Sign in to save your progress, vote, and build your own decks.Sign in
josiewilders
34 cards·by josiewilders
Define autotroph
An organism that makes its own organic nutrients from an inorganic carbon source
Define heterotroph
An organism that requires organic nutrients to supply it with a source of carbon
What is used during photosynthesis to produce complex organic molecules
Light energy
How many stages are there in photosynthesis
Two
Where does photosynthesis occur?
In the chloroplasts
What are the stages of photosynthesis called?
Light-dependent and Light-independent
Where does the light-dependent stage occur?
Thylakoid membrane
Where does the light-independent stage occur?
Stroma
How does the structure of the chloroplasts enable them to carry out their functions
Grana creates a large surface area to hold pigments. Stroma stores starch, contains sugars,
enzymes etc.
Define photosynthetic pigment
A molecule that absorbs some wavelengths of light and not others.
What is the use of light energy in the light-dependent stage?
it is used to add a phosphate group to ADP to form ATP, and to reduce NADP to form NADPH.
What does ATP and NADPH do in the light-dependent reaction?
ATP transfers energy and NADPH transfers hydrogen.
What are the two types of photophosphorylation called?
Cyclic and non-cyclic phosphorylation.
What is the first stage of non-cyclic photophosphorylation?
1. Light energy excites electrons in chlorophyll.
What is the second stage of non-cyclic photophosphorylation?
Photolysis of water produces protons, electrons and O2.
What is the third stage of non-cyclic photophosphorylation?
There is a proton gradient so protons move down the conc. gradient via an enzyme ATP synthase.
The energy from this movement produces ATP
What is the fourth stage of non-cyclic photophosphorylation?
Finally the electrons are transferred to NADP along with a proton from the stroma to produce
NADPH
Which type of photophosphorylation uses both PS1 and PS2?
Non-cyclic
Which type of photophosphorylation only uses PS1?
Cyclic
What are the end products of non cyclic?
NADPH, ATP and O2
What is the end product of cyclic
ATP
What is the role of water in the light-dependent stage?
Water is split by photolysis to produce electrons, protons and O2. The electrons replace
those lost by PS2
Which products of the light-dependent stage are used in the Calvin cycle
ATP and NADPH
What is the role of CO2 in the Calvin cycle?
it combines with RuBP to form 2xglycerate 3-phosphate.
What can TP be used to make?
Carbohydrates, lipids and amino acids.
What happens to the majority of TP?
It is recycled to RuBP
What is the first stage of the Calvin cycle?
Fixation of CO2 by the enzyme Ribulose bisphosphate carboxylase (rubisco)
What is the second stage of the Calvin cycle?
An unstable 6C molecule is formed and broken down in to 2 x glycerate 3-phosphate
What is the third stage of the Calvin cycle?
GP is reduced using NADPH into triose phosphate.
What proportion of TP is used to regenerate RuBP?
5/6
How does light affect the levels of GP, RuBP, TP?
In low light the products of the light-dependent stage in short supply this means conversion
of GP to TP and RuBP is slow
How does temperature affect the levels of GP, RuBP and TP?
All reactions in Calvin are catalysed by enzymes. At low temps enzymes slow
thereforereaction slow. RuBP, GP and TP fall.
How does CO2 affect the levels of GP, RuBP and TP?
At low CO2 conc. conversion of RUBP to GP is slow. Levels of RuBP rise and GP and TP fall.
Whatr are the limiting factors in photosynthesis?
Light intensity, CO2 conc, temperature