5.6 Photosynthesis

Question 1

What is the general formula for photosynthesis?

Answer 1

6CO2+ 6H2O + energy from photons -> C6H12O6 +6O2

Question 2

What is a photon?

Answer 2

Particle of light

Question 3

What are organisms called that photosynthesize

Answer 3

Photoautrops

Question 4

What is Autrophic Nutrience?
C energy -> synthesize

Answer 4

Organisms that use chemical energy to synthesize large organic molecules from small inorganic molecules e.g H2O & CO2

Question 5

Why is photosynthesis a form of carbon fixation?
What does it require/not require?

Answer 5

-Inorganic carbon (CO2) is converted to organic compounds (oxygen)
-light dependent/ independent

Question 6

Is photosynthesis endo or exothereminc does it release or require energy?

Answer 6

It is Endothermic
The process requires energy

Question 7

Why do Photoautotrops (organism that photosynthesize e.g plants) use respiration?

Answer 7

So the organic molecules that were synthesized can release energy

Question 8

What is the compensation point?
Net

Answer 8

The net gain or loss of O2

Question 9

What is the compensation period?

Answer 9

How long it takes to reach the compensation point

Question 10

What does the peak mean in compensation graph?
Op

Answer 10

Optimum rate of photosynthesis

Question 11

Name 6 things that is in the structure of chloroplasts

Answer 11

-intergranal lamellae
- grana
- thylakoids
- outer membrane
- inner membrane
- stomata

Question 12

Within the thylakoid there are pigments. What are those pigments called?
Where is the pigments located in within the thylakoids? And shape?

Answer 12

• Photosynthetic pigments
• Photo system - funnel like shape

Question 13

Name the 3 steps that occur in the photosystem within the thylakoids that reflects the wavelength of light along with its colour?

Answer 13

• Pigments in the photosystem absorb the wavelength and reflects the wavelength of light
  -each pigment appears in our eyes and brains. The colour of the wavelength of light is reflecting.

Question 14

What are the two types of chlorophyll?

Answer 14

Chlorophyll a
Chlorophyll b

Question 15

What colour does chlorophyll a appear? 2
What two colors does it absorb? 2

Answer 15

Blue or green
Mostly red light some blue light

Question 16

What colour does chlorophyll b appear? 2

Answer 16

-Green or yellow

Question 17

At the end of light dependent reaction (thylakoids) what does it produce?
What is the by product?

Answer 17

-ATP, reduced NADP

-Oxygen

Question 18

Explain what happens during photolysis?
What are the products?

Answer 18

-In presence of light, an enzyme on PS11 splits water into

• protons~ H+
• electrons~ e-
• oxygen~ O2

Question 19

What are the two things that oxygen is used for? And their outcomes if used?

Answer 19

-Aerobic respiration- use oxygen
-Photosynthesis- high light energy- Oxygen is a by product

Question 20

What is photophosphorylation?

Answer 20

Generation of ATP from ADP and inorganic phosphate in presence of light.

Question 21

What are the two types of photophosphorylation?
What are the differences?

Answer 21

-Cyclic and Non- cyclic

-Non Cyclic involves PS11 and PS1. Produce: ATP and reduced NADP.
- Cyclic involves PS1. Produce: smaller amount of ATP.

Question 22

What are the steps that occur during non-cyclic photophosphorylation to get to the point where electrons release energy as they passed along thylakoid membrane.

Answer 22

• photon of light strikes PS11, this excites pair of electrons.
• The energised electrons escapes chlorophyll molecule and is captured by electrons carriers in the thylakoid membrane.
• These electrons are replaced by electrons derived from photolysis.
• Electrons are passed through the thylakoid membrane by passing from carrier to carrier through reduction and oxidation reactions
• As electrons pass through thylakoid membrane they release energy.

Question 23

During non-cyclic photophosph -orylation after electrons release energy what are the next steps to when proton gradient is formed.

Answer 23

• The energy is used to pump protons from the thylakoid membrane to the thylakoid space.
• Eventually electrons are captured by another molecule of chlorophyll a in PS1. These electrons replace those lost from excitation in PS1.
• Ferredoxin accepts the electron from PS1 and passes it to NADP in the stroma.
• Protons accumulate in the thylakoid space it creates a proton gradient across the membrane.

Question 24

During non-cyclic photophos -phorylation after creating a proton gradient what are the final steps?

Answer 24

• Protons diffuse out through channels associated with ATP synthase.
• As they do so the flow of protons causes ADP and inorganic phosphate (Pi) to join forming ATP.
• As the protons pass through the channel they are accepted along with electrons (that ferrodoxin passed) by NADP, to form a reduced NADP, reduction is catalysed by the reduction of NADP reductase.

Question 25

What has Non-cyclic photophosphorylation formed and from what process?

Where are the products? what are they waiting for?

Answer 25

• ATP: photophsphorylation
• Reduced NADP
• Stroma - waiting for light independent reaction.

Question 26

What does Cyclic photophosphorylation involve?

To make?

Answer 26

-PS1
-To make smaller amount of ATP compared to non-cyclic photophosphorylation