Question 1

Phospholipid bilayers play crucial roles within plant cells.

Which statement(s) linked to the importance of membranes in plant cells is/are true?

1 - ATP synthase embedded in thylakoid membranes maintains chemiosmotic gradients

2 - phospholipid bilayers within the chloroplast are impermeable to protons

3 - thylakoid membranes contain electron transport chain proteins

  A  

1, 2, and 3

  B  

only 1 and 2

  C  

only 2 and 3

  D  

only 1

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Question 2

RuBisCO is an enzyme that fixes carbon dioxide in photosynthesis. In some conditions, RuBisCO also carries out oxygen fixation.

The graph below shows how the carbon dioxide and oxygen fixing activities of RuBisCO are affected by temperature.

What are the correct percentage changes in RuBisCO carbon dioxide and oxygen fixing activities between 30°C and 40°C?

  A  

carbon dioxide fixation -12.7%, oxygen fixation 23.3%

  B  

carbon dioxide fixation -14.6%, oxygen fixation 18.9%

  C  

carbon dioxide fixation -2.4%, oxygen fixation 54.2%

  D  

carbon dioxide fixation -3.6%, oxygen fixation 35.1%

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Question 3

Cyanobacteria are photosynthetic prokaryotes.

A scientist exposed cyanobacteria to light of different colours and intensities and made the following observations:

1 - most cyanobacteria are blue in colour

2 - at low light intensities, glucose production in cyanobacteria is low

3 - when light intensity reaches a certain level the rate of glucose production in cyanobacteria stops increasing

What correctly explains these observations?

  A  

the pigments in cyanobacteria absorb blue light and light intensity is a limiting factor for the rate of photosynthesis

  B  

the pigments in cyanobacteria absorb red light and light intensity is not a limiting factor for the rate of photosynthesis

  C  

the pigments in cyanobacteria absorb blue light and light intensity is not a limiting factor for the rate of photosynthesis

  D  

the pigments in cyanobacteria absorb red light and light intensity is a limiting factor for the rate of photosynthesis

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Question 4

What is the source of electrons in photosynthesis?

  A  

ATP

  B  

CO2

  C  

H2O


  D  

NADPH


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Question 5

Photolysis is the process of splitting water using light energy.

What is the region of the chloroplast in which this process takes place?

  A  

outer membrane

  B  

stroma

  C  

thylakoid lumen


  D  

thylakoid membrane


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Question 6

The statements below relate to the Calvin cycle:

1 - molecules of triose phosphate are required for the synthesis of nucleic acids

2 - the production of triose phosphate from glycerate-3-phosphate requires ATP and reduced NAD

3 - reactions of the Calvin cycle occur at a faster rate when stomata are closed

Which statement(s) is/are correct?

  A  

1, 2, and 3 are correct

  B  

only 1 and 2 are correct

  C  

only 2 and 3 are correct

  D  

only 1 is correct


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Question 7

What is the location of ATP synthase in a chloroplast?

  A  

inner membrane

  B  

stroma

  C  

thylakoid lumen

  D  

thylakoid membrane


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Question 8

Photosynthetic pigments in a leaf were separated using paper chromatography.

The resulting chromatogram is shown below.

What is the retention factor (Rf) for the most soluble pigment?

  A  

0.33


  B  

0.93


  C  

1.07


  D  

3.04


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Question 9

How many molecules of CO2 must enter the Calvin cycle to produce one molecule of glucose?

  A  

3

  B  

5

  C  

12

  D  

6

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Question 10

Which enzyme catalyses the fixation of carbon dioxide in the Calvin cycle?

  A  

ATP synthase

  B  

RuBisCO

  C  

NADP reductase

  D  

phosphoglycerate kinase

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Question 11

In the Calvin cycle, what molecule does CO₂ initially combine with?

  A  

ATP

  B  

ribulose bisphosphate (RuBP)

  C  

glycerate-3-phosphate (GP)

  D  

triose phosphate (TP)

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Question 12

Which molecule is the final electron acceptor in the light-dependent reactions?

  A  

oxygen

  B  

carbon dioxide

  C  

glucose

  D  

NADP

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Question 13

What is the main purpose of the light-dependent reactions in photosynthesis?

  A  

to produce glucose directly from CO2

  B  

to produce ATP and reduced NADP

  C  

to break down carbohydrate molecules

  D  

to convert oxygen into carbon dioxide

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