Cellular Respiration

Question 1

the breakdown of organic molecules can be described as..?

Answer 1

exergonic

Question 2

fermentation

Answer 2

partial degradation of sugars that occurs without O2

Question 3

aerobic Respiration

Answer 3

consumes organic molecules and O2 and yields ATP

Question 4

anaerobic respiration

Answer 4

similar to aerobic respiration but consumes compounds other than O2

Question 5

Cellular Respiration

Answer 5

includes both aerobic and anaerobic respiration but is often used to refer to aerobic respiration

Question 6

redox reaction

Answer 6

transfer of electrons

Question 7

oxidation

Answer 7

substance loses electrons

Question 8

reduction

Answer 8

substance gains electrons

Question 9

reducing agent

Answer 9

electron donor (substance being oxidized)

Question 10

if a particular redox rxn. doesn’t transfer electrons it…

Answer 10

changes the electron sharing in covalent bonds

Question 11

what is oxidized/reduced during cellular respiration

Answer 11

• glucose is oxidized
• oxygen is reduced

Question 12

dehydrogenase

Answer 12

enzyme used in reduction of NAD+
(NAD+ —> NADH)
- NAD+ is the oxidizing agent (electron acceptor)

Question 13

stages of cellular respiration

Answer 13

• glycolysis
• citric acid cycle (Kreb’s Cycle)
• oxidative phosphorylation

Question 14

glycolysis

Answer 14

breaks down glucose into two molecules of pyruvate

Question 15

citric acid cycle

Answer 15

completes breakdown of glucose

Question 16

oxidative phosphorylation

Answer 16

accounts for 90% of the ATP generated by cellular respiration

Question 17

phases of glycolysis

Answer 17

• energy investment phase
• energy payoff phase

Question 18

substrate-level phsphoylation

Answer 18

accounts for smaller amounts of ATP formed in glycolysis and citric-acid cycle

Question 19

what accounts for the most energy extracted from food?

Answer 19

following glycolysis and the C.A.C, NADH and FADH2

Question 20

what do NADH and FADH2 do?

Answer 20

these two electron carriers donate electrons to the electron transport chain, which powers ATP synthesis via oxidative phosphorylation

Question 21

where is the electron transport chain?

Answer 21

in the cristae of the mitochondrion

Question 22

what makes up the ETC?

Answer 22

proteins which exist in multiprotein complexes

Question 23

what do the carriers do in the ETC?

Answer 23

alternate reduced and oxidized states as they accept and donate electrons

Question 24

what do electrons do in the ETC?

Answer 24

electrons drop in free energy as they go down the chain and are finally passed to O2, forming H2O

Question 25

where are electrons tranferred?

Answer 25

from NADH or FADH2 to the ETC

Question 26

what are electrons passed through

Answer 26

a number of proteins including cytochromes (each with an iron atom) to O2

Question 27

does the ETC generate ATP?

Answer 27

no

Question 28

what is the ETC’s function?

Answer 28

to break the large free-energy drop from food to O2 into smaller steps that release energy in manageable amounts

Question 29

what does electron transfer in the ETC cause?

Answer 29

it causes proteins to pump H+ from the mitochondrial matrix to the intermembrane space

Question 30

ATP synthase

Answer 30

where channels, which pass H+ through the membrane, are located

Question 31

what driver the phosphorylation of ATP?

Answer 31

ATP synthase using the exergonic of H+

Question 32

chemiosmosis

Answer 32

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

Question 33

what happens to the H+ stored in the H+ gradient across the membrane?

Answer 33

the H+ stored in a H+ gradient couples redox reaction of the ETC to ATP synthesis

Question 34

proton-motive force

Answer 34

a term used to refer o the H+ gradient, emphasizing its capacity to do work

Question 35

sequence of energy flow during cellular respiration

Answer 35

glucose–>NADH–>ETC–>proton-motive force–> ATP

Question 36

how much ATP is made during cellular respiration?

Answer 36

about 40% of the energy in a glucose molecule is transferred to ATP during cellular respiration, making about 38 ATP

Question 37

under what condition can glycolysis produce ATP?

Answer 37

aerobic or anaerobic conditions
(with or without O2)

Question 38

glycolysis in the absence of O2

Answer 38

glycolysis couples with fermentation or anaerobic respiration to produce ATP

Question 39

describe fermentation

Answer 39

• uses phosphorylation to generate ATP
• consists of glycolysis plus rxn.s that generate NAD+, which can be reused by glycolysis

Question 40

two common types of fermentation

Answer 40

alcohol fermentation and lactic acid fermentation

Question 41

alcohol fermentation

Answer 41

pyruvate is converted to ethanol in two steps, with the first releasing CO2

Question 42

when is alcohol fermentation used?

Answer 42

(by yeast) is used in brewing, winemaking, and breadmaking

Question 43

lactic acid fermentation

Answer 43

pyruvate is reduced to NADH, forming lactate as an end product, with no release of CO2

Question 44

when is lactic acid fermentation used?

Answer 44

(by some fungi) to make cheese and yogurt

Question 45

what do human muscles use?

Answer 45

human muscles use lactic acid fermentation to generate ATP when O2 is scarce

Question 46

what do fermentation and cellular respiration have in common?

Answer 46

both processes use glycolysis to oxidize glucose and other organic fuels to pyruvate

Question 47

where do fermentation and cellular respiration differ?

Answer 47

the processes have different final electron acceptors
- Cell. Resp. = O2
- Fermentation = org. molecule (pyruvate or acetalaldehyde)

Question 48

obligate anaerobes

Answer 48

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

Question 49

facultative anaerobes