Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Module 5 > Photosynthesis > Flashcards

Photosynthesis Flashcards

1
Q

What’s the relationship between photosynthesis & respiration

A

Products of one = raw materials of the other

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

Photosynthesis = (exothermic / endothermic) vs respiration = (endothermic / exothermic)

A

Photosynthesis = endo
Respiration = exo

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

What’s a ‘compensation point’

A

Where no net fain / loss of CO2 etc
Rate of photosynthesis = rate of respiration

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

Chloroplast structure

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

What’s special about the outer membrane of the chloroplast

A

Highly permeable to ions / small molecules

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

What does the inner membrane of chloroplast have (what type of proteins)

A

Transport, which control flow of molecules between the stroma and the cytosol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the stroma, what happens in it, what does it contain

A

The fluid filled matrix of the chloroplast
- when the light independent sgage occurs
Has:
- enzymes required for light independent stage
- starch grains
- small ribosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How is the stroma adapted for its function?

A

Surround the granum & thylakoid membrane so products of the LDS can be easily & rapidly passed to stroma for the LIS
- it also contains enzymes required for the LIS

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

What are thylakoids, what occurs in them, & what do they contain

A

They’re flattened, membrane bound, fluid-filled sacs (folded from thylakoid membranes)
- they contain photosynthetic pigments in photosystems
- where the light dependent state occurs

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

Where they occur: LDS vs LIS

A

LDS - thylakoid membranes of the thylakoid in granum
LIS - stroma

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

What are the granum & how are they adapted

A

A stack of thylakoids
- these stacks create a large SA to ensure maximum light absorption
Connected together by lamellae

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

Photosystems are in the thylakoid: what are these & whats their significance

A

Funnel shaped structures
Antenna complex of photosynthetic pigments
Surrounding chlorophyll A reaction centre
Held in place by proteins embedded in the grana

-> they absorb light energy in a wide range of wavelengths + their arrangement allows for maximum absorption of it, so they can excite the electrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Photosynthetic pigments examples

A

Carotenoid
Chlorophyll a & b
Xanthophyll

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

Absorption peak of PS1 vs PS2

A

PS1 = 700 nm (but comes after)
PS2 = 680nm (but comes first)

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

Stages of the light dependent stage in the thylakoid membrane

A
  1. Light harvested in photosystems
  2. Photolysis of water
  3. Photophosphorylation
  4. Reduction of NAD
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Stage 2 LDS: photolysis of water: what occurs

A

The splitting apart of water in the presence of light & an enzyme to form:
2H2O -> 4H+ + 4e- + O2

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

What is photophosphorylation in the lds

A

The production of ATP from ADP + an inorganic phosphate group
In the presence of light

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

How are electrons passed along the ETC using iron ions

A
  • captured by electron carrier
  • iron ion in the e- carriers accept the e- to be reduced to Fe2+
  • Fe2+ then donates the e- to the next electron carrier in chain & is deoxidised to Fe3+
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is an electron carrier

A
  • proteins embedded in the thylakoid membrane
  • contain an iron ion which is constantly reduced & oxidised to pass an e- along the ETC
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

LDS diagram simple

A
21
Q

Light dependent stage diagram. Plz familiarise

A
22
Q

Light dependent extra notes: what happens before the 1st ETC

A
  1. Light energy absorbed by PSII
    -> PSII gives off electrons
    Electrons from it, enter the first ETC
    e- lost in PSII are replaced by e- formed from the photolysis of H2O
23
Q

Light dependent extra notes: what happens during the 1st ETC

A
  1. Electrons from PS2 passed along 1st ETC, releasing energy
  2. Energy transferred to proteins
  3. Proteins use energy to pump H+ ions from stroma into the thylakoid space by active transport
  4. Photolysis of water occurs in thylakoid space
  5. H+ ions are released into the space
  6. So a lower pH & higher H+ conc there, so a conc gradient is created
  7. Chemiosmosis occurs- H+ ions pass through ATP synthase, down the conc gradient, across partially permeable thylakoid membrane by facilitated diffuse
  8. H+ ions provide energy for ATP synthase to produce ATP from ADP phosphorylation
  9. Electrons leave the ETC
24
Q

What happens after the electrons leave etc 1

A

Non cyclic or cyclic photophosphorylation

25
Q

Cyclic vs non cyclic photophosphorylation

A

Cyclic don’t product NADPH
Cyclic = only PS1 involved

26
Q

What happens in non cyclic photophosphorylation

A

Electrons enter PS1
light energy is absorbed by PS1
PS1 gives off e-
E- enters 2nd ETC
E- reduce NADP from stroma to NADPH via NADP reducers
Products = oxygen, ATP & NADPH

27
Q

Products of non-cyclic photophosphorylation

A

Oxygen
ATP
NADPH

28
Q

What happens in cyclic photophosphorylation after PS1 gives off e-, and that e- enters the 1st ETC

A

E- release energy to transport proteins as repassed along ETC 1
Then re-enter PS1
Proteins actively pump H+ ions into the thylakoid space (active transport)
Chemiosmosis
H+ enters stroma & give ATP synthase energy
ADP + Pi -> ATP

29
Q

Cyclic photophosphorylation occurs in times of […] light intensity

A

High

30
Q

Why does cyclic photophosphorylation only use ETC 1

A

Can’t accept an more e- after as all the ETC proteins have been reduced

31
Q

Calvin cycle (LIS) reactants

A

ATP
NADPH
CO2

32
Q

Calvin cycle products

A

Complex organic molecules e.g. starch/sucrose etc

33
Q

Stages of the Calvin cycle

A
  1. Carbon fixation stage
  2. Reduction stage
  3. Regenation stage
34
Q

Explain LIS

A
35
Q

3C
3C
5C
LIS MOLECULES

A

3C - GP
3C - TP
5C - RuBP

36
Q

The Calvin cycle is light independent but only runs in the daylight… why? What does it need

A
  • a continuous supply of ATP & NADPH
    # conc of Mg ions increases in daylight
  • RuBisCo also activated by extra ATP in stroma
    When H+ ions are pumped from the stroma -> to thylakoid space, pH raises to around 8, which is optimum pH for RuBisCo
37
Q

What happens in stage 1 of the Calvin cycle : carbon fixation

A

CO2 reacts with RuBP (catalysed by RuBisCo)
- RuBP accepts a -COOH groups (becomes carboxylated)
- unstable, 6C intermediate formed
This intermediate immediately splits into 2 GP (3C molecules)

38
Q

What happens in stage 2 (the reduction stage) of the Calvin cycle (what happens to the 2 GP molecules)

A
  1. GP reduced to TP, by ATP & NADPH
  2. TP, ADP, & an inorganic phosphate group & NADP are formed

ATP = provides energy
NADPH = reducing agent

39
Q

What happens in the regeneration stage of the Calvin cycle ( to the 3 TP)

A
  • TP used to regenerate RuBP (using energy from ATP)
  • ADP, inorganic phosphate group, and RuP formed
  • RuP reacts wiry the phosphate group, using the energy, to form RuBP
40
Q

Why are Mg ions important in the Calvin chcle

A

Mg ions act as a cofactor for Rubisco
They attach to its active sites to activate it

41
Q

Factors affecting photosynthesis

A

Temperature
CO2 conc
Water stress (stomatal closure)
Light intensity

42
Q

How does light intensity affect photosynthesis

A
43
Q

How does carbon dioxide affect photosynthesis

A
44
Q

How does water stress, leading to stomatal closure affect photosynthesis

A
45
Q

How can temperatures from 25-30°C affect photosynthesis

A
46
Q

How do temperatures above 40°C affect photosynthesis

A
47
Q
A
48
Q
A

Module 5 (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions