Unit 4.3: Cellular respiration

Question 1

Where does glycolysis occurs and does it required O2?

Answer 1

occurs in cytosol and it is anaerobic

Question 2

What are the reactants and the products of glycolysis?

Answer 2

Reactants: glucose, ADP + Pi, NAD+

Products: pyruvate, ATP, NADH, H2O

Question 3

What is glucose?

Answer 3

monosaccharide carbohydrate

Question 4

Name two sources of glucose?

Answer 4

from food (carbohydrates) 
and breakdown of glycogen stored in liver and muscle cells

Question 5

List the classes of enzymes used in glycolysis

Answer 5

kinase: transfer of phosphate between ATP an another molecule
isomerase: change conformation
dehydrogenase: removes a hydrogen
mutase: transfers functional group from a position to another within the same molecule
enolase: removes water

Question 6

When does fermentation occurs?

Answer 6

When end products of glycolysis accumulate (NADH and pyruvate)

Question 7

How is called the transformation of pyruvate to lactic acid in a lactic acid fermentation

Answer 7

lactate dehydrogenase

Question 8

Where does lactic acid fermentation fermentation occurs?

Answer 8

lactic acid bacteria,
animal that live in low O2 environment
muscles cells during strenuous exercises

Question 9

advantages of lactic acid fermentation?

Answer 9

regenerates NAD+ needed for glycolysis to continue and provide ATP

Question 10

disadvantages of lactic acid fermentation?

Answer 10

short-term due to decrease in pH
creates oxygen dept
lactic acid transported to liver cell

Question 11

How many reaction are consecutive in alcohol fermentation

Answer 11

2! Pyruvate decarboxylase and alcohol dehydrogenase.

end products: CO2 and ethanol

Question 12

Where does alcohol fermentation occurs?

Answer 12

in yeast, some bacteria, in plant roots (if flooded), very rare in animals

Question 13

advantages of alcohol fermentation?

Answer 13

regenerates NAD+ for glycolysis and provide ATP

Question 14

disadvantages of alcohol fermentation?

Answer 14

ethanol is toxic

Question 15

What is pyruvate oxidation?

Answer 15

3 steps : pyruvate goes through decarboxylation (lost CO2), oxidation (NAD+ forms NADH), conjugation to CoA (addition of coenzyme A) to make acetyl coA

Question 16

Where does pyruvate oxidation occur?

Answer 16

in mitochondia

Question 17

What does the citric acid cycle (krebs cycle or TCA cycle) provide?

Answer 17

Provides NADH, FADH2 for electron transport system. It occurs in mitochondrial matrix.

Question 18

What us the ratio of CO2, NADH, FADH2, GTP per acetyl-coA

Answer 18

2 CO2, 3 NADH, 1 FADH2, 1 GTP *** (can be converted to ATP) (x2 per glucose)

Question 19

In the electron transport system, a series of what type of reactions occurs in the complexes?

Answer 19

Redox reactions

Question 20

Where do they eventually transfer electrons

Answer 20

To O2 in complex IV

Question 21

Name the complexes that use a proton pump?

Answer 21

Complex 1,3,4

Question 22

Where does the energy use to pump protons out of matrix into intermembrane space come from?

Answer 22

energy from electron transfer

Question 23

Describe complex 1

Answer 23

Enzyme: NADH dehydrogenase

transfers electrons from NADH to Q

Question 24

Describe complex 2

Answer 24

Enzyme: succinate dehydrogenase

transfers electrons from FADH2 to Q

Question 25

Describe uniquinone

Answer 25

a lipid, transfers electrons from complex 1 to complex 3, from complex 2 to complex 3. Carries 2 electrons

Question 26

Describe complex 3

Answer 26

Enzyme: cytochrome reductase, transfers electrons from Q to cytochrome c

Question 27

Describe complex 4

Answer 27

enzyme: cytochrome oxidase, transfers electrons from cytochrome c to oxygen

Question 28

Describe cytochrome c

Answer 28

transfers electrons from complex 3 to complex 4

Question 29

What are the two ETS reactions overall and from where do they start?

Answer 29

1) start with NADH from citric acid cycle
complex 1 - Q - complex 3 - cyt.c - complex 4
2) start FADH2 from citric acid cycle
complex 2 - Q - complex 3 - cyt. c - complex 4

Question 30

Name one difference between the two ETS reactions?

Answer 30

the one which starts with FADH2 has one less proton pump used; fewer protons pumped out of matrix

Question 31

What is chemiosmosis

Answer 31

ATP production using ATP synthase (complex 5)

Question 32

How many ATP are produced per NADH in ETS

Answer 32

3 ATP produced per NADH in ETS

2 ATP produced per FADH2 in ETS

Question 33

In the process of ETS, what enter through inner mt membrane into matrix?

Answer 33

O2 enters, CO2 exits