Bioenergetics Unit 2 Quiz

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Questions and Answers

What is defined as the study of energy transfer in biological systems?

Bioenergetics (correct)

Metabolism

Catalysis

Thermodynamics

Which of the following best describes catabolism?

Synthesis of biomolecules using energy

Utilization of energy to perform work

Processes that maintain cellular order

Reactions that break down large biomolecules to release energy (correct)

What does the First Law of Thermodynamics state?

Spontaneous processes require external energy input

Natural processes are maintenance of order

Energy can be created or destroyed in a closed system

Energy can only be converted from one type to another (correct)

Which statement correctly reflects the Second Law of Thermodynamics?

Spontaneous processes increase the state of disorder Signup and view all the answers

What is the role of energy in maintaining cellular order?

Energy is required to decrease entropy Signup and view all the answers

What characterizes an endergonic reaction?

It requires input energy to proceed. Signup and view all the answers

How is energy captured for use in endergonic reactions?

As high-energy electrons on nucleotides. Signup and view all the answers

What does the equilibrium constant (Keq) indicate about a reversible reaction?

The ratio of products to substrates at equilibrium. Signup and view all the answers

What role does the net free energy change (∆G) play in reaction reversibility?

It indicates whether a reaction can proceed in the reverse direction. Signup and view all the answers

High negative ∆G reactions typically require what for the reverse reaction?

Significant energy input. Signup and view all the answers

What is the primary fuel source used by the body during moderate to high-intensity muscular effort?

Carbohydrates Signup and view all the answers

How much energy can protein provide for cellular activity?

10-15% Signup and view all the answers

Which statement accurately describes ATP hydrolysis?

It provides energy, releasing 7.3 kcal/mol. Signup and view all the answers

What regulates metabolism in relation to ATP?

The ratio of ATP to ADP Signup and view all the answers

What characterizes the ATP – PCr energy system?

It supplies ATP immediately at a high rate. Signup and view all the answers

What is the primary role of ATP in the cell?

Powering muscle contractions and cellular work Signup and view all the answers

What is the main characteristic of the Glycolytic System?

Operates in the absence of oxygen Signup and view all the answers

What is the consequence of ATP turnover rates in a cell?

They need to match rates of ATP production. Signup and view all the answers

What is the primary function of phosphocreatine (PCr) in energy metabolism?

Replenishes ATP during recovery Signup and view all the answers

Which of the following regulates the flow of molecules through metabolic pathways?

Maintaining a constant ratio of ATP-to-ADP Signup and view all the answers

What is the primary energy source utilized during the phosphagen system?

Phosphocreatine Signup and view all the answers

How long does it generally take for full recovery of phosphocreatine (PCr) after exercise?

2-4 minutes Signup and view all the answers

What happens to the levels of ATP immediately after the start of exercise?

ATP levels remain constant Signup and view all the answers

Which enzyme is primarily involved in the reaction between phosphocreatine and ADP?

Creatine Kinase Signup and view all the answers

What is the outcome of the CK reaction and ATP hydrolysis at the sarcomere?

Decrease in phosphocreatine concentration Signup and view all the answers

What does EPOC stand for, and how is it related to ATP replenishment?

Excess Post-Exercise Oxygen Consumption Signup and view all the answers

What is the primary role of AMP in relation to enzyme activity during energy requirements?

Activates glycogen phosphorylase kinase Signup and view all the answers

What does a high KM value indicate about an enzyme or transporter?

Low affinity for substrate Signup and view all the answers

Which glucose transporter is known for being insulin-responsive?

GLUT 4 Signup and view all the answers

Which of the following statements about Vmax is true?

Vmax can only be achieved at high substrate concentrations Signup and view all the answers

Where does the adenylate kinase reaction primarily occur?

In the cytosol Signup and view all the answers

When is the adenylate kinase reaction most likely to occur?

As energy requirements increase Signup and view all the answers

Which glucose transporter exhibits very high affinity for glucose?

GLUT 3 Signup and view all the answers

What characterizes GLUT 2 among glucose transporters?

Bi-directional transport Signup and view all the answers

Study Notes

Bioenergetics Overview

Study of energy transfer in biological systems, covering metabolism involving catabolism (energy-releasing reactions) and anabolism (energy-utilizing reactions).
Cells perform reactions to maintain energy balance and facilitate biological functions.

Thermodynamics Principles

First Law: Energy in a closed system is constant—energy cannot be created or destroyed, only transformed.
Second Law: Spontaneous processes tend toward disorder (entropy) which requires energy to maintain order (endergonic reactions).

Energy Concepts

Energy: Capacity to do work; work defined as force applied over a distance.
Power: Rate of doing work (work/time).
Body performance depends on energy conversion.

Glucose Metabolism

Metabolic reactions can be exergonic (release energy) or endergonic (require energy), often coupled to fulfill energy requirements.
High-energy electrons are stored as NADH and FADH2 for later energy use.

Reversible Reactions

Many cellular reactions are reversible and reach equilibrium defined by the ratio of products to substrates.
Reactions move towards equilibrium based on ΔG, where a negative ΔG indicates favoring products.

Fuel Utilization

At rest: Body uses carbohydrates (CHO) and lipids for energy.
During exertion: CHO becomes the primary fuel source; lipids are more important during prolonged low-intensity activities.
Protein contributes up to 10-15% of energy and serves structural roles.

ATP: Energy Currency

ATP (adenosine triphosphate) has high-energy phosphate bonds, mainly hydrolyzed to release energy (ΔG = -7.3 kcal/mol).
ATP homeostasis is crucial for muscle contraction and cellular work, requiring regulation of ATP production and turnover.

Energy Pathways

Three main systems to maintain ATP levels:
- ATP-PCr System: Immediate energy supply; high rate but low capacity.
- Glycolytic System: Intermediate rate and capacity; non-oxidative, supports aerobic metabolism.
- Oxidative System: Slower rate, very high ATP capacity.

Metabolism Regulation

Flow of energy in metabolic pathways is managed by controlling enzyme concentration, producing allosteric modulators, isolating enzymes, and maintaining ATP/ADP ratios.

Phosphagen System

Utilizes phosphocreatine (PCr) for rapid ATP production near muscle fibers.
Phosphocreatine levels drop during activity while ATP remains stable; recovery of PCr occurs quickly post-exercise.

Adenylate Kinase Reaction

Converts ADP into ATP and AMP, indicating increased energy demand; AMP signals enhanced glycolysis activity through enzyme activation.

Glycolysis and Lactate Production

Glycolysis converts glucose to pyruvate, yielding energy. Lactate accumulation can occur, especially during intense muscular activity without oxygen.

Glucose Transport

Transporters (GLUT 1, GLUT 2, GLUT 3, GLUT 4, GLUT 5) facilitate glucose uptake, each with specific locations and affinities for glucose.
Vmax indicates maximum reaction velocity; KM represents substrate concentration at which half Vmax is achieved, reflecting enzyme affinity.

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Description

Test your knowledge on bioenergetics in this Unit 2 quiz. Explore topics including biological energy transfer, metabolic pathways, and the roles of enzymes and substrates. This quiz will help reinforce your understanding of ATP, glycolysis, lipid metabolism, and more.