B4.3 Photosynthesis

Question 1

How do plants make their own food?

Answer 1

• carbon dioxide from the air through pored called stomata

- water from the soil through root hairs

Question 2

What is the substance called where plant’s trap energy from the Sun?

Answer 2

Chlorophyll ( in the chloroplasts in their cells)

Question 3

Define chlorophyll

Answer 3

Green substance found in choloroplats, where light energy is trapped for photosynthesis.

Question 4

Define photosynthesis

Answer 4

Process by which plants build carbohydrates from carbon dioxide and water, using sunlight energy.

Question 5

Equation of photosynthesis

Answer 5

Sunlight
Carbon dioxide + water -> glucose + oxygen
6CO2 6H2O C6H12O6 6O2
Chlorophyll

Question 6

Recall the two stages of photosynthesis.

Answer 6

Stage 1: uses light energy to split water into waste oxygen gas and hydrogen ions.

Stage 2: occurs day/night, and combines with carbon monoxide to form glucose and water (used up during photosynthesis

Question 7

What does the plant make in photosynthesis?

Answer 7

1. Food- glucose (a carbohydrate) used for respiration in the plant cells. Rest stored in the plant
2. Oxygen- waste gas produced during photosynthesis. Some used for respiration in the plant cells. Also given off through stomata into the plant’s surroundings

Question 8

Is glucose is not used, what can it be changed into?

Answer 8

Starch

Question 9

What can stored glucose be used for?

Answer 9

Respiration at night (when no sunlight, so glucoose cannot be made by photosynthesis.

Question 10

What is the glucose converted into?

Answer 10

Sucrose (stored in fruit) - transported around the plant to parts that need it

Question 11

Other than sugars, what else are plants made of?

Answer 11

• cellulose (form cell walls)
• proteins (for growth and repair)
• fats (food store and growth)

Question 12

Three advantages of glucose being stored at starch

Answer 12

1. Starch can be converted into glucose for respiration in plant cells
2. Insoluble- will not dissolve it water & flow out of the cells where it is stored
3. Does not affecr water concentration inside the cells

Question 13

Photosynthesis during daytime?

Answer 13

Plants photosynthesise at a faster rate than they respire, taking in more carbon dioxide for photosynthesis and releasing the extra oxygen produced.

Question 14

Photosynthesis during night-time?

Answer 14

Plants respire but do not photosynthesise. Oxygen is taken into the leaf snd waste carbon dioxide is released.