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Flashcards in Photosynthesis Deck (38)
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1
Q

What is the granum

A

The stack of thylakoids

2
Q

What is a thylakoid

A

A single part of the granum stack

3
Q

What is the stroma

A

Inner area filled with enzymes

4
Q

Why do chloroplasts have multiple pigments?

A

There’s different wavelengths so more pigment means more wavelengths are absorbed

5
Q

What is a photo system

A

A group of pigments that work together to absorb as much wavelength as possible. They’re embedded into the thylakoid membrane

6
Q

Describe the light dependent reaction

A

Light hits photo system
Chlorophyll molecule gets excited
Electrons leave molecule and move along electron transport chain
Energy lost and used to transport protons from stroma into thylakoid membrane space
NADP is final electron acceptor and becomes reduced
Protons activate ATP synthase
ADP + PI -> ATP

7
Q

What is photolysis

A

H2O split into electrons and protons

8
Q

Why does photolysis occur in the light dependent reaction

A

Replaces electrons lost when electrons leave photosystem

So reduces photosystem

9
Q

What is photophosphorylation

A

Phosphorylation in the presence of light

10
Q

Where is ATP made during the light dependent reaction

A

In the stroma

11
Q

What adaptations do leaves have

A

Large SA collect as much light as possible
Stomata open and close as light intensity changes
Packed mesophyll so sunlight hits chloroplasts
Thin so short diffusion pathway

12
Q

What is the word equation for photosynthesis

A

Co2 + water -> glucose + oxygen

13
Q

What is the photosynthesis equation (not words)

A

6 Co2 + 6 H2O
->
C6H12O6 + 6 o2

14
Q

What part of the light dependent reaction is cyclic photophosphorylation and how

A

Photosystem I

Electrons rejoin ETC allowing more energy to make ATP

15
Q

What are the products of the light dependent reaction

A

ATP and NADPH

16
Q

What is the light independent reaction also known as

A

The Calvin cycle

17
Q

How many RUBP are produced for every 1 molecule of glucose made

A

6

18
Q

What products are required for the Calvin cycle

A

ATP and NADPH

19
Q

Why is the stroma the best place for the light independent reaction to take place

A

It has all the enzymes required for the cycle

20
Q

Where does the light independent reaction take place

A

In the stroma

21
Q

Describe the Calvin cycle

A
Co2 comes in
RUBP joins co2 because of enzyme rubisco
6 carbon compound unstable so breaks into 2 3 carbon compounds = GP
GP reduced by ATP and NADPH
2 TP molecules form
Cycle happens 6 times then
Carbon comes away to make glucose
Spare TP used to regenerate RUBP
22
Q

What is glucose from the light independent reaction used for

A

Make starch, lipids, cellulose, amino acids etc. Basically all organic molecules plant needs

23
Q

In evidence experiment for Calvin cycle, why is co2 supplied to algae radioactively labelled

A

Allows the substances to be identified as CO2 in all of them

24
Q

In evidence experiment of Calvin cycle, how might the hot methanol stop further chemical reactions taking place?

A

The high temperature and methanol denature the enzyme that catalyse reactions

25
Q

In evidence experiment of Calvin cycle, why is hot alcohol used

A

Hot temperature denature enzyme that catalyse the reaction

26
Q

In evidence experiment of Calvin cycle, why is a rapid action tap used

A

Allows small sample

To quickly be released

27
Q

What are the limiting factors of photosynthesis

A

Lack of light
Lack of co2
Temperature (too hot or too cold)

28
Q

In a photosynthesis experiment, why must it be airtight?

A

To stop the co2 bubbles from going into the atmosphere instead of being counted

29
Q

How does different light intensities affect photosynthesis

A

Light = more co2 so more photosynthesis

No light = respiration not photosynthesis

30
Q

What is the natural level of co2

A

0.03%

31
Q

What happens in photosynthesis if the temperature is too cold

A

There is not enough kinetic energy

32
Q

What happens in photosynthesis if the temperature is too hot

A
Bonds break 
Shape not held
Active site lost
No enzyme-substrate complex
Enzyme denatured
33
Q

Explain what’s happens during the light-independent reaction

A
Co2 combines with RUBP
GP produced
GP reduced to TP
Using NADPH and energy from ATP
TP converted to organic substances
34
Q

Name parts of a chloroplast

A
Double membrane
Stroma
Thylakoid
Granum
Inter-granal thylakoid
35
Q

Explain why the rate of photosynthesis increases when the percentage of light absorbed increases

A

Light provides energy for light dependent reactions

36
Q

Why is green light wavelength not absorbed

A

Green plants reflect green light

37
Q

Describe the part played by chlorophyll in photosynthesis

A

Light energy is absorbed by chlorophyll
Electrons excited
ATP formed

38
Q

Why might hydrogen sulphide be used in photosynthesis

A

Provide hydrogen for light dependent reactions