T4 bioenergetics

Question 1

why is photosynthesis endothermic?

Answer 1

it takes in energy from its surroundings

Question 2

what is the equation for photosynthesis?

Answer 2

carbon + water –> glucose + oxygen

Question 3

what are the 4 limiting factors of photosynthesis?

Answer 3

amount of chlorophyll
concentration of carbon dioxide
light intensity
temperature

Question 4

if we increase the light intensity what happens

Answer 4

the rate of photosynthesis increases

Question 5

if we increase temperature what happens

Answer 5

reaction will work faster and in the optimum point it reaches it will denature and the rate of photosynthesis will decrease

Question 6

name 5 ways glucose is used in a plant from photosynthesis

Answer 6

1. release energy from mitochondria for respiration
   2.produce insoluble starch
   3.coverts to fats and oils for energy storage
2. produce amino acids to protein synthesise which plants need to absorb nitrate ions from soil
   5.cellulose made from glucose

Question 7

pondweed practical for photosynthesis

Answer 7

1. start by boiling a tube and placing it 10cm away from an LED light source
   - led is used so it doesn’t release much heat
   - if you don’t have LED place s beaker of water in between light and tube as it will absorb heat
2. fill boiling tube with sodium hydrogen carbonate solution
   - this is used as it releases carbon dioxide which is needed for photosynthesis
3. put pondweed inside tube with the cut end faced on the top
4. leave for 5 minutes
5. oxygen gas bubbles will form
6. get stop watch and record the number of gas bubbles in one minute
7. repeat experiment but with the distance of light being 10cm 20cm 30cm and 40cm away and calculate the mean

Question 8

what are the disadvantages of photosynthesis pondweed practical

Answer 8

too many gas bubbles formed to count
bubbles not always the same size

Question 9

what can you do to fix the problem of pondweed photosynthesis practical

Answer 9

use a measuring cylinder, place on top of the ends of pondweed and measure volume of oxygen gas produced

Question 10

what happens when you double the distance of light to pondweed

Answer 10

the light intensity falls by 4 times

Question 11

why is respiration an exothermic reaction

Answer 11

it releases energy

Question 12

when muscle cells respire and are in shortage of oxygen how do they respire?

Answer 12

anaerobically

Question 13

when muscle cells respire anaerobically what is the equation?

Answer 13

glucose—>lactic acid

Question 14

why does anaerobic respiration release less energy than aerobic respiration

Answer 14

the oxidation of glucose is incomplete

Question 15

what is the equation for anaerobic respiration in yeast cells and plants

Answer 15

glucose—> carbon dioxide + ethonal

Question 16

what is anaerobic respiration in yeast cells called

Answer 16

fermentation

Question 17

what increases during exercise in order for more oxygen in body cells

Answer 17

breathing rate and breathing volume increase

Question 18

what chemical builds up when the muscles do not receive enough supply of oxygen

Answer 18

lactic acid

Question 19

what does lactic acid cause the muscle to feel

Answer 19

fatigued

Question 20

what happens when the body tries to get rid of the lactic acid

Answer 20

oxygen debt

Question 21

how is the lactic acid transported by out of

Answer 21

the blood

Question 22

where is the lactic acid put back and converted into

Answer 22

the liver and converted to glucose in a series of chemical reactions