B1.4.1 Photosynthesis

Question 1

What do plants have to take in to make food?

Answer 1

• Carbon dioxide
• Water

Question 2

How do plants obtain these substances?

Answer 2

C02- diffuses from the air into the plant through the stomata
H20- enters the roots from the soil through root hair cells via osmosis

Question 3

When these substances react, what do they produce?

Answer 3

Oxygen- some is used during respiration, rest is a waste product released back into the environment
Glucose- used as a food source

Question 4

What is the word equation for photosynthesis?

Answer 4

Carbon dioxide + water —> glucose + oxygen

Question 5

What is the symbol equation for photosynthesis?

Answer 5

6CO2+6H20 —> C6H12O6 + 6O2

Question 6

Where does photosynthesis occur?

Answer 6

Inside the plants chloroplasts, meaning that it only occurs in the leaf but slightly in the green stem too

Question 7

Why are leaves and stems green?

Answer 7

Since they contain the pigment chlorophyll in their chloroplasts

Question 8

Where does glucose store energy?

Answer 8

Within it’s chemical bonds

Question 9

What is the first main stage of photosynthesis reactions?

Answer 9

Energy transferred from light splits water molecules into oxygen gas into hydrogen ions

Question 10

What is the second main stage of photosynthesis reactions?

Answer 10

C02 gas combines with hydrogen ions to make glucose

Question 11

What type of reaction is photosynthesis?

Answer 11

Endothermic

Question 12

What does this type of reaction mean?

Answer 12

It means that energy must be transferred from the surroundings to keep it going.

Question 13

What is a photometer?

Answer 13

An instrument for measuring light intensity

Question 14

What is phototropism?

Answer 14

the phenomenon by which the plant bends in the direction of light

Question 15

What does photoconductive mean?

Answer 15

A material whose resistance decreases when it absorbs light

Question 16

Explain why photosynthesis can’t occur in root cells?

Answer 16

They don’t have access to light energy from the sun, which is required for the process of photosynthesis to happen.

Question 17

State three ways plants use glucose:

Answer 17

• In respiration
• to convert into other sugar molecules
• to convert into starch, a store of energy

Question 18

Compare respiration and photosynthesis

Answer 18

Photosynthesis is the opposite of aerobic respiration, in the sense that their reactions are the other way around. Photosynthesis’ products - carbon dioxide and water - are aerobic respiration’s reactants, and its’ products - glucose and oxygen - are the reactants in photosynthesis.

Question 19

Define photosynthesis

Answer 19

The process by which plants harness the energy from the sun and transfer this energy into a useable food source in the form of glucose that can be stored as starch