bioenergetics

Question 1

Is photosynthesis exothermic or endothermic?

Answer 1

endothermic because energy is transferred from the environment.

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

What are the five ways plants use glucose?

Answer 4

• for respiration
• making cellulose
• making amino acids
• stored as oils or fats
• stored as starch

Question 5

What are amino acids made from?

Answer 5

glucose and nitrate ions

Question 6

What affects the rate of photosynthesis?

Answer 6

• light intensity
• concentration of CO2
• temperature

Question 7

How can chlorophyll be the limiting factor in photosynthesis?

Answer 7

amount of chlorophyll can be affected by disease or lack of nutrients SO less photosynthesis can occur as the plant can’t absorb as much light

Question 8

What is the equation for light intensity?

Answer 8

1/distance^2

Question 9

How can farmers artificially create the ideal conditions for farming?

Answer 9

• greenhouse- for heat
• artificial light- for light
• paraffin heater- for CO2
• fertilisers-for nutrients

Question 10

What is respiration?

Answer 10

the process of transferring energy from glucose which goes on in every cell

Question 11

Is respiration endothermic or exothermic?

Answer 11

exothermic because it transfers energy to the environment

Question 12

How do organisms use the energy transferred by respiration?

Answer 12

• to build up larger molecules from smaller ones
• for muscles to contract
• to keep their body temperature steady in colder surroundings (in mammals and birds)

Question 13

What can small glucose molecules form when joined together in reactions?

Answer 13

• starch
• glycogen
• cellulose

Question 14

What are lipids from?

Answer 14

one molecule of glycerol and three fatty acids

Question 15

What is metabolism?

Answer 15

all the chemical reactions in an organism

Question 16

What is aerobic respiration?

Answer 16

respiration using oxygen

Question 17

What is the word equation for aerobic respiration?

Answer 17

glucose + oxygen
———————————>
carbon dioxide + water

Question 18

What is the symbol equation for aerobic respiration?

Answer 18

C6H12O6 + 6O2 –> 6CO2 + 6H2O

Question 19

What is anaerobic respiration?

Answer 19

respiration without oxygen
the incomplete breakdown of glucose making lactic acid

Question 20

What is the word equation for anaerobic respiration in muscle cells?

Answer 20

glucose —-> lactic acid

Question 21

What is anaerobic respiration in yeast cells called?

Answer 21

fermentation

Question 22

What is the word equation for fermentation?

Answer 22

glucose —-> ethanol + carbon
dioxide

Question 23

What is fermentation used for?

Answer 23

• to make bread- CO2 makes the bread rise
• to make beer and wine- fermentation process that produces alcohol

Question 24

Why do you respire more during exercise?

Answer 24

your muscle contract more so you need more energy which you can get from respiration

Question 25

How do you respire more during exercise?

Answer 25

- breathing rate and volume increase to get more oxygen into the blood - heart rate increases to get the oxygenated blood around the body faster and remove CO2

Question 26

What happens when you do really vigorous exercise?

Answer 26

your body can't supply oxygen to your muscles quickly enough so they start respiring anaerobically. - lactic acid starts building up in the muscles which can become painful - causes muscle fatigue and they stop contracting efficiently

Question 27

What is 'oxygen debt'?

Answer 27

the amount of extra oxygen your body needs to react with the build up lactic acid and remove it from the cells

Question 28

Why do you have high breathing and pulse rate after exercise?

Answer 28

to repay oxygen debt and get oxygen to the muscles as quick as possible

Question 29

How does the body cope with high levels of lactic acid?

Answer 29

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