Photosynthesis

Question 1

How do plants grow?

Answer 1

By making their own food

Question 2

What plants can make their own food?

Answer 2

Only green plants because they contain chlorophyll

Question 3

Plants are:

Answer 3

Autotrophs or producers

Question 4

Can bacteria do photosynthesis?

Autotrophic bacteria

Answer 4

Yes, however they only contain chlorophyll and not chloroplasts. They need the chlorophyll and other chemicals that are built into their plasma membranes.

Question 5

What are the two types of bacteria?

Answer 5

• Autotrophs

- Chemosynthetic

Question 6

What are chemosynthetic bacteria?

Answer 6

It means that they get their energy they need from chemical reactions between inorganic molecules.

Question 7

where does photosynthesis take place?

Answer 7

In plant cells with chloroplasts mainly in the leaves.

Question 8

What is the structure of the leaf?

Answer 8

• Leaves are flat and wide to create and large surface area.
• Leaves are thin so gasses can reach cells easily.
• Leaves have lots of veins to carry water to cells and glucose away.
• Leaves have holes called stomata. They allows gases in and out.

Question 9

What does chlorophyll do?

Answer 9

It absorbs the energy from the sunlight that allows carbon dioxide and water to react.

Question 10

What is inside a chloroplast?

Answer 10

1. Stroma: A liquid interior or matrix full of enzymes.
2. Thylakoid membranes: flat, sac-like structures grouped together into stacks called GRANA. They contain the chlorophyll.

Question 11

What are pigments?

Answer 11

• They are substance that absorb visible light.

Question 12

What are the two types of pigments?

Answer 12

• Chlorophyll A (The main photosynthetic pigment)

- Chlorophyll B (an accessory pigment)

Question 13

What is photosynthesis?

Answer 13

It is a chemical reaction that absorbs light energy to change carbon dioxide and water into glucose and the by-product oxygen and water.

Question 14

What is the photosynthesis formula?

Answer 14

6CO2 + 12H2O –> C6 H12 O6 + 6O2 + 6H2O

Question 15

How does water enter a plant?

Answer 15

Water from the soil enters a plant through the roots .

Question 16

Why are roots branched and spread out?

Answer 16

• to absorb water (and mineral salts) from a large amount of soil.
• to anchor the plant in the soil.

Question 17

Why is water important?

Answer 17

• To provide dissolved minerals that keep plants healthy.
• to transport substances
• to keep the plant rigid and upright.
• to keep the plant cool
• To allow chemical reactions to occur.

Question 18

Why do plants need glucose?

Answer 18

• Some glucose is used in cellular respiration.
• Some is converted into starch for storage .
• Some is used to make new chemicals such as proteins, sugars and fats.

Question 19

What are the two types of reactions in photosynthesis?

Answer 19

1. Light Dependent Reactions (Requires sunlight).

2. Light Independent Phase or Dark reactions. (Occurs without sunlight).

Question 20

Light Dependent Reactions:

Answer 20

• It occurs in the Grana.
• It spilts water
• releases oxygen
• produces ATP to form NADPH.

Question 21

Light Independent Phase or Dark reactions.

Answer 21

• Also known as the Calvin Cycle
• It occurs in the Stroma
• It forms sugar from carbon dioxide
• It uses ATP for energy
• It uses NADPH for reducing power.

Question 22

What limits photosynthesis?

Answer 22

• the amount of light
• carbon dioxide levels
• temperature
• amount of water
• pollution

Question 23

Summary:

Answer 23

• Light energy is trapped by the chlorophyll and it is used to split water molecules into hydrogen and oxygen.
• The hydrogen then combines with carbon dioxide molecules to make glucose, water and the oxygen is released into the atmosphere as a ‘waste’ product.