BIOENERGETICS

Question 1

what is photosynthesis?

Answer 1

a chemical reaction in plants, algae etc when sunlight is present

Question 2

what is the word equation for photosynthesis?

Answer 2

carbon dioxide + water –> glucose + oxygen

Question 3

what is the symbol equation for photosynthesis?

Answer 3

6CO2 + 6H2O → C6H12O6 + 6O2

Question 4

where is the energy transferred to and how?

Answer 4

chloroplasts by light

Question 5

how do plants use glucose?

Answer 5

respiration - transfers energy from glucose into useful substances
make cellulose - glucose is converted to cellulose to make strong cell walls
make proteins - combine cellulose with nitrate ions from the soil to make amino acids to make proteins
stored as oils/fats - turned to lipids
stored as starch - glucose is turned to starch and stored in plant organs fro when photosynthesis isnt happening

Question 6

graph lines level off when the factor is no longer limiting

Question 7

describe the rate of photosynthesis practical.

Answer 7

1. place a source of white light at a specific distance with a ruler beside to change the distance each time
2. put pondweed in a test tube with water in it
3. place the test tube on a clamp infront of the light source
4. place a syringe at the lid of the test tube so oxygen can be measured
5. leave the pondweed to photosynthesise for an amount of time
6. the syringe shows the amount of oxygen given off
7. repeat with the light source at different distances

Question 8

what is the relationship between distance and light intensity?

Answer 8

light intensity decreases in proportion to the square of the distance

Question 9

what is the inverse square law?

Answer 9

light intensity ⍺ 1/distance²

Question 10

how do farmers create the ideal conditions for plants?

Answer 10

grow in a greenhouse - trap sun heat (winter - heater/summer - ventilation), free from disease/pest
artificial light for when sun goes down
paraffin heater - makes co2 a by-product
expensive

Question 11

what is respiration

Answer 11

process of transferring energy from glucose, in every cell

Question 12

how do organisms use the energy from respiration?

Answer 12

build up larger molecules from smaller ones
allow muscles to contract (in animals)
keep body temp steady (in birds and mammals)

Question 13

what is metabolism?

Answer 13

all chemical reactions in an organism

Question 14

what are chemical reactions controlled by?

Answer 14

enzymes (biological catalysts)

Question 15

examples of when small molecules make large ones?

Answer 15

small glucose molecules join togther to form starch, glycogen and cellulose
lipid molecule is made from 1 glycerol molecule and 3 fatty acid

Question 16

what is glycogen?

Answer 16

storage molecule

Question 17

example of when large molecules are broken into smaller ones?

Answer 17

glucose is broken down in respiration
excess protein is broken down to produce urea (excreted in urine)

Question 18

what type of respiration uses oxygen?

Answer 18

aerobic

Question 19

where does aerobic respiration take place?

Answer 19

mitochondria

Question 20

what is the word and symbol equation for aerobic respiration?

Answer 20

glucose + oxygen –> carbon dioxide + water
C6H12O6 + 6O2 → 6CO2 + 6H2O

Question 21

what is anaerobic respiration?

Answer 21

respiration without oxygen - used if there’s not enough oxygen (incomplete breakdown of glucose, making lactic acid)

Question 22

why isnt anaerobic respiration not as efficient as aerobic?

Answer 22

doesn’t transfer as much energy as aerobic - glucose isn’t fully oxidised (not comined w oxygen)

Question 23

what is produced in anaerobic respiration in plant/yeast cells?

Answer 23

ethanol and carbon dioxide (instead of lactic acid)w

Question 24

what is fermentation?

Answer 24

anaerobic respiration in yeast cells

Question 25

what makes bread rise?

Answer 25

carbon dioxide from fermentation

Question 26

where do muscles get energy for contraction?

Answer 26

respiration

Question 27

why do you need more energy when excercising?

Answer 27

your muscles contract more frequently - increase in respiration in cells mean more oxygen is needed in them

Question 28

what happens when breathing rate and breath volume increase?

Answer 28

you need more oxygen in your blood as heart rate also increases which removed carbon dioxide faster

Question 29

what is an oxygen debt?

Answer 29

amount of extra oxygen your body needs to react with the build up of lactic acid to remove it - repay the oxygen you didn’t get to your muscles

Question 30

how else can the body cope with high levels of lactic acid?

Answer 30

the blood that enters your muscles transport the lactic acid to the liver where lactic acid is converted back to glucose

Question 31

how can you investigate the effect of exercise on the body?

Answer 31

1. take your pulse from your wrist
2. count the number of pulses in 1 minute
3. repeat this after sitting for 5 minutes, after 5 minutes of walking, after 5 minutes of jogging and after 5 minutes of running
4. plot the data on a bar chart - x axis type of exercise, y axis pulse rate