Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Biology module 5 > Photosynthesis > Flashcards

Photosynthesis Flashcards

(45 cards)

Start Studying
1
Q

What is photosynthesis?

A

Process where captured light energy is used to make glucose from CO2 and water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the overall equation for photosynthesis?

A

6CO2 + 6H2O + light energy → C6H12O6 + 6O2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the 3 key stages of photosynthesis?

A

Light energy captured = by pigments
Light-dependent reaction = light energy converted into chemical energy
Light-independent reaction = sugars and other organic molecules produced

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the function of chloroplasts?

A

Site of photosynthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Where are chloroplast found?

A

In some algae and plant cells

in plants they are mainly found in mesophyll tissues of leaves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the main roles of chloroplasts?

A
  • absorb light energy to drive photosynthesis
  • convert light energy into chemical energy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the main structures in the chloroplast?

A
  • double membrane
  • thylakoids
  • grana
  • lamellae
  • starch grains
  • ribosomes
  • ## chloroplast DNA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are grana?

A

Stacks of thylakoids which are flattened sacs contain complexes of pigments like chlorophyll in their membranes to absorb light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are lamellae?

A

Membranous extensions connecting thylakoids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the stroma?

A

Fluid surrounding thylakoids where light-independent reaction occurs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the absorption spectrum?

A

Spectrum showing range of wavelengths absorbed by pigments in chloroplast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the main photosynthetic pigments?

A
  • chlorophyll a
  • chlorophyll b
  • Xanthophylls and carotenoid
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is chlorophyll A?

A

Main pigment that absorbs red and blue light and reflects green light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is chlorophyll B?

A

Accessory pigment mostly found with chlorophyll a in light-harvesting complexes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are Xanthophylls and carotenoids?

A

Absorb different wavelengths than chlorophyll broadening spectrum of light that can drive photosynthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are photosystems?

A

Clusters pigments in chloroplasts embedded in thylakoid membranes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What do photosystems contain?

A

Light-harvesting system = contains pigments e.g chlorophyll a, chlorophyll b and carotenoids

Reaction centre = contains two chlorophyll a molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What happens in a photosystem?

A
  • light-harvesting system absorbs light energy
  • energy transferred to reaction centre
  • reaction centre emits high-energy electrons to drive light-dependent reactions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is photophosphorylation?

Study These Flashcards
A

Process by which ATP is formed using light energy

20
Q

What happens in non-cyclic phosphorylation?

Study These Flashcards
A

Uses water and light energy to produces ATP reduced NADP, and oxygen as a by-product

21
Q

What are the key stages of non-cyclic phosphorylation?

Study These Flashcards
A

1) absorption of light energy by pigments
2) electron transfer along electron transport chain
3) photolysis of water
4) chemiosmosis

22
Q

Outline the process of light absorption and the electron transport chain?

Study These Flashcards
A

1) light energy absorbed by pigments
2) excites electrons in pigments in PSI and PSII reaction centres
3) electrons are lost from pigments (photoactivation)
4) electrons transferred to electron carrier molecule
5) electrons passed along ETC releasing energy as they go
6) electron from PSII replaces lost electron from PSI

23
Q

Outline the process of photolysis of water?

Study These Flashcards
A

1) light is used to split water into electrons, protons, and oxygen
2) electrons replace those lost from PSII during photoactivation
3) protons used for ATP production combining with electrons to reduce NADP
4) O2 gas is released as a by-product

24
Q

What is the balanced symbol equation for photolysis?

Study These Flashcards
A

2H2O → 4H+ + 4e- + O2

25
What does chemiosmosis produce?
ATP and reduced NADP
26
Outline the process of chemiosmosis?
1) energy lost by electrons along ETC used to pump protons across the thylakoid membrane into thylakoid space 2) produces a proton gradient with higher concentration in thylakoid space 3) protons diffuse through ATP synthase into stroma 4) movement powers ATP synthase to produce ATP from ADP and Pi 5) NADP takes up protons and electrons from PSI in stroma and is reduced 6) reduced NADP is carried into light-independent reaction
27
What happens during cyclic phosphorylation?
Uses light energy to produce small amounts of ATP typically occurring when NADP isn't available so no reduced NADP or oxygen is produced
28
Outline the key stages of cyclic phosphorylation?
1) light energy absorbed by pigments exciting electrons in PSI pigments only 2) electrons lost from pigments in PSI 3) electrons transferred to an electron carrier molecule and passed along ETC releasing energy 4) energy powers active proton transport across thylakoid membrane from stroma into thylakoid space 5) ATP produced as protons flow back into stroma through ATP synthase 6) electrons returned to PSI so no NADP is reduced
29
Where does the light dependant reaction occur?
Occurs in stroma of chloroplasts
30
What are the reactants of the light independant reaction?
- NADPH from light-dependent reaction - CO2 - ATP
31
What are the products of the light independant reaction?
- glucose - other organic molecules
32
What is the other name for the LIDR and what are the 3 main stages?
Calvin cycle - carbon fixation - GP reduction - RuBP regeneration
33
Outline the process of carbon fixation?
1) CO2 reacts with 5C compound ribulose bisphosphate (RuBP) forming an unstable 6C compound 2) 6C compound splits into two 3C glycerate-3-phosphate (GP) molecules 3) catalysed by enzyme rubisco
34
Outline the process of GP reduction?
1) GP reduced into triose phosphate (TP) 2) uses energy from hydrolysis of ATP 3) requires protons and electrons from NADPH which itself is oxidised to regenerate NADP 4) NADP re-formed returns to LDR to be reduced again
35
Outline the process of RuBP regeneration?
1) most TP used to regenerate RuBP using ATP 2) rest of TP can be used to make other organic molecules
36
How many turns of the Calvin cycle are required to make 1 glucose?
6 turns to make glucose (6C)
37
What are some examples of what TP can make?
- simple sugars (e.g. glucose) - larger carbs (e.g. starch) - amino acids - lipids - nucleotides
38
What is required for photosynthesis to occur?
- photosynthetic pigments - CO2 - water - light - suitable temperature
39
What is a limiting factor?
Requirement in shortest supply which if increased allows the rate of photosynthesis to increase
40
What are the 3 limiting factors of the photosynthesis reaction?
- light intensity - CO2 concentration - temperature
41
Describe and explain how light intensity affects photosynthesis?
Low light intensity = limits LDR so not much ATP and reduced NADPH are produced slowing light-independent stage and photosynthesis rate is low Intermediate light intensity = produces more ATP and NADPH in light-dependent stage regenerates RuBP in light-independent stage more quickly so GP gets converted to TP increasing photosynthesis rate Very high light intensity = more light than needed so another factor like temperature becomes limiting and rate plateaus
42
What is the light compensation point?
Point is when volume of O2 produced and CO2 absorbed in photosynthesis is balanced by the O2 absorbed and CO2 produced by respiration
43
Describe and explain how CO2 concentration affects photosynthesis?
Low CO2 conc = limits light-independent reaction as less CO2 is fixed reducing production of GP and TP so photosynthesis rate is low Intermediate CO2 conc = allows faster production of GP and TP increasing photosynthesis rate High CO2 conc = another factor like light becomes limiting
44
What is the saturation point?
Point when factor being measured is no longer limiting reaction so something else is becomes the limiting factor
45
Describe and explain how temperature affects photosynthesis?
Low temp = provides little ke slowing enzyme-catalysed stages of photosynthesis e.g CO2 fixation controlled by rubisco so photosynthesis rate is low Intermediate temp = increases Ke supplied to reactions increasing the rate of photosynthesis up to an optimum point Very high temps = denatures enzymes so photosynthesis rate sharply drops

Biology module 5 (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions