Photosynthesis and respiration

Question 1

What is the equation for photosynthesis?

Answer 1

6CO2 + 6H2O = C6H12O6 (glucose) + 6O2

Question 2

What is the equation for respiration?

Answer 2

C6H1206 + 6O2 = 6CO2 + 6H20 + energy

Question 3

Why is ATP a suitable source of energy in animals?

Answer 3

A small molecule
Simple reaction to hydrolyse into energy
Inorganic phosphate can be used to make compounds more reactive
Can travel via diffusion, soluble can travel easily
Quickly resynthesised and hydrolysed
Can’t pass in or out the cell

Question 4

What does photoionisation mean?

Answer 4

Light energy excites electrons in an atom giving them more energy causing them to be released.

Question 5

Describe the process of the light dependant reactions

Answer 5

In thylakoid membranes, H electrons from the photolysis of water, excited by light energy (chlorophyll become photo ionised), jump to a higher energy level, accepted by the primary electron acceptor and travels down to PS2, excited again and phosphorylate ATP, same in PS1. Finally picked up by NADP which gets reduced and taken to the LIR.

Question 6

Describe the process of the light independent reactions

Answer 6

In the stroma of the chloroplast, ribulose biphosphate uses and enzyme rubisco and CO2 to become 2 molecules of GP (3C), 2 ATP are used and 2 NADPH are used to leave 2 TP molecules. These are used to make molecules like glucose lipids and amino acids. Using 1 ATP the process can occur again.

Question 7

Name all the limiting factors of photosynthesis

Answer 7

Temperature
Light intensity
CO2 concentration

Question 8

What is the site of the LIR?

Answer 8

The stroma of the chloroplast

Question 9

What is the site of the LDR?

Answer 9

The thylakoid membranes of the chloroplast

Question 10

What is the site of the electron transport chain?

Answer 10

The cristae

Question 11

What is the site of the link reaction and Krebs cycle?

Answer 11

The matrix

Question 12

What occurs in glycolysis?

Answer 12

Glucose is converted to hexose diphosphate using energy from 2 ATP, this becomes two triode phosphate molecules, these each become one piruvate molecule whilst reducing one NAD each and 2 ATP each.
(overall 4 ATP and 2 NADH)

Question 13

What occurs in the link reaction?

Answer 13

Pyruvate reduces one NAD and has CO2 removed leaving Acetyl co enzyme A

Question 14

What is the site of glycolysis?

Answer 14

Cytoplasm

Question 15

What occurs in Krebs cycle?

Answer 15

Oxaloacetic acid combines with acetyl co enzyme A leaving co enzyme A and citric acid. One NAD is reduced and CO2 is removed leaving a 5C molecule. One molecule of ATP is resynthesised, one NAD is reduced and one CO2 is removed to make a 4C molecule. Then one FAD is reduced to make another 4C. Then one NAD is reduced to start the cycle again.

Question 16

What occurs in the electron transport chain?

Answer 16

Carrier molecules NADH and FADH drop of H ions, protons and electrons are separated. Electrons are accepted by electron accepting proteins and travel along each of them releasing energy each time until O2 is used as the final electron acceptor. This energy is used to release the protons into the intermediate space. ATP synthase uses the protons to resynthesise ADP+Pi into ATP.

Question 17

What occurs in anaerobic respiration in animals?

Answer 17

glucose resynthesises two ATP molecules and reduces two NAD, making pyruvate, Pyruvate is converted into lactate by using two reduced NADH molecules.

Question 18

What occurs in anaerobic respiration in yeast?

Answer 18

Glucose resynthesises two ATP molecules and reduces two NAD, making pyruvate, CO2 is removed making a 2C molecule which uses H from 2NAD to create ethanol.