B2.4 Photosynthesis and sampling fact sheet
Plant tissues and organs
1. List three plant organs (1)
2. Name the tissues in the cross section of the leaf
(4)
Roots, stem and leaf
A = Epidermis
B and C = Phloem and Xylem
D = Mesophyll
3. Give the function of the mesophyll tissue (1)
Carries out photosynthesis
4. Give the function of the epidermis tissue (1)
Covers the plant
5. Give the function of the xylem tissue (1)
Transports water
6. Give the function of the phloem tissue (1)
Transports sugars
7. Give the function of the stomata (1)
Allows gases in and out of the leaf
Photosynthesis
8. Write the word equation for photosynthesis. (2)
9. Where in plant cells does photosynthesis take
place? (1)
10. Describe the function of chlorophyll (1)
11. What does the plant do with the glucose it
produces during photosynthesis? (5)
12. What additional chemical does the plant need in
order to produce amino acids for proteins and
where does it get it from? (1)
13. What process do plants AND animals do with
glucose? (1)
14. Which process/ processes do plants do during
the day and why? (2)
15. Which process/ processes do plants do during
the night and why? (1)
Carbon dioxide + water
In the chloroplasts

Glucose + Oxygen
Absorbs the light energy for photosynthesis
 Stores it as insoluble starch
 Produces fats or oil for storage
 Produces cellulose which strengthens the cell wall
 Produces proteins
 Carries out respiration to release energy
Nitrate ions from the soil
Aerobic respiration to release energy
Photosynthesis because light energy is available.
They do this to store the energy in glucose.
Aerobic respiration because they need to release
the energy from the glucose to carry out various
processes.
Aerobic respiration because they need to release
the energy from the glucose to carry out various
processes.
16. Which gas do plants produce more of during the
day and why? (2)
17. Which gas/ gases do plants produce during the
night and why? (1)
Limiting factors
18. What is limiting the rate of photosynthesis at
points A and B? (2)
Oxygen due to photosynthesis. They will release
carbon dioxide from respiration but will then use this for
photosynthesis to release oxygen.
Carbon dioxide because they are respiring. No
oxygen is released as they don’t photosynthesise at
night.
A = Low carbon dioxide concentration
B = Low temperature or light intensity
B
A
19. What is limiting the rate of photosynthesis at
points A and B? (2)
A = Low light intensity
B = Low carbon dioxide concentration or
temperature
B
A
20. What is limiting the rate of photosynthesis at
points A and B? (2)
A = Low temperature
B = The enzymes have denatured
B
A
21. How can farmers manipulate the conditions to
increase the rate of photosynthesis and increase
growth? (3)
Sampling
22. Define ‘habitat’
23. Name physical factors that may affect living
organisms in a habitat (6)
24. Define ‘data’
a. Increase light intensity (using lights in the
greenhouse)
b. Increase carbon dioxide concentration (burn
paraffin in greenhouse)
c. Increase temperature (up to a point) – using
greenhouse heaters
Where an organism lives
Temperature, availability of nutrients, amount of light,
availability of water, availability of oxygen and carbon
dioxide
Facts and statistics that are collected
25.
26.
27.
28.
29.
Define ‘quantitative data’
Define ‘distribution’
Define ‘environment’
Define ‘quadrat’
Define ‘transect’
30. State 2 ways to obtain data on the distribution of
organisms (2)
31. Skill – Describe how to estimate numbers of a
particular species of plant in a field (5)
32. Skill – Describe how to investigate the changing
distribution of species across an area (4)
Evaluating collected data
33. How can you improve the reliability of your
data?
34. How can you ensure that your investigation is
valid?
35. How do you know if your data is reproducible?
36. How do you know if your data is valid? (3)
37. Way to calculate mean
38. Skill - Calculate the mean of these numbers
8, 12, 7, 15, 6, 14
39. Way to calculate median
40. Skill - Calculate the median of these numbers
8, 12, 7, 15, 6, 14
41. Way to calculate mode
42. Skill - Calculate the mode of these numbers
8, 15, 15, 12, 6, 15
Data with numerical values
The way living things are spread over an area
Living and non-living things in a habitat
A frame to place over a small area of habitat (eg 1m2)
A line along which samples are taken at regular
intervals
 Random sampling with a quadrat
 Sampling along a transect
 Divide the area into a grid
 Use a random number generator to randomly
choose squares on the grid
 Count species numbers in at least 10 quadrats
 Calculate mean number per quadrat or (m2)
 Multiply by total area (m2) of the field to
estimate numbers in whole area.
 Use tape measure to produce transect and
place across the area
 Place quadrats at regular intervals along the
tape (eg every 1m)
 Count numbers of different species in each
quadrat
 Repeat transect (more than 3) along garden at
intervals (random or regular)
Take a greater number of samples
As many control variables as possible will have been
controlled/ kept the same
Other people who have done the investigation will
have similar results (in a similar pattern)
It will be repeatable, reproducible and answer the
hypothesis
Add up all data values and divide by the number of
values you have
8+12+7+15+6+14 = 62
62/ 6 = 10 (rounded down as 10.3)
Write down all numbers, smallest to largest. Select
number that’s in the middle. If 2 numbers are in the
middle, take the mean of them
6, 7, 8, 12, 14, 15
Two middle numbers are 8 and 12, so now need mean
of these = 10
The value you have the most of
15