Photosynthesis

?
  • Created by: Ruhab21
  • Created on: 28-09-20 22:36
What is the main photosynthetic tissue in a leaf?
Palisade mesophyll tissue
1 of 42
Describe an experiment to test the density of the stomata.
1) Apply clear nail polish to the lower epidermis of a leaf 2) Peel the nail polish off to show lower epidermis 3) Use a microscope and count the quantity of stomata
2 of 42
Where is the light DEpendent stage?
Thylakoid membrane
3 of 42
Where is the light INdependent stage?
Stroma of chloroplast
4 of 42
What is the role of the granum in a chloroplast?
Increased surface area for ATP synthase
5 of 42
What is the role of the thylakoid disc.
Electrochemical gradient is established during chemiosmosis.
6 of 42
What is the role of photosynthetic pigments
They absorb light energy from the sun and convert it to chemical energy
7 of 42
1) Which is the primary pigment? 2) What wavelengths of light does it absorb?
1) Chlorophyll a 2) Red and Blue Wavelengths (Good way to remember has Gill Colours red and blue)
8 of 42
1) What are the accessory pigments 2)What wavelengths do they absorb?
1) Chlorophyll b and Carotene 2) Red and Blue for Chlorophyll b but just blue for Carotene
9 of 42
What is the role of acetone in chromatography?
Acetone dissolves the membranes and allows the pigment to be extracted from the thylakoid membranes.
10 of 42
What is an absorption spectrum?
A graph that shows amount of light absorbed by EACH pigment at each wavelength of light
11 of 42
What is an action spectrum?
A graph that shows the rate of photosynthesis at different wavelengths.
12 of 42
Explain why accessory pigments are important in photosynthesis (2 marks)
1) They absorb wavelengths of light which primary pigments can't 2)This ensures a wider range of wavelengths absorbed increasing the efficiency of photosynthesis.
13 of 42
Why add a solvent?
To dissolve solute and carry the pigment up the chromatography filter paper
14 of 42
How would you conduct an experiment to measure the rate?
Count the number of bubbles produced by an underwater plant over a period of time
15 of 42
When comparing both spectrums, what would you see and what does it mean?
Theres a close correlation between the graphs and this shows that the photons are responsible for the light used in photosynthesis.
16 of 42
What was Engelmanns experiment used for?
To determine which wavelengths of light are most effective in photosynthesis
17 of 42
Describe Engelmann's experiment
Place algae in a suspension of mobile, aerobic bacteria 2)Bacteria evenly spread 3) Photosynthesis produces oxygen which the bacteria need 4) Bacteria tend toward blue and red which means blue and red wavelengths are most effective for photosynthesis
18 of 42
What is an antenna complex?
(Double Kuh Sound to remember this) Cluster of Chlorophylls and accessory pigments in the thylakoid membrane
19 of 42
What is the role of accessory pigments in the thylakoid membrane?
Absorb energy from photons to pass to the reaction centre
20 of 42
What is the reaction centre in an antenna complex
Two chlorophyll a molecules
21 of 42
Describe non cyclic photophosphorylation
1) PS2 absorbs photons of light and 2 electrons from the excited reaction centre are raised to higher level 2) The electrons are passed to an electron acceptor 3) The electrons pass from carrier to carrier losing energy along the way
22 of 42
Describe Cyclic Photophosphorylation
1) Proton Pump Pumps H+ ions from stroma to cavity 2) Elec chem grad occurs 3) H+ ions travel up stalked particle, makes ADP + Pi = ATP 4)Electrons go to PS1 and light photons excite the reaction centre and are raised to higher level
23 of 42
State how is NADPH made
H+ + e- + NADP ------> NADPH
24 of 42
What is the role of photolysis in non cyclic photophosphorylation.
It replaces the electrons in PS2 to increase stability and increase H+ ions in the cavity thus aiding the electrochemical gradient
25 of 42
How many areas of the membrane are permeable to H+ ions and why?
1) H+ is a small polar molecule therefore is repelled by the fatty acid tails. 2) Only thing permeable is the stalked particle
26 of 42
Suggest Why is it important that the only permeable part is the stalked particle?
allows the electrochemical gradient to form therefore when the H+ ions travel back to the stroma, they can only do so in the stalked particle and ATP can form
27 of 42
When is cyclic photophosphorylation used?
In bacteria and primitive plants or when there's low CO2 levels in higher plants
28 of 42
Describe cyclic photophosphorylation
1) Light energy absorbed by PS1 and absorbed by chlorophyll a 2) Electrons become excited, are released from the Mg2+, at centre of chlorophyll 3) Electron passes along carriers and protons are pumped, makes Elec chem grad 4) ATP made so e-go to PS1
29 of 42
What are the differences in the products from noncyclic and cyclic photophosphorylation?
Non Cyclic Photophosphorylation makes oxygen and reduced NADP
30 of 42
Where is the light independant stage?
The stroma
31 of 42
Describe the Calvin cycle
1) RuBP is fixated to CO2 by the RUBSICO enzyme 2) This forms an unstable 6C compound which splits into two of Glycerate 3 phosphates 3) 2 reduced NADP molecules are oxidised and 1 ATP molecule is hydrolysed
32 of 42
Describe Final Steps for Calvin Cycle
4) NADPH and ATP these phosphorylate GP into 2 triose phosphate molecules 5) 1 carbon molecule leaves the triose phosphate molecules 6) The remaining 5 carbons and a hydrolysed ATP form RuBP again
33 of 42
What is the 1 carbon from the Calvin cycle used for?
Synthesising glucose, amino acids and proteins
34 of 42
How would a deficiency of magnesium be apparent in plants?
Chlorosis; Magnesium is being moved to new leaves so theres yellowing
35 of 42
How does temperature affect the rate of photosynthesis?
As temp increases, enzyme activity does until it reaches enzyme denaturation and the tertiary structure of enzymes change. The enzyme substrate complex can no longer form
36 of 42
Does increase of temp affect LD or LI step more and why?
LD doesnt require as many eznymes so it cant produce as much ATP or reduced NADP quick enough for the increased activity of LIS so the rate is limited
37 of 42
What is the effect of CO2 on the rate of photosynthesis?
As CO2 increases, the rate increases as Calvin cycle activity increases
38 of 42
What could be the problem with too much CO2 in photosynthesis?
CO2 diffuses into the leaves and dissolves in water. Carbonic acid forms and dissociates into H+ and HCO3-. It makes the leave more acidic and enzymes denature.
39 of 42
What is the effect of light intensity on the rate of photosynthesis?
Light dependent reaction speeds up. ATP and reduced NADP produced at a faster rate. Organic molecules from calvin cycle are produced faster.
40 of 42
What is photorespiration? (not on spec
Its when leaves are exposed to bright light and rubisco catalyses oxygen and ribulose bisphosphate, releasing CO2
41 of 42
List some features from photorespiration (not on spec).
Doesnt release ATP Uses oxygen and releases carbon dioxide occurs in bright light and high temp occurs at the same time as photosynthesis uses the made compounds yield of photosynthates decreases
42 of 42

Other cards in this set

Card 2

Front

Describe an experiment to test the density of the stomata.

Back

1) Apply clear nail polish to the lower epidermis of a leaf 2) Peel the nail polish off to show lower epidermis 3) Use a microscope and count the quantity of stomata

Card 3

Front

Where is the light DEpendent stage?

Back

Preview of the front of card 3

Card 4

Front

Where is the light INdependent stage?

Back

Preview of the front of card 4

Card 5

Front

What is the role of the granum in a chloroplast?

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Human, animal and plant physiology resources »