Chapter 6 AP BIO

quiz - By hailee oppmann

What is metabolism?

The chemical reactions of life that transform energy from one form to another.

What is the difference between catabolic and anabolic reactions?

Catabolic reactions break down molecules (e.g., hydrolysis), while anabolic reactions build up molecules (e.g., dehydration synthesis).

Define kinetic energy.

The energy of motion.

Define potential energy.

Stored energy based on position or state.

What are the first and second laws of thermodynamics?

1st: Energy cannot be created or destroyed, only transformed. 2nd: Entropy of an isolated system always increases.

What type of reaction is hydrolysis?

A catabolic reaction that breaks down molecules by adding water.

What type of reaction is dehydration synthesis?

An anabolic reaction that builds molecules by removing water.

What are exergonic reactions?

Reactions that release energy, typically associated with digestion and catabolism.

What are endergonic reactions?

Reactions that require an input of energy, typically associated with synthesis and anabolism.

What does ΔG represent?

The change in free energy, indicating the ability to do work.

What is activation energy?

The amount of energy needed to destabilize the bonds of a molecule and initiate a reaction.

How do enzymes affect activation energy?

Enzymes reduce the activation energy required to start a reaction.

What is the enzyme-substrate complex?

A temporary association formed when a substrate binds to an enzyme.

What is the active site of an enzyme?

The region of the enzyme where the substrate binds and the reaction occurs.

What is specificity in enzymes?

The ability of an enzyme to work with a specific substrate.

What is denaturation in enzymes?

The alteration of an enzyme's structure due to changes in temperature, pH, or salinity, affecting its function.

What is the lock and key model of enzyme action?

A simplistic model where the substrate fits into the enzyme's active site like a key fits into a lock.

What is the induced fit model of enzyme action?

A more accurate model where the enzyme changes shape to fit the substrate more tightly upon binding.

What role do enzymes play in biological reactions?

They act as biological catalysts, increasing the rate of reactions without being consumed.

What is ATP?

A cellular energy molecule that stores and transfers energy within cells.

What happens during the phosphorylation of ATP?

ATP transfers a phosphate group to another molecule, facilitating energy transfer.

What is the significance of coupling exergonic and endergonic reactions?

It allows the energy released from exergonic reactions to drive endergonic reactions.

Why do stable polymers not spontaneously digest into monomers?

Because stable covalent bonds require activation energy to break.

What is the role of enzymes in reducing activation energy?

Enzymes provide an alternative pathway for the reaction with a lower activation energy.

What is the effect of temperature on enzyme activity?

Temperature changes can affect enzyme structure and function, potentially leading to denaturation.

How many different enzymes are typically found in cells?

Thousands of different enzymes control various biochemical reactions in cells.

What happens to the reaction rate as enzyme concentration increases?

The reaction rate increases until it levels off due to substrate becoming a limiting factor.

What is the effect of substrate concentration on enzyme activity?

As substrate concentration increases, the reaction rate increases until all enzymes are saturated.

What temperature range is optimal for human enzymes?

The optimal temperature range for human enzymes is 35°-40°C, with body temperature at 37°C.

How does temperature affect enzyme function?

Increased temperature can disrupt bonds in the enzyme, leading to denaturation and loss of 3D shape.

What is the optimal pH range for most human enzymes?

The optimal pH range for most human enzymes is between pH 6-8.

What happens to enzymes at extreme pH levels?

Extreme pH levels can disrupt attractions between charged amino acids, affecting the enzyme's secondary and tertiary structure.

How does salinity affect enzyme function?

can disrupt attractions between charged amino acids, leading to denaturation of the enzyme.

What are activators in enzyme function?

Activators are non-protein compounds that enhance enzyme activity, including cofactors and coenzymes.

What is a competitive inhibitor?

A competitive inhibitor competes with the substrate for the active site of the enzyme.

Give an example of a competitive inhibitor.

Penicillin is a competitive inhibitor that blocks an enzyme bacteria use to build cell walls.

What is a non-competitive inhibitor?

A non-competitive inhibitor binds to a site other than the active site, causing a conformational change that inactivates the enzyme.

What is irreversible inhibition?

Irreversible inhibition occurs when an inhibitor permanently binds to an enzyme, altering its shape and function.

What is allosteric regulation?

Allosteric regulation involves conformational changes in an enzyme due to regulatory molecules that can either inhibit or activate the enzyme.

What is feedback inhibition?

Feedback inhibition is a regulatory mechanism where the final product of a metabolic pathway inhibits an earlier step to prevent overproduction.

What is cooperativity in enzyme function?

Cooperativity occurs when the binding of a substrate to one active site increases the likelihood of binding at other active sites.

How does hemoglobin demonstrate cooperativity?

first O2 binding facilitates the binding of additional O2 molecules due to conformational changes.

What role do vitamins play in enzyme function?

often act as coenzymes, binding to enzymes and assisting in their catalytic activity.

What is the relationship between enzyme concentration and reaction rate?

Higher enzyme concentration leads to a higher reaction rate until substrate availability limits the reaction.

What is the significance of metabolic pathways?

organize chemical reactions into sequential steps, enhancing efficiency and regulation.

What is the role of intermediates in metabolic pathways?

allow for control and regulation of the pathway, preventing unnecessary accumulation of products.

What happens to enzymes at high temperatures?

Enzymes can denature at high temperatures, losing their functional shape and activity.

How does pH affect enzyme structure?

can add or remove H+ ions, disrupting the enzyme's structure and function.

What is the pH of pepsin, the enzyme found in the stomach?

pH 2-3

What is the pH of trypsin, the enzyme found in the small intestines?

pH 8

How does salt concentration affect enzyme function?

Changes in salinity can disrupt attractions between charged amino acids, affecting the enzyme's secondary and tertiary structure, potentially leading to denaturation.

Give examples of cofactors.

Magnesium (Mg), Potassium (K), Calcium (Ca), Zinc (Zn), Iron (Fe), Copper (Cu).

What are coenzymes and provide examples?

Non-protein organic molecules that bind to enzymes; examples include NAD (niacin, B3), FAD (riboflavin, B2), and Coenzyme A.

What are inhibitors in enzyme function?

Molecules that reduce enzyme activity.

What is an example of a competitive inhibitor?

Penicillin, which blocks an enzyme bacteria use to build cell walls.

How can the effects of a competitive inhibitor be overcome?

By increasing the concentration of the substrate to out-compete the inhibitor for the active site.

What is an example of a non-competitive inhibitor?

Cyanide, which irreversibly inhibits Cytochrome C in cellular respiration.

Provide an example of feedback inhibition.

Isoleucine acts as an allosteric inhibitor of the first enzyme in its synthesis pathway from threonine.