Opener Photosynthesis Quiz

Explain what Photosynthesis is, where in the plant it takes place ( include equation for photosynthesis in your answer )

Answer explanation

it is a process of _______

it takes place in the chloroplast

6CO2 + 6H2O --> C6H12O6 + 6O2

State what gives leaves it's green colour

Answer explanation

chlorophyll

State the chemicals needed and the products produced for photosynthesis.

Answer explanation

carbon dioxide + water

with chlorophyll and sunlight/light energy

makes oxygen + glucose

Draw the structure of the leaf and circle the apex

Explain how the leaf has adapted for photosynthesis using it's external structure

Answer explanation

- is green in colour ( contains chlorophyll to absorb light energy )

- is flat/thin ( CO2 and O2 can diffuse and absorb easily )

- high surface area ( maximum amount of sun can be absorbed by the leaf )

- veins ( carry water and ions throughout the leaf and sucrose out the leaf )

When testing leaves for starch.

Explain why leaves must be decolourised before testing

Answer explanation

- leaf loses its green pigment ( chlorophyll ) and so hence when tested with iodine solution the blue/black colour can easily be observed as a sign starch is present

State 3 factors that affect the rate photosynthesis and explain how those three factors have an impact on the rate of photosynthesis ( does it increase it's rate, does it decrease it's rate, also mention limiting factors )

Answer explanation

- light intensity ( increasing light intensity increases rate of photosynthesis )

- temperature ( increasing temperature increases collisions hence increases the rate of photosynthesis )

- CO2 concentration ( increasing CO2 increases rate of photosynthesis )

- mention of limiting factor ( there is a point/limit to where the factors that affect the rate of photosynthesis rate until they further cannot )

Describe an experiment used to show chlorophyll is needed for photosynthesis ( HINT : the experiment can be summarised with 4-5 steps )

Answer explanation

1. get a destarched variegated plant ( white and green )

2. place in light for about 6-7 hours

3. pick a leaf and draw/photograph it carefully

4. Test leaf for starch

5. Take a photo or Draw leaf after being tested for starch and label blue black parts

Describe an experiment to show that light is needed for photosynthesis ( HINT : experiment consists of 1-4 steps and ethanol is involved in the experiment )

Answer explanation

1. Boil plant in ethanol to destarch it

2. Cover pats of leaf with tin foil to black paper ( Ensuring to secure with tape or paper clips )

3. Leave plant in light for 3-6 hours

4. Test leaf for starch with iodine solution

Suggest two reasons why it's important for plants to store starch

Answer explanation

1. For emergency reasons such as drought when plant can photosynthesise

2. They convert it to glucose to use for energy