Photosynthesis, Respiration And Metabolism

Question 1

Photosynthesis is an endothermic reaction, what does this mean?

Answer 1

It needs an input of energy from the environment

Question 2

How to calculate light intensity

Answer 2

1/distance ^2

Question 3

Key points on water in photosynthesis

Answer 3

• Taken into the plant through root hair cells by osmosis
• Travels to leaf through xylem cells
• Light intensity breaks the water molecules to create glucose with co2

Question 4

Key points of carbon dioxide in photosynthesis

Answer 4

• Taken in through stomata by diffusion

- co2 atoms combine with H atoms to create glucose

Question 5

Key points of sunlight in photosynthesis

Answer 5

-Light intensity splits water molecules into H+ ions and oxygen molecules, the H combines with co2 to create glucose, the oxygen is released through stomata by diffusion.

Question 6

Key points of chlorophyll in photosynthesis

Answer 6

• Found in chloroplasts in cytoplasm, traps sunlight energy.

- Mostly found in palisade mesophyll layer.

Question 7

Key points of glucose in photosynthesis

Answer 7

• Made in the leaf, stored as insoluble starch.
• Used for respiration to provide and release ATP energy.
• Used to produce fat or oil for storage.
• Produces cellulose for cell Wall.
• Used to produce amino acids for protein synthesis.

Question 8

Key points of oxygen in photosynthesis

Answer 8

• Escapes plant through stomata by diffusion

- Some is kept for respiration.

Question 9

Respiration definition

Answer 9

The enzyme controlled reaction whereby energy is released from glucose. Occurs in the mitochondria, and is a exothermic reaction, releasing energy.

Question 10

What are the two types of respiration?

Answer 10

• Aerobic respiration

- Anaerobic respiration

Question 11

Equation for aerobic respiration

Answer 11

Glucose + oxygen -> carbon dioxide + water + ATP

Question 12

Equation for anaerobic respiration

Answer 12

Glucose -> lactic acid + small amount of energy

Question 13

Equation for photosynthesis

Answer 13

Carbon dioxide + water ->(light) -> glucose + oxygen

Question 14

Key points for Aerobic respiration

Answer 14

• Glucose is fully broken down, all the energy is released.

- Oxygen is in plentiful supply

Question 15

Key points for anaerobic respiration

Answer 15

• Glucose is partially broken down, only some energy is released
• Oxygen is not in plentiful supply, meaning lactic acid is released
• Occurs during vigorous exercise
• Occurs in mitochondria
• Is a quick source of energy.
• Builds up oxygen debt

Question 16

What is the energy released from respiration used for?

Answer 16

• Chemical reactions to build larger molecules from smaller ones
• Energy is needed for movement
• Maintaining a constant internal body temperature e.g. 37 degrees

Question 17

How can glucose be used for respiration

Answer 17

• Glucose is absorbed by diffusion into the bloodstream from the small intestine.
• Then the blood delivers glucose to muscles by capillaries
• Glucose can be used for respiration.

Question 18

How does the body respond to exercise?

Answer 18

• Our bodies require more oxygen and glucose when exercising in order to respire quicker, as the muscles are working harder and faster.
• Heart and lungs have to work harder, meaning:
• Heart rate increases to supply more oxygen and glucose to muscles
• Breathing rate increases to supply more oxygen
• Increases the rate of co2 and lactic acid removal.
• Stored up glycogen converted back to glucose for respiration.
• Higher rate of respiration.

Question 19

Metabolic functions from the liver

Answer 19

• Detoxification of poisonous substances such as ethanol from alcohol.
• Passing the breakdown products into the blood so they can be excreted in the urine via the kidneys.
• Breaking down worn out red blood cells and storing the iron until it is need to synthesise more blood cells.

Question 20

Key points of removing lactic acid:

Answer 20

• Blood flowing through the muscles transports lactic acid to the liver, where it is converted back to glucose.
• Once the lactic is converted to glucose, which is broken down to form carbon dioxide and water, the oxygen debt has been repaid.

Question 21

Equation for Anaerobic respiration in plants and yeast cells:

Answer 21

Glucose -> ethanol + carbon dioxide

Question 22

What is fermentation?

Answer 22

Anaerobic respiration in yeast cells