2.4 CELULAR RESPIRATION

Question 1

• Active site

Answer 1

the area on the enzyme where the substrate will bind to it

Question 2

Allosteric inhibition

Answer 2

occurs when the binding of an inhibitor to the enzyme’s regulatory site triggers a conformational change that’ll decrease the affinity for substrate at other active sites

Question 3

Cellular respiration

location?
formula? 
input? 
output? 
net yield?

Answer 3

the process by which cells metabolize glucose to produce ATP (energy) for metabolic activity in an organism

location: mitochondria
formula: C6H12O6+ O2 –> 6CO2 + 6H2O + ATP (energy)
inputs: Glucose, oxygen
output: Carbon dioxide, water, energy (ATP)
net yield: 34 ATP per glucose molecule

Question 4

Coenzyme A

Answer 4

composed of adenosine triphosphate (ATP – the fuel bodies run on), cysteine (an amino acid), and pantothenic acid (vitamin B-5).

Question 5

Committed step

Answer 5

The first irreversible reaction is the phosphorylation of fructose 6-phosphate to fructose 1,6-bisphosphate.

• Thus, it is highly appropriate for phosphofructokinase to be the primary control site in glycolysis.

Question 6

Cytoplasm

Answer 6

the fluid that fills the cell, which includes the cytosol along with filaments, proteins, ions and macromolecular structures as well as the organelles suspended in the cytosol.

Question 7

Feedback inhibition

Answer 7

the product of the late reaction in a metabolic pathway will inhibit the continuation of that particular pathway

Question 8

Energy payoff

Answer 8

steps 1-5 of glycolysis in which two molecules of ATP are consumed to donate phosphate groups

Question 9

Glucose oxidation

Answer 9

the process by which glucose gets oxidizes to carbon dioxide

Question 10

FADH2

Answer 10

this coenzyme acts as a high-energy electron carrier used to transport electrons generated in Glycolysis and Krebs Cycle to the Electron Transport Chain.

Question 11

Mitochondria

Answer 11

hjb

Question 12

Mitochondrial matrix

Answer 12

mvbn

Question 13

NAD+

/NADH

Answer 13

hjb

Question 14

Glycolysis

Answer 14

the breakdown process of a glucose molecule to ultimately form energy in the form of ATP within cells

Question 15

Inner mitochondrial membrane

Answer 15

this s the structure where the intermembrane structure can be found within it

Question 16

Mitochondria

Answer 16

an energy producing organelle that transforms glucose into ATP; can be foround within porkaryotes and eukaryotes

Question 17

Mitochondrial matrix

Answer 17

The folded inner membrane encloses a space

Question 18

NAD+

/NADH

Answer 18

the reduced form fo this feamle mudicia s

Question 19

Oxidizing agent

Answer 19

teh reactcnat that gets an H ion added to it to form an reduced agent

Question 20

Substrate-level phosphorylation

Answer 20

jhl

Question 21

Reducing agent

Answer 21

teh reactcnat that gets an H iion removed from ti ovrvded to it to form an reduced agent

Question 22

Redox reaction

Answer 22

a reactioin ub tyoe un shuch a1 gdett of w1

Question 23

Substrate-level phosphorylation

Answer 23

the process by which a PO3- group produced as a result of a enzyme binding to its substrate

Question 24

step 1

Answer 24

A phosphate group is transferred from ATP to glucose, making glucose-6-phosphate. Glucose-6-phosphate is more reactive than glucose, and the addition of the phosphate also traps glucose inside the cell since glucose with a phosphate can’t readily cross the membrane.

Question 25

step 2

Answer 25

Glucose-6-phosphate is converted into its isomer, fructose-6-phosphate.

Question 26

step 3

Answer 26

A phosphate group is transferred from ATP to fructose-6-phosphate, producing fructose-1,6-bisphosphate. This step is catalyzed by the enzyme phosphofructokinase, which can be regulated to speed up or slow down the glycolysis pathway.

Question 27

step 4

Answer 27

Fructose-1,6-bisphosphate splits to form two three-carbon sugars: dihydroxyacetone phosphate (DHAP) and glyceraldehyde-3-phosphate. They are isomers of each other, but only one—glyceraldehyde-3-phosphate—can directly continue through the next steps of glycolysis.

Question 28

step 5

Answer 28

DHAP is converted into glyceraldehyde-3-phosphate. The two molecules exist in equilibrium, but the equilibrium is “pulled” strongly downward, in the scheme of the diagram above, as glyceraldehyde-3-phosphate is used up. Thus, all of DHAP is eventually converted.

Question 29

step 6

Answer 29

Two half reactions occur simultaneously: 1) Glyceraldehyde-3-phosphate (one of the three-carbon sugars formed in the initial phase) is oxidized, and 2) NAD+ is reduced to NADH+ H+. The overall reaction is exergonic, releasing energy that is then used to phosphorylate the molecule, forming 1,3-bisphosphoglycerate.

Question 30

step 7

Answer 30

1,3-bisphosphoglycerate donates one of its phosphate groups to ATP and turning into 3-phosphoglycerate in the process.

Question 31

step 8

Answer 31

3-phosphoglycerate is converted into its isomer, 2-phosphoglycerate.

Question 32

step 9

Answer 32

2-phosphoglycerate loses a molecule of water, becoming phosphoenolpyruvate (PEP). PEP is an unstable molecule, poised to lose its phosphate group in the final step of glycolysis.

Question 33

step 10

Answer 33

PEP readily donates its phosphate group to ADP, making a second molecule of ATP. As it loses its phosphate, PEP is converted to pyruvate, the end product of glycolysis.

Question 34

3 irreversible steps in glycolysis

Answer 34

hexokinase; phosphofructokinase; pyruvate kinase