Respiration

Question 1

Name the 4 stages of aerobic respiration?

Answer 1

1)glycolysis
2)link reaction
3)Krebs cycle
4) oxidative phosphorylation

Question 2

Where does glycolysis occur?

Answer 2

In the cytoplasm

Question 3

Define glycolysis

Answer 3

Breaking down glucose into Pyruvate whilst producing ATP and harvesting protons and electrons along the way

Question 4

What is the overall yield of ATP in glycolysis?

Answer 4

2( 4 is produced but 2 is invested)

Question 5

What is the overall yield of NADH

Answer 5

2

Question 6

What is the overall yield of Pyruvate?

Answer 6

2

Question 7

ET: ATP is useful in many biological processes. Explain why [4]

Answer 7

-releases energy in small/manageable amounts
-broken down in one step/makes energy available rapidly
-phosphorylates
-reformed

Question 8

ET: explain why it is important for plants to produce ATP during respiration in addition to photosynthesis [5]

Answer 8

-in dark no ATP production in photosynthesis
-some tissues unable to photosynthesise/produce ATP
-ATP cannot be moved from cell to cell/stored
-plants use more ATP than produced in photosynthesis
-ATP for active transport

Question 9

ET: Describe glycolysis [5/6]

Answer 9

-glucose is phosphorylated into glucose phosphate using 2x ATP
-glucose phosphate breaks down into 2x Triose phosphate
-2x Triose phosphate are oxidised into 2x Pyruvate using 2x NAD
-this forms 2x NADH and 4x ATP
-this occurs in cytoplasm

Question 10

ET: describe the link reaction

Answer 10

-oxidation of Pyruvate (with NAD)to remove hydrogen and release CO2
-addition of coenzyme A to produce acetyl CoA

Question 11

Where does the link reaction take place?

Answer 11

Mitochondria (matrix)

Question 12

Where does the Krebs cycle take place?

Answer 12

Mitochondria (matrix)

Question 13

ET:Describe what happens in the Krebs cycle

Answer 13

-acetyl co enzyme A combines with a 4 carbon molecule to form a 6 carbon molecule
-the 6 carbon molecule is oxidised into a 5 carbon molecule using NAD+. Decarboxylation occurs.
-the 5 carbon molecule is oxidised into a 4 carbon molecule using FAD+. Decarboxylation occurs.
-ATP is also generated.

Question 14

ET: Describe how ATP is made in the mitochondria [6]

Answer 14

1. ATP produced in Krebs cycle.
2. Krebs cycle / link reaction produces reduced coenzyme / reduced
   NAD / reduced FAD; Accept description of either Krebs cycle or
   link reaction
3. Electrons released from reduced / coenzymes / NAD / FAD;
4. Electrons pass along carriers / through electron transport chain /
   through series of redox reactions;
5. Energy released
6. Protons move into intermembrane space; Allow description of
   movement through membrane
7. ATP synthase; Accept ATPase. Reject stalked particles
8. ADP / ADP + Pi; Accept H+ or hydrogen ions and cristae

Question 15

ET: explain why oxygen is needed for the production of ATP on the cristae of the mitochondrion [3]

Answer 15

-ATP formed as electrons pass along transport chain
-oxygen accepts electrons from electron transport chain
-forms H2O/oxidises reduced NAD

Question 16

ET:Human skeletal muscle can respire both aerobically and anaerobically. Describe
what happens to pyruvate in anaerobic conditions and explain why anaerobic
respiration is advantageous to human skeletal muscle. [4]

Answer 16

-forms lactate
-use of reduced NAD
-regenerates NAD
-NAD can be reused to oxidise more respiratory substrate
-can still release energy from ATP when oxygen is in short supply

Question 17

Where does the electron transfer chain occur in the cell?

Answer 17

Cytoplasm

Question 18

Explain why less ATP is produced by respiration without oxygen

Answer 18

Oxygen is the termina/ acceptor;(No) electron transfer chain / proton transfer / no
oxidative phosphorylation; Accept ETC abbreviation
Which produces most of the ATP (in aerobic respiration);Only glycolysis takes
place;Pyruvate used to make lactate; Accept lactic acid

Question 19

Draw the diagram for glycolysis

Answer 19

Question 20

Draw the diagram for link reaction

Answer 20

Question 21

Draw the diagram for Krebs cycle

Answer 21

Question 22

where does oxidate phosphorylation occur?

Answer 22

Through the cristae of the mitochondria

Question 23

what does oxidative phosphorylation involve the use of, and which cycle is it from?

Answer 23

NADH and FADH2 from the krebs cycle.
They are used to start a series of redox reactions.
Energy is harvested from these reactions

Question 24

finish the sentence:
The transfer of electrons through the electron transfer chain…

Answer 24

-provides energy to the inner membrane proteins.
-allows protons to be transferred from the matrix to the intermembrane space. (By active transport)

Question 25

finish the sentence: The transfer of protons from the intermembrane space to the matrix happens via…

Answer 25

Chemiosmosis

Question 26

finish the sentence: In the final inner membrane protein, the electrons react with oxygen and protons to form…

Answer 26

Water

Question 27

chemiosmosis occurs through wich enzyme?

Answer 27

ATP synthase

Question 28

in which of the 4 stages of aerobic respiration is NAD produced?

Answer 28

Oxidative phosphorylation

Question 29

during which of the 4 stages of aerobic respiration is NADH produced?

Answer 29

Glycolysis Link reaction Krebs cycle

Question 30

during which of the 4 stages of aerobic respirtion is both NADH and FADH2 required?

Answer 30

Oxidative phosphorylation

Question 31

in which of the 4 stages is there a net yield of 2 ATP molecules?

Answer 31

Glycolysis Krebs cycle

Question 33

what is the role of oxygen in aerobic respiraton?

Answer 33

Protons produced in glycolysis and the Krebs cycle combine with **oxygen** and electrons to form water which allows ETC to function Final electron acceptor

Question 34

One type of mitochondrial dysfunction prevents the mitochondria cristae from being fully formed. Suggest how a lack of mitochondrial cristae can affect respiration.

Answer 34

There is a smaller surface area of the inner mitochondrial membrane. This means that there are fewer electron transport chains for oxidative phosphorylation. As a result, less ATP is produced in aerobic respiration / oxidative phosphorylation.