Bioenergetics - Photosynthesis and respiration

Question 1

photosynthesis word equation

Answer 1

carbon dioxide + water —> glucose + oxygen

Question 2

photosynthesis symbol equation

Answer 2

6CO2 + 6H20 -> C6H12O6 + 6O2

Question 3

what kind of reaction is photosynthesis

Answer 3

endothermic, because energy is absorbed from the environment

Question 4

where does photosynthesis take place

Answer 4

in the chloroplasts in the leaves

Question 5

5 ways plants use glucose

Answer 5

• used to release energy in respiration
• converted into insoluble starch for storage (can be converted back into starch when needed)
• used to produce fat or oil for storage
• used to produce cellulose, which strengthens the cell wall
• used to produce amino acids for protein synthesis (and nitrate ions)

Question 6

what are the 4 factors that affect the rate of photosynthesis

Answer 6

• concentration of CO2
• temperature
• light intensity
• amount of chlorophyll

Question 7

what happens if a plant gets too hot

Answer 7

the enzymes needed for photosynthesis will become denatured and will no longer work

Question 8

why do greenhouses have the ideal conditions for photosynthesis

Answer 8

because they help trap the suns heat, making sure that temperature doesn’t become a limiting factor, but during the heat they might use shades and ventilation
- they supply artificial light when the sun goes down
- farmers and gardeners can also increase the CO2 concentration by using a paraffin heater to heat the greenhouse (as paraffin burns,it makes CO2 as a by product)

Question 9

advantages of greenhouses

Answer 9

• keeps plants free from pests and diseases
• farmers can keep the conditions just right for photosynthesis

Question 10

why is respiration so important

Answer 10

it transfers the energy that the cell needs to do just about anything, anf it is used for all living processes

Question 11

what kind of reaction is respiration

Answer 11

exothermic, as it transfers energy tp the environment

Question 12

examples of how organisms use energy transferred by respiration

Answer 12

• to build up larger molecules from smaller ones, like proteins from amino acids
• in animals, used to contract muscles so they can move about
• in mammals and birds, to keep warm in colder surroundings

Question 13

what is metabolism

Answer 13

the sum of all the reactions in a cell or the body

Question 14

examples of when smaller molecules are used to make bigger ones

Answer 14

• lots of glucose molecules join together to form starch, glycogen and cellulose
• lipid molecules made from one molecule of glycogen and 3 fatty acids
• glucose is combined with nitrate ions to make amino acids, which are then made into proteins

Question 15

examples of when larger molecules are broken down into smaller ones

Answer 15

• glucose is broken down during respiration
• excess protein is broken down in a reaction to produce urea, which is then excreted in urine

Question 16

what is aerobic respiration

Answer 16

respiration using oxygen

Question 17

equation for aerobic respiration

Answer 17

glucose + oxygen —> carbon dioxide + water

Question 18

what is anaerobic respiration

Answer 18

respiration without oxygen

Question 19

what is the difference in energy between aerobic and anaerobic respiration

Answer 19

As the oxidation of glucose is incomplete in anaerobic respiration much
less energy is transferred than in aerobic respiration.

Question 20

word equation for anaerobic respiration in muscle cells

Answer 20

glucose —> lactic acid

Question 21

when will the body start doing anaerobic respiration

Answer 21

when you do vigorous exercise and your body can’t supply enough oxygen to your muscles

Question 22

difference between anaerobic respiration in plants and yeast compared to in animals

Answer 22

they produce ethanol and carbon dioxide rather than lactic acid

Question 23

what is the word equation for anaerobic respiration in yeast and plant cells

Answer 23

glucose —> ethanol + carbon dioxide

Question 24

what is the process of anaerobic respiration in yeast called

Answer 24

fermentation

Question 25

uses of fermentation

Answer 25

• beer and wine making
• bread making, the carbon dioxide from fermentation makes bread rise

Question 26

what happens to the body as you exercise more

Answer 26

• aerobic respiration increases, meaning that the body cells require more oxygen
• your breathing rate and volume increases to get more oxygen into the blood, then your heart rate increases to get the oxygenated blood around the body faster, removing CO2 quicker

Question 27

what happens to the body once you start doing really vigorous exercise

Answer 27

your body cannot supply oxygen to your muscles quick enough, so they start respiring anaerobically,

lactic acid builds up in the muscles because of the incomplete oxidation of glucose,

at this point the body has to remove the lactic acid from the muscles, this creates oxygen debt

Question 28

what is muscle fatigue

Answer 28

when the muscles get tired and stop contracting efficiently

Question 29

what is oxygen debt

Answer 29

the amount of extra oxygen your body needs to react with lactic acid to remove it fromcells

Question 30

how can lactic acid be removed from cells

Answer 30

• the lactic acid is transported out of muscles by the blood
• its then taken to the liver and converted back into glucose

Question 31

what does chlorophyll do

Answer 31

absorbs light energy

Question 32

what effect does light intensity have on the rate of photosynthesis

Answer 32

1. when light intensity is zero, the rate of photosynthesis is zero, plants need light to carry it out
2. as we increase the light intensity, the rate of photosynthesis increases, because the plant has more light energy to carry out the photosynthesis, so the reaction gets faster
3. if we keep increasing the light intensity, there comes a point where the rate of photosynthesis no longer increases

• at this point, light intensity is no longer the limiting factor

Question 33

why do farmers want to increase the rate of photosynthesis

Answer 33

it will increase the yield of the crops they produce

Question 34

disadvantages of greenhouses

Answer 34

• expensive
• some gardeners use oil burners as these release heat and carbon dioxide at the same time

Question 35

what is energy used for

Answer 35

• movement
• to keep warm
• for chemical reactions to build larger molecules

Question 36

why is the carbon dioxide produced from fermentation useful when making bread

Answer 36

it creates bubbles in the dough, causing it to rise