Energy systems in muscles

Question 1

What happens during vigorous exercise?

Answer 1

The muscles do not get sufficient oxygen to support the electron transport chain

Question 2

what happens when the muscles don’t get sufficient oxygen?

Answer 2

Pyruvate is converted into lactate

Question 3

What does the conversion of pyruvate to lactate involve?

Answer 3

The transfer of hydrogen from the NADH produced during glycolysis to pyruvate in order to produce lactate

Question 4

What is needed to maintain ATP production through glycolysis

Answer 4

NAD

Question 5

What happens when lactate accumulates

Answer 5

muscle fatigue occurs

Question 6

When is the oxygen debt repaid

Answer 6

When exercise is complete

Question 7

What happens after exercise is complete?

Answer 7

It allows respiration to provide the energy to convert lactate back to pyruvate and glucose in the liver

Question 8

What do slow twitch fibres do?

Answer 8

Contract relatively slowly but can substain contractions for longer

Question 9

Example of slow twitch

Answer 9

long distance running, cycling or cross country skiing

Question 10

What do slow twitch muscles rely on?

Answer 10

Aerobic respiration to generate ATP

Question 11

What is the major storage fuel of slow twitch muscle fibres?

Answer 11

Fats

Question 12

What do fast twitch muscles do?

Answer 12

Contract relatively quickly over short period of time

Question 13

Examples of fast twitch

Answer 13

Sprinting or weightlifting

Question 14

How can fast twitch muscle fibres generate ATP

Answer 14

Through glycolysis only

Question 15

Features of fast twitch muscles

Answer 15

Fewer mitochondria

lower blood supply

Question 16

What is the major storage fuel of fast twitch muscle fibres?

Answer 16

Glycogen

Question 17

Features of slow twitch muscles

Answer 17

Many mitochondria
Large blood supply
High concentration of the oxygen storing protein myoglobin

Question 18

What do most human muscle tissue contain?

Answer 18

A mixture of both slow and fast twitch muscle fibres.

Athletes show a distinct pattern of muscle fibres that reflect their sporting activities

Question 19

How long does it take for creatine phosphate to run out?

Answer 19

About 10 seconds

Question 20

Why does creatine phosphate break down to release energy and phosphate

Answer 20

because they are used to convert ADP to ATP at a fast rate and therefore help support strenuous exercise in muscle cells

Question 21

When is creatine phosphate restored?

Answer 21

When energy demand on muscle cells is low

Question 22

Why do skeletal muscles contract?

Answer 22

To bring about about the movements of strenuous exercise

Question 23

What twitch fibres does skeletal muscles have?

Answer 23

Slow twitch and fast twitch fibres

Question 24

What is skeletal muscle?

Answer 24

muscle attached to the skeleton and contract to cause movement during exercise

Question 25

Give an account of lactic acid metabolism in muscle cells

Answer 25

During exercise muscles do not have oxygen for aerobic respiration/ electron transport chain Pyruvate acid is converted to lactic acid Transfer of hydrogen from NADH, regenerates NAD needed to maintain ATp production by glycolysis Lactic acid builds up causing fatigue Lactic acid is converted back into pyruvate

Question 26

Describe fermentation in human muscle cells

Answer 26

Anaerobic In the absence of sufficient oxygen pyruvate is converted to lactic acid

Question 27

Describe the role of creatine phosphate in cells

Answer 27

It breaks down to release energy and phosphate, used to convert ADP to ATP at a fast rate

Question 28

Give an account of slow twitch muscle fibres

Answer 28

Contract slowly but maintain concentration for a long period of time They rely on aerobic respiration THe have many mitochondria/large blood supply/ a high concentration of myoglobin Their main strogaeb fuel is fats Marathon runners have lots of slow twitch muscle fibres

Question 29

Give an account of fast twitch muscle fibres

Answer 29

Contract quickly but cannot maintain contractions for a long time They generate ATP through glycolysis They have few mitochondria and a low blood supply Their main storage fuel source are glycogen and creatine phosphate Sprinters have lots of fast twitch muscle fibres