Photosynthesis

Question 1

Photosynthesis

Answer 1

Photosynthesis is the process where plants use carbon dioxide, water and light energy and Chlorophyll to produce food.

Question 2

Why is chlorophyll green?

Answer 2

Chlorophyll is green because it absorbs all light from the sun, but reflects the green light.

Question 3

What do plants need to photosynthesise?

Answer 3

Light energy: Provided by the sun

Carbon dioxide: Plants obtain carbon dioxide from the atmosphere.

Water: Plants get water from the ground.

Chlorophyll: Green plants contain the pigment chlorophyll.

Question 4

Products of photosynthesis

Answer 4

Glucose (a simplified form of sugar) is produced by plants.

Oxygen is produced as a by-product, and plant release it into the atmosphere.

Question 5

Gaseous exchange

Answer 5

Plants absorb carbon dioxide and release oxygen through a process known as a gaseous exchange which happens in the stomata.
> Gaseous exchange is the absorption and emission of gases.

Stomata can be found in other parts of a plant that are above ground like the stems of a plant.

Question 6

Glucose use in plants

Answer 6

Plants use glucose to respire.

The energy that is released during respiration is used for:
• Propagation;
• Cell division;
• Growth;

Some glucose is converted into cellulose which forms cell walls. It provides support and sturdiness to plants.

Excess glucose is stored as starch. Stored starch in plants serves as a food source for other living organisms.

Question 7

Plants without chlorophyll

Answer 7

Plants that don’t have chlorophyll must use other ways to get food.

Question 8

Saprophytes

Answer 8

Saprophytes are plants that can survive on dead organic tissue.

Question 9

Parasites

Answer 9

Parasitic plants live on living organic tissue and obtain all their nutrients from the host.

Question 10

Respiration

Answer 10

Respiration is the process by which energy is released from food in a series of chemical reaction.

Breathing is the process where the air is inhaled and exhaled. Respiration is the process where energy is released from food.

Question 11

Types of respiration

Answer 11

Aerobic respiration & Anaerobic respiration

Question 12

Aerobic respiration

Answer 12

Needs oxygen to occur
Where does it occur?
• People, plants and animals
Requirements
• Glucose, Oxygen
Producers
• Energy, Carbon dioxide and Water

Question 13

Anaerobic respiration

Answer 13

Does not need oxygen to occur
Where does it occur?
• Some bacteria and yeast
Requirements
• Glucose
Producers
• Energy, Carbon dioxide and Lactic acid/alcohol

Question 14

Comparison between photosynthesis and respiration

Answer 14

Photosynthesis
• Takes place in plants.
• Oxygen and glucose are formed during the process.
• Photosynthesis needs sunlight.
• Food is produced.
• Energy is stored.
• Only takes place in cells that contain chlorophyll.
• An anabolic (constructive) metabolic process.

Respiration
• Takes place in plants and animals.
• Water and carbon dioxide are formed during this process.
• Lactic acid/alcohol is also formed during anaerobic respiration.
• Respiration does not need light.
• Food is broken down.
• Energy is released.
• Takes place in all living cells.
• A catabolic (destructive) metabolic process.