription.
Explanation
The regulation of gene expression leads to cell specialization because methylation of certain regions of DNA prevents transcription. Methylation is a process where methyl groups are added to the DNA molecule, which can inhibit the binding of transcription factors and RNA polymerase to the DNA, thus preventing the transcription of specific genes. This allows cells to selectively activate or deactivate certain genes, leading to the development of specialized cell types with different functions and characteristics.

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• 41.

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

• A.

Carrier

• B.

Heterozygous

• C.

Homozygous dominant

• D.

Homozygous recessive

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

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• 42.

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

• A.

All 3 black offspring

• B.

Exactly 2 of the black offspring Exactly 2 of the black offspring Exactly 2 of the black offspring Exactly 2 of the black offspring

• C.

Both albino offspring

• D.

Both parents

D. Both parents
Explanation
Both parents must be heterozygous for the trait because they produced both black and albino offspring. If both parents were homozygous for black fur, then all of their offspring would also have black fur. However, since they produced albino offspring, it indicates that at least one of the parents carries the recessive allele for albinism. Therefore, both parents must be heterozygous for the trait.

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• 43.

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?

• A.

Co-dominant

• B.

Dominant

• C.

Recessive

• D.

C. Recessive
Explanation
Round eye shape is a recessive trait because Jeanine inherited 2 alleles for round eye shape and has round eye shape, while her brother inherited 1 allele for round eye shape and 1 allele for almond eye shape and has almond eye shape. This indicates that the almond eye shape allele is dominant over the round eye shape allele, and round eye shape is only expressed when an individual has two copies of the recessive allele.

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• 44.

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 (XBXb) and a male (XBY)?

• A.

Color-blind daughter

• B.

Color-blind son

• C.

Daughter with normal color vision

• D.

Son with normal color vision

A. Color-blind daughter
• 45.

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

• A.

They ate heterotrophs.

• B.

They produced spores.

• C.

• D.

They reproduced asexually.

C. They made their own food.
Explanation
Early autotrophs had an advantage over early heterotrophs because they were capable of producing their own food through photosynthesis or chemosynthesis. This ability allowed them to obtain energy directly from the environment, without relying on consuming other organisms. In contrast, early heterotrophs had to rely on consuming other organisms for their energy needs. By being able to produce their own food, autotrophs had a more reliable and sustainable source of energy, which gave them a competitive edge in their environment.

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• 46.

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?

• A.

8/16

• B.

4/16

• C.

2/16

• D.

1/16

B. 4/16
Explanation
In a dihybrid cross, the genotype of the F1 individuals is AaBb x AaBB. When these individuals are crossed, the possible genotypes in the F2 generation are AABb, AaBb, AABb, and AaBB. Out of these four possible genotypes, only one genotype (AaBb) has the combination of alleles AaBb. Therefore, the expected ratio of AaBb individuals in the F2 generation is 1 out of 4, which is equivalent to 4/16.

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• 47.

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?

• A.

AA or Aa

• B.

AA

• C.

Aa

• D.

Aa

C. Aa
Explanation
The question is asking for the genotype of Individual 1 in the diagram. The diagram is not provided, so we cannot determine the specific alleles present in Individual 1. However, we know that Alkaptonuria is determined by 2 alleles at 1 locus. Therefore, the genotype for Individual 1 could be either AA or Aa, as both of these genotypes have the potential to carry the alleles responsible for Alkaptonuria.

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• 48.

Which example best illustrates the process of natural selection?

• A.

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

• B.

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

• C.

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

• D.

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

B. Giraffe necks varied in length, and the shorter-necked giraffes were at a disadvantage.
Explanation
The example that best illustrates the process of natural selection is when giraffe necks varied in length, and the shorter-necked giraffes were at a disadvantage. This scenario demonstrates the key elements of natural selection, where there is variation in a population and certain traits provide a disadvantage or advantage in survival and reproduction. In this case, the shorter-necked giraffes have a harder time reaching food, which reduces their chances of survival and passing on their genes. As a result, over time, the population will have a higher proportion of giraffes with longer necks, as they are better adapted to their environment.

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• 49.

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?

• A.

Artificial

• B.

Directional

• C.

Disruptive

• D.

Stabilizing

B. Directional
Explanation
In this cricket population, the number of males with flat wings has increased over generations. This change in the population is due to the selective pressure imposed by the parasitic flies. The flies detect and kill male crickets that produce mating songs by rubbing their curved wings together. As a result, the males with flat wings, who do not sing, have a higher survival rate and are able to mate with females. This leads to a directional selection, where the population is shifting towards a specific trait (flat wings) that provides a selective advantage in the presence of the parasitic flies.

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• 50.

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

• A.

Smaller horses bred with larger horses, creating hybrids.

• B.

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

• C.

Larger horses consumed the food supply of the smaller horses.

• D.

Larger horses produced a slightly greater number of surviving offspring.