Cellular Respiration

Question 1

What is a catabolic pathway

Answer 1

Metabolic pathway that releases stored energy by breaking down complex molecules

Question 2

What is a redox reaction

Answer 2

Reaction that involves reduction and oxidation
R - gain of electrons
O - loss of electrons

Question 3

What is NAD and which form is oxidised and which form is reduced

Answer 3

A coenzyme that is a high energy electron carrier
O - NAD+
R - NADH

Question 4

What are the 3 steps in cellular respiration and where do they occur

Answer 4

Glycolysis - Cytoplasm
Pyruvate oxidation and Kreb’s cycle - Mitochondrial matrix
Oxidative phosphorylation - Inner mitochondrial membrane

Question 5

step 1 - What does Hexokinase (with 1 ATP) convert glucose into

Answer 5

Glucose-6-Phosphate

Question 6

step 2 - Glucose-6-Phosphate is converted into one of its isomer - which one and what enzyme is used

Answer 6

Fructose-6-Phosphate
Phosphoglucoisomerase

Question 7

step 3 - A phosphate group is then added to Fructose-6-phosphate using 1 ATP- what is made and what enzyme is used

Answer 7

Fructose-1,6-bisphosphate
Phosphofructokinase

Question 8

step 4 - Fructose-1,6-bisphosphate is broken down into one of 2 2 3C molecules - What are these and what enzyme is used

Answer 8

Glyceraldehyde-3-phosphate (G3P)
Dihydroxyacetone phosphate (DHAP)
Aldolase

Question 9

step 5 - G3P and DHAP can be converted between one another by what enzyme

Answer 9

Isomerase

Question 10

step 6 - Each G3P is converted into 1,3-bisphosphoglycerate - what enzyme does this and what is produced

Answer 10

Triose phosphate dehydrogenase
NADH

Question 11

step 7 - Phosphoglycerokinase breaks down 1,3-bisphosphoglycerate into what - what is produced

Answer 11

3-Phosphoglycerate
1 ATP

Question 12

step 8 - The phosphate group is moved onto another carbon in 3-Phosphoglycerate to form what - what enzyme is used

Answer 12

2-Phosphoglycerate
Phosphoglyceromutase

Question 13

step 9 - 2-phosphoglycerate is converted to Phosphoenol-pyruvate (PEP) - what enzyme does this and what is formed

Answer 13

Enolase
1 H2O

Question 14

What are the net products formed from glycolysis from 1 glucose molecule

Answer 14

2 ATP
2 NADH
2 Pyruvate
2 H2O

Question 14

step 10 - Outline the product formed from PEP, what enzyme is used and what else is produced

Answer 14

Pyruvate
Pyruvate Kinase
1 ATP

Question 15

What multienzyme is used in Pyruvate oxidation

Answer 15

Pyruvate dehydrogenase complex

Question 16

step 1 - What is removed from pyruvate to form a 2C fragment and what else is produced

Answer 16

Carboxyl group
CO2

Question 17

step 2 - What is formed when the 2C fragment is oxidised and what else is produced

Answer 17

Acetate
NADH

Question 18

step 3 - What happens to the acetate group

Answer 18

Coenzyme A is added to form Acetyl CoA

Question 19

What are the net products formed from Pyruvate oxidation from 1 glucose molecule

Answer 19

2 Acetyl CoA
2 CO2
2 NADH

Question 20

What are the net products formed from the Kreb’s cycle

Answer 20

4 CO2
2 ATP
6 NADH
2 FADH

Question 21

What is substrate level phosphorylation

Answer 21

When an enzyme adds a phosphate group to ADP to form ATP

Question 22

What are the three main steps in oxidative phosphorylation

Answer 22

ETC, Chemiosmosis and ATP synthase

Question 23

Give a basic over view of the ETC (3)

Answer 23

Electrons are donated by carriers to ETC
Energy is lost each time they move from one protein complex to another
This energy is used to pump H+ ions from the matrix into the intermembrane space

Question 24

What are the prosthetic groups on the innermembrane proteins also called

Answer 24

Redox centres

Question 25

Where are NADH's (2) and FADH's electrons transferred to - what is the redox centre

Answer 25

NADH - Complex I - FMN then FE.S FADH - Complex II - FE.s

Question 26

What are the electrons passed to after complex I and II - why can it move within the membrane

Answer 26

Ubiquone / Coenzyme Q It is a non-proteinous hydrophobic enzyme

Question 27

What are complex III and IV made up of

Answer 27

Cytochromes

Question 28

Where do the electrons end up at the end of the ETC

Answer 28

With oxygen to form water

Question 29

How is the PMF created

Answer 29

As electrons move down the ETC the transmembrane complexes use the energy to pump H+ ions from the matric into the innermembrane space

Question 30

Where do the H+ ions enter the ATP synthase

Answer 30

At the Stator

Question 31

H+ then enters the rotor causing what to lead to what

Answer 31

A conformational change leading to the spinning of the rotor

Question 32

What does the spinning rotor also cause to spin

Answer 32

The rod

Question 33

What does the rod extend into and what does this activate

Answer 33

Catalytic knob Catalytic sites to allow joining of ADP to Pi

Question 34

Overall net gains of ATP for Cellular respiration

Answer 34

30 ATP

Question 35

3 reasons why an exact number of ATP molecules cannot be stated

Answer 35

Phosphorylation and redox are not directly coupled - ATP won’t be a whole number PMF can be used to drive other kinds of work Yield will vary depending on proteins used to transport electrons