Chapter 7: Aerobic Cellular Respiration in Eukaryotes

Question 1

cellular respiration

Answer 1

catabolic pathway that uses oxygen in the breakdown of glucose to extract energy from chemical bonds in the form of ATP

Question 2

cellular respiration takes place in

Answer 2

the mitochondria

Question 3

autotrophs

Answer 3

organisms that are able to synthesize their own food (complex organic molecules)

Question 4

heterotrophs

Answer 4

organisms that cannot synthesize their own food and must feed on other plants and animals to obtain energy

Question 5

regardless of being autotrophs or heterotrophs…

Answer 5

energy has to be extracted from organic compounds through cellular respiration

Question 6

___ is reduced to H2O

Answer 6

oxygen

Question 7

___ is oxidized into CO2

Answer 7

glucose

Question 8

the build up of ATP is ____

Answer 8

endergonic

Question 9

cellular respiration is an _____ reaction and ____ energy

Answer 9

exergonic, releases

Question 10

cellular respiration produces ____ ATP in eukaryotes

Answer 10

36

Question 11

cellular respiration produces ____ ATP in prokaryotes

Answer 11

38

Question 12

steps of aerobic cellular respiration in eukaryotes

Answer 12

1. glycolysis
2. pyruvate oxidation
3. krebs cycle
4. electron transport chain

Question 13

glycolysis takes place in the __________

Answer 13

cytoplasm of the cell

Question 14

step 1 of glycolysis

Answer 14

glucose is phosphorylated by ATP to become glucose 6-phosphate

Question 15

step 2 of glycolysis

Answer 15

rearrangement to become fructose 6-phosphate

Question 16

step 3 of glycolysis

Answer 16

ATP phosphorylates fructose 6-phosphate into fructose 1,6-bisphosphate

Question 17

steps 4-5 of glycolysis

Answer 17

the 6 carbon molecule splits into two 3-carbon molecules, 1 G3P and one that is converted to G3P in another reaction

Question 18

step 6 of glycolysis

Answer 18

G3P is oxidized and phosphorylated into two NADH molecules and two molecules of BPG, each with one high energy phosphate bond

Question 19

step 7 of glycolysis

Answer 19

high energy phosphate bonds are removed by 2 ADP molecules, producing 2 ATP molecules and leaving 2 3PG molecules

Question 20

step 8 of glycolysis

Answer 20

both molecules of 3PG are converted into 2 molecules of 2PG

Question 21

step 9 of glycolysis

Answer 21

H2O is removed from 2PG, creating 2 PEP molecules each with a high-energy phosphate bond

Question 22

step 10 of glycolysis

Answer 22

high energy phosphate bonds are removed by 2 ADP molecules, produces 2 ATP molecules and 2 pyruvate molecules

Question 23

outcome of glycolysis

Answer 23

2 pyruvate
2 ATP
2 NADH

Question 24

pyruvate oxidation occurs in _____

Answer 24

the matrix of the mitochondria

Question 25

pyruvate oxidation

Answer 25

pyruvate is oxidized to an acetyl group by CoA and CO2 is removed. oxidation of pyruvate occurs twice

Question 26

the enzyme that catalyzes pyruvate oxidation is _______

Answer 26

pyruvate dehydrogenase

Question 27

the enzyme that removes CO2 is called ______

Answer 27

pyruvate decarboxylase

Question 28

outcome of pyruvate oxidation

Answer 28

2 NADH 2 Acetyl CoA 2 CO2

Question 29

the krebs cycle takes place in _______

Answer 29

the matrix of the mitochondria

Question 30

step 1 of krebs cycle

Answer 30

the unstable bond attaching the acetyl group to CoA breaks. the acetyl group attaches to oxaloacetate, forming citrate

Question 31

step 2 of krebs cycle

Answer 31

a molecule of water is removed and then added to change citrate into its isomer, isocitrate.

Question 32

step 3 of krebs cycle

Answer 32

isocitrate is oxidized, a molecule of CO2 is removed, and NAD+ is reduced to NADH to form a-ketoglutarate

Question 33

step 4 of krebs cycle

Answer 33

a-ketoglutarate is reduced and a molecule of CO2 is removed to form succinyl CoA

Question 34

step 5 of krebs cycle

Answer 34

succinyl CoA is converted into succinate and substrate level phosphorylation takes place. the unstable bond between CoA and succinate breaks, which helps phosphorylate GDP to form GTP. GTP then transfers its phosphate to ADP to form ATP

Question 35

step 6 of krebs cycle

Answer 35

succinate is oxidized when 2 of its hydrogens are transferred to FAD, forming FADH2, resulting in the compound fumarate

Question 36

step 7 of krebs cycle

Answer 36

H2O is added to fumarate to convert it into malate

Question 37

step 8 of krebs cycle

Answer 37

malate is oxidized and NAD is reduced to NADH, forming oxaloacetate. the oxaloacetate is able to combine with the other acetyl CoA and repeat the cycle

Question 38

outcome of krebs cycle

Answer 38

6 NADH 4 CO2 2 FADH2 2 ATP

Question 39

electron transport chain

Answer 39

reduced compounds from glycolysis, pyruvate oxidation, and krebs cycle enter the electron transport chain and carry their electrons into the inner mitochondrial membrane (cristae), where they transfer their electrons to a series of membrane associated proteins

Question 40

step 1 of ETC

Answer 40

NADH contributes its electrons to the first protein in the electron transport chain (NADH dehydrogenase) while FADH2 feeds its electrons to Q later in the electron transport chain

Question 41

step 2 of ETC

Answer 41

electrons are carried to the next carrier protein, bc1 complex, then to C, and finally to the cytochrome oxidase complex, where O2 is reduced into H2O

Question 42

step 3 of ETC

Answer 42

some energy released as electrons is used to pump protons from the matrix into the intermembrane space, creating a proton gradient. the protons diffuse back into the matrix through specific channels. ATP synthase catalyzes the phosphorylation of ADP to create ATP (chemiosmosis)

Question 43

oxidative phosphorylation

Answer 43

ATP production tied to the ETC where **O2 is the final electron acceptor**

Question 44

theoretical yield of ATP in eukaryotes

Answer 44

32 ATP through ETC. each NADH produces 3 ATP & each FADH2 produces 2 ATP

Question 45

actual yield of ATP in eukaryotes

Answer 45

30 ATP through ETC. each NADH produces 2.5 ATP & each FADH2 produces 1.5 ATP

Question 46

the actual yield exists because _______

Answer 46

the inner mitochondrial membrane is leaky to protons, allowing some of them to re-enter the matrix without passing ATP synthase

Question 47

in cellular respiration of fat, ______

Answer 47

fat is broken down into glycerol and fatty acids

Question 48

step 1 of cellular respiration of fat

Answer 48

phosphate is added to glycerol, converting it to G3P or another compound that enters glycolysis

Question 49

step 2 of cellular respiration of fat

Answer 49

fatty acids are oxidized in the matrix of the mitochondria and split enzymatically into 2-carbon acetyl groups that are bound to CoA (acetyl CoA formed will enter the krebs cycle)

Question 50

the process of cellular respiration of fat is called _______

Answer 50

b-oxidation

Question 51

b-oxidation

Answer 51

2-carbon acetyl groups are removed from a fatty acid and combined with CoA to form acetyl CoA until the entire fatty acid has been broken down

Question 52

lipids are rich in energy because ______

Answer 52

they are highly reduced (many hydrogen atoms and few oxygen atoms)

Question 53

in aerobic respiration of eukaryotes, a molecule of 6-carbon fatty acids generates up to ____ ATP

Answer 53

44

Question 54

for every acetyl CoA that enters the krebs cycle, _____ ATP are produced

Answer 54

12

Question 55

step 1 of cellular respiration of protein

Answer 55

proteins are broken down into their individual amino acids

Question 56

step 2 of cellular respiration of protein

Answer 56

amino group (NH2) is removed from each amino acid in a process called **deamination**

Question 57

step 3 of cellular respiration of protein

Answer 57

carbon molecule that is left is converted into a molecule that takes part in glycolysis or krebs cycle