Bioenergetics Flashcards

1
Q

what do plants use for their energy source

A

light

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2
Q

what reaction do plants use to trap the light energy

A

photosynthesis

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3
Q

is photosyntheisis exo / endo thermic

A

endothermic as it takes in energy from surroundings

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4
Q

where does photosynthesis take place

A

leaves

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5
Q

what do leaves contain, what does this do

A

chlorophyll absorb light energy

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6
Q

what happens in first stage of photosyntheisis

A

plant takes carbon dioxide + water into the leaf

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7
Q

second stage of photosynthesis

A

light energy absorbed by chlorophyll

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8
Q

what is the light energy (taken in during photosynthesis) used for

A

used to convert the carbon dioxide and water into glucose

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9
Q

word equation for photosynthesis

A

carbon dioxide + water
( light energy ) =
glucose + oxygen

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10
Q

chemical equation for photosynthesis

A

CO2 + H2O = C6H12O6 + O2

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11
Q

photosynthesis is an ……….
reaction in which …… is transferred from the ……… to the
……… by …..

A

Photosynthesis is an endothermic
reaction in which energy is transferred from the environment to the
chloroplasts by light.

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12
Q

what happens as light intensity increases
why

A

rate of photosynthesis increases

plant has more light energy to carry out photosynthesis reaction, so reaction gets faster

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13
Q

how can you tell if light intensity was a limiting factor

A

if we increase light intensity
and
rate of photosynthesis also increases
that tells us light intensity was limiting

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14
Q

what does it mean if a factor is limiting

A

rate of photosynthesis wasn’t as fast as possible because something wasn’t high enough
(light intensity
temp
co2 conc..
chlorophyl)

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15
Q

what happens if we keep increasing light intensity

A

we reach a point where rate of photosynthesis no longer increases

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16
Q

what happens to the graph for rate of photosynthesis / light intensity when light intensity is no longer a limiting factor

A

the graph levels of, a straight line

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16
Q

what happens to the graph for rate of photosynthesis / light intensity when light intensity is no longer a limiting factor

A

the graph levels of, a straight line

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17
Q

when the graph for rate of photosynthesis / light intensity levels off, what 2 things does this mean

A

light intensity is no longer the limiting factor
something else is now in short supply eg CO2

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18
Q

when something eg co2 is the limiting factor, what does this look like on the graph

A

horizontal line going upwards from 0

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19
Q

when something eg co2 is the limiting factor, what does this look like on the graph

A

horizontal line going upwards from 0

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20
Q

when something eg co2 is the limiting factor, what does this look like on the graph

A

horizontal line going upwards from 0

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21
Q

what does the graph for CO2 / rate of photosynthesis look like

A

same as graph for light intensity

horizontal up to a certain point - limiting factor
graph levels off, straight line- no longer limiting factor, something else is in short supply

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22
Q

why does lack of chlorophyll lead to lower rate of photosynthesis

A

because leaves trap less light energy than normal

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23
Q

what does an increase in temperature do to the rate of photosynthesis
how
3 points

A

as we increase temperature,
the enzymes in photosynthesis work faster
so rate increases

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24
Q

what happens if we keep increasing the temp

A

the enzymes denature
rate of photosynthesis falls

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25
Q

describe graph for temperature and rate of photosynthesis

A

steady increase, horizontal line till a point.
begins to curve down wards.
falls more rapidly

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26
Q

5 uses of glucose from photosynthesis

breathe storage fat to strengthen the protien

A
  • used for respiration
  • converted into insoluble starch for storage
  • 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.
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27
Q

what is glucose used for in respiration

A

to release energy in respiration

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28
Q

where does respiration take place

A

in mitrochondria

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29
Q

when does photosynthesis produce glucose

A

in the day, when there’s light

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30
Q

when do plant cells respire

A

all the time, even at night

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31
Q

what do plants do with starch

A

convert it back into glucose when needed (eg night)

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32
Q

what do plants use fats and oils as

A

as a storage from of energy

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33
Q

what does cellulose do

A

strengthens the cell wall

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34
Q

what is cellulose made from

A

from glucose- produced by photosynthesis

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35
Q

what are amino acids used by the plant for

A

amino acids used to synthesise protiens

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36
Q

what do plants do to make amino acids from glucose

A

absorb nitrate ions from the soil

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37
Q

what is the aim of the RP for photosynthesis

A

Investigate the effect of light intensity on the rate of photosynthesis using an aquatic organism such as pondweed

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38
Q

RP
what is the effect of light intensity measured by

A

measured by counting the number of O2 bubbles formed per minute.

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39
Q

RP
what 8 equipment is needed for photosynthesis RP

A

● a boiling tube
● freshly cut 10 cm piece of pondweed
● a light source
● a ruler
● a test tube rack
● a stopwatch
● 0.2% solution sodium hydrogen carbonate
● a glass rod

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40
Q

describe 4 brief steps for RP photosynthesis

A

. place cut pondweed in boiling tube (containing sodium hydrogen carbonate solution) at a fixed distance from a light source
. count no. of bubbles produced in 1 minute using stopwatch
. repeat several times, different distances/ light intensities and calculate a mean for each distance
. plot a graph for light intensity (x) against rate of photosynthesis (bubbles per minute,y)

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41
Q

step 1 in depth

A

Place a test tube rack containing a boiling tube 10 cm away from the light source, measured using the ruler.

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42
Q

step 2 in depth

A

Fill boiling tube with a fixed volume of sodium hydrogen carbonate solution.

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43
Q

step 3 in depth

A

Place the cut pondweed into the boiling tube with the cut end at the top. Gently push the pondweed down with the glass rod.

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44
Q

step 4 in depth

A

Leave the boiling tube for 5 minutes.

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45
Q

step 5 in depth

A

Start the stopwatch + count number of bubbles produced in one minute.

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46
Q

step 6 in depth

A

For each light intensity/distance, repeat the count twice more and take a mean.

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47
Q

step 7 in depth

A

record in table

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48
Q

step 8 in depth

A

repeat steps 1-7 for more distances

49
Q

step 9 in depth

A

plot graph for rate of photosynthesis( bubbles ) and light intensity

50
Q

why is it best to use an led light source for RP photosynthesis

A

dont release much heat- would change the temp of the experiment

51
Q

what would we do if we had to use a normal light bulb instead of a led light

A

place beaker of water between light and tube so it absorbs light

52
Q

what does sodium hydro carbonate solution release

A

carbon dioxide (needed for photosynthesis)

53
Q

where do the bubbles come from

A

the cut end of the pondweed

54
Q

why can you see bubbles

A

because oxygen is produced from photosynthesis

55
Q

2 problems with experiment

A

bubbles too fast to count properly
bubbles not the same size

56
Q

what solves the problems in the experiment

A

we can measure volume of oxygen produced instead of counting bubbles

57
Q
A

place pondweed under funnel
catch bubbles in measuring cylinder filled with water
use measuring cylinder to measure volume of oxygen produced

58
Q

why can we use the no. of bubbles to calculate rate of photosynthesis

A

oxygen bubbles are a product of photosynthesis.
no. of bubbles produced in a given time is proportional to rate of photosynthesis

59
Q

describe the relationship between light intensity and rate of photosynthesis from inverse square law

A

if you double distance
number of bubbles per minute falls by a factor of 4

60
Q

Potential Hazards

A

There is a potential allergy risk from the pondweed.
Lamp may get hot.
Be careful to keep water away from electrical power outlets and wiring

61
Q

what is the equation for inverse square law

A

light intensity =
1/distance squared
between pondweed and light source

62
Q

describe graph for light intensity on rate of reaction.
describe what it means

A

initially rate increases as light intensity increases
light intensity is limiting
rate stops increasing at a certain point
something else must be limiting

63
Q

how can we tell what has become the new limiting factor in a graph of light intensity and rate of photosynthesis

A

if we increase something else
eg carbon dioxide
and do the same experiment again
and the rate of photosynthesis increases to a higher number this time,
(graph goes higher before leveling off)
then we know that Co2 was the limiting factor

64
Q

what 3 things can be changed in an experiment to affect rate of photosynthesis

A

light intensity
temp
co2 concentration
(very hard to change chlorophyll

65
Q

how can you tell if a factor is no longer the limiting factor

A

is you increase it but rate of photosynthesis stays the same

66
Q

what happens if we increase the temp too much

A

enzynes in leaf will start to denature
rate of photosynthesis will fall

67
Q

why do farmers want to increase rate of photosynthesis

A

it will increase the yeild of crops they produce

68
Q

what do farmers do to increase rate of photosynthesis

A

light and heat greenhouses
add extra CO2

69
Q

what is an issue with using a greenhouse

A

expensive so
extra price needs to be justified by increase in yield

70
Q

what do farmers use to save costs in greenhouses
how does this save cost

A

oil burners,
release heat & CO2 at the same time

71
Q

explain what farmers use greenhouses for

A

enhancing conditions through limiting factors to gain maximum rate of photosynthesis while still maintaining profit

72
Q

define cellular respiration

A

exothermic reaction which releases energy + continuously occurring in living cells

73
Q

3 things we need energy for

A

movememt
keep warm
chemical reactions

74
Q

how are protiens made

A

chemically joining amino acids

75
Q

what are the two types of respiration

A

aerobic
anaerobic

76
Q

word equation for aerobic respiration

A

glucose + oxygen = carbon dioxide + water

77
Q

what is released in respiration

A

energy

78
Q

why does anaerobic respiration release a lot of energy

A

the glucose has been fully oxidised

79
Q

2 cells where anaerobic respiration can be used

A

muscle cells
plant/ yeast cells

80
Q

what do muscle cells need energy for

A

for contraction

81
Q

Anaerobic respiration in muscles is represented by the equation:

A

glucose —– > lactic acid

82
Q

what happens in anaerobic respiration in muscle cells

A

glucose is converted to lactic acid

83
Q

why does anaerobic respiration release less energy than aerobic

A

because the oxidation of glucose is incomplete

84
Q

Anaerobic respiration in plant and yeast cells is represented by the
equation:

A

glucose —-> ethanol + carbon dioxide

85
Q

what does anaerobic respiration mean

A

respiration without oxygen

86
Q

what happens during anaerobic respiration in plant and muscle cells

A

glucose is converted into ethanol and co2

87
Q

what is fermentation

A

anaerobic respiration in yeast cells

88
Q

2 things fermentation of yeast cells is used for

A

to make bread
alcoholic drinks

89
Q

what is the alcohol produced from fermentation

A

ethanol

90
Q

why is fermentation of yeast useful to make bread

A

the co2 produced from anaerobic respiration in yeast cell (fermentation)
creates bubbles in the dough
causing bread to rise

91
Q

during exercise, what does the body need energy for

A

for muscle contraction

92
Q

during exercise, what does the body react to

A

the increased demand for energy

93
Q

what increases during exercise

A

heart rate
breathing rate
breath volume

94
Q

why does aerobic respiration increase during exercise

A

the body cells require more oxygen

95
Q

why does breathing rate and volume increase,

A

to get more oxygen into the blood stream

96
Q

why does heart rate increase

A

to pump oxygenated blood round the body

97
Q

when does anaerobic respiration take place in muscles

A

when not enough oxygen can be supplied to the muscles - exercising hards

98
Q

what does the incomplete oxidation of glucose leads to

A

build up of lactic acid + oxygen debt

99
Q

what happens during long periods of vigorous activity

A

. During long periods of vigorous
activity muscles become fatigued and stop contracting efficiently.

100
Q

how is the condition oxygen debt created

A

the body has to remove the lactic acid from the muscles

101
Q

how is lactic acid transported out of muscles

A

by the blood

102
Q

where does the blood transport the lactic acid

A

to the liver

103
Q

what happens to the lactic acid when it reaches the liver

A

converted back to glucose

104
Q

describe process of lactic acid being formed to it being converted back into glucose

A

when not enough oxygen can be supplied to muscle cells, anaerobic respiration takes place in the muscles.
lactic acid is produced
Blood flowing through the muscles transports the lactic acid
to the liver where it is converted back into glucose.

105
Q

what is the oxygen debt

A

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

106
Q

why is the oxygen debt formed

A

because reacting with the accumulated lactic acid and removing it from cells requires oxygen

107
Q

what is one way the body overcomes oxygen debt

A

breathe rapidly after exercise

108
Q

what do enzymes use the energy released by respiration for

A

to synthesise new molecules in the cell

109
Q

define metabolism

A

sum of all the chemical reaction in a cell or body

110
Q

2 things glucose is converted to in plants

A

cellulose and starch and amino acids

111
Q

what does cellulose in a plant do

A

strengthens plant cell wall

112
Q

what is starch

A

a storage form of glucose

113
Q

what is glucose reacted with in plants to make amino acids

A

nitrate ions

114
Q

what are amino acids used for

A

to synthesise proteins

115
Q

what 2 things is glucose converted into in humans + animals

A

glycogen
lipid

116
Q

what is glycogen

A

a storage form of glucose

117
Q

how are lipids made

A

1 molecule of glycerol
3 molecules of fatty acids
reacted together

118
Q

where are lipids found

A

in cell membrane

119
Q

what happens to excess protiens

A

broken down into chemical urea

120
Q

what happens to the urea

A

excreted by kidneys