Bioenergetics

Question 1

what is photosynthesis

Answer 1

the process by which plants make glucose from sunlight. it is an endothermic reaction in which energy is transferred from the environment to the chloroplasts by light.

Question 2

word equation for photosynthesis

Answer 2

light
carbon dioxide + water —> glucose + oxygen

Question 3

what is the chemical symbol for glucose

Answer 3

C. H. O
6. 12. 6

Question 4

how does temperature effect photosynthesis

Answer 4

-increase in temp, photosynthesis increases
- trend continues until enzymes denature and rate of reaction decreases as the reaction is controlled by enzymes

Question 5

how does light intensity affect photosynthesis

Answer 5

-the higher the light intensity, the faster the rate of the reaction

Question 6

how does carbon dioxide concentration affect photosynthesis

Answer 6

-carbon dioxide needed to make glucose
-as concentration increases, rate of reaction increases

Question 7

how does the amount of chlorophyll affect rate of photosynthesis

Answer 7

-converts light energy to food for the plant so it is essential
-if chlorophyll levels are reduced the rate of photosynthesis decreases

Question 8

what is a limiting factor

Answer 8

an environmental condition which in low levels restricts any increase in the rate of photosynthesis

Question 9

how does a limiting factor affect the rate of photosynthesis

Answer 9

despite increases in other factors the rate of photosynthesis will not increase any more

Question 10

how can you see a limiting factor on a graph

Answer 10

the curve levelling off

Question 11

what does a graph with once limiting factor look like

Answer 11

if it has one line which levels off
factor on the horizontal axis and rate of photosynthesis on vertical axis

Question 12

what does a graph with two limiting factors look like?

Answer 12

two lines
the investigation involves increasing the factor on the horizontal axis and is carried out at two different other environmental conditions

Question 13

what is light intensity measured in

Answer 13

lux

Question 14

how do farmers use knowledge of limiting factors

Answer 14

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

Question 15

what is inverse proportion

Answer 15

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

Question 16

what is the inverse square law

Answer 16

light intensity { 1/distance^2

Question 17

how is glucose used from photosynthesis

Answer 17

respiration
converted into soluble starch for storage (roots stems leaves)
produce fat or oil for storage (in seeds)
produce cellulose to strengthen cell walls
combined with nitrates from soil to form amino acids which produce proteins

Question 18

what is respiration

Answer 18

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

Question 19

what kind of reaction is respiration

Answer 19

exothermic

Question 20

how does aerobic respiration work

Answer 20

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

Question 21

how does anaerobic respiration work

Answer 21

occurs when there is not enough oxygen
it does not yield as much energy as aerobic respiration
it is only used as a last resort
the oxidation of glucose is incomplete

Question 22

why is more energy needed in exercise

Answer 22

for muscles to contract for respiration to occur faster therefore more oxygen needs to be supplied to cells and more co2 removed

Question 23

how is more energy provided during exercise

Answer 23

heart rate increasing
breathing rate increasing
breath volume increasing

Question 24

when does anaerobic respiration occur

Answer 24

if there is not enough oxygen being supplied eg vigorous exercise

Question 25

why does anaerobic respiration build up creating an oxygen debt

Answer 25

lactic acid is a byproduct of this reaction and oxygen is needed to break lactic acid down

Question 26

what is oxygen debt

Answer 26

the amount of extra oxygen the body needs after exercise to react with the accumulated lactic acid and remove it from the cells

Question 27

what does oxygen debt result in

Answer 27

muscles tiring and not contracting properly

Question 28

how is lactic acid transported

Answer 28

blood flowing through the muscles transports the lactic acid to the liver where it is converted back to glucose

Question 29

what is metabolism

Answer 29

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

Question 30

how are new molecules made

Answer 30

the energy transferred in the cells by respiration is used in the processes of metabolism to make new molecules

Question 31

how are the processes of using metabolism to make new molecules controlled

Answer 31

these processes are controlled by enzymes

Question 32

examples of metabolic reactions

Answer 32

-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 the breakdown of proteins for excretion