Cellular Respiration

Question 1

What is respiration

Answer 1

A series of metabolic pathways that allow chemical energy to be released from food molecules in the form of ATP

Question 2

What is the role of ATP inside a cell

Answer 2

Used to transfer energy to cellular processes that require energy. Such as anabolic reaction and M.M.A.T.S

Question 3

Name the enzyme involved in the production of ATP

Answer 3

ATP synthase

Question 4

What are the three stages of ATP synthesis ?

Answer 4

1) Glycolysis
2) Citric Acid Cycle
3) Electron Transport Chain

Question 5

What are the locations of the three stages of ATP synthesis?

Answer 5

Glycolysis - cytoplasm
citric acid cycle - in the matrix of the mitochondria ( as there are lots of enzymes present which makes reactions easier)
Electron transport chain - on the inner mitochondrial membrane

Question 6

What are the three parts of the mitochondria

Answer 6

1) Smooth outer membrane
2) (Highly folded) inner membrane
3) matrix of the mitochondria (inside inner membrane) *see PLP

Question 7

Describe glycolysis

Answer 7

-Glucose is broken down into two molecules of pyruvate
Energy investment phase - Two molecules of ATP are required for the phosphorylation of glucose and intermediates.
Energy Pay off phase - 4x molecules of ATP are produced and results in a net gain of 2x ATP, Dehydrogenase enzymes Remove hydrogen ions and electrons from intermediates and pass them to coenzyme NAD to form NADH

Question 8

What do coenzymes do ?

Answer 8

Move stuff

Question 9

Describe what happens to pyruvate under aerobic conditions (fate of pyruvate)

Answer 9

Pyruvate is broken down to an Acetyl group that combines with coenzyme A to form Acetyl coenzyme A

Question 10

What happens in the citric acid cycle

Answer 10

1) The acetyl group from acetyl coenzyme A combines with oxaloacetate to form citrate.
2) During a series of enzyme controlled steps, citrate is gradually converted back into oxaloacetate, this results in the generation of ATP and the release of carbon dioxide.

Dehydrogenase enzymes Remove hydrogen ions and electrons from intermediates and pass them to coenzyme NAD to form NADH which is then passed on to the electron transport chain (NAD is a coenzyme)

Question 11

What is the purpose of NADH

Answer 11

To carry and pass the hydrogen ions and electrons from NADH to the electron transport chain on the inner mitochondrial membrane.

Question 12

What is the electron transport chain

Answer 12

It consists of a series of carrier proteins attached to the inner mitochondrial membrane

Question 13

Outline what happens during the electron transport chain

Answer 13

1) NAD releases high energy electrons along the electron transport chain.
2) This energy allows hydrogen ions from NADH to be pumped across the inner mitochondrial membrane.
3) Hydrogen ions flow back through the membrane proteins ATP synthase which generates a high quantity of ATP.
4) Hydrogen ions and electrons combine with oxygen to form water.

Question 14

What is the function of oxygen in the electron transport chain

Answer 14

It is the final hydrogen/electron acceptor (combines with exiting hydrogen ions and electrons to form water)

Question 15

Why is lactate produced ?

Answer 15

-During intense exercise muscle cells do not receive enough oxygen to support the electron transport chain.
-Under these anaerobic conditions pyruvate is converted to lactate which causes muscle fatigue.
-This regenerates the NAD required to maintain ATP production during glycolysis.

Question 16

How is lactate produced?

Answer 16

-Lactate metabolism involves the transfer of hydrogen ions from NADH, produced during glycolysis, to pyruvate to produce lactate.
-This regenerates the NAD required to maintain ATP production during glycolysis.

Question 17

When is oxygen debt repaid

Answer 17

Oxygen debt is the temporary lack of oxygen availability in muscle cells after/during intense exercise, body cannot provide enough oxygen to breakdown lactate.
-Oxygen debt is repaid when exercise is complete, this allows lactate to be converted back to pyruvate and glucose in the liver.

Question 18

What are the two types of skeletal muscle

Answer 18

Type 1 - Slow twitch muscle fibres
Type 2 - Fast twitch muscle fibres

Question 19

What are features of type 1, slow twitch, muscle fibres

Answer 19

1) slow twitch muscle fibres have a slow speed of contraction, they sustain a long contraction time and the have a slow speed of which they become fatigued.
2) Aerobic respiration is the respiratory pathway usually used to generate ATP, in slow twitch muscle fibres
3) slow twitch muscle fibres have many mitochondria and a high concentration of myoglobin
4) slow twitch muscle fibres use fats as their major storage fuel.
5) slow twitch muscle fibres are used for endurance events such as long distance running, they also have a large blood supply.

Question 20

What are the features of type 2, fast twitch, muscle fibres

Answer 20

1) Fast twitch muscle fibres have a fast speed of contraction, they sustain a short length of contraction and have a fast speed to become fatigued.
2) Glycolysis is the only respiratory pathway used to generate ATP in Fast twitch muscle fibres.
3) Fast twitch muscle fibres have fewer mitochondria and a lower concentration of myoglobin.
4) Fast twitch muscle fibres use glycogen as their major storage fuel.
5) Fast twitch muscle fibres are used for power evets, such as power lifting, sprinting and weightlifting, they also has a lower blood supply.

Question 21

What is myoglobin

Answer 21

Myoglobin is an oxygen storing protein present in muscle cells. It can extract oxygen from the blood for use by muscle cells.

Question 22

How would the structure of a human muscle tissue differ from one athlete to another ?

Answer 22

Most human muscle tissue contain a mixture of both slow and fast twitch muscle fibres.
-Athletes show distinct pattern of muscle fibres that reflects their sporting activity.