4.4.1.3 Uses of Glucose from Photosynthesis Flashcards
Uses of glucose from photosynthesis:
- Respiration
- Starch
- Proteins
- Cellulose
- Amino Acids
- Lipids (fats And oils)
Uses of glucose from photosynthesis: How is starch made?
By building glucose into large starch molecules, converted into insoluble starch
Uses of glucose from photosynthesis: Respiration
Used for aerobic respiration with releases energy
Uses of glucose from photosynthesis: Uses of starch
Storage of energy
Uses of glucose from photosynthesis: How’s protein made?
By combining nitrate ions (that are absorbed from the soil by active transport) and other minerals (protein synthesis)
Uses of glucose from photosynthesis: Uses of protein
- For growth and repair
- Used to produce amino acids for protein synthesis
Uses of glucose from photosynthesis: How’s cellulose made?
By building glucose into a large carbohydrate called cellulose
Uses of glucose from photosynthesis: Uses of cellulose
Makes up and strengthens the cell wall
Uses of glucose from photosynthesis: How are lipids (fats and oils) made?
By building glucose into fat or oils
Explain plant respiration:
- Oxygen is a waste product of photosynthesis
- When plant cells respire they use some of this oxygen
- Plants respire continually because they need a constant supply of energy to keep them alive
- Glucose used for: used to make proteins for plant growth and repair, used as energy, used to make cellulose for plant cell walls, stored as starch, stored as fat and oils, photosynthesis
- Oxygen is used for: photosynthesis, used in respiration, released into air by stomata
What happens if there is an increase in chlorophyll?
- An increase in chlorophyll means there an increase in photosynthesis which means there is an increase in the amount of glucose produced which means there is an increase in aerobic respiration in mitochondria which means there is an increase in energy for growth
- An increase in chlorophyll means there an increase in photosynthesis which means there is an increase in the amount of glucose produced which means there is an increase in amino acids converted which means there is an increase in protein which means there is growth (as protein is used for growth and repair)
What is the apparatus needed to test a leaf for starch?
- 2 beakers
- Boiling tube
- Eye protection
- Kettle of hot water
- Iodine solution
- White tile
- Tongs
- Forceps
- Ethanol (highly flammable)
- Variegated leaf
What is the method used to test a leaf for starch?
- Look at the leaf that you have been given. Draw the leaf carefully in the box on the next page noting its shape and colour.
- Fill a beaker with a very hot water from a. kettle or water bath and add the leaf.
- Leave the leaf for 1 minute. This will get rid of the waterproof layer, break open the cells and make the leaf soft.
- Take out the leaf, put it into a boiling tube and cover it with ethanol.
- Put the tube into a beaker of hot water. Ethanol boils at 78 degrees C, so it should come to the boil.
- Pour the ethanol into a waste beaker and dip the leaf back into the hot water to remove the ethanol.
- Spread the leaf out on the white tile. Add about five drops of iodine to the lead and observe. It should take about two minutes for the iodine to soak in.
- Draw the leaf in the second box and label the different colours you see.
Testing a leaf for starch experiment: Variegated leaf before and after iodine test
- White parts of leaf dyed colour of iodine (orange/brown)
- Green parts (parts with chlorophyll) turned blue/black
- If a plant is variegated, the green part of the leaf will turn blue/black after the starch test as it has chlorophyll so it will photosynthesise to produce glucose which will be converted to starch (reaction) testing positive for starch the starch test
- As no chlorophyll = no photosynthesis = no glucose produced = nothing converted to starch = testing negative for starch test therefore being dyed the colour of starch, which is orange/brown
- The white part of a variegated leaf would be dyed the colour of iodine orange/brown - this is because if a part of a leaf is white it means it has no chlorophyll (as it is a green pigment and would be showing) which means no photosynthesis would be able to take place which means no glucose would be produces which means there would be no starch converted so the white parts of the leaf would turn orange/brown rather than blue/black as it would be dyed the normal colour of iodine
Testing a leaf for starch experiment: Would there be any starch in the white part of a variegated leaf? Explain your answer:
No, because if a part of a leaf is white it means it has no chlorophyll (as it is a green pigment and would be showing) which means no photosynthesis would be able to take place which means no glucose would be produces which means there would be no starch converted so the white parts of the leaf would turn orange/brown rather than blue/black as it would be dyed the normal colour of iodine
