anaerobic metabolism

Question 1

what are other names for the glycolytic system

Answer 1

glycogenolysis
glycolysis
lactate production

Question 2

what are the characteristics of carbs

Answer 2

only macro that can generate ATP both anaerobically and aerobically

Question 3

where are carbs stored the most

Answer 3

muscle - readily available

Question 4

where can carbs be found in the body

Answer 4

blood
muscle - most available for exercise
liver - transport to muscle via blood
ingested - from digestion to muscle via blood

Question 5

how does glucose enter a muscle cell

Answer 5

glucose transporter 4 (GLUT4)

Question 6

what is GLUT4

Answer 6

• transport protein to get glucose inside the cell (uses facilitated diffusion)
• specific to muscle cells
• in cell membrane

Question 7

what is GLUT4 sensitive to

Answer 7

insulin
- insulin sends GLUT4 to the cell membrane from the vesicles inside the cell to get glucose inside the cell

Question 8

when is pyruvate converted to lactate

Answer 8

high intensity exercise
- otherwise pyruvate enters the cell

Question 9

how many pyruvate or lactate are produced from 1 glucose

Answer 9

2 pyruvate OR lactate per 1 glucose molecule
(everything after fructose in the chain is doubled)

Question 10

what is the ATP consumption vs production from anaerobic metabolism using GLUCOSE

Answer 10

uses 2 ATP
creates 4 ATP
NET = 2 ATP

Question 11

what is the ATP consumption vs production from anaerobic metabolism using GLYCOGEN

Answer 11

uses 1 ATP
creates 4 ATP
NET = 3 ATP

Question 12

what is the function of hexokinase (HK)

Answer 12

converts glucose to glucose 6 phosphate (G6P)

Question 13

how is G6P produced

Answer 13

ATP is hydrolysed to ADP + Pi + H+
Pi will be attached to glucose to produce G6P
- G6P can’t leave the cell
irreversible reaction

Question 14

what are the 2 fates of G6P

Answer 14

• undergoes glycolysis
• stored as glycogen

Question 15

how is G6P stored as glycogen

Answer 15

1. phosphoglucomutase converts G6P to G1P
2. glycogen synthase converts G1P to glycogen

Question 16

what is the process to convert back to G6P from glycogen

Answer 16

1. glycogen phosphorylase (PHOS) breaks down glycogen to G1P
2. phosphoglucomutase converts G1P back to G6P (bi directional pathway)

Question 16

what is the function of phosphofructokinase

Answer 16

rate limiting enzyme in the process of converting G6P to pyruvate

Question 17

what is PFK activated and inhibited by

Answer 17

activated
- ADP, AMP, Pi, G6P (substrate)

inhibited
- ATP, H+

Question 18

what is the difference between glycolysis and glycogenolysis

Answer 18

glycolysis = glucose breakdown
glycogenolysis = glycogen break down

Question 19

what is the yield from glycolysis

Answer 19

2 ATP
- requires 2, produces 4

2 NADH + H+

Question 20

how does NADH get back to NAD+

Answer 20

oxidised by lactate dehydrogenase
redox reaction of NADH and NAD+ happens consistently

Question 21

where does glycogenolysis occur

Answer 21

sarcoplasm - outside mito

Question 22

what catalyses glycogenolysis

Answer 22

glycogen phosphorylase (PHOS)
- convert glycogen to G1P

Question 23

what is PHOS

Answer 23

rate limiting enzyme

Question 24

what is PHOS activated and inhibited by

Answer 24

activated (break down more glycogen) - Ca2+, AMP, Pi, epi inhibited (don't need more glycogen) - H+, ATP, G6P

Question 25

what is the yield from glycogenolysis

Answer 25

3 ATP - requires 1, produces 4

Question 26

where does pyruvate go

Answer 26

always into the cell - amount depends on how fast you need ATP

Question 27

what happens to pyruvate when ATP is needed fast

Answer 27

pyruvate builds up cant be taken in by mito fast enough - converted to lactate

Question 28

what happens to pyruvate when ATP is needed slower

Answer 28

pyruvate can go into the mito more smoothly - less build up outside

Question 29

what are the two types of glycolysis

Answer 29

anaerobic and aerobic

Question 30

what is the use of oxygen, speed, ATP production and product of anaerobic glycolysis

Answer 30

oxygen = no speed = fast ATP production = low product = LACTATE

Question 31

what is the use of oxygen, speed, ATP production and product of aerobic glycolysis

Answer 31

oxygen = yes speed = slow ATP production = high product = PYRUVATE

Question 32

what is the function of lactate dehydrogenase

Answer 32

helps converts pyruvate to lactate NADH + H+ --> NAD+ (can convert back to pyruvate)

Question 33

when is lactate formed

Answer 33

when pyruvate and NADH + H+ accumulate (mismatch between glycolytic rate and capacity of mito to accept pyruvate)

Question 34

how / when is lactate removed

Answer 34

- can be converted back to pyruvate during low intensity exercise - can go out of the cell to the bloodstream and travel to other organs (liver, heart, etc) as a source of fuel

Question 35

what is the relation between lactate production and exercise intensity

Answer 35

as exercise intensity increases, lactate generation increases

Question 36

does lactate cause fatigue

Answer 36

NO - causes pain but not fatigue

Question 37

when does lactate cause pain

Answer 37

when ATP demand > aerobic metabolism ATP supply - cellular pH drops - impairs enzyme activity and cross bridge cycling

Question 38

which system contributes the most to ATP production in the first few seconds of exercise

Answer 38

PCr - gradually reduces

Question 39

which system contributes the most to ATP production in between 5 and 30 seconds of exercise

Answer 39

glycolysis - takes over from PCr and then gradully decreases

Question 40

when does oxidative phosphorylation increase

Answer 40

around 30 seconds (all systems work together even at the highest intensity)