Photosynthesis Revision pack
Revision Pack
Photosynthesis
Past Paper Questions
Name:
,Photosynthesis Revision pack
Q1.
Chloroplasts contain chlorophyll a and chlorophyll b. Scientists found tobacco plants with a
mutation that caused them to make more chlorophyll b than normal tobacco plants. They
investigated the effect of this mutation on the rate of photosynthesis.
The scientists carried out the following investigation.
• They grew normal and mutant tobacco plants. They grew some of each in low light
intensity and grew others in high light intensity.
• They isolated samples of chloroplasts from mature plants of both types.
• Finally, they measured oxygen production by the chloroplasts they had isolated from the
plants.
The figure below shows the scientists’ results.
Light intensity / μmol photons m-2s-1
(a) Explain why the scientists measured the rate of production of oxygen in this investigation.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
(2)
In each trial, the scientists collected oxygen for 15 minutes.
,Photosynthesis Revision pack
(b) Calculate the difference in the oxygen produced by the chloroplasts from mutant plants
grown in low and high light intensities at a light intensity of 500 μmol photons m–2 s–1.
Show your working.
Difference ____________________ μmol O 2 mg–1 hour–1
(2)
(c) The scientists suggested that mutant plants producing more chlorophyll b would grow
faster than normal plants in all light intensities.
Explain how these data support this suggestion.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
(Extra space) _______________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
(4)
(Total 8 marks)
Q2.
An investigation was carried out to find the effect of increasing carbon dioxide concentration on
the rate of photosynthesis in a particular type of plant. The graph shows the results.
,Photosynthesis Revision pack
(a) (i) In this investigation, temperature was kept constant. Explain why.
______________________________________________________________
______________________________________________________________
(1)
(ii) Suggest suitable units for measuring the rate of photosynthesis in this investigation.
______________________________________________________________
(2)
(b) (i) Give the evidence from the graph that carbon dioxide is limiting the rate of
photosynthesis between A and B.
______________________________________________________________
______________________________________________________________
(1)
(ii) Explain the shape of the curve between B and C.
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
(2)
(Total 6 marks)
Q3.
,Photosynthesis Revision pack
There is evidence that the first photosynthetic organisms were primitive water-dwelling bacteria.
The very first of these lived near the surface of the water in lakes and contained a purple
pigment that absorbed light most strongly in the green region of the spectrum. Later, other
bacteria evolved that lived on the top of sediment at the bottom of the lakes (Figure 1). Gene
mutations had enabled these bacteria to synthesise chlorophyll instead of the purple pigment
present in the bacteria living near to the surface. Chlorophyll absorbs light most strongly in the
blue and red regions of the spectrum (Figure 2).
Figure 1
(a) Describe how light energy absorbed by chlorophyll molecules is used to synthesise ATP.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
, Photosynthesis Revision pack
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
(5)
(b) Use Figure 2 to explain how natural selection would favour the evolution of sediment-
dwelling bacteria containing a different photosynthetic pigment from those living near the
surface of the water.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
(6)
(Total 11 marks)
Q4.
In the light-dependent reaction of photosynthesis, light energy generates ATP.
Describe how.
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
Revision Pack
Photosynthesis
Past Paper Questions
Name:
,Photosynthesis Revision pack
Q1.
Chloroplasts contain chlorophyll a and chlorophyll b. Scientists found tobacco plants with a
mutation that caused them to make more chlorophyll b than normal tobacco plants. They
investigated the effect of this mutation on the rate of photosynthesis.
The scientists carried out the following investigation.
• They grew normal and mutant tobacco plants. They grew some of each in low light
intensity and grew others in high light intensity.
• They isolated samples of chloroplasts from mature plants of both types.
• Finally, they measured oxygen production by the chloroplasts they had isolated from the
plants.
The figure below shows the scientists’ results.
Light intensity / μmol photons m-2s-1
(a) Explain why the scientists measured the rate of production of oxygen in this investigation.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
(2)
In each trial, the scientists collected oxygen for 15 minutes.
,Photosynthesis Revision pack
(b) Calculate the difference in the oxygen produced by the chloroplasts from mutant plants
grown in low and high light intensities at a light intensity of 500 μmol photons m–2 s–1.
Show your working.
Difference ____________________ μmol O 2 mg–1 hour–1
(2)
(c) The scientists suggested that mutant plants producing more chlorophyll b would grow
faster than normal plants in all light intensities.
Explain how these data support this suggestion.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
(Extra space) _______________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
(4)
(Total 8 marks)
Q2.
An investigation was carried out to find the effect of increasing carbon dioxide concentration on
the rate of photosynthesis in a particular type of plant. The graph shows the results.
,Photosynthesis Revision pack
(a) (i) In this investigation, temperature was kept constant. Explain why.
______________________________________________________________
______________________________________________________________
(1)
(ii) Suggest suitable units for measuring the rate of photosynthesis in this investigation.
______________________________________________________________
(2)
(b) (i) Give the evidence from the graph that carbon dioxide is limiting the rate of
photosynthesis between A and B.
______________________________________________________________
______________________________________________________________
(1)
(ii) Explain the shape of the curve between B and C.
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
(2)
(Total 6 marks)
Q3.
,Photosynthesis Revision pack
There is evidence that the first photosynthetic organisms were primitive water-dwelling bacteria.
The very first of these lived near the surface of the water in lakes and contained a purple
pigment that absorbed light most strongly in the green region of the spectrum. Later, other
bacteria evolved that lived on the top of sediment at the bottom of the lakes (Figure 1). Gene
mutations had enabled these bacteria to synthesise chlorophyll instead of the purple pigment
present in the bacteria living near to the surface. Chlorophyll absorbs light most strongly in the
blue and red regions of the spectrum (Figure 2).
Figure 1
(a) Describe how light energy absorbed by chlorophyll molecules is used to synthesise ATP.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
, Photosynthesis Revision pack
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
(5)
(b) Use Figure 2 to explain how natural selection would favour the evolution of sediment-
dwelling bacteria containing a different photosynthetic pigment from those living near the
surface of the water.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
(6)
(Total 11 marks)
Q4.
In the light-dependent reaction of photosynthesis, light energy generates ATP.
Describe how.
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
