Unit 5 - chatgpt Flashcards
(55 cards)
What are the two main stages of photosynthesis?
Light-dependent reaction (LDR) and Light-independent reaction (Calvin Cycle).
Where does the light-dependent reaction take place?
In the thylakoid membranes of the chloroplast.
What are the main products of the LDR?
ATP, reduced NADP (NADPH), and O2 (as a byproduct).
How is ATP produced in the LDR?
Through chemiosmosis:
electrons move through the electron transport chain,
releasing energy used to pump protons by active transpot into the thylakoid space from stroma.
Protons diffuse into stroma through ATP synthase,
synthesizing ATP from ADP and Pi.
What happens to water in the LDR?
It undergoes photolysis to produce electrons (for ETC), protons (for NADP reduction), and O2 (waste).
Where does the light-independent reaction occur?
In the stroma of the chloroplast.
What molecule does CO2 combine with in the Calvin cycle?
RuBP (Ribulose bisphosphate), catalysed by Rubisco.
What are the products of the Calvin Cycle used for?
TP (triose phosphate) is used to form glucose and regenerate RuBP.
What limits the rate of photosynthesis?
Light intensity, CO2 concentration, and temperature.
Where does glycolysis occur?
In the cytoplasm.
What are the products of glycolysis?
2 pyruvate, 2 ATP (net), and 2 NADH.
What happens in the link reaction?
Pyruvate is decarboxylated and oxidised to form acetate, which combines with CoA to form acetyl-CoA. NAD+ is reduced to NADH.
Where does the link reaction occur?
In the mitochondrial matrix.
What are the key stages of the Krebs Cycle?
Acetyl-CoA combines with oxaloacetate to form citrate (a 6-carbon molecule).
Citrate undergoes dehydrogenation (producing NADH) and decarboxylation (releasing CO2) to form a 5-carbon intermediate.
This intermediate undergoes another decarboxylation and dehydrogenation, producing NADH and releasing CO2, forming a 4-carbon intermediate.
The 4-carbon intermediate is converted back to oxaloacetate, completing the cycle and regenerating oxaloacetate.
This oxidation produces NADH and FADH2 and ATP
When does substrate-level phosphorylation occur in respiration?
In the Krebs cycle when a 4-carbon intermediate is converted to another 4-carbon compound.
Glycolysis - TP oxidised to pyruvate
Where does oxidative phosphorylation occur?
In the inner mitochondrial membrane.
How is ATP produced during oxidative phosphorylation?
Enzymes remove the hydrogen from reduced NAD/FAD and split it into H+ (proton) and a high energy e-.
e- flow through the ETC of carriers (oxidation-reduction reactions) releasing energy at each lower energy level.
Energy released actively transports H+ across inner membrane into inter membrane space.
H+ diffuse down an electrochemical gradient back into the matrix through ATP synthase synthesising ATP from ADP and Pi by chemiosmosis.
Reduced NAD powers 3 pumps, reduced FAD powers 2 pumps.
O2 acts as the final H+ and e- acceptor forming H2O which maintains the flow of electrons.
What acts as the final electron acceptor in the ETC?
Oxygen. It combines with electrons and protons to form water.
What happens under anaerobic conditions in animals?
Pyruvate is reduced to lactate by accepting H from NADH, regenerating NAD+ so glycolysis can continue.
What happens under anaerobic conditions in yeast/plants?
Pyruvate is decarboxylated to ethanal, then reduced to ethanol using NADH, regenerating NAD+.
How are lipids used in respiration?
Lipids are hydrolysed into glycerol (converted to TP) and fatty acids (converted to acetyl-CoA).
How are proteins used in respiration?
Proteins are deaminated. The remaining keto acids enter glycolysis or the Krebs cycle depending on their structure.
Why do lipids release more energy than carbohydrates?
They have more C-H bonds, so more ATP is generated from oxidative phosphorylation.
Define gross primary production (GPP).
The total quantity of chemical energy stored in plant biomass per unit area per unit time.
