Respiration

Question 1

What is respiration

Answer 1

the process of braking down glucose to produce energy that can be used in a cell (ATP)

Question 2

What is the equation for respiration

Answer 2

Glucose + Oxygen –> Carbon dioxide and water

C6H12O6 + 6O2 –> 6CO2 + 6H20 + 38ATP

Question 3

What are the stages of respiration

Answer 3

Glycolysis
Link Reaction
Krebs Cycle (Citric acid cycle)
Electron transport chain (Oxidative phosphorylation)

Question 4

Which stage of respiration is present in both aerobic and anaerobic respiration

Answer 4

Glycolysis

Question 5

Where does aerobic respiration take place

Answer 5

Mitochondria

Question 6

Where does glycolysis take place

Answer 6

Cytoplasm

Question 7

Describe the process of glycolysis

Answer 7

• Glucose is phosphorylated to make glucose phosphate- 6 carbon (1 ATP USED)
• Glucose phosphate is phosphorylated to fructose bisphosphate -6 carbon- (1 ATP USED)
• Fructose Bisphosphate is split into 2 molecules of triose phoshate
• each triose phosphate molecule is oxidised to pyruvate (1 NAD -> NADH and 2ADP -> 2ATP per molecule of pyruvate)

Question 8

What is the net gain of Glycolysis

Answer 8

2 ATP

2 NADH

Question 9

What is NAD

Answer 9

Coenzyme that gets reduced to NADH

NADH is a reducing agent

Question 10

What happens to Pyruvate in anaerobic conditions

Answer 10

NADH reduces pyruvate to lactate releasing 1 ATP

or ethanol in yeast

Question 11

What is the link reaction

Answer 11

pyruvate enters mitochondrial matrix
2 Pyruvate are decarboxylated (CO2 is removed and NAD -> NADH) to acetate which joins with co enzyme A to form ACETYL CoA

Question 12

Describe the process of the Krebs cycle

Answer 12

• Acetyl Co A reacts with 4 carbon molecule (oxaloacetate) to form 6 carbon molecule and releases CoA
• 6 carbon molecule decarboxylated -> 5 carbon compound (reduced NAD formed) (CO2 released
• 5 carbon compound-> 4 carbon compound (reduced NAD FORMED, ATP FORMED) (CO2 released
• 4 carbon compound-> 4 Carbon compound (reduced FAD released)
• 4 carbon compound-> 4 carbon compound (oxaloacetate) (reduced NAD)

Question 13

What is the product of the Krebs cycle for 1 molecule of Glucose

Answer 13

6 NADH
2 FADH2
2 ATP
4 CO2

Question 14

Where does the electron transport chain take place inn respiration

Answer 14

inner membrane of the mitochondrion

Question 15

What process happens in the electron transport chain

Answer 15

Oxidative phosphorylation

Question 16

How many reducing agents enter the ETC from 1 molecule of glucose

Answer 16

• 10 NADH (2 from glycolysis, 2 from link reaction, 6 from Kreb cycle)
• 2FADH (from Kreb cycle)

Question 17

How many molecules of ATP are produced (indirectly) by NADH

Answer 17

3 molecules ATP

Question 18

How many molecules of ATP are produced (indirectly) by FADH

Answer 18

2 molecules ATP

Question 19

How does the electron transport chain work

Answer 19

• NADH loses its electron to the first complex in the electron transport chain. H+ is released from NADH-> NAD+
• the electron now in the first electron accepting complex is at a lower energy level. the energy lost is used to actively pump H+ ions into the intermembrane space
• FADH2 also loses its electron and H+ further down the chain.
• The H+ diffuses down its concentration gradient back across the inner mitochondrial membrane through ATP synthase which uses the chemosmotic gradient to produce ATP

Question 20

What other organic substances can be used in respiration

Answer 20

Lipids
proteins
both are added into the kreb cycle.

Question 21

How are lipids used in respiration

Answer 21

fatty acid and glycerol are hydrolysed

fatty acid broken into acetyl and join with co A to enter Kreb cycle

Question 22

What is net primary productivity

Answer 22

it represents the dry mass and gross production minus the respiratory losses