AP Biology Unit 3 Cellular Energetics

Enzymes ___________________ activation energy to speed up chemical reactions.

• increase

• decrease

How does the active site of an enzyme determine the substrate for that enzyme?

• The active site has the right polarity to interact with the substrate.

• The active site is hydrophobic and interacts with other hydrophobic amino acids on the substrate

• The active site has a specific shape that fits the shape of the substrate

• The active site uses energy to form covalent bonds with the substrate

How does a competitive inhibitor affect an enzymes function?

• It binds to an allosteric site that alters the shape of the enzyme

• It changes the polarity of the enzyme, decreasing the rate of reaction

• It denatures the enzyme which increases the activation energy for the reaction.

• It binds to the active site, preventing the enzyme from catalyzing the reaction

Which of these factors can affect the initial rate of an enzyme reaction?

• Enzyme concentration

• Substrate concentration

• Temperature

• pH

• All of the above

Based on this graph, which enzyme would function best in a basic environment?

• A

• B

Why is the hydrolysis of ATP important to a cells function?

• It provides a source of phosphate for the cell.

• It releases energy that can be used to power cellular processes

• It absorbs excess hydrogen ions in the cell to regulate the internal pH

• It acts as a catalyst for chemical reactions in the cell.

Why do plants not store 100% of the light energy absorbed by chlorophyll in glucose molecules?

• Most of the energy is used to power the reaction or is lost as heat

• Plants do not have a high energy requirement, so they do not need to convert 100% of the energy

• The energy is used to power ATP synthase proteins on the thylakoid membrane

• The remaining energy is used actively transport oxygen out of the cell.

Tags

NGSS.HS-LS1-5

What is the best reason that plants do not perform photosynthesis at night?

• They close their stomata at night to rest

• They do not have an energy source to power the light reactions

• Only a few types of plants are nocturnal

• There is less carbon dioxide released into the air at night

What are the net products of photosynthesis?

• 6 CO₂, 6 H₂O, Energy

• 6 O₂ and 6 H₂O

• C₆H₁₂O₆ and 6 O₂

• 6 CO₂ and C₆H₁₂O₆

Tags

NGSS.HS-LS1-6

What factors affect the rate of photosynthesis?

• CO₂ concentration

• H₂O available

• Temperature

• Light intensity

• All of the above

Tags

NGSS.HS-LS2-5