Energy enzymes metabolisms

Question 1

What is energy in a biological context?

Answer 1

The ability to do work or cause change.

Question 2

What is kinetic energy?

Answer 2

Energy of motion (e.g., heat, light, movement).

Question 3

What is potential energy?

Answer 3

Stored energy (e.g., chemical energy in ATP, water in a dam).

Question 4

How can energy be transformed between forms?

Answer 4

Potential energy can be converted into kinetic energy (e.g., ATP hydrolysis releases energy for movement).

Question 5

What is an example of kinetic energy in cells?

Answer 5

Ion movement across membranes, muscle contractions.

Question 6

What is an example of potential energy in cells?

Answer 6

The chemical bonds in glucose or ATP.

Question 7

Why do cells store energy as potential energy?

Answer 7

To release it when needed for work (e.g., metabolism).

Question 8

How does energy storage in a dam relate to cells?

Answer 8

Like a dam, cells build up electrochemical gradients to store energy.

Question 9

What role do molecular bonds play in energy storage?

Answer 9

Strong bonds hold potential energy until broken.

Question 10

How does energy storage allow cells to regulate metabolism?

Answer 10

Cells store energy for controlled, efficient release rather than immediate use.

Question 11

What does the first law of thermodynamics state?

Answer 11

Energy is conserved; it cannot be created or destroyed.

Question 12

What does the second law of thermodynamics state?

Answer 12

Energy transfer increases entropy (disorder) in a system.

Question 13

Why are biological systems not 100% efficient?

Answer 13

Some energy is always lost as heat during transformations.

Question 14

How does entropy relate to biological reactions?

Answer 14

Systems naturally become more disordered unless energy is used to maintain order.

Question 15

Why must cells continually obtain energy?

Answer 15

To counteract entropy and maintain order.

Question 15

How does heat contribute to entropy?

Answer 15

It disperses energy randomly, increasing disorder.

Question 16

What role does metabolism play in energy transformation?

Answer 16

Metabolism converts energy to usable forms while producing heat.

Question 17

What is an example of entropy in living systems?

Answer 17

The breakdown of complex molecules into simpler ones (e.g., digestion).

Question 18

Why is energy transfer in cells only about 40% efficient?

Answer 18

The rest is lost as heat due to entropy.

Question 19

What is Gibbs free energy?

Answer 19

The energy available for work in a system.

Question 20

How does enthalpy relate to free energy?

Answer 20

Enthalpy is total energy, including unusable heat.

Question 21

What does a negative ΔG indicate?

Answer 21

The reaction is exergonic and spontaneous.

Question 22

What does a positive ΔG indicate?

Answer 22

The reaction is endergonic and requires energy input.

Question 23

How does entropy affect free energy?

Answer 23

Higher entropy reduces free energy available for work.

Question 24

Why does diffusion occur spontaneously?

Answer 24

It increases entropy and decreases free energy.

Question 25

What is an example of an exergonic reaction?

Answer 25

ATP hydrolysis.

Question 26

What is an example of an endergonic reaction?

Answer 26

DNA synthesis or any anabolic pathway.

Question 27

Why do living organisms require a constant energy input?

Answer 27

To counteract entropy and drive endergonic processes.

Question 28

What happens if entropy decreases?

Answer 28

The system requires energy input to maintain order.

Question 29

Why are membranes important for energy storage?

Answer 29

They separate charges and concentrations, creating potential energy.

Question 30

What is an electrochemical gradient?

Answer 30

A difference in ion concentration and charge across a membrane.

Question 31

How do cells use electrochemical gradients?

Answer 31

To power ATP synthesis and transport molecules.

Question 32

What is an example of membrane potential in action?

Answer 32

e.g. Nerve impulses in neurons or muscle contraction.

Question 33

Why do gradients store potential energy?

Answer 33

Movement of ions down the gradient releases energy.

Question 34

How do ion pumps contribute to energy storage?

Answer 34

They use ATP to establish electrochemical gradients.

Question 35

What happens if a gradient is lost?

Answer 35

The stored energy is depleted, and processes like ATP synthesis stop.

Question 36

What role do proton gradients play in mitochondria?

Answer 36

They drive ATP synthesis through oxidative phosphorylation.

Question 37

How does the sodium-potassium pump contribute to gradients?

Answer 37

It maintains charge separation essential for cellular function.

Question 38

What would happen if membrane integrity is compromised?

Answer 38

Cells lose the ability to store and use potential energy effectively.

Question 39

Why is ATP called the energy currency of the cell?

Answer 39

It transfers energy efficiently to power cellular functions.

Question 40

How does ATP store energy?

Answer 40

In the bonds between its phosphate groups.

Question 41

What happens when ATP is hydrolyzed?

Answer 41

It releases energy and forms ADP + Pi.

Question 42

Why is ATP hydrolysis exergonic?

Answer 42

Breaking phosphate bonds releases stored energy.

Question 43

What does phosphorylation do?

Answer 43

It makes molecules more reactive by adding a phosphate group.

Question 44

What is ATP synthesis coupled with?

Answer 44

Exergonic reactions like cellular respiration.

Question 45

Why do cells constantly regenerate ATP?

Answer 45

ATP is used rapidly and must be replenished.

Question 46

What is ATP’s role in metabolism?

Answer 46

It links catabolic (energy-releasing) and anabolic (energy-consuming) reaction