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MCAS Biochemistry questions

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Sample Questions
Feb 2016

ATP molecules in cells undergo a process called hydrolysis. The equation below represents this process.

ATP + H2O → ADP + Pi

( Pi = inorganic phosphate)

What always happens within cells as a result of ATP hydrolysis?

A. Water is produced.
B. Chemical energy is released.
C. Phosphorus atoms are used up.
D. Carbohydrate building blocks are formed.


An English doctor is given credit for developing the modern terrarium in the 1800s. The doctor kept some plants in a sealed glass jar containing soil and air. The plants survived in the sealed jar for four years. What two processes allowed the plants to cycle nutrients and survive in the sealed jar?

A. meiosis and fertilization
B. mutualism and commensalism
C. photosynthesis and cellular respiration
D. asexual reproduction and sexual reproduction


Scientists use satellite data to produce images such as the one below, showing the density of plants across Earth’s different land areas. Scientists study these images to determine how plant density changes during a year. They can then use this information to help predict carbon dioxide concentrations in the atmosphere in different locations and at different times of the year.

vegetation density map
Which of the following best explains why scientists can predict carbon dioxide concentrations from plant density data?

A. Plants add carbon dioxide to theatmosphere during germination.
B. Plants add carbon dioxide to the atmosphere during transpiration.
C. Plants remove carbon dioxide from the atmosphere during photosynthesis.
D. Plants remove carbon dioxide from the atmosphere during cellular respiration.


Which of the following are mainly cycled through the processes of photosynthesis and cellular respiration?

A. carbon and sulfur
B. carbon and oxygen
C. nitrogen and sulfur
D. nitrogen and oxygen


Some diseases decrease the activity of certain enzymes in the mitochondria of cells. Which of the following is the most direct result of this decreased enzyme activity?

A. The cells are not able to divide by mitosis.
B. The cells are not able to move water by diffusion.
C. The cells produce less ATP by cellular respiration.
D. The cells produce fewer sugars by photosynthesis.




Feb 2017 MCAS.

Some bacteria produce cellulase, a substance that speeds up the breakdown
of cellulose in plant cell walls. Cellulase is an example of which of the following?
A. a carbohydrate     B. an enzyme      C. a hormone      D. an organelle


Feb 2017 MCAS.  Protein pumps actively transport ions across a cell’s plasma membrane. What molecule directly supplies the energy required for this transport?

A. ATP        B. cholesterol        C. oxygen        D. tRNA


Spring 2017

Collagen is found in connective tissue throughout the human body. Collagen is made of three amino acid chains that are twisted around one another. Which of the following best explains why collagen is classified as a protein?

A. It is found in a tissue.
B. It is made up of amino acids.
C. It is made up of twisted chains.
D. It is found throughout the human body


Spring 2017

Which of the following is a characteristic that distinguishes
viruses from B. thetaiotaomicron and S. epidermidis?
A. Viruses lack mitochondria.
B. Viruses lack genetic material.
C. Viruses are unable to accumulate mutations.
D. Viruses are unable to reproduce outside of host cells.


Which of the following describes one way B. thetaiotaomicron helps in digestion?
A. It breaks down lipids into fatty acids.
B. It breaks down proteins into amino acids.
C. It breaks down polysaccharides into simpler sugars.
D. It breaks down nucleic acids into nitrogenous bases.


A scientist is trying to determine how closely related two species of plants are. Which of the following would be most useful for the scientist to compare?

A. the root depths of the plants
B. the leaf structures of the plants
C. the genetic sequences of the plants
D. the nutrient requirements of the plants


Spring 2017 . Which of the following best describes how enzymes affect chemical reactions?

A. They speed up the rate of reactions.
B. They change the reactants into ions.
C. They dissolve the products of
D. They take the place of one of the


The diagram below shows a chloroplast and some of the components of the
reactions that occur in chloroplasts.

Which of the following is a product of the reactions that take place in a chloroplast?

A. hydrogen gas
B. nitrate
C. oxygen gas
D. protein


In which of the following ways does the plasma membrane [lipid bilayer] regulate the entry of molecules into a cell?

A. The membrane allows only certain molecules to move into the cell.
B. The membrane destroys most molecules so that they do not enter the cell.
C. The membrane changes only certain molecules into ions before they move into the cell.
D. The membrane allows most molecules to transfer energy to the cell without entering the cell.


Spring 2017

In a cell, a phosphate group is added to ADP to form ATP. Which of the
following best describes the importance of the formation of ATP?

A. It connects amino acids.
B. It provides energy for the cell.
C. It creates new polysaccharides.
D. It catalyzes chemical reactions.


The energy that primary consumers use for metabolism and growth comes
directly from which of the following sources?

A. organic compounds synthesized by producers
B. organic compounds released by decomposers
C. organic compounds stored in carnivore tissues
D. organic compounds absorbed from the environment


Which of the following statements describes a difference between
photosynthesis and cellular respiration in plants?

A. Photosynthesis occurs only during the day, whereas cellular respiration occurs only at night.
B. Photosynthesis involves only one reaction, whereas cellular respiration involves many steps.
C. Photosynthesis occurs only in cells containing chlorophyll, but cellular respiration occurs in all cells.
D. Photosynthesis converts light energy into chemical energy, but cellular respiration converts light energy into heat energy


During the processes of respiration and photosynthesis in plant cells, what are the three primary elements that cycle between the mitochondria and chloroplasts?

A. carbon, iron, and sulfur
B. hydrogen, carbon, and oxygen
C. carbon, nitrogen, and phosphorus
D. hydrogen, oxygen, and potassium


Which of the following happens when a phosphate-phosphate bond in an ATP molecule is broken?

A. Energy is released in a cell.
B. Light energy is absorbed in a plant cell.
C. Water is transported into an animal cell.
D. Lysosome contents are released in a cell.


Some cell types contain thousands of mitochondria. These cells are likely
to use large amounts of which of the following?

B. carbon dioxide
D. nitrogen


The table below provides information about the composition and function of four
important molecules in living organisms.

MCAS molecule biochemistry function
Which of the molecules in this table is a carbohydrate?
A. 1
B. 2
C. 3
D. 4


Question 23 is an open-response question.
• Show all your work (diagrams, tables, or computations) in your Student Answer Booklet. If you do the work in your head, explain in writing how you did the work. Write your answer to question 23 in the space provided in your Student Answer Booklet.

●23 Catalase is an enzyme that protects cells from damage by helping convert the toxin hydrogen peroxide (H O2 2) into water (H O2 ) and oxygen (O2). A student is investigating how different pH values and different temperatures affect catalase activity. The table below shows the student’s data.

Catalase experiment data

a. Identify the test tube that most likely has physical conditions similar to the conditions in human cells. Explain your answer.

b. Describe how catalase activity changes as pH decreases. Use data from the table to support your answer.

c. Describe how catalase activity changes as temperature increases. Use data from the table to support your answer.

d. Explain why temperature affects catalase activity in the way you described in part (c)


The body structure of a reef-building coral consists of a hard skeleton covering soft tissue. Which of the following elements is most common in the coral’s soft tissue?

A. carbon
B. chlorine
C. sodium
D. zinc


The growth of most plants is limited by the amount of nitrogen available. Which of the following effects does low nitrogen availability most likely have on the carbon cycle?

A. More carbon dioxide is taken up by plants.
B. Carbon dioxide is trapped in the soil around plants.
C. Less carbon dioxide is removed from the atmosphere.
D. Carbon dioxide is converted to carbonates by bacteria.


Which process do elk and other Yellowstone animals use to convert energy in their food into ATP?

A. cellular respiration
B. filtration
C. osmosis
D. photosynthesis


Which of the following will most likely change when an enzyme is added to a reaction?

A. the pH of the reaction
B. the rate of the reaction
C. the products of the reaction
D. the temperature of the reaction


Cellulose is a compound found in plants. It is made of a long
chain of molecules with ringed structures. The molecules contain
mostly carbon, hydrogen, and oxygen atoms in a ratio of approximately
1 carbon : 2 hydrogen : 1 oxygen.

To which category of biological molecules does cellulose belong?

A. carbohydrates
B. nucleic acids
C. phospholipids
D. proteins


Some types of bacteria are able to perform photosynthesis. These bacteria must therefore contain which of the following in their membranes?

A. chlorophyll
B. glucose
C. mitochondria
D. ribosomes


What directly supplies the energy needed to actively transport sodium ions across the plasma membrane of a cell?

Creative Biomart Lipidsome-Based-Membrane-Protein-Production

A. ATP               B. DNA            C. enzyme            D. lipids


Photosynthesis is most likely to occur in which of the following cells?

MCAS cell types


Many farm animals eat hay, which is made by cutting and drying plants such as ryegrass and timothy grass. Scientists analyzed the composition of hay after it was cut and again after it was dried.  The amounts of which common biological elements would have decreased the most as the hay dried?

A. sulfur and calcium
B. phosphorus and zinc
C. oxygen and hydrogen
D. nitrogen and chlorine



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