EOC Biology Practice Test #3 Review Questions Answers

Last Updated on March 20, 2026

EOC Biology Practice Test #3 Review Questions and Answers: This free test is designed to prepare students for their final biology exams. It is specifically tailored for high school students who have completed a year-long biology course, providing them with an opportunity to gauge their understanding of key concepts, principles, and processes learned throughout the course.

The practice test consists of 40 multiple-choice questions covering a wide range of biology topics, including cell biology, genetics, evolution, ecology, and physiology. Experienced educators have carefully crafted each question to ensure alignment with state and national curriculum standards.

EOC Biology Practice Test #3

Practice Test #3

293

EOC Biology Practice Test #3

EOC Biology Practice Test #3
Total Items: 40
Time Limit: 60 minutes
Score: You can find your test score as a percentage at the end of the test!

In pea plants, the allele for white flowers is recessive to the allele for purple flowers. In a generation of pea plants, 89 plants produced purple flowers and 31 plants produced white flowers. Which of the following is the best conclusion you can make about the parent plants of this generation?

A. Both parent plants are heterozygous for flower color.

B. Both parent plants were homozygous with purple flowers.

C. One parent plant had white flowers and the other was heterozygous for flower color.

D. One parent plant was heterozygous for flower color and the other was homozygous with purple flowers.

When an organism has more than 10 fingers or toes, the condition is known as polydactylism. Although polydactylism is rare, it is a dominant trait. If two cats that are heterozygous for polydactylism mate and have a litter with a total of 12 kittens, how many of them would you expect to have more than 10 fingers or toes

The allele for brown eyes is dominant to the allele for blue eyes. Which of the following best explains how two brown-‐eyed parents could produce a blue-‐eyed child?

A. Each parent must be carrying the recessive allele for blue eyes.

B. Eye color is a sex-‐linked trait and male children could have only the allele for blue eyes.

C. Mutations after fertilization could alter gene sequences and change alleles.

D. One parent must have had only blue-‐eyed parents.

Some organisms are able to reproduce asexually through mitosis, while cells of organisms that reproduce sexually will undergo meiosis to produce gametes. Which process do you predict would be most beneficial to a species during a drastic change in environmental conditions?

A. Meiosis; it results in more daughter cells, which increases the population of the species

B. Meiosis; it results in more genetic variation, which would help ensure the species will survive.

C. Mitosis; it results in more genetic mutations, which may be advantageous to the species.

D. Mitosis; it results in more offspring in a short time, which increases the odds that some will survive.

Which of the following best describes how the process of crossing over during meiosis leads to an increase in genetic diversity?

A. During prophase I, DNA replication takes place, and homologous chromosomes trade places with each other before lining up in preparation for metaphase.

B. During prophase I, DNA segments are exchanged between homologous chromosomes, resulting in different combinations of alleles.

C. During prophase II, fragments of DNA break off of chromosomes and attach to the ends of other chromosomes, resulting in different gene sequences.

D. During prophase II, sister chromatids separate from each other, and as they travel to opposite ends of the cell, DNA segments of nearby chromosomes are exchanged

Which of the following best explains why meiosis results in greater genetic diversity than mitosis?

A. After meiosis, daughter cells are diploid and have twice as much genetic material, which can be divided in many more possible combinations

B. After meiosis, haploid daughter cells are fertilized, which doubles their number of chromosomes and increases the number of possible genes.

C. During meiosis, chromosomes assort themselves independently of each other, which allows for more different possible combinations of chromosomes.

D. During meiosis, more daughter cells are produced, which increases the likelihood that fertilization will occur.

Which of the following best compares the processes of mitosis and meiosis?

A. Mitosis involves one division cycle and results in diploid daughter cells, while meiosis consists of two division cycles and results in haploid gametes.

Mitosis involves one division cycle and results in haploid gametes, while meiosis consists of two division cycles and results in diploid daughter cells.

Mitosis involves two division cycles and results in diploid daughter cells, while meiosis consists of one division cycle and results in haploid gametes.

Mitosis involves two division cycles and results in haploid gametes, while meiosis consists of one division cycle and results in diploid daughter cells.

Which equation describes what happens in photosynthesis?

A. C₆ H₁₂ O₆ + H₂ 0 → CO₂ + energy

B. 6CO₂ + 6H₂O + energy → C₆H₁₂O₆ + 6O₂

C. C₆H₁₂O₆ + 6O₂→ 6CO₂+ 6H₂O + energy

D. CO₂+ O₂ + H₂0 + energy → CH₂O₅

What are the reactants for cellular respiration?

A. H₂O and O₂

B. Glucose and O₂

C. Glucose and CO₂

D. H2₂ and CO₂

Oxygen is a product of photosynthesis. The primary role of this oxygen in cellular respiration is to

A. yield energy in the form of ATP as it is passed down the respiratory chain.

B. act as an acceptor for electrons and hydrogen, forming water.

C. combine with carbon, forming CO 2 .

D. combine with lactate, forming pyruvate.

Which of the following best compares the membranes found in different types of cells?

A. Animal cells have cell membranes and cell walls, but plant cells do not have cell membranes.

B. Animal cells have membrane-‐bound organelles, while plant cells carry out the functions necessary for life in the cytoplasm.

C. Prokaryotes have only cell membranes, while eukaryotes have both cell walls and cell membranes.

D. Prokaryotes and eukaryotes both have cell membranes, but eukaryotes also have membrane-‐bound organelles.

Which of the following best compares the structures found in plant cells and animal cells?

A. Animal cells contain cell walls and a large central vacuole while plant cells contain cell membranes and many small vacuoles.

B. Animal cells do not contain chloroplasts, cell walls, or a large central vacuole while plant cells do.

C. Plant cells contain rough endoplasmic reticulum and a Golgi apparatus while animal cells contain smooth endoplasmic reticulum surrounded by lysosomes.

D. Plant cells have rigid cell walls and do not contain mitochondria or ribosomes while animal cells do.

Which statement best compares a eukaryote and a prokaryote?

A. Eukaryotes have a cell wall, while prokaryotes have a cell membrane.

B. Eukaryotes have membrane-‐bound organelles, while prokaryotes have few specialized structures.

C. Eukaryotes use active transport to move substances across the cell membrane, while prokaryotes use facilitated diffusion.

D. Eukaryotes use flagella to move themselves through substances, while prokaryotes are not able to move.

Which of the following characteristics defines a cell as a eukaryote?

A. Being able to move

B. Being able to reproduce

C. Having a nucleus

D. Having ribosomes

Early elements of the cell theory followed soon after the development of Hooke's light microscope. What does this relationship suggest about the evolution of the cell theory since Hooke?

A. Improvements in technology are closely related to changes in the cell theory

B. Isolated scientists contributed pieces of the cell theory to form the whole.

C. Progress on the cell theory was delayed by a lack of technological progress.

D. Scientists needed to focus less on cells and more on microscope development

Which of the following best summarizes why the technological invention of microscopes was important to biology?

A. It allowed for development of the cell theory.

B. It created a means of funding for cell research.

C. It created public interest and support for research.

D. It proved that cells could form spontaneously.

Some proteins catalyze biochemical reactions. If a genetic defect prevented a protein catalyst from being produced, which of the following do you predict would happen in the cell?

A. The cell would find a different type of protein to catalyze the reaction.

B. The reaction the protein catalyzes would proceed very slowly or not at all.

C. The reaction the protein catalyzes would only occur in some places in the cell

D. The reverse reaction of the one the protein catalyzes would begin to proceed.

Which of the following best describes the difference between the functions of nucleic acids and enzymes?

A. Nucleic acids are used as the building blocks of proteins, while enzymes are used as the building blocks of phospholipids

B. Nucleic acids contain the genetic code for protein synthesis, while enzymes catalyze chemical reactions.

C. Nucleic acids inhibit biochemical reactions, while enzymes provide structural support in cells.

D. Nucleic acids transmit signals that begin biochemical processes, while enzymes convert carbohydrates into lipids and proteins.

Which of the following best compares the structures of lipids and carbohydrates?

A. Both are made up of monosaccharide monomers, but lipids are hydrophobic and carbohydrates are hydrophilic.

B. Both consist of carbon, hydrogen, and oxygen, but carbohydrates have repeating structural units and lipids do not

C. Both contain carbon and hydrogen, but carbohydrates also contain oxygen and lipids contain nitrogen.

D. Both have a carbon backbone, but lipids also have an amino group and carbohydrates have a carboxylic acid group

A variety of organic molecules have been found in meteorites that have landed on Earth, including individual amino acids and lipid molecules. To date, however, no microspheres have been found on these meteorites. Why is it unlikely that microspheres will ever be found on a meteorite even though lipids can form in them?

A. Amino acids cannot form the enzymes needed to construct microspheres in a meteorite.

B. Any microspheres that formed would be destroyed by the radiation in space.

C. Groups of lipids will only form into microspheres when they are in liquid water.

D. Individual lipids can only begin to form microspheres when oxygen is present.

Assume a group of scientists has managed to set up an experiment simulating the conditions of early Earth that resulted in a cell with DNA using RNA to produce proteins from amino acids as modern cells do. What conclusion could they draw from this experiment?

A. It is possible for a cell similar to a modern cell to form under the conditions of the experiment.

Modern cells developed from inorganic compounds in the conditions that existed on early Earth.

The conditions of their experiment exactly replicated the conditions found on early Earth.

The way modern cells function is the only way a cell could be constructed and survive.

In which of the following circumstances would it be most likely for large organic molecules to form during a laboratory experiment?

A. If amino acids and nucleic acids both formed

B. If oxygen were slowly added as the experiment progressed

C. If RNA segments that could act as catalysts formed

D. If the mixture were repeatedly heated and cooled

Water has a much higher specific heat than most other covalent compounds. What do you predict might happen if water had a low specific heat instead?

A. Flooding would occur and animals would be forced to migrate.

B. Harmful organisms living in water would reproduce at a rapid rate.

C. Organisms that are sensitive to changes in temperature would die.

D. Plants would not have enough water to effectively carry out photosynthesis.

Which of the following best describes a result of the polar nature of water molecules?

A. Ionic compounds dissolve easily in water.

B. The volume of water decreases by nearly half when it is frozen.

C. Water molecules repel each other.

D. Water molecules repel most other substances.

To help patients replenish bodily fluids quickly during an illness, doctors need to understand how cells behave in their environment. Doctors have confidence in what they know about how cells behave because

A. cell theory has been tested, refined, and observed to be true over hundreds of years

B. large medical institutions have conducted their own experiments justifying cell theory

C. the basics of cell theory have not changed much since the original experiments

D. what we know about cell theory has been published in reputable journals

Scientific law and a scientific theory are similar in that both

A. are based on what we expect to happen based on natural history

B. describe the events that can be observed in nature

C. explain why events and conditions occur as they do in the natural world

D. represent a large amount of scientific investigation and evidence

A student is conducting an investigation to determine the effect of temperature on the metabolism of yeast (Saccharomyces cerevisiae). Yeast and sugar are added to water, the gas produced is captured, and its volume is recorded. Which variables should be held constant during this investigation?

A. Mass of sugar and water temperature

B. Mass of yeast and mass of sugar

C. Volume of gas and water temperature

D. Volume of gas and mass of yeast

Based on your knowledge of scientific investigations, which stage of scientific investigation did the invention of the microscope significantly advance?

A. Communicating the results of experimentation

B. Gathering the data for the investigation

C. Generating explanations of phenomena

D. Planning the investigation and experimentation

If a company claims that its product has been proven scientifically, which of the following should have taken place if the results are to be considered reliable?

A. The company should have held discussions with leading industry scientists.

B. Technology should have been used in both the gathering of data and data analysis.

C. Results should have been peer reviewed and repeated producing the same findings.

D. The results of the investigation should have been published in popular magazines.

Many insects, such as mosquitoes and dragonflies, spend their juvenile stage as aquatic larvae before becoming winged and airborne adults. Most years, these insects are extremely abundant in the Arctic tundra in summer. What might account for this?

A. Adult insects spend the long Arctic winter laying thousands of eggs under the ice of frozen ponds.

B. Many insects migrate long distances to take advantage of good breeding areas in the tundra.

C. Pools of water which make good breeding areas are plentiful in summer as the permafrost melts.

D. Summer rains in the Arctic tundra replenish breeding ponds that dried up during the winter.

Which of the following describes how the amount of energy changes as it flows from one trophic level to the next in the marine food web shown below?

A. Energy increases as it is transferred from penguins to seals, since seals are more massive than penguins.

B. Energy decreases as it is transferred from zooplankton to fish, since zooplankton are producers and fish are consumers.

C. When krill consume phytoplankton, about 90 percent of the phytoplankton’s energy is transferred to the krill.

D. When sea birds consume fish, about 10 percent of the fish’s energy is transferred to the sea birds.

Which of the following correctly traces the energy transfer through the trophic levels in the marine food web shown below?

A. Fish -> sea birds -> seal -> penguin

B. Phytoplankton -> krill -> fish -> seal

C. Seal -> sea birds -> fish -> phytoplankton

Zooplankton -> phytoplankton -> krill -> squid

Which of the following best explains the difference in the amount of energy available in each tropic level of this food web?

A. There is more available energy in the seal than there is in the phytoplankton

B. There is more available energy in the penguin than there is in the zooplankton

C. There is less available energy in the seal than there is in the phytoplankton

D. There is less available energy in the zooplankton than there is in the penguin

A cell is replicating its DNA. Part of the DNA strand reads A-‐C-‐C-‐G-‐T-‐A-‐C. The new strand built off this section reads T-‐G-‐G-‐A-‐A-‐T-‐G. What effect might this have when the DNA replicates in the future?

A. Cells having the new DNA version will look or operate differently from cells with the original DNA.

B. Only the sections of DNA without mistakes will be used in the future so the DNA strand will shorten.

C. The DNA will be exactly like the original since only the original strand of DNA is used as a template.

D. When the new strand is used as a template the strand built from it will differ from the original DNA

A codon is a sequence of three nucleotides that code for an amino acid. If the DNA sequence shown here goes through transcription and translation, how many amino acids will result from this sequence?

Why do cells need both tRNA and mRNA

A. Only tRNA bends into a shape that can carry specific amino acids

B. Only mRNA can be used to repair mistakes in the DNA sequence.

C. The tRNA in used on the ribosomes and the mRNA is used in the nucleus

D. The mRNA brings information to the nucleus for the tRNA to use

If a snake species were introduced to an ecosystem where it had no natural predators, what long-‐term effect do you predict the snakes would have on the population dynamics of the ecosystem?

A. They would breed with native snake species, resulting in an increase in biodiversity in the ecosystem.

B. They would compete with native snake species for resources, causing a decline in native snake populations and possibly extinction

C. They would form mutualistic relationships with native snakes, since they would occupy the same niche in the ecosystem.

D. They would serve as a food source for predators of native snakes, causing an increase in native snake populations.

Which of the following describes how an abiotic factor can impact the population dynamics in an ecosystem?

A. A parasite that invades a host can reproduce and cause a decline in the host species population.

B. Organisms that compete for the same resources will keep each other from overpopulating.

C. Predators will prevent herbivores from depleting the plants and other resources in an ecosystem

D. Seasonal variations in temperature can cause some of the individuals in a population to die.

Rainbow trout need at least 6.0 mg/L of dissolved oxygen to survive. Biologists are trying to reestablish rainbow trout in a mountain stream but the stream only has 5.5 mg/L of dissolved oxygen. Which of the following would be the most useful to encourage the development of the rainbow trout population?

A. Create more bends in the stream to allow the water to slow down.

B. Cut down trees along the stream to allow more sunlight to warm the water

C. Pull out aquatic plants growing in the stream to allow oxygen to accumulate.

D. Remove dams along the stream to allow the water to flow faster

A population of rodents becomes stranded on a remote island. Eventually, the population reaches the island’s carrying capacity. At this point, the birth and death rates are

A. relatively equal

B. crashing.

C. density dependent.

D. density independent

Your score is

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