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100+ Free MCAS Biology Practice Questions

Pass your MCAS High School Biology Test exam on the first try — instant access, no signup required.

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An experiment tests how light intensity affects the rate of photosynthesis in a water plant by counting oxygen bubbles produced per minute. In this experiment, the rate of photosynthesis (bubbles per minute) is the

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Key Facts: MCAS Biology Exam

The MCAS High School Biology test is Massachusetts's free state Biology assessment that measures mastery of the 2016 STE Curriculum Framework across Molecules to Organisms, Heredity, Evolution, and Ecology, using selected-response and constructed-response items over two sessions, with results reported in four achievement levels.

Sample MCAS Biology Practice Questions

Try these sample questions to test your MCAS Biology exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1Which type of bond holds the two complementary strands of a DNA double helix together?
A.Hydrogen bonds between paired nitrogenous bases
B.Peptide bonds between amino acids
C.Covalent bonds between phosphate groups
D.Ionic bonds between sugar molecules
Explanation: The two strands of DNA are held together by hydrogen bonds between complementary base pairs: adenine pairs with thymine (two hydrogen bonds) and guanine pairs with cytosine (three hydrogen bonds). These relatively weak bonds allow the strands to separate during replication and transcription.
2During photosynthesis, plants convert carbon dioxide and water into glucose and oxygen using energy from sunlight. In which organelle does this process occur?
A.Chloroplast
B.Mitochondrion
C.Nucleus
D.Ribosome
Explanation: Photosynthesis takes place in the chloroplast, which contains the green pigment chlorophyll that absorbs light energy. The light reactions occur in the thylakoid membranes and the Calvin cycle occurs in the stroma.
3A scientist observes that an enzyme stops functioning when the solution is heated to a high temperature. Which explanation best accounts for this loss of function?
A.The high temperature denatured the enzyme, changing its shape
B.The high temperature increased the enzyme's concentration
C.The high temperature converted the enzyme into a substrate
D.The high temperature made the enzyme more specific
Explanation: Enzymes are proteins whose function depends on their three-dimensional shape, especially the active site. High temperatures disrupt the bonds that maintain this shape, denaturing the enzyme so the substrate no longer fits the active site, which stops catalysis.
4Which statement correctly describes the relationship between cellular respiration and photosynthesis?
A.Both processes only occur in plant cells
B.The products of photosynthesis are the reactants of cellular respiration
C.Both processes release oxygen as a waste product
D.Cellular respiration uses sunlight as its energy source
Explanation: Photosynthesis produces glucose and oxygen, which are the reactants used in cellular respiration. In turn, respiration produces carbon dioxide and water, the reactants of photosynthesis, linking the two processes in a cycle of matter and energy.
5The cell membrane is described as selectively permeable. What does this mean?
A.It allows all substances to pass through equally
B.It blocks all substances from entering or leaving the cell
C.It controls which substances move into and out of the cell
D.It only allows water to pass through
Explanation: A selectively permeable membrane regulates the passage of materials, allowing some substances to cross while restricting others. This control is achieved through the phospholipid bilayer and embedded transport proteins, maintaining homeostasis inside the cell.
6A red blood cell is placed in a hypotonic solution. What is most likely to happen to the cell?
A.It will shrink as water leaves the cell
B.It will swell and may burst as water enters the cell
C.It will remain unchanged because no water moves
D.It will divide into two new cells
Explanation: In a hypotonic solution, the solute concentration outside the cell is lower than inside, so water moves into the cell by osmosis. The cell swells and, because red blood cells lack a rigid cell wall, may burst (lyse).
7Which of the following is the primary function of carbohydrates in living organisms?
A.Storing and transmitting genetic information
B.Serving as a major source of energy
C.Catalyzing chemical reactions
D.Forming the main component of cell membranes
Explanation: Carbohydrates such as glucose are a major and readily available source of energy for cells. They are broken down during cellular respiration to release the energy stored in their chemical bonds.
8What is the role of the sequence of nucleotides (codons) in a strand of messenger RNA (mRNA) during translation?
A.It determines the sequence of amino acids in a protein
B.It determines the number of chromosomes in a cell
C.It signals the cell to begin DNA replication
D.It controls the rate of cellular respiration
Explanation: During translation, ribosomes read mRNA codons (groups of three nucleotides), and each codon specifies a particular amino acid. The order of codons therefore determines the order of amino acids assembled into a polypeptide.
9In a pea plant, the allele for purple flowers (P) is dominant over the allele for white flowers (p). If two heterozygous plants (Pp) are crossed, what fraction of the offspring is expected to have white flowers?
A.0 (none)
B.1/4
C.1/2
D.3/4
Explanation: A cross between two heterozygotes (Pp x Pp) produces offspring in a genotypic ratio of 1 PP : 2 Pp : 1 pp. Only the pp genotype (1/4 of offspring) shows the recessive white-flower phenotype.
10Which process produces genetically identical daughter cells with the same number of chromosomes as the parent cell?
A.Meiosis
B.Mitosis
C.Fertilization
D.Crossing over
Explanation: Mitosis is the division of the nucleus that produces two daughter cells genetically identical to the parent cell, each with the same diploid chromosome number. It is used for growth, repair, and asexual reproduction.

About the MCAS Biology Exam

The MCAS High School Biology test is a Massachusetts state science assessment that measures how well students have learned the high school Biology standards in the April 2016 Massachusetts Science and Technology/Engineering (STE) Curriculum Framework. It is administered by the Department of Elementary and Secondary Education (DESE) as part of the Massachusetts Comprehensive Assessment System (MCAS). Most students take a computer-based version, with a paper-based version available as an accommodation. The test is built around four content reporting categories: Molecules to Organisms (about 35 percent), Heredity (about 20 percent), Evolution (about 20 percent), and Ecology (about 20 percent). Items are also coded to science practice categories covering investigations and questioning, mathematics and data, and evidence, reasoning, and modeling, and at least half of the items are dual-coded to a science practice. The test uses selected-response questions, including multiple-choice and multiple-select, along with constructed-response questions across two sessions. Results are reported on a scale and placed in four achievement levels. Following a November 2024 ballot measure, passing the high school MCAS is no longer required to earn a Competency Determination for graduation, though the test is still administered.

Questions

100 scored questions

Time Limit

Administered in two sessions; the test is not strictly timed, and students may take the time they reasonably need to complete each session.

Passing Score

Scores are reported in four achievement levels (Not Meeting, Partially Meeting, Meeting, and Exceeding Expectations); a scaled score of 500 marks the Meeting Expectations threshold.

Exam Fee

Free for students; the assessment is funded by Massachusetts and administered through public school districts. (Massachusetts Department of Elementary and Secondary Education (DESE), Student Assessment Services)

MCAS Biology Exam Content Outline

Approx. 35%

Molecules to Organisms

Cell structure and function, biochemistry and macromolecules, photosynthesis and cellular respiration, transport and homeostasis, and how body systems interact to sustain life (LS1).

Approx. 20%

Heredity

DNA structure and replication, transcription and translation, mitosis and meiosis, Mendelian inheritance and Punnett squares, mutations, and trait variation (LS3).

Approx. 20%

Evolution

Natural selection, adaptation, common ancestry, evidence for evolution, speciation, classification, and biodiversity (LS4).

Approx. 20%

Ecology

Energy flow and trophic levels, cycling of matter, population dynamics and carrying capacity, species interactions, and human impacts on ecosystems (LS2).

How to Pass the MCAS Biology Exam

What You Need to Know

  • Passing score: Scores are reported in four achievement levels (Not Meeting, Partially Meeting, Meeting, and Exceeding Expectations); a scaled score of 500 marks the Meeting Expectations threshold.
  • Exam length: 100 questions
  • Time limit: Administered in two sessions; the test is not strictly timed, and students may take the time they reasonably need to complete each session.
  • Exam fee: Free for students; the assessment is funded by Massachusetts and administered through public school districts.

Keys to Passing

  • Complete 500+ practice questions
  • Score 80%+ consistently before scheduling
  • Focus on highest-weighted sections
  • Use our AI tutor for tough concepts

MCAS Biology Study Tips from Top Performers

1Focus most heavily on Molecules to Organisms, since it makes up about 35 percent of the test, then review Heredity, Evolution, and Ecology, which are about 20 percent each.
2Master core cell and biochemistry ideas such as cell structure, enzymes, transport across membranes, photosynthesis, and cellular respiration.
3Practice genetics problems with Punnett squares, and understand DNA structure, transcription, translation, mutations, and how meiosis creates variation.
4Be ready to explain natural selection using evidence such as fossils, homologous structures, and shared DNA, and connect it to adaptation and biodiversity.
5Review ecology topics including energy flow through trophic levels, the carbon and nitrogen cycles, carrying capacity, and human impacts on ecosystems.
6Work through official DESE released MCAS Biology items and apply science practices by analyzing data tables, graphs, and diagrams rather than just memorizing facts.

Frequently Asked Questions

What is the MCAS High School Biology test?

It is a Massachusetts state science assessment administered by the Department of Elementary and Secondary Education (DESE) as part of the Massachusetts Comprehensive Assessment System (MCAS). It measures how well high school students have learned the Biology standards in the 2016 Massachusetts Science and Technology/Engineering Curriculum Framework.

What topics are on the MCAS Biology test?

The test covers four content reporting categories: Molecules to Organisms (cells, biochemistry, photosynthesis, respiration, and body systems), Heredity (DNA, genetics, and inheritance), Evolution (natural selection and biodiversity), and Ecology (energy flow, cycles of matter, and ecosystems).

How is the MCAS Biology test scored?

Scores are reported on a scale and placed into four achievement levels: Not Meeting Expectations, Partially Meeting Expectations, Meeting Expectations, and Exceeding Expectations. A scaled score of 500 marks the threshold of the Meeting Expectations level.

How is the test structured and how long is it?

The high school Biology test is given in two sessions that combine selected-response questions, including multiple-choice and multiple-select items, with constructed-response questions. Recent forms have included roughly 42 questions, about 21 per session, and the test is not strictly timed.

Is passing the MCAS Biology test required to graduate in Massachusetts?

No. Following a November 2024 ballot measure, the high school MCAS is no longer used to earn a Competency Determination for graduation. The test is still administered by the state, and students still demonstrate readiness primarily through required coursework.

Is the MCAS Biology test free?

Yes. The test is free to students because it is funded by Massachusetts and administered through public school districts as part of the Massachusetts Comprehensive Assessment System.