Photosynthesis and respiration

Question 1

how are plants adapted to photosynthesise?

Answer 1

-leaves are broad - increase SA FOR LIGHT

-thin leaves - decrease diffusion distance

-chlorophyll to absorb light

-have veins which bring water from xylem to cells/
remove products of photosynthesis in phloem

-air spaces allow co2 into cells/o2 to leave by diffusion

-grad cells open/ close stomata to regulate gas exchange

Question 2

photosynthesis equation?

Answer 2

carbon dioxide + water —> glucose + oxygen
6Co2 + 6H2O —>
C6h12o2 + 6o2

Question 3

how do plants use glucose ? (5)

Answer 3

1)PRODUCE fat or oil for storage
2)RESPIRATION- glucose is broken down using oxygen to provide energy
3)BUILT INTO INSOLUBLE STARCH for storage
4)CELLULOSE - builds cellulose which strengthens cell wall
5)PRODUCE AMINO ACIDS- glucose combines with nitrate ions in the soil

Question 4

REQUIRED PRACTICAL : Photosynthesis

Answer 4

1)use lamp. pondweed, metre stick , beaker/boiling tube
2)fill boiling tube with water and SODIUM HYDROGEN CARBONATE to ensure enough co2
3)put pondweed in tube/push to bottom
4)put boiling tube in beaker of water to ensure light’s heat doesn’t affect experiment
5)put beaker/tube almost touching lamp for 5 mins.
start stopwatch and count no. bubbles in 15 secs. multiply by 4 and record results
keep moving beaker at different distances from light.

Question 5

what is a limiting factor and 3 limiting factors of photosynthesis?

Answer 5

things that can be in short supply so plants can’t photosynthesise as fast as they can
LIGHT - no light - photosynthesis will stop
TEMPERATURE - too cool, photosynthesis decreases, too hot, enzymes denature/it slows down process
C02 -

Question 6

Why is oxygen debt created in anaerobic exercise?

Answer 6

The incomplete oxidation of glucose causes a build up of lactic acid- which needs to be broken down

Question 7

what is energy released used for ?

Answer 7

1)build bigger molecules from smaller ones
2)muscle contraction
3)maintain a stable body temp
4)active transport
5)build sugars, nitrates, other nutrients Ito amino acids

Question 8

liver’s functions ?

Answer 8

detoxify substances like ethanol
passing breakdown products into blood to be excreted in urine via the kidney
break down old, worn out blood cells /storing iron to Mae more blood cells
liver converts lactic acid back to glucose, by oxidising it

Question 9

aerobic respiration equation?

Answer 9

glucose + oxygen –> co2 + water + (energy)

Question 10

anaerobic repartition equation?

Answer 10

glucose –> lactic acid + (energy)

Question 11

what is oxygen debt and equation?

Answer 11

the amount of oxgen needed to break down lactic acid into co2 + water is oxygen debt.
lactic acid + oxygen –> co2 + water

Question 12

anaerobic respiration in yeast cells?

Answer 12

glucose –> ethanol + Co2

Question 13

compare aerobic repsiration and anaerobic respiration?

Answer 13

aerobic releases MORE energy , than anaerobic
aerobic needs O2, anaerobic doesnt
aerobic produces CO2 + water, anaerobic produces lactic acid
glcuoses is completely broken down in aerobic repsiration, but partially broken in anaerobic

Question 14

how does the build up lactic acid cause muscles to contract less efficently?

Answer 14

Lactic acid is toxic / Lowers pH of muscles
slowing down enzyme activity

Question 15

What is the equation for photosynthesis (word and chemical)

Answer 15

Carbon dioxide + water —> glucose + oxygen
CO2 + H2O—> C6H12O6 + O2

Question 16

Is photosynthesis an exothermic reaction or an endothermic reaction? Why

Answer 16

ENDOTHERMIC
Light energy is transferred from the environment to the chloroplasts.

Question 17

Explain two factors that affects the rate of photosynthesis

Answer 17

Temperature- a rise in temperature increases the kinetic energy of the particles therefore rate of photosynthesis will increase. However once temperature goes above a certain limit (45C) the enzymes will denature and rate of photosynthesis’s will decrease.

CO2 concentration- a high concentration of CO2 will result in a faster rate of photosynthesis. This is because plants absorb co2 and water to produce glucose and oxygen. However because co2 is a limiting factor the graph will level off.

Question 18

Why are limiting factors important economically?

Answer 18

So conditions are enhanced in greenhouses to gain the maximum rate of photosynthesis while still maintaining profit.

Question 19

What is glucose produced in photosynthesis used for? (3)

Answer 19

Respiration

Produce amino acids for proteins synthesis

Produce cellulose which strengthens the cell wall

Question 20

What is oxygen debt?
(Talk about liver)

Answer 20

Blood flowing through the muscles transports lactic acid to the liver where it is converted back into glucose. Oxygen debt is the amount of extra oxygen the body needs after exercise to react with the accumulated lactic acid and remove it from the cells.

Question 21

How does the liver help with oxygen debt

Answer 21

It converts lactic acid back into glucose.

Question 22

What is metabolism?

Answer 22

The sum of all reactions in a cell/body

Question 23

Effect of temperature of photosynthesis

Answer 23

It will INCREASE the rate of photosynthesis. However once temperature rises to about 45C enzymes DENATURE and rate of photosynthesis decreases

Question 24

Effect of CO2 and light intensity on rate of photosynthesis

Answer 24

Rate of photosynthesis will increases until a factor becomes limiting

Question 25

What does metabolism include? (3)

Answer 25

Respiration
The use of glucose and nitrate ions to form amino acids
Formation of lipid molecules from glycerol and 3 fatty acids