Feb caps Flashcards
write the symbol equation for photolysis
H2O –> ½ O2 + 2e- + 2H+
Describe photoionisation of chlorophyll
light energy is absorbed by the chlorophyll and
the energy results in the electrons becoming
excited and raising up an energy level to leave
the chlorophyll. Therefore the chlorophyll has
been ionised by light. Some of the energy from
the released electrons is used to make ATP and
reduced NADP in chemiosmosis.
Where does the light-dependent reaction (LDR) occur?
Thylakoid membrane
What are the three key reactions in the LDR?
Photoionisation of chlorophyll
Photolysis
Chemiosmosis
describe chemiosmosis in 4 key
stages
Step 1: The electrons that gained energy and left the
chlorophyll move along a series of proteins embedded
within the thylakoid membrane.
Step 2: As they move along, they release energy and some of
the energy from electrons is used to pump the protons
across chloroplast membranes.
Step 3: An electrochemical gradient is created. The protons
pass through the enzyme ATP synthase, which results in
the production of ATP.
Step 4: The protons combine with the co-enzyme NADP to
become reduced NADP. As the protons move from a high to
low concentration gradient this is known as chemiosmosis.
why is the LIR temperature sensitive?
It involves the enzyme Rubisco
What is the role of ATP in the Calvin cycle?
To provide the energy to reduce GP to TP
To provide the energy to regenerate RuBP from
TP
What is the role of NADPH in the Calvin cycle?
To provide an H to reduce GP to TP
What is the triose phosphate used for?
1 To donate one carbon each turn of the cycle to
go towards making a hexose sugar
2 To regenerate RuBP so the cycle can continue
Which molecules from the LDR are used in the
LIR?
1 ATP
2 Reduced NADP
Where does the LIR occur?
The stroma of the chloroplast
What can the hexose sugars made be used
for?
Whilst glucose is the product, this
monosaccharide can join to form disaccharides
such as sucrose, and
polysaccharides such as cellulose and starch. It
can also be converted into glycerol and
therefore combine with fatty acids to make
lipids for the plant.
draw the calvin cycle
draw glycolysis
describe glycolysis
Substrate level phosphorylation
- The glucose has 2 phosphate
groups added to it from 2 ATP
molecules.
Phosphorylation makes the
glucose-2-phosphate unstable
and it splits into two x 3-carbon
compounds, triose phosphate
(TP).
The 2 TP molecules are oxidised
to form 2 pyruvate molecules by
removing an H from each. The H
is picked up by 2 NAD molecules
to become reduced NAD. This
process also releases 4 ATP.
Where do the four stages of aerobic
respiration occur?
- Glycolysis - cytoplasm
- Link reaction - Mitochondrial matrix
- Krebs cycle - Mitochondrial matrix
- Oxidative Phosphorylation - Cristae /inner
mitochondrial membrane
What are the products of glycolysis?
2 x pyruvate
Net gain of 2 ATP
2 X reduced NAD
describe the key stages in
the link reaction.
The pyruvate made in
glycolysis is oxidised to
acetate.
NAD picks up the hydrogen
and becomes reduced NAD.
A carbon atom is lost as
carbon dioxide.
Acetate combines with
coenzyme A to produce acetyl
coenzyme A.
draw the link reaction
describe the key stages in the
Krebs cycle.
The acetyl CoA reacts with a four-carbon molecule, releasing
coenzyme A and producing a six-carbon molecule that enters the
Krebs cycle.
In a series of oxidation-reduction reactions, the Krebs cycle
generates 8 reduced coenzymes, 2 ATP by substrate-level
phosphorylation, and 4 carbon dioxides are lost.
draw the krebs cycle
What are the products of the Krebs cycle (from 1
glucose molecule originally) ?
6 x reduced NAD
2 x reduced FAD
4 x carbon dioxide
2 x ATP
What is the role of oxygen in oxidative
phosphorylation?
Oxygen is the final electron acceptor in the electron
transport chain. The oxygen combines with the
electrons and the protons to form water.
what happens to the reduced co-enzymes in this
stage?
All of the accumulated reduced coenzymes release
the hydrogens which are split into protons (H+) and
electrons (e-).
