Ch 9.1: Cellular Respiration and Fermentation

Question 1

How is citrate formed?

Answer 1

the acetyl group of acetyl CoA joins by combining with oxaloacetate

Question 2

Where is the electron transport chain embedded in eukaryotic cells?

Answer 2

the inner mitochondrial membrane

Question 3

Where is the electron transport chain embedded in prokaryotes?

Answer 3

the plasma membrane

Question 4

What is a cytochrome?

Answer 4

carrier proteins in the electron transport chain, which is a protein with heme groups containing an iron atom

Question 5

What is ATP synthase?

Answer 5

the protein complex, in which the H+ moves into binding sites on the rotor of ATP synthase, causing it to spin in a way that catalyzes phosphorylation of ADP to ATP

Question 6

What is chemiosmosis?

Answer 6

the use of energy in a H+ gradient to drive cellular work

Question 7

What is the proton-motive force?

Answer 7

the H+ gradient

Question 8

What is the sequence of energy throughout cellular respiration?

Answer 8

glucose–> NADH–> electron transport chain–> proton-motive force–> ATP

Question 9

How much ATP is made in cellular respiration?

Answer 9

about 34% of the energy in a glucose molecule is transferred to ATP, making about 32 ATP (the rest of the energy is lost as heat)

Question 10

What happens when cellular respiration does not have oxygen?

Answer 10

without oxygen, the electron transport chain will cease to operate, and glycolysis couples with anaerobic respiration or fermentation to produce ATP

Question 11

How does anaerobic respiration complete cellular respiration without oxygen?

Answer 11

anaerobic respiration uses an electron transport chain with a final electron accepter other than oxygen, H2S (hydrogen sulfide) is made as a by-product instead of H20

Question 12

What is fermentation?

Answer 12

an extension of glycolysis that oxidizes NADH by transferring electrons to pyruvate or its derivatives

Question 13

What are two common types of fermentation?

Answer 13

alcohol fermentation and lactic acid fermentation

Question 14

What is the process of alcohol fermentation?

Answer 14

pyruvate is converted to ethanol in two steps: 1. the first step releases CO2 from pyruvate and 2. the second step produces NAD+ and ethanol

Question 15

What is the process of lactic acid fermentation?

Answer 15

pyruvate is reduced directly by NADH to form lactate and NAD+ and there is no release of CO2

Question 16

What are the similarities between fermentation, anaerobic, and aerobic respiration?

Answer 16

all use glycolysis to oxidize glucose and harvest the chemical energy of food, and NAD+ is the oxidizing agent that accepts electrons during glycolysis

Question 17

What are the differences in the mechanisms used to oxidize NADH to NAD+ for fermentation, anaerobic, and aerobic respiration?

Answer 17

Fermentation: an organic molecule (pyruvate or acetaldehyde) acts as a final electron acceptor
Cellular Respiration: electrons are transferred to the electron transport chain

Question 18

What are the differences in the amount of ATP produced per glucose molecule for fermentation, anaerobic, and aerobic respiration?

Answer 18

Fermentation: produces 2 ATP by substrate-level phosphorylation
Cellular Respiration: harvests much more ATP by oxidative phosphorylation (32 ATP)

Question 19

What do obligate anaerobes do?

Answer 19

they carry out fermentation or anaerobic respiration and cannot survive in the presence of O2

Question 20

What is facultative anaerobes?

Answer 20

cells that can survive using either fermentation or cellular respiration, ex. yeast and bacteria

Question 21

How are fatty acids broken down in Cellular Respiration?

Answer 21

by beta-oxidation, which yields acetyl CoA, NADH, and FADH2