Question 1

Green and purple bacteria do not produce O₂ because

Accepted Answer

Green and purple bacteria do not produce O2 because they lack photosystem II, which is responsible for the splitting of water molecules and the release of oxygen in oxygenic photosynthesis.

Question 2

In photosynthetic eukaryotes the enzymes for carbon fixation are found in the

Accepted Answer

Carbon fixation in photosynthetic eukaryotes occurs in the chloroplast stroma, where enzymes like Rubisco catalyze the conversion of carbon dioxide and ribulose bisphosphate into organic molecules.

Question 3

ATP and NADPH produced in the light-dependent reactions of photosynthesis

Accepted Answer

ATP and NADPH are produced in the light-dependent reactions of photosynthesis and are used in the Calvin cycle to fix carbon dioxide (CO2) into sugars, providing the necessary energy and reducing power for this process.

Question 4

In the Calvin-Benson cycle, Rubisco catalyses the

Accepted Answer

Rubisco catalyzes the fixation of CO2 (carbon dioxide) to RuBP (ribulose-1,5-bisphosphate) in the Calvin-Benson cycle, which is a crucial step in the process of carbon fixation in photosynthesis.

Question 5

Photorespiration lowers the efficiency of the Calvin-Benson cycle by reducing the number of

Accepted Answer

Photorespiration consumes oxygen and releases carbon dioxide, thereby reducing the efficiency of the Calvin-Benson cycle by decreasing the number of carbon dioxide molecules that are fixed into sugars.

Question 6

A C₄ plant

Accepted Answer

All the statements accurately describe C4 plants. They fix CO2 into oxaloacetate (a 4-carbon compound) in mesophyll cells, require more energy for photosynthesis than C3 plants, typically have Kranz anatomy to facilitate their unique photosynthetic pathway, and produce a 4-carbon organic acid as the first stable product of photosynthesis.

Question 7

A green plant is placed in an enclosed CO₂-free atmosphere containing 21 per cent O₂ in the light. The CO₂ concentration remains zero. Which of the following statements about this plant is true?

Accepted Answer

Photorespiration is undetectable in the absence of CO₂.

Question 8

CAM plants are like other types of C₄ plants in that

Accepted Answer

CO₂ for the Calvin-Benson cycle comes from the decarboxylation of malate.

Question 9

If a C4 plant was exposed to radioactive CO₂, which of the following compounds would be the first labelled by the radioactive carbon?

Accepted Answer

In C4 plants, the first compound that gets labeled with radioactive carbon during photosynthesis is oxaloacetate. This is because carbon dioxide is initially fixed into oxaloacetate by the enzyme PEP carboxylase in the mesophyll cells.

Question 10

What is an electron transport system?

Accepted Answer

The electron transport system refers to a series of membrane-bound proteins and smaller compounds in the membranes of mitochondria (in eukaryotes) or the plasma membrane (in prokaryotes) that transfer electrons through redox reactions. This process generates a proton gradient that is used to produce ATP, making it a crucial component of cellular respiration.

Question 11

Which of the following do not occur in both mitochondria and chloroplasts?

Accepted Answer

O₂ is a placeholder for oxygen (O2), and the use of oxygen to produce water occurs in mitochondria during the electron transport chain of cellular respiration, but not in chloroplasts, where water is split into oxygen, protons, and electrons during photosynthesis.

Question 12

The flow of electrons in photosynthesis is

Accepted Answer

The correct flow of electrons in photosynthesis starts from Photosystem II (PS II), then moves to the cytochrome b/f complex, followed by Photosystem I (PS I), and finally to NADP+ to form NADPH. This sequence reflects the Z-scheme of electron flow in the light reactions of photosynthesis.

Question 13

Fats are degraded by the process $\beta$-oxidation. What is the end product of this process?

Accepted Answer

The end product of the fatty acid β-oxidation process is Acetyl-CoA, which can then enter the citric acid cycle for further energy production.

Question 14

When the first autotrophic photosynthetic prokaryotes evolved, they metabolised CO₂ and H₂O by utilising energy from the sun. Based on your knowledge of photosynthesis and evolution, what would the end products of these early reactions have been?

Accepted Answer

The early autotrophic photosynthetic prokaryotes would have used sunlight to convert carbon dioxide (CO2) and water (H2O) into oxygen (O2) and carbohydrates, a fundamental process of photosynthesis.

Question 15

Using only glycolysis, a cell is able to produce 2 ATP from one glucose molecule. When combined with oxidative respiration, how many ATP can a cell produce from one glucose molecule?

Accepted Answer

When combined with oxidative respiration, a cell can produce approximately 36 ATP molecules from one glucose molecule. This total includes the 2 ATP from glycolysis, about 2 ATP from the Krebs cycle, and approximately 32 ATP from the electron transport chain and oxidative phosphorylation, though the exact number can vary slightly depending on the cell type and conditions.

Question 16

Which of the following statements in relation to fermentation is INCORRECT?

Accepted Answer

Each statement contains inaccuracies regarding fermentation: A) The code doesn't relate to a known condition for fermentation. B) Methanol is not a typical product of fermentation. C) Fermentation is not independent of glycolysis; it follows glycolysis to regenerate NAD+. D) Glucose is converted into pyruvate during glycolysis, not fermentation, though fermentation follows this process.

Question 17

How do carotenoids and phycobilins assist in photosynthesis?

Accepted Answer

Carotenoids and phycobilins expand the range of light wavelengths that plants can use for photosynthesis by absorbing wavelengths not efficiently captured by chlorophyll, thus enhancing the photosynthetic efficiency.

Question 18

Phycobilins can be found in

Accepted Answer

Phycobilins are water-soluble pigments found in the chloroplasts of some cyanobacteria and red algae, playing a key role in capturing light energy for photosynthesis, especially in deeper water where light penetration is limited. They are not found in higher plants, conifers, angiosperms, mosses, or liverworts.

Question 19

Which of the following are NOT found in chloroplasts?

Accepted Answer

Thylakoid tonoplast is not found in chloroplasts. The tonoplast is a membrane that encloses the central vacuole in plant cells, not a component of the chloroplast. The other options (stroma lamellae, granum, thylakoid membrane, and thylakoid lumen) are all parts of the chloroplast structure involved in photosynthesis.

Question 20

When a chlorophyll molecule absorbs a photon, how is the energy generated transferred from the chlorophyll in the first instance?

Accepted Answer

The energy absorbed by chlorophyll is initially transferred through excitation transfer, where the energy excites an electron to a higher energy state within the chlorophyll molecule.

Quiz 6: Harvesting Energy

Green and purple bacteria do not produce O₂ because

In photosynthetic eukaryotes the enzymes for carbon fixation are found in the

ATP and NADPH produced in the light-dependent reactions of photosynthesis

In the Calvin-Benson cycle, Rubisco catalyses the

Photorespiration lowers the efficiency of the Calvin-Benson cycle by reducing the number of

A C₄ plant

A green plant is placed in an enclosed CO₂-free atmosphere containing 21 per cent O₂ in the light. The CO₂ concentration remains zero. Which of the following statements about this plant is true?

CAM plants are like other types of C₄ plants in that

If a C4 plant was exposed to radioactive CO₂, which of the following compounds would be the first labelled by the radioactive carbon?

What is an electron transport system?

Which of the following do not occur in both mitochondria and chloroplasts?

The flow of electrons in photosynthesis is

Fats are degraded by the process $\beta$ -oxidation. What is the end product of this process?

When the first autotrophic photosynthetic prokaryotes evolved, they metabolised CO₂ and H₂O by utilising energy from the sun. Based on your knowledge of photosynthesis and evolution, what would the end products of these early reactions have been?

Using only glycolysis, a cell is able to produce 2 ATP from one glucose molecule. When combined with oxidative respiration, how many ATP can a cell produce from one glucose molecule?

Which of the following statements in relation to fermentation is INCORRECT?

How do carotenoids and phycobilins assist in photosynthesis?

Phycobilins can be found in

Which of the following are NOT found in chloroplasts?

When a chlorophyll molecule absorbs a photon, how is the energy generated transferred from the chlorophyll in the first instance?

Quiz 6: Harvesting Energy

Green and purple bacteria do not produce O2 because

In photosynthetic eukaryotes the enzymes for carbon fixation are found in the

ATP and NADPH produced in the light-dependent reactions of photosynthesis

In the Calvin-Benson cycle, Rubisco catalyses the

Photorespiration lowers the efficiency of the Calvin-Benson cycle by reducing the number of

A C4 plant

A green plant is placed in an enclosed CO2-free atmosphere containing 21 per cent O2 in the light. The CO2 concentration remains zero. Which of the following statements about this plant is true?

CAM plants are like other types of C4 plants in that

If a C4 plant was exposed to radioactive CO2, which of the following compounds would be the first labelled by the radioactive carbon?

What is an electron transport system?

Which of the following do not occur in both mitochondria and chloroplasts?

The flow of electrons in photosynthesis is

Fats are degraded by the process β\betaβ -oxidation. What is the end product of this process?

When the first autotrophic photosynthetic prokaryotes evolved, they metabolised CO2 and H2O by utilising energy from the sun. Based on your knowledge of photosynthesis and evolution, what would the end products of these early reactions have been?

Using only glycolysis, a cell is able to produce 2 ATP from one glucose molecule. When combined with oxidative respiration, how many ATP can a cell produce from one glucose molecule?

Which of the following statements in relation to fermentation is INCORRECT?

How do carotenoids and phycobilins assist in photosynthesis?

Phycobilins can be found in

Which of the following are NOT found in chloroplasts?

When a chlorophyll molecule absorbs a photon, how is the energy generated transferred from the chlorophyll in the first instance?

Green and purple bacteria do not produce O₂ because

A C₄ plant

A green plant is placed in an enclosed CO₂-free atmosphere containing 21 per cent O₂ in the light. The CO₂ concentration remains zero. Which of the following statements about this plant is true?

CAM plants are like other types of C₄ plants in that

If a C4 plant was exposed to radioactive CO₂, which of the following compounds would be the first labelled by the radioactive carbon?

Fats are degraded by the process $\beta$ -oxidation. What is the end product of this process?

When the first autotrophic photosynthetic prokaryotes evolved, they metabolised CO₂ and H₂O by utilising energy from the sun. Based on your knowledge of photosynthesis and evolution, what would the end products of these early reactions have been?