Respiration

Question 1

Where does glycolysis take place?

Answer 1

Cytoplasm

Question 2

What is the purpose of respiration?

Answer 2

Release ATP

Question 3

Is oxygen needed for glycolysis?

Answer 3

No
Glycolysis is the first series of reactions in both anaerobic and aerobic respiration.

Question 4

Name the chemical made when glucose is phosphorylated.

Answer 4

Glucose –> glucose phosphate

Question 5

How is triose phosphate made during glycolysis?

Answer 5

Glucose is phosphorylated to form glucose phosphate using ATP
Glucose phosphate is hydrolysed to form 2 molecules of triose phosphate

Question 6

Describe what happens to triose phosphate in glycolysis.

Answer 6

Triose phosphate -> pyruvate + ATP + NADH

Triose phosphate is oxidised to form pyruvate.

Question 7

In anaerobic reparation what is pyruvate converted into?

Answer 7

In animals - Lactate
In plants and yeast - Ethanol and carbon dioxide.

Question 8

What happens to NADH when pyruvate is converted into lactate?

Answer 8

Oxidised to regenerate NAD.
This allows glycolysis to continue

Question 9

Give 3 differences between aerobic and anaerobic respiration.

Answer 9

Aerobic releases more ATP than anaerobic.

Aerobic produces carbon dioxide and water whereas anaerobic produces lactate or ethanol + carbon dioxide.

Aerobic requires oxygen whereas anaerobic does not require oxygen.

Question 10

Which type of transport is used to get pyruvate into the mitochondria?

Answer 10

Active transport.

Question 11

Which organelle is responsible for aerobic respiration

Answer 11

Mitochondria

Question 12

Where precisely does Krebs’ cycle and the link reaction take place?

Answer 12

Matrix of mitochondria.

Question 13

Where precisely does the electron transport chain and oxidative phosphorylation take place.

Answer 13

Inner membrane of mitochondria.

Question 14

How is acetate made from pyruvate?

Answer 14

Pyruvate is oxidised / NADH is made.

Question 15

What is the name of the coenzyme that carries acetate.

Answer 15

Coenzyme A

Question 16

Name the process used to make ATP in Krebs’ cycle.

Answer 16

Substrate level phosphorylation.

Question 17

Name the particles transported into the intermembrane space during electron transport chain.

Answer 17

Protons or H+ ions

Question 18

Name the enzyme used to make ATP.

Answer 18

ATP synthetase

Question 19

How is energy provided to transport the protons/H+ into the intermembrane space?

Answer 19

Electrons lose energy as they travel along the electron transport chain. This energy is used to actively transport the protons into the intermembrane space.

Question 20

Name the four main stages of aerobic respiration

Answer 20

Glycolysis
Link reaction
Krebs cycle
Oxidative phosphorylation

Question 21

Outline the stages of glycolysis

Answer 21

Glucose is phosphorylated to glucose phosphate using 2 ATP
Glucose phosphate is hydrolysed into 2 molecules of triose phosphate.
Each triose phosphate is oxidised to make pyruvate releasing NADH and ATP

Question 22

What are the products of glycolysis?

Answer 22

2 x Pyruvate
2 x ATP (net)
2 x NADH

Question 23

Describe what happens in the link reaction.

Answer 23

Pyruvate is oxidised and decarboxylated
To form acetyl
NADH is produced
Carbon dioxide is released
Acetyl is attached to Coenzyme A

Question 24

Name the co enzymes involved in aerobic respiration

Answer 24

NAD
FAD
Coenzyme A

Question 25

What is a coenzyme?

Answer 25

A non-protein molecule which is needed for an enzyme to work

Question 26

Where does oxidative phopshorylation occur?

Answer 26

Cristae (inner membrane) of mitochondria

Question 27

Describe the process of oxidative phosphorylation within the mitochondria

Answer 27

NADH/FADH release electrons Electron pass along electron transfer chain Energy released caused protons to be pumped into the intermembrane space creating a electrochemcial gradient Protons/H+ diffuse through ATP synthase ATP is made from ADP and Pi Electrons form ETC move to oxygen (terminal electron acceptor)

Question 28

Why is oxygen needed for aerobic respiration?

Answer 28

Final electron acceptor H+ and electron transport change would stop NAD and FAD could not be reformed Other stages of respiration would stop

Question 29

The energy not harvested during the electron transport chain is lost as ...

Answer 29

Heat

Question 30

The mitochondria of metabolically active cells have more densely packed cristae. How does this help these cells?

Answer 30

Greater surface area of inner membrane provides more space for electron transport proteins and enzymes. Increases rate of oxidative phosphorylation

Question 31

What is the benefit of an electron transport chain rather than a single reaction?

Answer 31

Energy released in a more gradual way. Minimises energy wasted as heat.

Question 32

Which reaction is the only source of ATP in anaerobic conditions?

Answer 32

Glycolysis

Question 33

Can glucose cross the mitochondrial membrane?

Answer 33

No Glycolysis used to break it down to pyruvate which is then transported across the membrane.

Question 34

What is the equation for anaerobic respiration in plants and microorganisms?

Answer 34

Pyruvate + NADH --> Ethanol + CO2 + NAD

Question 35

What is the equation for anaerobic respiration in animals?

Answer 35

Pyruvate + NADH --> Lactate + NAD

Question 36

How does pyruvate enter the mitochondria?

Answer 36

Active transport

Question 37

Describe what happens in the Krebs cycle

Answer 37

Acetyl added to a 4C molecule to form a 6C molecule Decarboxylation released 2 X CO2 NAD and FAD are reduced ATP produced by substrate level phosphorylation

Question 38

Name 2 types of molecule that can e used as alternative respiratory substrates

Answer 38

Amino acids from proteins Glycerol and fatty acids from lipids

Question 39

How can lipids be used an a respiratory substrate?

Answer 39

Lipid --> glycerol + fatty acids Glycerol is phosphorylated to form triose phosphate Fatty acids converted into acetyl

Question 40

How can amino acids be used an a respiratory substrate?

Answer 40

Amino aid is deaminated to form: 3C compounds converted to pyruvate 4C/5C compounds form intermediates in Krebs cycle

Question 41

Name the stages of respiration that produce ATP by substrate level phosphorylation

Answer 41

Glycolysis Krebs cycle

Question 42

What is the advantage of producing ethanol/lactate during anaerobic respiration?

Answer 42

Converts NADH back into NAD so glycolysis can continue.

Question 43

What is the disadvantage of producing ethanol during anaerobic respiration?

Answer 43

Ethanol is a poison causing cells to die Ethanol dissolves cell membranes.

Question 44

What is the disadvantage of producing lactate during anaerobic respiration?

Answer 44

Acidic so decreases pH Results in muscle fatigue

Question 45

How many membranes does pyruvate need to pass through to enter the matrix of the mitochondria

Answer 45

2