Ch 9: Cellular Respiration and Fermentation

Question 1

How does energy exist and enter an ecosystem?

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Answer 1

energy enters as light and exits as heat

Question 2

Catabolic Pathways

Answer 2

release stored energy by breaking down complex molecules

Question 3

Two types of catabolic pathways

Answer 3

Fermentation, and aerobic respirations, anaerobic respiration

Question 4

What is fermentation?

Answer 4

a partial degradation of sugars that occurs without oxygen

Question 5

What is aerobic respiration?

Answer 5

consumes organic molecules ans oxygen and yields ATP

Question 6

How is anaerobic respiration different from aerobic respiratioon?

Answer 6

anerobic respiration consumes compounds other than oxygen

Question 7

What type of respiration is used in cellular respiration?

Answer 7

both aerobic and anaerobic respiration but its often used to refer to aerobic respiration

Question 8

Chemical equastion for cellular respiration

Answer 8

C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + Energy (ATP + heat)
ΔG = -686 kcal/mole glucose

Question 9

What is a redox reaction?

Answer 9

chemical reactions that transfer electrons between reactants

Question 10

What is oxidation?

Answer 10

the loss of electrons from a substance in a redox reaction

Question 11

What is reduction?

Answer 11

the addition of electrons to a substance in a redox reaction

Question 12

What is a reducing agent?

Answer 12

the electron donor, it reduces the electron acceptor

Question 13

What is a oxidizing agent?

Answer 13

the electron acceptor, it oxidizes the electron donor

Question 14

Besides transferring electrons, how can a redox reaction occur?

Answer 14

a redox reaction can occur with a change of electron sharing in covalent bonds

Question 15

How can energy be released?

Answer 15

the transfer of electrons during a chemical reaction releases energy, the movement of electrons closer to electronegative atoms release energy

Question 16

What is nicotinamide adenine dinucleotide (NAD+)?

Answer 16

a coenzye that functions as an electron carrier, oxidizing agent during cellular respiration

Question 17

What does NADH represent?

Answer 17

the reduced form of NAD+, represents stored energy that is tapped to synthesize ATP

Question 18

How is NADH formed?

Answer 18

enzymes called dehydrogenases remove a pair of hydrogen atoms fron the substrate, the 2 electrons and 1 proton is transferred to NAD+ forming NADH

Question 19

Why is an electron tranpsort chain used in cellular repiration?

Answer 19

its used to break the fall of electrons to O2 into several energy-relaesing steps

Question 20

Electron transport chain

Answer 20

consisits of a series of molecules built into the inner membrane of the mitochondria (or plasma membrane of prokarotes)

Question 21

Electron movement during cellular respiration:

Answer 21

glucose—> NADH—> electron transport chain—> oxygen

Question 22

The three stages of of harvesting energy from glucose by cellular respiration

Answer 22

gylcolysis, citric acid cycle, and oxidative phosphorylation

Question 23

What is the glycolysis stage?

Answer 23

glycolysis breaks down glucose into two molecules of pyruvate

Question 24

What is the citric acid cycle stage?

Answer 24

pyruvate oxidation and the citric acid cycle complete the breakdown of glucose to CO2 and form some ATP by substrate-level phosphorylation

Question 25

What is the oxidative phosphorylation stage?

Answer 25

during the oxidative phosphorylation the electron transfer chain and chemiosmosis facilitate synthesis of most of the cell’s ATP (90 %) through redox reactions

Question 26

Substrate-level phosphorylation

Answer 26

occurs when an enzyme transfers a phosphate group directly from a substrate to ADP

Question 27

Where does glycolysis occur?

Answer 27

in the cytoplasm

Question 28

Two major phases of glycolysis

Answer 28

energy investment phase and energy payoff phase

Question 29

What occurs in the energy investment phase?

Answer 29

2 ATP are used to split glucose into 2 three-carbon sugar molecules

Question 30

What occurs in the energy playoff phase?

Answer 30

4 ATP are synthesized, 2 NAD+ are reduced to NADH, the small sugars are oxidized to form 2 pyruvate and 2 H2O

Question 31

Acetyl CoA

Answer 31

pyruvate is converted to acetyl coenzyme A before entering the citric acid cycle