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BIOLOGY A2 > Photosynthesis > Flashcards

Photosynthesis Flashcards

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1
Q

Why do plants need energy? (4)

A

⦾ Photosynthesis (1)
⦾ AT (1)
⦾ DNA replication (1)
⦾ Cell division (1)

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2
Q

Why do animals need energy? (4)

A

⦾ Muscle contraction (1)
⦾ Body temp maintenance (1)
⦾ DNA replication (1)
⦾ Cell division (1)

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3
Q

Photosynthesis equation? (1)

A

⦾ 6CO2 + 6H2O → C6H12O6 + 6O2 (1)

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4
Q

Why is photosynthesis an example of a metabolic pathway? (1)

A

⦾ Occur in small series of reactions (controlled by enzymes) (1)

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5
Q

Respiration equation? (1)

A

⦾ C6H12O6 + 6O2 → 6CO2 + 6H2O (1)

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6
Q

2 types of Respiration? (2)

Give the equations for the 2 different places the 2nd type occur? (2)

A

⦾ Aerobic - with Oxygen (1)
⦾ Anaerobic - with/o Oxygen (1)

  • Plants + Yeast → Ethanol + CO2 (1)
  • Humans → Lactate energy (1)
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7
Q

ATP stands for? (1)

What is it? (1)

A

⦾ Adenosine TriPhosphate (1)

⦾ Store of energy (1)

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8
Q

ATP structure? (3)

A

⦾ Nucleotide base Adenine (1)
⦾ Ribose sugar (1)
⦾ 3 x Phosphate groups (1)

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9
Q

ATP properties?

A
  1. Stores/releases small energy amounts - reduce heat loss energy (1)
  2. Small soluble molecule - easily transported (1)
  3. Easily broken down - instantaneous energy release (1)
  4. Quickly remade (1)
  5. Phosphorylation - Added to other molecules to make more reactive by transferring 1 X its Pi groups (1)
  6. Can’t pass out cell - Always immediate energy supply (1)
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10
Q

Where does photosynthesis occur? (1)

A

⦾ Chloroplast (1)

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11
Q

What are the different structures of chloroplast? (6)

A

⦾ Grana - Stacked thylakoid (1)
⦾ Lamellae - Link Grana (1)
⦾ Photosynthetic pigments (1) - Coloured substances that
absorb light energy
- Inside thylakoid membrane
e.g. Chlorophyll a/b
⦾ Photosystems - Protein + Pigment: PSI (700nm) + PSII (680nm) (1)
⦾ Stroma - contains enzymes + sugars (1)
⦾ Starch - Stored carbohydrates (1)

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12
Q

Explain ‘REDOX’? (3)

A

⦾ Reduction Is Gain of Electrons, Addition of H + Loss of O2 (1)
⦾ Oxidation Is Loss of Electrons, Loss of H + Gain of O2 (1)
⦾ Occurs simultaneously (1)

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13
Q

Define Coezymes and give an example? (1)

A

⦾ Molecules aid enzyme function (1)
⦾ by transferring chemical groups from one molecule to another (1)
e.g. NADP transfers H

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14
Q

Give a short summary of the Light-Dependent reaction?

7

A

⦾ Requires light (1)
⦾ Occurs: thylakoid membrane of chloroplasts (1)
⦾ Photoionisation occurs: (1)
⦾ Chlorophyll absorbs light energy → excites e-s (1)
⦾ High energy e-s released from chlorophyll (1)
⦾ Chlorophyll’s now a +ve ion (1)
⦾ Uses of the energy: ADP + Pi → ATP (1)
NADP → NADPH

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15
Q

Give a short summary of the Light-Independent reaction? (3)

A

⦾ Relies on LDR products (1)
⦾ Occurs: Stroma (1)
⦾ ATP + NADPH provide energy + H to make glucose (1)

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16
Q

Energy uses of Photoionisation? (3)

A

⦾ Photophosphorylation ADP + Pi → ATP (1)
⦾ NADP → NADPH (1)
⦾ Photolysis of water into: H+, Electrons + O2 (1)

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17
Q

What are electron carriers? (1)

What do they do? (1)

A

⦾ Proteins linking photosystems (1)

⦾ Transfer electrons (1)

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18
Q

What are electron transport chains? (1)

What flows through them?(1)

A

⦾ Photosystems + electron carriers (1)

⦾ excited electrons (1)

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19
Q

Explain fully the process of the Light-Dependent reaction/Non-cyclic photophosphorylation? (11)

A
  1. PSII absorbs light energy → excites e-s in chloropyll (1)
    2.Excited e-s move to higher energy level. (1)
  2. ## High energy e-s released from chlorophyll + move down ETC to PSI (1)
  3. Excited e-s which left PSII must be replaced. (1)
  4. Photolysis - light energy splits water into:
    ☉ H+, Electrons + O2 (H2O → 2H+ + 1/2O2) (1)
    ———————————————————————————
  5. Excited e-s lose energy moving down ETC + energy’s used to transport H+ to thylakoid + create higher proton (H+) conc in thylakoid than stroma. (1)
  6. Proton (H+) conc. grad. across thylakoid membrane (1)
  7. ## Protons (H+) move down conc. grad. into stroma via ATP synthase (1)
  8. ## Energy from movement combines ADP + Pi → ATP (1)
  9. PSI absorbs light energy + excites e-s to higher energy level(1)
  10. e-s transferred to NADP (and a H+) to form → NADPH (1)
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20
Q

Define chemiosmotic theory? (3)

A

⦾ Process of e-s flowing down ETC (1)
⦾ creating proton grad. across membrane to (1)
⦾ drive ATP synthesis. (1)

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21
Q

What is Cyclic Photophosphorylation? (4)

A

⦾ ‘Cyclic’ - e-s from chlorophyll not passed onto NADP but back to PSI via e- carriers (1)
⦾ Only PSI used + ATP produced (1)
⦾ Therefore, e-s recycled + flow through PSI (1)
⦾ No NADPH/O2 produced - only small amounts of ATP (1)

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22
Q

What 2 products does the Light-Independent reaction require from the Light-Dependent reaction? (2)

A

⦾ ATP (1)

⦾ NADPH (1)

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23
Q

Where does the Light-Independent reaction occur? (1)

A

⦾ Stroma (1)

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24
Q

What is the overall reaction for the Light-Independent reaction? (1)

A

⦾ RuBP (5C) + CO2 → TP (3C) (1)

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25
Why is the Light-Dependent reaction a 'cycle'? (1)
⦾ RuBP regenerated (1)
26
What can the Light-Dependent reaction also be called? (1)
⦾ The Calvin Cycle (1)
27
``` What do the following stand for/mean? ⦾ Rubisco (1) ⦾ GP (1) ⦾ RuBP (1) ⦾ TP (1) ```
⦾ Rubisco - enzyme (1) ⦾ GP - gylcerate-3-phosphate (3C) (1) ⦾ RuBP - Ribulose biphosphate (5C) (1) ⦾ TP - Triose phosphate (3C) (1)
28
The Light-Independent reaction/Calvin Cycle: | Explain the formation of glycerate-3-phosphate? (3)
1. CO2 enters stomata + diffuses to stroma (1) 2. Combines with RuBP and rubisco (1) 3. Forms: unstable 6C compound which breaks down into 2 X GP (1)
29
What is the overall equation for the formation of gylcerate-3-phosphate? (1)
⦾ RuBP (5C) + CO2 + Rubisco → Unstable 6C compound → 2 X GP (3C) (1)
30
The Light-Independent reaction/Calvin Cycle: | Explain the formation of triose phosphate? (3)
4. ATP from LDR hydrolised to provide energy to reduce GP → TP (1) 5. NADPH is recycled to NADP to provide H+ for reaction (1) 6. TP has many uses - glucose - regenerate RuBP (1)
31
The Light-Independent reaction/Calvin Cycle: | Explain the regeneration of ribulose biphosphate? (2)
7. 5/6 TP molecules produced in reaction used to regenerate RuBP - which uses rest of ATP produced by LDR. (1) 8. 1/6 molecules produced in reaction used for organic compounds e.g. hexose sugar (1)
32
What are Hexose sugars? (1)
⦾ Simple 6C sugars (1) | ⦾ Use to make larger carbohydrates (1)
33
Explain how many times does the Calvin cycle need to turn to produce 1 hexose sugar? (7)
⦾ 6 X (1) ⦾ 3 X cycle produce 6 TP molecules (1) ⦾ 5/6 TP molecules used to regenerate RuBP (1) ⦾ 3 X cycle, only 1 TP molecule produced to make hexose sugar (1) ⦾ Hexose sugar has 6C so 2 TP needed to form 1 hexose sugar (1) ⦾ So cycle needs 6 X turn to produce 2 TP to be used for hexose sugar (1) ⦾ 6 turns need: 18 ATP + 12 NADPH from LDR (1)
34
Explain the 4 optimum conditions for photosynthesis?
1. High Light Intensity + Certain Wavelength: ⦾ Photosynthetic pigments a + b + carotene only absorb red + blue light in sunlight. 2. 25C Temperature: ⦾ Photo... involves enzymes ⦾ > 10C - inactive ⦾ <45C - denatured ⦾ High temps → stomata close to retain water ⦾ Causes photo... to slow down because less CO2 enters leaf when stomata close. 3. CO2 at 0.4%: ⦾ In air, CO2 = 0.04% gases in atm ⦾ Increase to 0.4%, increase rate ⦾ But any higher, stomata close 4. Constant water supply: ⦾ Too little → Photo... stops ⦾ Too much → Waterlogged soil and decreased uptake of minerals
35
Why do farmers try to create the optimum condition environment for their plants? (3)
⦾ Supply plant's needs (1) ⦾ Increase growth (1) ⦾ Increase yield (1)
36
How do farmers create optimum conditions in glasshouses? (5)
1. CO2 conc. ⦾ Burn propane in CO2 generator (1) 2. Light ⦾ Light through glass (1) ⦾ Lamps at night (1) ⦾ Red + Blue lights maximise photosynthesis (green reflected by plants) 3. Temperature: ⦾ Glasshouses trap heat from sunlight → warms air (1) ⦾ Heaters + coolers maintain optimum temp + air circulation maintains even temp throughout glasshouse (1)
37
What is a limiting factor? (1)
⦾ Variable that can slow down ROR (1)
38
What are the limiting factors of photosynthesis? (3)
1 ⦾ Light (1) 2 ⦾ Temperature (1) 3 ⦾ CO2 (1) ⦾ ALL need to be at good level
39
On what type of day is CO2 usually the limiting factor?
⦾ Warm, sunny windless day (1)
40
At which time of day is light intensity usually the limiting factor? (1)
⦾ Night (1)
41
What is 'the saturation point'? (1)
⦾ Factor no longer limits reaction + something else has become the limiting factor
42
What does it mean when a graph begins to level off? | for limiting factors in photosynthesis) (2
⦾ Doesn't mean photosynthesis has stopped (1) | ⦾ Rate of photosythesis isn't increasing anymore (1)
43
Chromatography experiment: | Chromatography purpose? (1)
⦾ Separates mixtures to identify components (1)
44
Chromatography experiment: | What is the mobile phase? (2)
⦾ Molecules can move (1) | ⦾ In paper + thin-layer chromatography, it's a liquid solvent (1)
45
Chromatography experiment: | What is the stationary phase? (3)
⦾ Molecules can't move (1) ⦾ Paper: chromatography paper (1) ⦾ Thin-layer: thin layer of solid on TLC plate (1)
46
Chromatography experiment: | What are the basic principles of chromatography? (3)
⦾ Mobile phase moves over stationary phase ⦾ Components in mixture spend different amounts of time in mobile + stationary phase ⦾ Components thats spend longer in mobile phase travel faster/further. Time spent in different phases is what separates out different components of mixture
47
Chromatography experiment: | What is the pattern of spots you end up with called?
⦾ Chromatogram
48
Chromatography experiment: | Plants contain different photosynthetic pigments in their leaves. Each pigment absorbs...
⦾ ...different wavelengths of light
49
Chromatography experiment: | Having more than 1 type of pigment in a leaf increases...
⦾ ...range of wavelengths of light plant can absorb
50
Chromatography experiment: | Different plants species contain different proportions and mixtures of...
⦾ ...pigments
51
Chromatography experiment: | What is an Rf value?
⦾ Distance a substance has moved from through stationary phase in relation to solvent.
52
Chromatography experiment: | Each pigment has a specific ___ values under specific ________.
⦾ Rf | ⦾ Condtions
53
Chromatography experiment: | Explain the method for how to use TLC to compare pigments present in shade-tolerant and shade-intolerant plants?`
1 ⦾ Grind up leaved from shade-tolerant plant being investigated with anhydrous Na2SO4. 2 ⦾ Add a few drops of propanone 3 ⦾ Transfer liquid to test tube and add petroleum ether 4 ⦾ Gently shake tube 5 ⦾ 2 distinct layers form in liquid - top layer is pigment mixed in with petroleum ether. 6 ⦾ Transfer some of liquid from top layer into 2nd test tube with anhydrous Na2SO4 7 ⦾ Draw horizontal line near bottom of TLC plate 8 ⦾ Build a concentrated spot of liquid of 6 ⦾ on the line. 9 ⦾ Do this by: applying several drops, ensuring each one is dry before next is added - point of origin. 10 ⦾ When plate's completely dry, place plate in small container with prepared solvent - just enough so point of origin is little above solvent 11 ⦾ Place lid on container + leave plate to develop 12 ⦾ As solvent spreads up plate, different pigments move with it but at different rate - therefore separate.
54
Chromatography experiment: | What do you do after the different pigments have separated out?
1 ⦾ Take plate out + mark solvent front with pencil | 2 ⦾ Leave plate to dry in well-ventilated place
55
Chromatography experiment: | What is the equation for calculating Rf values?
⦾ Rf B Distance travelled by spot value = ------ = ------------------------------------------ A Distance travelled by solvent
56
Chromatography experiment: | What is the solvent front?
⦾ The furthest point the solvent has reached
57
Chromatography experiment: | What are the top layer of the 2 distinct layers that form?
⦾ The pigment mixed in with the petroleum ether
58
Chromatography experiment: | What is the point of origin?
⦾ The point on the line of several drops of the final pigment which separate out.
59
Chromatography experiment: What are the health + safety aspects to consider? (4 marks)
1 ⦾ The chromatography solvent e.g. propanone or petroleum ether are toxic and highly flammable 2 ⦾
60
Chromatography experiment: | gsdfdjsgf
hdskhfkjdshbgjl
61
Chromatography experiment: | hsjdfch\sjdfgdjsgfjd\sgfju
hdjgcujdgvzd,hgfv
62
Investigating the actvity of dehydrogenase in chloroplast: What does NADP act as in photosystem I during the light-dependent reaction? What happens to the NADP as a result?
⦾ An electron acceptor | ⦾ It's reduced
63
Investigating the actvity of dehydrogenase in chloroplast: | What is the reaction catalysed by?
⦾ Dehydrogenase enzyme
64
Investigating the actvity of dehydrogenase in chloroplast: | How can the activity of the enzyme be investigated?
⦾ Adding redox indicator dye to chloroplast extracts
65
Investigating the actvity of dehydrogenase in chloroplast: | What does the REDOX indicator dye act as? (like NADP?)
⦾ Electron acceptor | ⦾ Gets reduced by dehydrogenase in chloroplasts
66
Investigating the actvity of dehydrogenase in chloroplast: | As the REDOX indicator dye gets reduced, what will you see?
⦾ Colour change
67
Investigating the actvity of dehydrogenase in chloroplast: Give an example of a dye? What colour does it change to?
⦾ DCPIP | ⦾ Blue to colourless (when reduced)
68
Investigating the actvity of dehydrogenase in chloroplast: | How can you measure the rate of dehydrogenase activity?
⦾ Measure rate at which REDOX indicator dye (DCPIP) changes colour ⦾ Use colorimeter
69
What is a colorimeter?
⦾ How much light solution absorbs when light source is directly shone through it ⦾ Coloured solution absorbs more light than colourless solution
70
What is phosphorylation? (1)
⦾ Adding Pi to molecule (1)
71
Under which process does phosphorylation occur? (1)
⦾ ADP + Pi via condensation reaction using energy (1)
72
Where is energy stored in ATP? (1)
⦾ Energy stored as chemical energy in phosphate bond (1)
73
Which enzyme catalyses the synthesis of ATP? (1)
⦾ ATP synthase (1)
74
When energy is needed, ATP... (1)
⦾ ...diffuses to part of cell energy's needed (1)
75
What happens when ATP reaches part of cell where its needed? (1)
⦾ Broken down into ADP + Pi (hydrolysis) (1)
76
Which enzyme catalyses the breakdown of ATP? (1)
⦾ ATP hydrolase (1)

BIOLOGY A2 (3 decks)

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