Respiration

Question 1

What are the two types of respiration and the difference between the two?

Answer 1

Aerobic is with oxygen while anaerobic is without oxygen

Question 2

What is the equation for aerobic respiration? Word+symbol

Answer 2

Glucose + oxygen = water + carbon dioxide + Energy

C6H12O6 + 6O2 ➡️ 6H2O + 6CO2 + Energy

Question 3

Name 4 properties of ATP:

Answer 3

• Releases small/ manageable amount of energy at a time so no energy is wasted as heat
• small soluble membrane that can be easily transported around the cell
• Easily broken so energy can be release instantaneously
• can be quickly remade
• Can make other molecules more reactive by transferring a phosphate group to them
• can’t pass out of the cell, so the cells always have an immediate supply of energy

Question 4

What is the compensation point?

Answer 4

Particular level of light intensity at which the rate of photosynthesis matches the rate of respiration.

Question 5

Where does respiration take place in the cell?

Answer 5

Mitrocondria

Question 6

What are the 4 stages of aerobic respiration?

Answer 6

1. Glycolysis
2. The link reaction
3. The Krebs cycle
4. Oxidative Phosphorylation

Question 7

What is a coenzyme and the name the ones present in respiration?

Answer 7

A molecule that aids the function of an enzyme by transferring a chemical group from one molecule to another.

NAD
FAD
Coenzyme A

Question 8

What is a good scientific name for glucose during this reaction?

Answer 8

A respiratory substrate

Question 9

Where does glycolysis take place in the mitochondria?

Answer 9

In the cytoplasm

Question 10

Glycolysis is split into two stages. What are they? And describe what happens in each one.

Answer 10

Phosphorylation:
Glucose is phosphorylated using a phosphate group from an ATP molecule forming glucose phosphate and ADP. A phosphate group is added to glucose phosphate from another ATP molecule to form hexose bisphosphate and another ADP.

Hexose bisphosphate is split into two molecules of triode phosphate.

Oxidation:
Triose phosphate is oxidised form two molecules of pyruvate. NAD collects the hydrogen ions forming 2 reduced NAD molecules. While 4 ATP molecules are produced.

Question 11

Why does ATP have a net gain of 2 at the end of glycolysis?

Answer 11

This is because two ATP molecules are used in the phosphorylation of glucose in glycolysis.

Question 12

End products of Glycolysis and where they go?

Answer 12

2 reduced NAD - oxidative phosphorylation

2 pyruvate - actively transported into the mitochondrial matrix for use in the link reaction

4 ATP - 2 used again for glycolysis and the rest used for energy

Question 13

In anaerobic respiration what happens to the pyruvate produced in glycolysis?

Answer 13

In plants: Converted into ethanal by decarboxylated pyruvate and then produces ethanol by oxidised reduced NAD into NAD.

Products: Ethanol + NAD

Animals: Lactate is formed while reduced NAD is oxidised into NAD.

Products: Lactate + NAD

Question 14

Why is production of NAD from reduced NAD after glycolysis important?

Answer 14

It means glycolysis can continue even when there isn’t much oxygen around, so small amount of ATP can be reproduced to keep biological processes going.

Question 15

Where does the link reaction happen in the mitochondria and what happens during the link reaction?

Answer 15

Mitochondrial matrix

Pyruvate is decarboxylated and is oxidised at the same time to form acetate and NAD is reduced to form reduced NAD.

Acetate is then combined with with Coenzyme A to form acetyl coenzyme a. ATP is not produced in this reaction.

Question 16

How many times does the link reaction happen per glucose molecule?

Answer 16

It happens twice as two pyruvate are formed and the link reaction occurs for each pyruvate.

Question 17

Products of link reaction and where do they go?

Answer 17

2 acetyl coenzyme A - goes to kreb cycle

2 carbon dioxide - released as a waste product

2 reduced NAD - goes to oxidative phosphorylation

Question 18

Where does the kreb cycle take place and what happens within it?

Answer 18

Matrix of mitochondria

Acetyl coenzyme a combined with a four carbon compound to form a 6 carbon compound (citrate). The coenzyme goes back to the link reaction to be used again

The 6 carbon compound is decarboxylated to form a 5 carbon compound. Dehydrogenation of NAD occurs to produce reduced NAD.

The 5 carbon compound is then decarboxylated again a four carbon compound. Dehydrogenation also occurs to form one molecule of reduced FAD, 3 molecules of reduced NAD. ATP is produced from ADP and Pi. Citrate is then converted in oxaloacetate.

Question 19

What is substrate level phosphorylation?

Answer 19

When a phosphate group is directly transferred from one molecule to another

Question 20

What is produced during the kreb cycle and where do they go?

Answer 20

1 coenzyme - link reaction

Oxaloacetate - regenerated for use in next Krebs cycle

2 carbon dioxide - released as a waste product

1 ATP - used for energy

3 reduced NAD - oxidative phosphorylation

1 reduced FAD - oxidative phosphorylation

Question 21

Where does oxidative phosphorylation take place and what happens?

Answer 21

Inner mitochondrial membrane

Hydrogen atoms released from reduced NAD and FAD are split into protons (H+) and electrons (e-). Reduced NAD and FAD are oxidised to make NAD and FAD.

The electrons move down the electron transport chain in the inner mitochondrial membrane, losing energy at each other.

This energy is needed to pump protons from the matrix into the inter membrane space.

The concentration of protons becomes greater in the inter membrane space than the mitochondrial matrix forming an electrochemical gradient.

Protons move back into the matrix via ATP synthase. This provides energy for the synthesis of ATP from ADP and Pi.

In the matrix, the proton, electrons and oxygen (final electron acceptor) combine to form water.

Question 22

What is effected by mitochondrial diseases? Ways it can affect other stages in respiration? Outcome of these diseases

Answer 22

ATP production

Can also affect proteins involved in oxidative phosphorylation and the Krebs cycle

Causes an increase in anaerobic respiration which mean more lactate is produced which leads to muscle fatigue and weakness.