Photosynthesis

Where do we get our energy from?

How do we release energy from food?

Food + Carbon dioxide +Oxygen + ENERGYWater

Respiration

(Glucose)

Plants can’t eat……what do they release energy from?

PhotosynthesisIn order to get energy plants must make

their own food.

The do this by the process of photosynthesis.

Why is this plant so unhealthy?

What do plants need to make food?

Photosynthesis

Water + Carbon dioxide Oxygen + Glucose sunlight

In light plants can photosynthesise and respire. In dark plants can only respire.

Food + Carbon dioxide +Oxygen + ENERGYWater(Glucose)

Respiration

+ FoodCarbon dioxide + OxygenWater Sunlight(Glucose)

Photosynthesis

What factors might affect how much photosynthesis a plant can do?

What factors might affect how much photosynthesis a plant can do?

100% 71% 50% 25% 12.5% 6.3% 0%

Photosynthesis InvestigationsCan use algae beads or Cabomba.

Algae Bead InvestigationIn a small beaker (mix together):• 2.5cm3 sodium alginate• 5cm3 algal cells

Then,• Put some calcium chloride in another

beaker• Position calcium chloride under an

open-ended syringe• Pour algal mixture into syringe• Rinse the algal balls with distilled water

Algae Bead Investigation1. Collect:

• Algae beads

• 7 mini jars

• spatula / spoon

• One of each type of filter

2. In each mini jar add 15 algae beads

3. Add bicarbonate indicator to each mini jar

4. Slot a filter onto each mini jar

5. Place mini jars in light bank or on window ledge

Cabomba Investigation

Step 1

In pairs add 5 fronds of Cabomba to each tube.

Step 2

Fill each tube with indicator.

Put the lid on a write your initials.

Step 3

Slide a different light filter on each tube, leave 1 with nothing on... Clearly label your tubes!

There is a top and bottom to the filters.

What does the indicator show?

Photosynthesis

Increasing CO2 in indicator

Decreasing CO2 in indicator

Less Photosynthesis took place

More Photosynthesis took place

What do your results tell you?

What effect does light intensity have on photosynthesis?

Each filter lets through a different amount of light.

In other words we are changing the light intensity reaching the algae.

100% 71% 50% 25% 12.5% 6.3% 0%

What does more CO2 tell us about the rate of photosynthesis?

DayPlants photosynthesise

and respire

Oxygen Carbon dioxide

Carbon dioxideOxygen

Respiration

Photosynthesis

What does more CO2 tell us about the rate of photosynthesis?

NightPlants only respire

Oxygen Carbon dioxide

Respiration

Song:http://www.youtube.com/watch?v=C1_uez5WX1o

Photosynthesis:http://www.bbc.co.uk/scotland/learning/bitesize/standard/biology/world_of_plants/making_food_rev4.shtml