Photosynthesis Overview Quiz

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Questions and Answers

Which respiratory substrate has the highest respiratory quotient (RQ) value?

Lipids

Proteins

Carbohydrates (correct)

Fatty acids

What is the primary role of pyruvate in anaerobic respiration in mammals?

It serves as a hydrogen acceptor to reoxidise NADH. (correct)

It generates ATP directly through substrate-level phosphorylation.

It is converted to fatty acids.

It acts as an initial substrate for the Krebs cycle.

During alcoholic fermentation in yeast, what product is formed from the decarboxylation of pyruvate?

Lactate

Ethanol

Carbon dioxide (correct)

Acetyl-CoA

Which respiratory substrate has an RQ value closest to 0.9?

Proteins Signup and view all the answers

What is the effect of low oxygen concentration on ATP production in an organism?

It necessitates the use of anaerobic respiration to produce ATP. Signup and view all the answers

What role does light energy play in photosynthesis?

It excites electrons to higher energy levels for ATP production. Signup and view all the answers

Where in the chloroplast does the light-independent reaction occur?

In the stroma. Signup and view all the answers

What are the main products of the light-dependent reactions of photosynthesis?

ATP and reduced NADP. Signup and view all the answers

Which factor does NOT affect the rate of photosynthesis?

Presence of chlorophyll. Signup and view all the answers

What is produced as a waste product during photosynthesis?

Oxygen. Signup and view all the answers

In the process of photolysis, what happens to water molecules?

They are split to release hydrogen and oxygen. Signup and view all the answers

Which of the following statements about the photosynthetic pigments is correct?

They are arranged in stacks known as grana. Signup and view all the answers

What is the Calvin cycle primarily responsible for?

Using ATP and reduced NADP to produce glucose. Signup and view all the answers

What is the role of RUBISCO in the light independent reaction?

To catalyze the combination of RuBP and carbon dioxide Signup and view all the answers

Which of the following best describes the fate of some triose phosphate (TP) molecules produced?

They are used to form RuBP Signup and view all the answers

What is produced during the link reaction when pyruvate is converted to acetyl?

NADH and CO2 Signup and view all the answers

What effect does low light intensity have on photosynthesis?

It reduces the conversion of GP to TP Signup and view all the answers

How many times does the Krebs cycle turn for each glucose molecule?

Twice Signup and view all the answers

What is the main purpose of oxidative phosphorylation?

To synthesize ATP Signup and view all the answers

Which factor is not considered a limiting factor in the photosynthesis process?

Soil pH Signup and view all the answers

What is the primary product of glycolysis?

Pyruvate Signup and view all the answers

Which molecule acts as the final electron acceptor in oxidative phosphorylation?

Oxygen Signup and view all the answers

What is the theoretical yield of ATP molecules from one glucose molecule during aerobic respiration?

38 ATP Signup and view all the answers

During aerobic respiration, what is released as a waste product?

Carbon dioxide Signup and view all the answers

What process is associated with the production of ATP in the Krebs cycle?

Substrate level phosphorylation Signup and view all the answers

What characterizes anaerobic respiration compared to aerobic respiration?

It occurs in the absence of oxygen Signup and view all the answers

Which of the following processes occurs in the cytoplasm?

Glycolysis Signup and view all the answers

Why is the theoretical yield of ATP rarely achieved in reality?

Leaky inner mitochondrial membrane Signup and view all the answers

What role does coenzyme A play in cellular respiration?

It delivers acetyl to the Krebs cycle Signup and view all the answers

Study Notes

Photosynthesis

Photosynthesis is the process of converting light energy into chemical energy in the form of glucose.
It occurs in chloroplasts, which contain thylakoid membranes (grana) and stroma.
Grana contain chlorophyll, which absorbs light energy.
Stroma contains enzymes for the light-independent reaction.

Light-Dependent Reaction

Light energy excites electrons in chlorophyll.
Excited electrons are passed along an electron transport chain.
This process generates ATP through photophosphorylation and reduces NADP to NADPH.

Light-Independent Reaction (Calvin Cycle)

Carbon dioxide is fixed to RuBP by the enzyme Rubisco.
RuBP is converted into two glycerate 3-phosphate (GP) molecules.
GP is converted to triose phosphate (TP) using ATP and reduced NADP.
Some TP is used to make glucose, which is converted to other organic compounds.
The remaining TP is used to regenerate RuBP.

Factors Affecting Photosynthesis

Light intensity, carbon dioxide concentration, and temperature are limiting factors.
Low light intensity limits the light-dependent reaction, reducing ATP and NADPH production.
Low carbon dioxide concentration limits the light-independent reaction, reducing the rate of carbon fixation.
Low temperature slows down enzyme activity, affecting both stages of photosynthesis.

Respiration

Respiration is the process of breaking down respiratory substrates to release energy.
Aerobic respiration occurs with oxygen, while anaerobic respiration occurs without oxygen.

Glycolysis

The first stage of both aerobic and anaerobic respiration.
Occurs in the cytoplasm.
Glucose is broken down into pyruvate, producing ATP, NADH, and carbon dioxide.

Aerobic Respiration

Pyruvate is converted to acetyl CoA in the link reaction.
Acetyl CoA enters the Krebs cycle, producing ATP, reduced NAD, and reduced FAD.
Reduced coenzymes (NADH and FADH) are used in oxidative phosphorylation.

Oxidative Phosphorylation

Occurs in the mitochondria.
Electrons from reduced coenzymes are passed along the electron transport chain.
The energy released is used to pump protons across the inner mitochondrial membrane.
Protons flow back through ATPase, producing ATP.
Oxygen acts as the final electron acceptor, combining with hydrogen ions to form water.

Respiratory Substrates

Carbohydrates, lipids, and proteins can be used as respiratory substrates.
Fatty acids release more energy than carbohydrates due to their higher hydrogen content.

Respiratory Quotient (RQ)

RQ is the ratio of carbon dioxide produced to oxygen consumed.
It can be used to determine which respiratory substrate is being used and whether anaerobic respiration is occurring.

Anaerobic Respiration

Occurs in low oxygen conditions.
Allows glycolysis to continue by regenerating NAD.
Mammals produce lactate, while yeast and plants produce ethanol.
This process is less efficient at ATP production than aerobic respiration.

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Description

Test your knowledge on the process of photosynthesis, including light-dependent and light-independent reactions. Explore the role of chloroplasts, chlorophyll, and the factors affecting photosynthesis in this engaging quiz.