Topic 4- Bioenergetics

Question 1

What is photosynthesis?

Answer 1

The process by which plants synthesis glucose using light from the sun. light energy converted into chemical energy

Question 2

Where does photosynthesis take place?

Answer 2

Within chloroplast, chlorophyll absorbs light energy

Question 2

Where does photosynthesis take place?

Answer 2

Within chloroplast, chlorophyll absorbs light energy

Question 3

Equation for photosynthesis

Answer 3

carbon dioxide+water=glucose+oxygen

Question 4

Is photosynthesis endothermic or exothermic?

Answer 4

Its endothermic, energyr transferred from environment to chlorpolast

Question 5

How can you show a plant give off oxygen?

Answer 5

Uisng a water plant, collect gas bubbles produced using photysnthesis, the gas will relight a glowing splint if oxygen is present

Question 6

Give example of leaf adaptation which maximises the rate of photosynthesis.

Answer 6

• broad leaves
• thin leaves (shortt diffusion distance)
• chlorophyll present
• veins
• guard cells
• air spaces

Question 7

Four main factors that affect the rate of photosynthesis

Answer 7

• Amount of chlorophyll
• carbon dioxide concentration
• light intensity
• temperature

Question 8

how does temperature affect the rate of photosynthesis

Answer 8

increasing the temperature increasws the rate as the kinetic energy of the particles is increased.
the rate decreases part a certain temperature as enzymes become denatured

Question 9

Explain how you can measure the rate of photosynthesis by measuring oxygen production

Answer 9

• put pondweed in a sealed tube of water, attached to a capillary tube and gas syringe
• oxygen gas produced causes the bubble in the capillary tube to move, the distance moved by the bubble is used to calculate the volume of oxygen produced

Question 10

What is aerobic respiration?

Answer 10

An exothermic reaction in which glucose reacts with oxygen to release energy which can be used by cells

Question 11

Where does aerobic respiration take place?

Answer 11

In the mitochondria

Question 12

Why do organisms require the energy released by respiration?

Answer 12

• synthesis of larger molecules
• muscle contractions
• active transport
• stable body temp

Question 13

What is anaerobic respiration?

Answer 13

An exothermic reaction in which glucose is broken down to release energy in the absence of oxygen

Question 14

Equation for anaerobic respiration

Answer 14

glucose= lactic acide (+energy)

Question 15

why is anaerobic respiration less efficient than aerobic?

Answer 15

glucose is not completely broken down, so less energy is transferred

Question 16

What is fermentation?

Answer 16

a type of anaerobic respiration that occurs in yeast cells

Question 17

equation for fermentation

Answer 17

glycose = ethanol + co2 (+energy)

Question 18

Difference between aerobic and anaerobic

Answer 18

• aerobic requires oxygen
• aerobic produces co2 and water
• anaerobic produces lactic acid or ethanol and co2
• aerobic transfers greater amount of energy

Question 19

What is metabolism?

Answer 19

sum of all reactions that take place in a cell or an organism

Question 20

How do cells use the energy transferred by respiration?

Answer 20

to continuously carry out enzyme-controlled processes which lead to the synthesis of new molecules

Question 21

Give examples of metabolic reactions

Answer 21

• respiration
• photosynthesis
• breakdown of excess proteins into urea
• glucose and nitrate ions into amino acids