The document discusses plant nutrition and photosynthesis. It defines photosynthesis as the process by which plants manufacture carbohydrates from carbon dioxide, water, and sunlight using chlorophyll. The key organelle that contains chlorophyll and allows this process is the chloroplast. The document then provides exercises about leaf structure, the process of photosynthesis, and factors that can affect photosynthesis rates.

1. Unit 6 – Plant Nutrition

2. Learning objectives
• Define photosynthesis.
• Write the word equation and chemical
equation for photosynthesis.
• Describe the effects of varying factors on
photosynthesis.

3. Section of a leaf

4. Key
• 1. Waxy cuticle, this gives the leaf a waterproof layer, which
lets in light.
• 2. Upper epidermis - provides an upper surface.
• 3. Palisade cells, which are packed full of chloroplasts.
• 4. Spongy mesophyll. Collection of damp, loosely packed cells.
• 5. Lower epidermis is the layer of cells on the lower surface.
• 6. Air space inside the leaf, allows contact between air and
moist cell surfaces.
• 7. Stoma, a hole in the leaf which gases diffuse through.
• 8. Guard cells, which change shape to close the stoma.

5. Photosynthesis video
• Video
• https://www.youtube.com/watch?v=HkyDoUR
zU4c

6. Exercise 1: Leaf Structure
1. ___________
2. ___________
3. ______________________
5. _____________________
7. __________
6. ________
4. __________
Waxy cuticle
Epidermis
Palisade mesophyll layer
Spongy mesophyll layer
Epidermis
Stomata
Air space

7. Exercise 2: Link the Boxes
Waxy cuticle
Stoma
Air spaces Waterproof layer atop the
epidermis
Pores that allow gaseous
exchange
Found in the spongy
mesophyll layer, enable
gases to reach the leaf
cells

8. Exercise 3: Link the Boxes
Epidermis
Palisade
mesophyll cell
Spongy mesophyll
cell
Contain numerous chloroplasts
and are densely packed, where
most of the photosynthesis
occurs
Loosely packed cells that do not
contain as many chloroplasts as
palisade cells
One-cell thick outer layer of
cells that prevent water loss
from the leaf

9. Exercise 4: Short Questions - Leaf
1. What do we call the continuation of the leaf stalk into the leaf-
blade?
2. What do we call the specially adapted cells that form holes in the
leaves to allow gaseous exchange?
3. What are these holes/pores called?
4. What is the name of the waxy waterproof layer found on top of the
epidermis?
5. What is the lamina?
Midrib
Guard cells
Stoma
Cuticle
The leaf-blade

10. Exercise 5: Short Questions - Leaf
1. What do we call the outer one-cell thick layer of cells that contain
no chloroplasts?
2. What is the function of this layer?
3. What are two differences between palisade mesophyll cells
(PMC) and spongy mesophyll cells (SMC)?
4. By what process does carbon dioxide enter and leave leaves?
The epidermis
To prevent water loss and to stop substances and organisms entering
the leaf
SMC – more loosely packed, less chloroplasts
Diffusion
PMC – more densely packed, more chloroplasts

11. Exercise 6: Insert the Missing Words
Chloroplasts __________ of plant cells that contain a green substance
called __________.
Scientists believe chlorophyll absorbs _____ energy and this energy is
then used to make _____.
The raw materials of photosynthesis are carbon dioxide and _____.
This waste product of this reaction is _______.
The carbon dioxide required is absorbed through the ______ in the
leaves – this is how the oxygen is also removed.
The water required is absorbed by the _____.
roots organelles light food
water chlorophyll oxygen stoma
organelles
chlorophyll
light
food
water
oxygen
stoma
roots

12. Exercise 7: Short Questions - Photosynthesis
1. Which organelles in plant cells contain a green substance called
chlorophyll?
2. Which two raw materials are required by green plants for
photosynthesis?
3. What is the waste product of photosynthesis?
4. How does this waste product leave the plant during the day?
5. What process requires this waste product to enable green
plants to release energy from their food?
Chloroplasts
Water and carbon dioxide
Oxygen
Through the stoma
Respiration

13. Exercise 8: Short Questions – Plant Nutrition
1. What do we call the process whereby green plants make
glucose using light energy and the raw materials carbon dioxide
and water?
2. During the night many green plants perform another process
whereby they release the energy from their food they have
made. What do we call this process?
3. The sugar glucose, the product of photosynthesis, is changed to
starch when it is being stored by the plant. Why?
4. What is the chemical formula of glucose?
Photosynthesis
Respiration
Glucose is soluble in water, starch is insoluble in water. By
storing the food starch it means it is easier for the plant to keep
the food in the required place
C6H12O6

14. Exercise 9: Short Questions – Plant Nutrition
1. What is the word equation for photosynthesis?
2. What is the chemical equation for photosynthesis?
3. Name the arrowed organelle.
4. Which substance does this organelle
contain that allows green plants to
absorb the Sun’s light energy for the
process of photosynthesis?
6H2O + 6CO2  C6H12O6 + 6O2
Chloroplast
Chlorophyll

15. Types of nutrition
• Green plants make their own food.
• They take inorganic substances from the air
and soil. (carbon dioxide, water and minerals)
• Plants use these substances to make complex
materials. (Carbohydrates, lipids, proteins,
vitamins)
• Substances made by living things are organic.

16. What is photosynthesis?
• Photosynthesis is the fundamental process by
which plants manufacture carbohydrates
from raw materials using energy from light.
• Plants use water from the soil, carbon dioxide
from the air and energy from sunlight to make
carbohydrates & oxygen.
• Photo = Light synthesis = manufacture

18. Word equation
• Plants use the green dye (or pigment) called chlorophyll to pick up
the energy from the sunlight.
• Plants make sugar and use some of it for energy to keep them alive
(respiration) but they also use some for growth and repair by
making fats and proteins.
• However, it is not always sunny so plants need to be able to store
some of the sugar they make, so they convert it to a storage
carbohydrate.

20. The role of chlorophyll
• Chorophyll is kept inside the chloroplasts of
plant cells.
• The green pigment traps sunlight energy.
• The cholrophyll molecule then releases the
energy to make carbon dioxide combine to
water.

21. Limiting Factors on photosynthesis
• Video

22. Factors effecting Photosynthesis