ch 7

Question 1

cellular respiration:

Answer 1

a series of chemical reactions that convert the energy stored in fuel molecules into a chemical form that can be used by cells (converts energy stored in food into ATP)
> catabolic

Question 2

CR stage 1:

Answer 2

glycolysis: breakdown of glucose to make 2 pyruvate
> glucose, fatty acids, or amino acids are partially broken down and a modest amount of energy is released
> takes place in cytoplasm

Question 3

CR stage 2:

Answer 3

pyruvate is converted into acetyl-CoA and CO2 is produced

Question 4

CR stage 3:

Answer 4

citric acid cycle: acetyl-CoA is broken down and more CO2 is released, along with a modest amount of energy, and electron carriers

Question 5

__ __ are molecules that store and transfer energy in the form of “high energy” or “excited” electrons

Answer 5

electron carriers

Question 6

CR stage 4:

Answer 6

oxidative phosphorylation: The electron carriers from stages 1−3 release their high-energy electrons to the electron-transport chain to produce ATP

Question 7

in eukaryotes, glycolysis takes place in the __, and the citric acid cycle and phosphorylation take place in __.

Answer 7

cytoplasm; mitochondria

Question 8

oxidation-reduction reactions:

Answer 8

Oxidation: loss of electrons/decrease in electron density
Reduction: gain of electrons/increase in electron density
> these reactions always yield a water and CO2

Question 9

because oxygen gains electrons, it’s called an __ __. it also oxidizes glucose, so it can be called an __ __. glucose is an __ __ and therefore a __ __.

Answer 9

electron acceptor; oxidizing agent

electron donor; reducing agent

Question 10

what is the final electron acceptor?

Answer 10

oxygen

Question 11

substrate-level phosphorylation:

Answer 11

a phosphorylated organic molecule transfers a phosphate group to ADP to produce ATP
> occurs during stages 1 and 3 of CR

Question 12

glycolysis:

Answer 12

a single molecule of glucose (6 carbons) is split into 2 molecules of pyruvate (3 carbons each), net production of 2 ATP and 2 NADH

Question 13

in mitochondria, the space between the inner and outer membranes is called the __ and the space enclosed by the inner membrane is called the mitochondrial __.

Answer 13

intermembrane space; matrix

Question 14

Acetyl CoA synthesis:

Answer 14

pyruvate from glycolysis is transported in mitochondria,, and converted into acetyl CoA in the mitochondrial matrix. results in the formation of one carbon dioxide and one NADH.
TOTAL= 2 acetyl CoA, 2 CO2 and 2 NADH

Question 15

what is produced in the citric acid cycle?

Answer 15

1 glucose produces 2 acetyl CoA which yields 2 ATP, 6 NADH, and 2 FADH2

Question 16

when oxygen accepts the final electron, it is reduced to __.

Answer 16

water

Question 17

electron transport chain:

Answer 17

transfers electrons through complexes I, III, and VI and is coupled with pumping of protons. result is accumulation of protons in the inter membrane space from mitochondrial matrix

Question 18

ATP synthase:

Answer 18

enzyme composed of F0 and F1
F0 forms the channel in inner mitochondrial membrane through which protons flow
F1 is catalytic unit that synthesizes ATP through mechanical rotational energy

Question 19

the complete oxidation of glucose yields __ molecules of ATP

Answer 19

32

Question 20

during __, electrons from NADH are transferred to pyruvate to produce lactic acid and NAD+.
> occurs in animals and bacteria

Answer 20

lactic acid fermentation

Question 21

during __, pyruvate releases carbon dioxide to form acetaldehyde, and electrons from NADH are transferred to acetaldehyde to produce ethanol and NAD+.
> occurs in plants and fungi

Answer 21

ethanol fermentation

Question 22

the breakdown of a molecule of glucose by fermentation yields _ molecules of ATP.

Answer 22

2

Question 23

glucose is stored as __ in animals and as __ in plants

Answer 23

glycogen; starch

Question 24

__ are a good source of energy because of their chemical structure: they are rich in carbon-carbon and carbon-hydrogen bonds

Answer 24

lipids

Question 25

ATP is not produced in β-oxidation, but instead __ and __ are produced

Answer 25

NADH; FADH2

Question 26

the complete oxidation of palmitic acid, a fatty acid with 16 carbons, produces __ molecules of ATP

Answer 26

106

Question 27

PFK-1 is an allosteric enzyme with many activators and inhibitors, describe how it works

Answer 27

When levels of ADP or AMP are high in the cell, these molecules will bind to PFK-1 and activate the enzyme so that glycolysis continues, increasing the amount of ATP in the cell. When levels of ATP are high, it will bind to the enzyme, inhibiting its activity and causing glycolysis to slow down.
> is also regulated by citrate, an intermediate of the citric acid cycle. When citrate binds to the enzyme, its activity is also slowed.