Investigating photosynthesis

Question 1

State the factors that affect the rate of photosynthesis

Answer 1

Light intensity carbon dioxide temperature

Question 2

Describe how to test a leaf for starch

Answer 2

1. Using forceps place it into a beaker of boiling water to kill it
2. Leaf into a boiling tube of boiling ethanol to remove all chlorophyll
3. Wash the leaf with water to remove ethanol
   Soften leaf and spread it out on white tile
4. Few drops of iodine solution
5. If turn yellow brown to blue black starch present

Question 3

How do you measure the rate of photosynthesis

Answer 3

Measuring amount of oxygen given off
- Place upturned test tube over pondweed
- Count the number of bubbles given off
- Time how long it takes to collect a specific volume of gas
- Once collected full tube of gas, place glowing splint in test tube if it relights oxygen present