Cellular Respiration

Question 1

What are common high energy electron carriers in cellular respiration?

Answer 1

NADH ad FADH2

Question 2

What are the four steps of cellular respiration?

Answer 2

1. glycolysis
2. pyruvate dehydrogenase complex
3. Krebs Cycle
4. Electron transport/oxidative phosphorylation

Question 3

What occurs during glycolysis?

Answer 3

glucose is partially oxidized and split in half to form two pyruvic acid molecules

Question 4

Where in the cell does glycolysis occur?

Answer 4

cytoplasm

Question 5

Does glycolysis require the presence of oxygen?

Answer 5

no

Question 6

What occurs during PDC?

Answer 6

pyruvate is decarboxylated to form an acetyl group

Question 7

What is the Krebs cycle also known as?

Answer 7

tricarboxylic acid cycle (TCA cycle)
citric acid cycle

Question 8

What occurs during the Krebs cycle?

Answer 8

acetyl group from PDC is added to oxaloacetate to form citric acid

Question 9

Which steps of cellular respiration can only occur when oxygen is present but doesnt actually use the oxygen?

Answer 9

Krebs Cycle
PDC

Question 10

Where does the Krebs cycle take place in the cell?

Answer 10

in the matrix of the mitochondria

Question 11

Where does the PDC take place in the cell?

Answer 11

in the matrix of the mitochondria

Question 12

What occurs during electron transport/oxidative phosphorylation?

Answer 12

high energy electron carriers are oxidized by the ETC creating a proton gradient that will drive the formation of ATP

Question 13

What is the net surplus of ATP and NADH formed during glycolysis?

Answer 13

2 ATP
2 NADH

Question 14

What is the overall simplified reaction for glycolysis?

Answer 14

glucose + 2 ADP + 2 P + 2 NAD+ –> 2 pyruvate + 2 ATP + 2 NADH + 2 H2O + 2H

Question 15

What enzyme catalyzes the first step of glycolysis?

Answer 15

hexokinase

Question 16

What feedback inhibits hexokinase?

Answer 16

the product, G6P

Question 17

What enzyme catalyzes the third step of glycolysis?

Answer 17

phosphofructokinase (PFK)

Question 18

What is the thermodynamically favorable and irreversible reaction of glycolysis?

Answer 18

the third step catalyzed by PFK

Question 19

What is a committed step?

Answer 19

irreversible step in a reaction that commits the reaction to proceed

Question 20

What is a generalization about what steps get regulated in a reaction?

Answer 20

they usually undergo allosteric regulation
early steps in a pathway tend to get regulated

Question 21

What are aerobic conditions? What are anaerobic conditions?

Answer 21

aerobic = in the presence of oxygen
anaerobic = in the absence of oxygen

Question 22

What is fermentation?

Answer 22

a process that has developed to allow glycolysis to continue under anaerobic conditions

Question 23

What are two examples of fermentation?

Answer 23

1. the reduction of pyruvate to lactate in human muscle cells
2. the reduction of pyruvate to ethanol in yeast cells

Question 24

What does it mean to be an activated acetyl unit?

Answer 24

activated means the acetyl unit is not floating around freely but is instead attached to a carrier, mainly coenzyme A forming acetyl-CoA

Question 25

What is a prosthetic group?

Answer 25

when a cofactor is tightly or covalently bonded to an enzyme

Question 26

What is a prosthetic group?

Answer 26

when a cofactor is tightly or covalently bonded to an enzyme

Question 27

What prosthetic group does PDC contain?

Answer 27

TPP = thiamine pyrophosphate