Bioenergetics

Question 1

What is photosynthesis?

Answer 1

the process by which plants make glucose from sunlight

Question 2

Photosynthesis is what kind of reaction?

Answer 2

endothermic in which energy is transferred from the environment to the chloroplasts by light

Question 3

What is the equation for photosynthesis?

Answer 3

carbon dioxide + water → glucose + oxygen

Question 4

What is the balanced equation for photosynthesis?

Answer 4

6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

Question 5

How is the rate of photosynthesis affected?

Answer 5

• temp
• light intensity
• carbon dioxide concentration
• amount of chlorophyll

Question 6

What effect does temperature have on the rate of photosynthesis?

Answer 6

with an increase in temp, the rate of photosynthesis increases. as the reaction is controlled by enzymes, this trend continues up to a certain temp until the enzymes begin to denature and the rate to reaction decreases

Question 7

What effect does light intensity have on the rate of photosynthesis?

Answer 7

for most plants, the higher the light intensity, the faster the rate of reaction

Question 8

What effect does carbon dioxide concentration have on the rate of photosynthesis?

Answer 8

carbon dioxide is also needed to make glucose, as the concentration of carbon dioxide increases, the rate of reaction increases

Question 9

How does the amount of chlorophyll affect the rate of photosynthesis?

Answer 9

chlorophyll is a pigment in the leaf that converts light energy to food for the plant, and is therefore essential. if, for example, chlorophyll levels are reduced through a magnesium deficiency, then the rate of photosynthesis would decrease

Question 10

What is a limiting factor?

Answer 10

an environmental condition which, in low levels, restricts any increase in the rate of photosynthesis. despite increases in other factors, the rate of photosynthesis will not increase any more, this can be seen on a graph as the curve levelling off

Question 11

What axis does the rate of photosynthesis go on?

Answer 11

vertical

Question 12

What is light intensity measured in?

Answer 12

lux

Question 13

How can farmers use the knowledge of limiting factors?

Answer 13

to enhance the conditions in the greenhouse for a greater rate of photosynthesis, this will increase growth leading to increased profits

Question 14

What is inverse proportion?

Answer 14

describes a relationship between two factors which involves one increasing whilst one decreasing

Question 15

What are the uses of glucose from photosynthesis?

Answer 15

• respiration
• converted into insoluble starch for storage
• to produce fat or oil for storage
• produce cellulose to strengthen cell walls
• combined with nitrates to form amino acids which produce proteins

Question 16

What is respiration?

Answer 16

the process of transferring energy from glucose so living processes can occur

Question 17

What kind of reaction is respiration?

Answer 17

exothermic

Question 18

Respiration can be…

Answer 18

aerobic or anaerobic

Question 19

What is the equation for respiration?

Answer 19

glucose + oxygen → carbon dioxide + water

Question 20

What is the formula for respiration?

Answer 20

C₆H₁₂O₆ + O₂ → CO₂ + H₂O

Question 21

What are the qualities of aerobic respiration?

Answer 21

this uses oxygen, yields the most energy, most of the reactions that make up aerobic respiration occur in mitochondria

Question 22

What are the qualities of anaerobic respiration?

Answer 22

occurs when there is not enough oxygen, does not yield as much energy as aerobic respiration, it is only used as a last resort, for example during a sprint where it is difficult to breathe in enough oxygen, the oxidation of glucose is incomplete

Question 23

What is the equation for anaerobic respiration in animals?

Answer 23

glucose → lactic acid

Question 24

What is the formula for anaerobic respiration in animals?

Answer 24

C₆H₁₂O₆ → lactic acid

Question 25

What is the equation for anaerobic respiration in yeast and plants?

Answer 25

glucose → ethanol + carbon dioxide

Question 26

What is the formula for anaerobic respiration in plants and yeast?

Answer 26

C₆H₁₂O₆ → ethanol + CO₂

Question 27

What is anaerobic respiration called in plants and yeast?

Answer 27

fermentation

Question 28

What is fermentation used for?

Answer 28

to make bread and alcoholic drinks

Question 29

What is the response to exercise?

Answer 29

more energy is needed in order for muscles to contract, respirations needs to occur faster and therefore more oxygen needs to be supplied to cells

Question 30

How does the body supply more oxygen to cells?

Answer 30

- heart rate increases - breathing rate increases - breathing volume increases

Question 31

What does a build up of lactic acid cause?

Answer 31

oxygen debt

Question 32

Why is oxygen debt made during anaerobic respiration?

Answer 32

oxygen is needed to break lactic acid down

Question 33

What is oxygen debt?

Answer 33

the amount of extra oxygen the body needs after exercise to react with accumulated lactic acid and remove it from the cells, this results in muscles tiring and not contracting properly, blood flowing through the muscles transports the lactic acid to the liver where it is converted back to glucose

Question 34

What is metabolism?

Answer 34

the sum of all the reactions in the body, the energy transferred in cells by respiration is used in the processes of metabolism to make new molecules

Question 35

What are metabolism processes controlled by?

Answer 35

enzymes

Question 36

What are examples of metabolic reactions?

Answer 36

- glucose molecules being converted to starch, glycogen and cellulose by being joined together - a glycerol molecule and three molecules of fatty acids forming a lipid molecule - glucose and nitrate ions forming amino acids, which are used to form proteins - the reactions in respiration - urea forming from the breakdown of proteins for excretion