Exam 2 Study

Question 1

What are the sources of energy available to chemo- and photo-autotrophs and heterotrophs?

Answer 1

Chemo-autotrophs use inorganic compounds, photo-autotrophs use sunlight, and heterotrophs consume organic substances.

Question 2

What is the first law of thermodynamics?

Answer 2

Energy cannot be created or destroyed, only transformed.

Question 3

What is the second law of thermodynamics?

Answer 3

In any energy transfer, the total entropy of a closed system can only increase.

Question 4

How does the movement of electrons relate to the flow of energy in chemical reactions?

Answer 4

The movement of electrons during chemical reactions transfers energy.

Question 5

What do free energy diagrams represent?

Answer 5

They illustrate the energy changes during biochemical reactions.

Question 6

What are exergonic reactions?

Answer 6

Reactions that release energy.

Question 7

What are endergonic reactions?

Answer 7

Reactions that absorb energy.

Question 8

Define oxidation reactions.

Answer 8

Reactions involving the loss of electrons.

Question 9

Define reduction reactions.

Answer 9

Reactions involving the gain of electrons.

Question 10

What are anabolic reactions?

Answer 10

Reactions that build larger molecules from smaller ones.

Question 11

What are catabolic reactions?

Answer 11

Reactions that break down larger molecules into smaller ones.

Question 12

What is the significance of coupled reactions in living cells?

Answer 12

They allow energy from exergonic reactions to drive endergonic reactions.

Question 13

Why is ATP considered the universal energy currency of life?

Answer 13

ATP provides a readily available form of energy for cellular processes.

Question 14

What is activation energy?

Answer 14

The energy required to initiate a chemical reaction.

Question 15

How can activation energy be overcome?

Answer 15

By increasing temperature or using catalysts.

Question 16

What role do enzymes play in chemical reactions?

Answer 16

Enzymes catalyze reactions, lowering activation energy.

Question 17

How does temperature affect enzyme catalysis?

Answer 17

Changing temperature can increase or decrease enzyme activity, affecting functional ranges.

Question 18

How can enzyme function be controlled?

Answer 18

Through inhibitors that decrease enzyme activity.

Question 19

What are endergonic steps in aerobic respiration?

Answer 19

Steps that require energy input, such as the synthesis of ATP.

Question 20

What are exergonic steps in aerobic respiration?

Answer 20

Steps that release energy, such as glycolysis.

Question 21

What is the role of enzymes in aerobic respiration?

Answer 21

They control the rate and efficiency of the metabolic pathways.

Question 22

What is the electron transport chain (ETC)?

Answer 22

A series of complexes that transfer electrons and produce ATP.

Question 23

How is a proton gradient established in aerobic respiration?

Answer 23

By pumping protons across the membrane during electron transport.

Question 24

Why is oxygen necessary for aerobic respiration?

Answer 24

Oxygen serves as the final electron acceptor in the ETC.

Question 25

What is the purpose of fermentation?

Answer 25

To produce energy when oxygen is not available.

Question 26

What is the energetic advantage of aerobic respiration over fermentation?

Answer 26

Aerobic respiration generates more ATP per glucose molecule.

Question 27

What evidence supports the universality of glycolysis?

Answer 27

Glycolysis is found in nearly all living organisms, indicating its ancient evolutionary origin.

Question 28

How do non-carbohydrate food sources fit into aerobic respiration?

Answer 28

They can be converted into intermediates that enter the metabolic pathways.

Question 29

What is the importance of photosynthesis in ecosystems?

Answer 29

Photosynthesis provides energy for the food chain.

Question 30

What is the evolutionary history of photosynthesis?

Answer 30

Photosynthesis likely developed over 2.5 billion years ago, impacting life evolution.

Question 31

How does energy transfer from light to chemical energy during photosynthesis?

Answer 31

Light energy is captured and converted to high-energy electrons for carbohydrate synthesis.

Question 32

What are the two systems involved in photosynthesis?

Answer 32

Light capture and conversion to high-energy electrons, followed by carbon fixation.

Question 33

What are the inputs and outputs of the light-harvesting steps in photosynthesis?

Answer 33

Inputs: light, water; Outputs: oxygen, high-energy electrons.

Question 34

How does the ETC in photosynthesis compare to that in aerobic respiration?

Answer 34

Both involve electron transfer but differ in inputs and final electron acceptors.

Question 35

What is carbon fixation?

Answer 35

The process of converting inorganic CO2 into organic compounds.

Question 36

What is the critical role of Rubisco?

Answer 36

Rubisco catalyzes the first step of carbon fixation but has rate limitations and is involved in photorespiration.

Question 37

What connects the light-harvesting reactions to the Calvin cycle?

Answer 37

The high-energy electrons produced in the light-harvesting reactions.

Question 38

Why do photosynthetic organisms store their products as complex carbohydrates?

Answer 38

To provide a stable energy source for later use.