AP Bio Unit 3

What is dehydration synthesis?

A process that forms bonds between molecules by removing a water molecule.

What is hydrolysis?

A process that breaks bonds between molecules by adding a water molecule.

Define exergonic reactions.

Chemical reactions that release energy.

Define endergonic reactions.

Chemical reactions that require an input of energy.

What is activation energy?

The initial input of energy required to kickstart a reaction.

What do enzymes do?

Enzymes lower activation energy and increase the rate of reaction without being consumed.

What are substrates?

Reactants that bind to an enzyme to form an enzyme-substrate complex.

What is the active site of an enzyme?

The specific region on an enzyme where a substrate binds.

What does the lock and key model describe?

An incorrect theory where the substrate fits perfectly into the enzyme's active site.

What is the induced fit model?

A theory stating that enzyme's active site changes shape to better fit the substrate.

Name factors that affect enzyme efficiency.

Enzyme concentration, substrate concentration, temperature, pH, salinity, activators, inhibitors.

What are coenzymes?

Non-protein organic molecules that bind near an active site to activate the enzyme.

What is competitive inhibition?

When an inhibitor competes with substrate for the active site of the enzyme.

Define noncompetitive inhibition.

An inhibitor that binds to an allosteric site, altering the active site and preventing substrate binding.

What is the end product of glycolysis?

Two pyruvate molecules, two NADH, and a net production of two ATP.

Where does glycolysis occur?

In the cytoplasm, outside the mitochondria.

What is the primary function of the Krebs cycle?

To complete the oxidation of organic molecules and generate electron carriers.

What is produced during one turn of the Krebs cycle?

1 ATP, 3 NADH, 2 CO2, and 1 FADH2.

What happens during oxidative phosphorylation?

H+ ions are pumped into the intermembrane space and then diffuse through ATP synthase to produce ATP.

What role does oxygen play in cellular respiration?

Oxygen is the final electron acceptor in the electron transport chain.

What is lactic acid fermentation?

A type of fermentation where NADH is oxidized to NAD+ and pyruvate is reduced to lactate.

What is the main product of alcohol fermentation?

Ethanol and carbon dioxide.

What is the function of chlorophyll?

To capture light energy for photosynthesis.

What is the light-dependent reaction?

The phase of photosynthesis that converts solar energy into chemical energy stored in ATP and NADPH.

Where does the Calvin Cycle take place?

In the stroma of chloroplasts.

What is the role of rubisco?

An enzyme that fixes CO2 in the Calvin cycle.

Define C3 plants.

Plants that use the typical photosynthesis process described, involving the Calvin Cycle.

What is the function of the electron transport chain in cellular respiration?

To pump hydrogen ions across the inner mitochondrial membrane, creating a proton gradient.

What are the two stages of cellular respiration?

Glycolysis and aerobic respiration.

What is anaerobic respiration?

A type of respiration that does not require oxygen and uses other electron acceptors.

What are obligate anaerobes?

Organisms that can only survive in environments without oxygen.

What is feedback inhibition?

Regulation where the end product of a pathway acts as an inhibitor of an earlier enzyme.

What is cooperativity?

When the binding of a substrate to an enzyme enhances the activity of that enzyme.

What do cofactors do?

Non-protein small inorganic compounds that bind with enzymes to activate them.

What is the purpose of the photosystems in light-dependent reactions?

To facilitate the transfer of electrons during photosynthesis.

What happens to water in the light-dependent reactions?

Water is split to release oxygen and provide electrons for the electron transport chain.

What is the main product of photosynthesis?

Glucose (sugar) is produced from carbon dioxide and water.

What is ATP synthase?

An enzyme that produces ATP using the proton gradient in oxidative phosphorylation.

What is the main difference between C4 and CAM plants compared to C3 plants?

They have alternative pathways to fix carbon dioxide to minimize water loss during photosynthesis.

What is the significance of the endosymbiont theory?

It explains the origin of chloroplasts and mitochondria as once free-living prokaryotes.

What are grana?

Stacks of thylakoids in chloroplasts where the light-dependent reactions take place.

What is chemiosmosis?

The movement of ions (H+) across a selectively permeable membrane, driving ATP synthesis.

How is ATP generated in glycolysis?

Through substrate-level phosphorylation when a phosphate group is directly transferred to ADP.