Higher Level Section B Questions on Photosynthesis
2007 HL
9.
(a)
State a precise role for each of the following in photosynthesis:
(i) Carbon dioxide
(ii) Water
(b)
Answer the following questions in relation to an activity that you carried out to
investigate the influence of light intensity OR carbon dioxide concentration on the rate of
photosynthesis.
(i) Name the plant that you used.
(ii) How did you vary light intensity OR carbon dioxide concentration?
(iii)State a factor that you kept constant during the investigation.
(iv)How did you ensure that the factor that you mentioned in (iii) remained constant?
(v)How did you measure the rate of photosynthesis?
(vi)Using labelled axes, sketch a graph to show how the rate of photosynthesis varied
with the factor mentioned in (ii) above.
Answer
2010 HL
8.
(b) For which purpose did you use each of the following in the course of your practical
studies?
(i) Methylene blue or iodine solution when examining cells with the microscope.
(ii) An aquatic plant such as pondweed rather than a terrestrial plant when investigating
the rate of photosynthesis.
(iii)
1.
Washing-up liquid or other detergent while extracting DNA from
plant tissue.
2.
(iv)
Freezer-cold ethanol while extracting DNA from plant tissue.
1.
Antiseptic wash solution in the investigation of the growth of leaf
yeast on agar plates.
2.
Petroleum jelly in the investigation of the growth of leaf yeast on
agar plates.
(v)
1.
Biuret solution or alkaline copper sulphate in food testing.
2. Brown paper or Sudan III in food testing.
Answer
2013 HL
9.
(a)
(b)
(i)
Explain the importance of double-blind testing in scientific experimentation.
(ii)
How does a hypothesis differ from a theory?
Answer the following in relation to investigations that you carried out in the course of
your practical studies.
(i) When investigating the effect of either carbon dioxide concentration or light intensity
on the rate of photosynthesis:
1. How did you vary your chosen factor?
2. Using suitably labelled axes, draw a graph of the results that you obtained.
Answer
Ordinary Level Questions Section B on Photosythesis
2013 OL
7.
(a)
(i)
(ii)
(b)
Where in a plant cell does photosynthesis take place?
Name the gas released during photosynthesis
Answer the following questions in relation to an investigation that you carried out to
study the effect of light intensity or carbon dioxide concentration on the rate of
photosynthesis.
Tick the factor you will refer to.
(i) Name the plant that you used.
(ii)
How did you vary the light intensity or the carbon dioxide concentration?
(iii)
Name one factor that you kept constant during the investigation.
(iv)
How did you keep that factor constant?
(v)
How did you measure the rate of photosynthesis?
(vi)
What was the result of your investigation?
Answer
2007 HL Q9
9.
(a) (i)
(ii)
(b) (i)
(ii)
supplies carbon or correct comment related to CO2
3
supplies hydrogen or protons (H+) or electrons or photolysis or
described [allow formation of carbohydrate or named once]
3
Elodea or other correctly named aquatic plant
3
lamp distance or wattage or quantity of NaHCO3
3
(iii) carbon dioxide or light or temperature
water bath or described or lamp distance or wattage or
NaHCO3
bubbles or volume / time
(v)
or data logger / sensor named
vertical axis labelled rate + horizontal axis labelled [light or
(vi) CO2]
curve matching axes labels
(iv)
3
3
2(3)
3
3
2010 HL Q8
8.
(a)
(b)
(i)
Educated guess or (possible) explanation
3
(ii)
Comparison (with experiment)
3
(i)
As a stain or to see more clearly
3
(ii)
(iii)
(iv)
(v)
To see (or measure ) gas (or bubbles)
[negative for terrestrial plants]
1. (Detergent) breaks down membranes
2. To separate (or see) the DNA
1. To prevent contamination or described
2. Attach leaves (or leaf parts)
1. Test for (soluble) protein
2. Test for fat (or lipid or oil)
3
3
3
3
3
3
3
2013 HL Q9
9.
(a)
(i)
Avoidance of bias
3
(ii)
Hypothesis can develop into a theory or explained
3
(b)
(i)
1.
CO2 –
vary NaHCO3 conc.
OR
Light –
(ii)
(iii)
(iv)
3
vary lamp (or plant) distance or vary lamp wattage
2.
Graph with labelled axes (rate on y-axis) + rise
3
1.
As a selectively permeable membrane
3
2.
Change (increase or decrease) in mass (volume) or described
3
1.
e.g. Iodine → yellow (or orange or brown)
3
2.
Dropper or use of filter paper
3
1.
Milk agar or starch agar
3
2.
Boiled seeds
3
2013 OL Q7
7.
(a)
1+5
(i)
Chloroplast
(1 pt)
(ii)
Oxygen
(1 pt)
If parts (ii), (iii), (iv) and (vi) are not consistent from answer to answer
then go with version that yields the greater marks.
8(3)
Name of plant (must be aquatic)
(1 pt)
(b)
(i)
(ii)
(iii)
(iv)
Increased or decreased lamp-beaker distance
OR
Different concs of NaHCO3
e.g. Temperature/ light intensity if CO2 ticked/ CO2 conc. if light
intensity ticked
Water bath if temperature/ (same) lamp at same distance if light
intensity/ same conc NaHCO3 if CO2 conc.
(1 pt)
(1 pt)
(1 pt)
(v)
(Count) bubbles/ per unit time
(2 pts)
(vi)
Greater light intensity or higher CO2 conc./ → higher rate of
photosynthesis
OR
Opposite statement
(2 pts)