5- Energy Transfers in and between organisms

Question 1

Why is oxygen needed for the production of ATP on the Cristae of the mitochondrion.
(3)

Answer 1

ATP is formed as electrons pass along ETC.
Oxygen accepts electrons from ETC
Forms H20/ oxidises reduced NAD

Question 2

Without ATP and reduced NADP why is there less uptake of CO2?

Answer 2

Less GP is converted into TP
Less TP is converted to RuBP

Question 3

Name the substance which combines with CO2 in a chloroplast?

Answer 3

RuBP

Question 4

Why does inhibiting the electron transfer decrease uptake of CO2?
(2)

Answer 4

It decreases ATP producuction
So less reduced NADP is produced

Question 5

Where is NAD reduced?

Answer 5

Glycolysis
Krebs cycle

Question 6

Where is NADP reduced?

Answer 6

Light dependent reaction

Question 7

Where is ATP produced?

Answer 7

Glycolysis
Krebs cycle
Light dependent reaction

Question 8

Where is ATP required?

Answer 8

Glycolysis

Question 9

In the production of ATP from ADP and phosphate, what substrate is added?

Answer 9

Pyruvate

Question 10

In anaerobic respiration what is the net yield of ATP per glucose molecule?

Answer 10

2

Question 11

Give two advantages of ATP as an energy storage molecule ?

Answer 11

Stores / releases small amount of energy
Immediate source of energy

Question 12

Describe how NAD is regenerated in anaerobic respiration in yeast cells?

Answer 12

Formed when reduced NAD is used to reduce pyruvate.

Question 13

Where in the cell is rubisco found?

Answer 13

Stroma

Question 14

If concentration of oxygen increases, what happens to rate of absorption of CO2?

Answer 14

As oxygen concentration increases less rubisco binds with CO2
Competition between oxygen and carbon dioxide for rubisco

Question 15

During the LIR reaction of photosynthesis, carbon dioxide is converted to organic substances.
Describe how
(6)

Answer 15

CO2 combines with RuBP
Produces two GP molecules (this is catalysed by rubisco enzyme)
GP reduced to TP
Using reduced NADP
Using energy from ATP

Question 16

Word equation for photsynthesis?

Answer 16

Carbon dioxide + water + (light) = glucose and oxygen

Question 17

Where is the site of photosynthesis?

Answer 17

Chloroplasts

Question 18

Factors which affect rate of photosynthesis?

Answer 18

Carbon dioxide concentration
Light intensity
Temperature

Question 19

How are chloroplasts adapted for photosynthesis? (4)

Answer 19

• stacks of thylakoid membrane called grana provide large SA
• network of proteins hold the chlorophyll to absorb the max light.
  -ATP synthase channels allow ATP synthesis and proton gradient.
  -contain DNA and ribosomes allowing for shnthesis of proteins.

Question 20

Light dependent reaction (5)
( Photosynthesis stage 1 )

Answer 20

-photons of light hit chlorophyll causing e to become excited (PHOTOIONISATION)
-photolysis of water ( 1 molecule of H2O = 1 O2 + 4H+ + 4e )
- 4 electrons replace lost from chlorophyll and H+ move into stroma
- e moves down ETC provides energy for 4H+ to thylakoid.
- e moves down chain to PSI , e combines with H+ to form Hydrogen
- Used to reduce NADP into NADPH ( reduced NADP)
- Proton gradient with high conc in thylakoid and low conc in stroma move by diffusion.
- Aids photophosphorylation ( enzyme ATP synthase breaks ATP into ADP and phosphate

Question 21

Light independent reaction ( Calvin cycle )
(Photosynthesis Stage 2 )

Answer 21

1. CO2 fixation
   - Diffused through stomata, fixed with RuBP ( carboxylation )
   - rubisco enzyme
   - 6 carbon formed but turns into 2 G3P
2. REDUCTION
   - 2 G3P contains -COOH group (acid)
   - Reduced NADP reduces 2 G3P (ATP provides energy) produces 2TP
3. REGENERATION OF RuBP
   - 5TP regenerate 3RuBP
4. 2TP form hexose sugar and then glucose

6 turns produce 1 molecule of glucose

Question 22

Aerobic respiration definition

Answer 22

Splitting of a respiratory substrate to release CO2 as waste product.
Releases energy

Question 23

Anaerobic respiration definition

Answer 23

Absence of oxygen
Produces lactic acid

Question 24

Where does glycolysis take place

Answer 24

Cytoplasm

Question 25

What does glycolysis produce ?

Answer 25

2 molecules of pyruvate
2 ATP
2 NADH

Question 26

What happens to glucose in glycolysis ?

Answer 26

It is phosphorylated

Question 27

What happens to pyruvate in anaerobic respiration ?

Answer 27

Converted to lactate using NADH

Question 28

What does one molecule of glucose produce in glycolysis?

Answer 28

2 ATP ( net gain )
2 reduced NAP ( NADPH)
2 pyruvate

Question 29

What happens to 2 pyruvate molecules from glycolysis ?

Answer 29

Actively transported to mitochondria for link reaction

Question 30

What enzyme is involved in link reaction ?

Answer 30

Decarboxylase

Question 31

What does Decarboxylase enzyme do in link reaction ?

Answer 31

Removes CO2 with H removed to reduce NAD

Question 32

What are the products of link reaction ?

Answer 32

Acetyl coenzyme A

Question 33

How is acetyl coenzyme A formed ?

Answer 33

Acetate combines with coenzyme A

Question 34

How many acetyl coenzyme A produced per molecule of glucose ?

Answer 34

2

Question 35

Where does the krebs cycle take place ?

Answer 35

Matrix of mitochondria

Question 36

What is given to 4 carbon to produce 6 carbon molecule ?

Answer 36

2 carbon acetate from acetyl coenzyme A

Question 37

How many time does the krebs cycle turn per molecule of glucose ?

Answer 37

2

Question 38

In krebs cycle , per glucose molecule , what are the products ?

Answer 38

2 ATP
6 NADH
2 FADH
4 CO2

Question 39

Process of oxidative phosphorylation ? (4)

Answer 39

1. Reduced NAD ( NADH) from krebs releases hydrogen , protons and electrons
   Reduced FAD ( FADH) releases hydrogen , protons and electrons
   Protons move to mitochondrial matrix and e go to ETC
2. e move down protein complexes with higher affinity. Each H released by NADH, 4 protons pumped across into inter membrane space.
   3.e accepted by final acceptor oxygen, plus hydrogen forming water.
3. Pumping of protons creates proton gradient , so they move through protein channel.
   This provided energy for ATP synthase to produce ATP.

Question 40

Where does the light dependent reaction take place?

Answer 40

Thylakoid membrane

Question 41

Where does the light independent reaction take place?

Answer 41

Stroma

Question 42

Where does the link reaction occur ?

Answer 42

Mitochondrial matrix

Question 43

Where does the krebs cycle occur ?

Answer 43

Mitochondrial matrix

Question 44

Where does oxidative phosphorylation occur ?

Answer 44

Mitochondria