3.1-3.2 Enzymes Review

In the context of cellular energetics, which statement best defines an enzyme?

• A biological catalyst, usually a protein, that lowers activation energy and speeds reactions without being consumed

• A structural protein that provides mechanical support to cells

• A lipid that stores long-term energy in membranes

• A nucleic acid that encodes hereditary information

Within enzyme-mediated reactions, what is a substrate?

• The reactant molecule an enzyme binds and acts upon

• The product released after catalysis

• The protein region that changes pH

• An allosteric inhibitor that reduces enzyme activity

What does the term enzyme–substrate complex describe?

• The temporary association formed when a substrate binds the enzyme's active site during catalysis

• A permanent fusion of enzyme and product after the reaction

• A collection of multiple enzymes assembled in a membrane

• An inactive enzyme that requires a cofactor

What is the active site of an enzyme?

• The region of the enzyme with a specific shape and chemistry where the substrate binds and the reaction occurs

• The cellular compartment that stores enzymes

• The site where ATP is synthesized inside mitochondria

• The location on a substrate where water is removed

Which option best defines a catalyst in biochemical reactions?

• A substance that increases reaction rate by lowering activation energy and is not consumed

• A molecule that provides energy by being oxidized into ATP

• A reactant that is converted into product and used up

• A substance that stops reactions by blocking substrates

Tags

NGSS.HS-PS1-4

NGSS.HS-PS1-5

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In environmental impacts on enzyme function, pH refers to which concept?

• A measure of hydrogen ion concentration that can alter enzyme shape and activity

• The concentration of substrate available for an enzyme

• The temperature scale used for enzyme assays

• The electrical charge of the active site only

In the context of protein structure and function, what does it mean for an enzyme to denature?

• It loses its 3D shape and activity due to enviornmental changes - extreme pH or heat, without necessarily breaking peptide bonds

• It is cut into amino acids by proteases, permanently destroying primary structure

• It gains additional subunits to increase catalytic efficiency

• It binds an inhibitor reversibly at the active site

Which statement best describes ATP in cellular energy transformations?

• Adenosine triphosphate serves as the primary energy currency; hydrolysis of its terminal phosphate releases usable energy

• A structural nucleic acid that encodes genes used for metabolism

• A storage polysaccharide that provides long‑term energy reserves

• A membrane lipid that forms bilayers and stores potential energy

Tags

NGSS.HS-LS1-7

Which choice accurately defines kinetic energy?

• Energy associated with motion of objects or molecules

• Energy stored in chemical bonds due to position

• Energy that cannot be transformed according to thermodynamics

• Energy exclusively found in ATP

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NGSS.HS-PS2-1

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Which choice accurately defines potential energy in biological systems?

• Energy stored due to position or arrangement, such as in chemical bonds or gradients

• Energy of motion of particles

• Energy released as heat only

• Energy measured only by changes in pH

Tags

NGSS.HS-LS1-7

NGSS.HS-LS1-5

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