13.4 Respiration

Question 1

What is the word equation for respiration?

Answer 1

Glucose + oxygen –> Carbon dioxide + Water + ATP

Question 2

What is the number equation for respiration?

Answer 2

C6H12 + 6O2 –> 6CO2 + 6H2O + ATP

Question 3

Why is ATP useful?

Answer 3

ATP can be dephosphorylated and phosphorylated again many times
It is a single step process
It is an immediate source of energy
Provides small packets of energy
Cannot pass out of cells

Question 4

How is a mitochondria adapted to its function?

Answer 4

Large surface area - it has folded Cristae for more ETC
Matrix full of ribosomes and enzymes to complete the Krebs cycle
Small inter membrane space to build up a proton gradient quickly

Question 5

Name the 4 process’ of aerobic respiration

Answer 5

Glycolysis
Link reaction
Kreb’s cycle
Electron transport chain

Question 6

Where does glycolysis take place?

Answer 6

Cytoplasm of the cell

Question 7

Where does the link reaction take place?

Answer 7

Matrix of the mitochondria

Question 8

Where does the Kreb’s cycle take place?

Answer 8

Matrix of the mitochondria

Question 9

Where does the electron transport chain occur?

Answer 9

Intermembrane space

Question 10

What are the two ways that ATP can be generated?

Answer 10

Substrate level phosphorylation
Oxidation phosphorylation

Question 11

What is substrate level phosphorylation and where does it occur?

Answer 11

When ATP is generated directly through energy released via respiration
Glycolysis and the Krebs cycle

Question 12

What is oxidative phosphorylation and where does it occur?

Answer 12

When ATP is generated from the chemical energy released when a reduced hydrogen carrier our coenzyme has been oxidised
Electron transport chain

Question 13

What is produced in glycolysis?

Answer 13

2 net ATP molecules
2 reduced NAP molecules
2 pyuruvate molecules

Question 14

Describe glycolysis

Answer 14

Glucose is phosphorylated twice in order to produce phosphorylated glucose. The phosphate molecules are provided by the hydrolysis of ATP.
The unstable glucose molecules splits up into 2 3 carbon compounds, triode phosphate.
each trios phosphate is then oxidised too pyruvate which involves the loss of a hydrogen via dehydrogenase.
This reduces NAD to reduced NAD.
The energy produced at this step also 1 ATP molecule via substrate level phosphorylation

Question 15

Describe the link reaction

Answer 15

Pyruvate is actively transported into the matrix of the mitochondria.
Pyruvate is oxidised to acetate, this produces one carbon dioxide molecule and reduces an NAD molecule
Coenzyme A combines with the acetate to form acetyl coenzyme A

Question 16

What is produced in the link reaction?

Answer 16

Reduced NAD
CO2
Acetyl coenzyme A

Question 17

Describe the Krebs cycle

Answer 17

Acetyl coenzyme A combines with a 4 carbon compound to produce a 6 carbon compound
The 6 carbon compound loses a CO2 molecule and a hydrogen which reduced NAD
The 5 carbon compound then loses another carbon dioxide molecule and 2 hydrogen molecules, 2 NAD and an FAD are reduced
Enough energy is also produced to provide 1 molecule of ATP
The cycle continues

Question 18

What is produced in the Krebs cycle?

Answer 18

2 CO2 molecules
3 reduced NAD
Reduced FAD
1 molecule of ATP via substrate level phosphoprylation

Question 19

How many times does the kerbs cycle occur per molecule of glucose?

Answer 19

Twice

Question 20

Describe the electron transfer chain

Answer 20

The reduced FAD and NAD are oxidised by losing hydrogen.
The electrons from the hydrogen atom are passed down a series of electron carriers, losing energy in a series of redox reactions.
The energy is then used to pump the protons through the inner membrane into the inter membrane space.
Some of the energy is lost through heat.
The H+ ions diffuse down a proton gradient across the inner membrane via ATP synthase, producing ATP
The electrons recombine with the hydrogens to form water.
Oxygen is the final electron acceptor.

Question 21

Water is a waste product in aerobic respiration, describe how it is formed

Answer 21

Oxygen is the final electron acceptor
The oxygen, electrons and hydrogen ions recombine to form water

Question 22

Describe how ATP is made in the mitochondria

Answer 22

• Substrate level phosphorylation produces ATP in the Krebs cycle
• Krebs cycle and link reaction produces reduced NAD and FAD
• The electrons released from the reduced FAD and NAD pass along a series of carrier proteins through a series of redox reactions
• Energy is released and protons are pumped into the inter membrane space
• ATP is formed from ADP and Pi from the protons diffusing through the ATP synthase

Question 23

Describe the roles of the coenzyme and carrier proteins in the synthesis of ATP

Answer 23

• Reduced NAD and FAD
• Electrons transferred from the coenzyme to coenzyme via a series of redox reactions
• Energy released as electrons passed along 0
• The energy is used to synthesise ATP ATP from ADP and Pi using ATP synthase
• H+ ions pumped into the inter membrane space
• H+ ions diffuse back through ATP synthase

Question 24

Describe how oxidation takes place in glycolysis and the Krebs cycle

Answer 24

• Removal of hydrogen any dehydrogenase
• H accepted by NAD and forms reduced NAD
• In the Krebs cycle FAD is reduced too

Question 25

What isanaerobic respiration.

Answer 25

Respiration in the absence of oxygen