Energy and Enzymes

These flashcards cover key concepts from the lecture on energy and enzymes, focusing on definitions, processes, and important molecules.

What is energy defined as?

Energy is the ability to do work.

What are the two major forms of energy?

Kinetic energy and potential energy.

Give an example of kinetic energy.

Energy associated with movement, such as a moving car.

Give an example of potential energy.

Energy stored in chemical bonds, such as in glucose.

What does the first law of thermodynamics state?

Energy cannot be created or destroyed, only transferred or transformed.

What does the second law of thermodynamics state?

Total entropy in a system always increases; systems tend toward disorder.

What are exergonic reactions characterized by?

They release energy and are spontaneous.

What are endergonic reactions characterized by?

They absorb energy and are non-spontaneous.

What is ATP?

ATP (adenosine triphosphate) is the energy currency of the cell.

Why is ATP considered high in potential energy?

ATP has unstable phosphate bonds that store potential energy.

What is the process of energetic coupling?

Using energy released from ATP hydrolysis to drive endergonic reactions.

What happens during ATP hydrolysis?

ATP is converted to ADP and inorganic phosphate, releasing energy.

What is the role of enzymes in biological reactions?

Enzymes act as catalysts to speed up chemical reactions by lowering activation energy.

How do enzymes achieve specificity?

Enzymes bind substrates with high specificity through their active sites.

What is passive strain in enzymes?

Enzymes exert physical strain on substrates to facilitate bond breaking.

What does induced fit refer to in enzyme function?

Induced fit refers to the conformational change of an enzyme when substrate binds.

What is a metabolic pathway?

A series of chemical reactions catalyzed by specific enzymes.

What occurs if an enzyme in a metabolic pathway does not function properly?

The product cannot be made, affecting downstream reactions.

What is feedback inhibition?

A regulatory mechanism where the end product inhibits an enzyme in the pathway.

Define REDOX reactions.

Reduction/Oxidation reactions involve the transfer of electrons between molecules.

What is an electron donor?

An atom or molecule that loses or donates electrons in a REDOX reaction.

What is an electron acceptor?

An atom or molecule that gains electrons in a REDOX reaction.

Name two examples of electron carriers in cellular respiration.

NADH and FADH2.

Which form of NADH has higher potential energy?

The reduced form, NADH, has higher potential energy than its oxidized form, NAD+.

What is the activation energy?

The minimum energy required for a chemical reaction to occur.

How do enzymes lower activation energy?

By providing an alternative reaction pathway that requires less energy.

What happens to enzymes during a reaction?

Enzymes are not consumed; they return to their original state.

What role does ATP play in endergonic reactions?

ATP provides energy to drive endergonic reactions via hydrolysis.

What is the significance of the active site of an enzyme?

The active site is where substrate binding and the catalytic activity occur.

Describe the transition state during a chemical reaction.

The transition state is the state in which reactants are converted to products.

How can the concentration of products affect a metabolic pathway?

High concentrations of product can inhibit enzymes, thus regulating the pathway.

What is the importance of enzyme specificity?

Specificity ensures that enzymes catalyze the correct reactions.

What occurs when there is an excess concentration of the final product in feedback inhibition?

It inhibits one of the enzymes in the pathway, reducing product formation.

How do enzymes facilitate chemical reactions?

By binding substrates and stabilizing the transition state.

What is the role of ADP in energy transfer?

ADP is formed when ATP is hydrolyzed, serving as a lower-energy carrier.

What is an example of an exergonic reaction?

Respiration, where glucose is broken down to release energy.

What is an example of an endergonic reaction?

Photosynthesis, where light energy is used to synthesize glucose.