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A-Level Biology > Photosynthesis and etc > Flashcards

Photosynthesis and etc Flashcards

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1
Q

What is the photosynthesis equation?

A

Carbon dioxide + water —-> glucose + oxygen

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2
Q

What is the photosynthesis symbol equation?

A

6CO2 + 6H2O —-> C6H12O6 + 6O2

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3
Q

What is the importance of photosynthesis?

A

Provides energy all living things require
Produces O2
Chlorophyll converts it to chemical energy
Plants use molecules to produce ATP for respiration
Non-photosynthetic organisms feed on molecules produced by plants

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4
Q

What are the features of a plant cell?

A 
Amyloplast
SER
RER
Nucleus
Ribosomes
Cell wall
Golgi apparatus 
Chloroplast
Vacuole
Cell membrane
Mitochondria
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5
Q

What makes leaves good at photosynthesis?

A 
Large SA
Thin
Transparent cuticle 
Palisade cells long, thin + tightly packed
Many stomata 
Air spaces
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6
Q

Why is it it good that leaves have a large SA?

A

Absorb max light

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7
Q

Why is it it good that leaves are thin?

A

Efficient gas exchange

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8
Q

Why is it it good that leaves have a transparent cuticle?

A

Allows light to upper mesophyll

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9
Q

Why is it it good that leaves have palisade cells that are long,thin + tightly packed?

A

Max light absorption

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10
Q

Why is it it good that leaves have many stomatas?

A

Efficient gas exchange + short diffusion distance

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11
Q

Why is it it good that leaves have air spaces?

A

Rapid gas exchange

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12
Q

What structures are present in a chloroplast?

A 
Outer membrane
Inner membrane
Thykaloid sticks 
Stroma
Grana 
Intergranal lamellae
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13
Q

What do thykaloid discs contain?

A

Chlorophyll

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14
Q

What is grana?

A

Stacks of thykaloid sticks

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15
Q

What is the stroma?

A

Fluid-filled matrix around grana

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16
Q

Where does the LIDR take place?

A

Stroma

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17
Q

Where can starch grains be found?

A

Stroma

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18
Q

What do some thykaloid sticks have?

A

Tube shaped extensions

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19
Q

What does the tube shaped extensions connect?

A

Grana

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20
Q

What is it called when the tube shaped extensions join the grana?

A

Intergranal lamellae

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21
Q

What is the function of granal membranes?

A

Large SA for chlorophyll, electron carriers + enzymes

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22
Q

What is the function of the network of proteins in grana holding chlorophyll in specific way?

A

Allows for max light absorption

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23
Q

What is the function of the fluid in the stroma containing enzymes?

A

Needed for LDR

Allows to maintain optimum enzyme conc

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24
Q

What is the function of chloroplasts containing DNA + ribosomes?

A

Can quickly + easily manufacture proteins needed for photosynthesis

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25
What is the function of granal membranes having ATP synthase channels?
Catalyse production of ATP | Selectively permeable
26
What is the function of stroma surrounding grana?
Products from LDR easily diffuse into stroma for LIDR
27
What is the law of limiting factors?
When a process depends on two or more factors, the rate of that process is the limited by the factor which is in shortest supply
28
What factors affect photosynthesis?
``` Light intensity Availability of H2O Temperature Availability of chlorophyll Availability of CO2 ```
29
What is the compensation point?
When the rate of photosynthesis = rate of respiration
30
What does the graph look like for CO2 conc against rate of photosynthesis?
Increases then plateaus
31
What does the graph look like for chlorophyll against rate of photosynthesis?
Increases then plateaus
32
What does the graph look like for temperature against rate of photosynthesis?
Increases the decreases | Upside down "U"
33
Why is the temperature graph different?
Increases till optimum More KE so more successful collisions Too hot so breaks H bonds so active site denatures
34
What are the three main stages in photosynthesis?
Capturing of light energy LDR LIDR
35
What does chlorophyll A absorb?
Mainly red-orange + blue-violet part of visible light spectrum
36
Describe the first step of LDR | Making ATP
Photon of light absorbed = boosts energy level of pair of chlorophyll electrons Excited electrons leave chlorophyll molecule Chlorophyll molecule oxidised ETC gains electrons = photoionsiation
37
Describe 2nd step of LDR | ETC and Photosystems
``` Excited electrons taken up ETC Move along ETC from PS2 Series of redox reactions Each carrier slightly lower energy than previous So electrons lose energy at each stage ```
38
Why do the electrons move?
Each carrier has slightly higher affinity for electrons than last This draws electrons along chain to PS1
39
What are photosystems ?
Functional and structural proteins in photosynthesis
40
What do photosystems do?
Absorb light + transfer energy and electrons
41
Where are photosystems found?
Thykaloid membrane
42
What happens to the energy that is lost?
Used to synthesise ATP in photophosphorylation
43
Why do excited electrons pass through 2 photosystems?
Further absorbed light energy = increases energy of electrons Makes energy sufficient for reduction of NADP to NADPH
44
Describe the 2nd step 2.0 of LDR | NADP+
NADP final acceptor in ETC so becomes reduced Reduced to NADPH NADPH stores electrons + protons till they are transferred to LIDR
45
What is NADP+?
Coenzyme that accepts protons + electrons
46
Describe the 3rd step of LDR | Photolysis of water
H2O split from light energy absorbed by chlorophyll A When absorbs light chlorophyll oxidised Electrons produced from photolysis of water used to reduce chlorophyll
47
What is the equation for photolysis of water?
2H2O ----> O2 + 4H+ + 4e-
48
Why are protons very important in LDR?
Taken up by NADP = final acceptor | Vital for LDR
49
Why does LDR have 2 photosystems?
So electrons have enough energy to be picked up by NADP+ (coenzyme)
50
What is chemiosmosis?
The process of electrons flowing down the electron transport chain creating a proton gradient across the membrane to drive ATP synthesis
51
Where does the LDR
Thykaloid sticks
52
What is the LIDR called?
Calvin Cycle
53
What products of LDR are needed for LIDR?
NADPH - used to form simple sugar | ATP - hydrolysis of ATP provides energy
54
What are the three stages of LIDR?
Carbon fixation Reduction Regeneration
55
Brief description of carbon fixation stage (1)
CO2 combined with RuBP to make 2x GP
56
What is RuBP?
Ribulose bisphosphate
57
What is GP?
Glycerate 3-phosphate
58
Describe carbon fixation stage (1) in LIDR
``` CO2 diffuses into stroma through stomata Reacts with 5C RuBP Catalysed by rubisco Forms unstable 6C compound Immediately broken down into 2x GP ```
59
What is rubisco?
Ribulose bisphosphate carboxylase
60
Brief description of reduction stage (2)
ATP and NADPH used to reduce GP to TP
61
What is TP?
Triose phosphate
62
Describe reduction stage (2) in LIDR
NADPH (from LDR) reduces 3C GP into 2x 3C TP using ATP (from LDR) NADP reformed + returned to LDR
63
Brief description of regeneration stage (3)
RuBP regenerated
64
Describe of regeneration stage (3) in LIDR
TP has 2 uses: 5/6 - regenerates RuBP using ATP (from LDR) 1/6 - forms organic substance
65
How many times does the Calvin Cycle need to turn to produce one glucose molecule?
6
66
How many ATPs and NADPHs does the Calvin Cycle need to make one glucose molecule?
18 ATP | 12 NADPH
67
Describe what happens in the chemiosmotic theory?
Proton pumps produces H+ from stroma into thykaloid membrane Active transport H+ pass through chemiosmotic channel to stroma Diffusion Produces ATP Catalyses combo of ADP + Pi as they pass through
68
Where is the energy needed for active transport taken from in the chemiosmotic theory?
Energy from excited electrons that pass along ETC | Produces ATP
69
What happens as H+ pass through chemiosmotic channel?
Change the structure of the enzyme
70
What type of protein in the proton pump in the chemiosmotic theory?
Intrinsic protein

A-Level Biology (21 decks)

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