Photosynthesis Flashcards

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1
Q

What is photosynthesis?

A

It’s the process by which green plants use co2 and water to make glucose and oxygen using energy in sunlight and the enzymes in chlorophyll

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2
Q

What are the roles of photosynthesis?

A
Plants = make food
Animals = food for plants
Organisms = oxygen to breathe
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3
Q

What is the word equation of photosynthesis?

A

Carbon dioxide, water and light - chlorophyll - = glucose and oxygen

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4
Q

What is the balanced chemical equation of photosynthesis

A

6CO2 + 6H20 - light and chlorophyll - C6H12O6 and 6O2

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5
Q

What are the factors necessary for photosynthesis?

A

Light, water, co2 and chlorophyll

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6
Q

Where do plants get light for photosynthesis?

A

From the sun

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7
Q

Where do plants get water for photosynthesis?

A

Water in the soil that is absorbed by root hairs and transported to xylem cells

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8
Q

How do plants get co2 for photosynthesis?

A

Atmosphere

Respiration

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9
Q

What is chlorophyll made up of?

A

Magnesium

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10
Q

Where in a plant does photosynthesis take place?

A

The leaf

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11
Q

Where in a leaf does photosynthesis take place?

A

Palisade cells

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12
Q

Where in the palisade cells does photosynthesis takes place / Where precisely in a plant cell does photosynthesis occur

A

Chloroplasts

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13
Q

Where in the chloroplast does photosynthesis take place?

A

The grana [granum-stacks of blisters]

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14
Q

What energy does photosynthesis convert from and to

A

Light energy to kinetic energy

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15
Q

What are the roles of energy carriers such as NADP+ and ATP

A

Trap and transfer energy in cellular activities

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16
Q

What does ADP stand for and where is it found

A

Adenosine Diphosphate and is found in the cells of all organisms

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17
Q

What is ADP made up of?

A

Adenosine, 5 carbon sugar called ribose and 2 phosphate groups

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18
Q

What kind of a molecule is adp

A

A low energy molecule

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19
Q

How is ATP formed?

A

If another phosphate is added to ADP by phosphorylation

ADP + energy + P = ATP + H20

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20
Q

What does ATP stand for

A

Adenosine triphosphate

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21
Q

Why is extra energy added when ADP forms ATP

A

Because there is an extra bond between the last two phosphate groups

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22
Q

What is phosphorylation?

A

Addition of a phosphate

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23
Q

What kind of a molecule is ATP

A

High energy molecule

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24
Q

How is ADP formed from ATP

A

ATP cannot store energy for long and breaks down energy and converting back to ADP

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25
Q

Energy released by the cell is used for what

A

Cellular reactions - protein production and muscle movement

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26
Q

What kind of a bond is there between the two phosphates in ADP

A

Unstable bond

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27
Q

What kind of a bond is there between the phosphates in ATP

A

Stable bond

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28
Q

What is NADP+?

A

It is a low energy molecule involved in photosynthesis

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29
Q

How dos NADP+ form NADPH?

A

Combines with two high energy electrons and a proton to form NADPH
NADP+ + 2é + H+ = NADPH

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30
Q

What is NADPH

A

It is a high energy molecule which is used to from glucose in photosynthesis

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31
Q

How does NADPH form NADP+

A

Releasing two high energy electrons and a proton

NADPH = NADP+ + 2é + H+

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32
Q

What can gardeners do to increase the rate of photosynthesis in greenhouses?

A

Increasing Co2 concentration = adding co2 into the air by burning gases
Increasing light intensity = artificial light or a very bright light bulb
Increasing temperature = enzymes involved to work faster

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33
Q

Name the molecule that traps the energy in sunlight?

A

Chlorophyll

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34
Q

What molecule is split by the energy in sunlight?

A

H2O

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35
Q

Describe pathway one light stage

A

Suns energy is trapped by chlorophyll
Energy is passed to reaction centre chlorophyll
Electrons become excited or energised and pick up an electron acceptor molecule
The electrons spin out of control and to chlorophyll via enzymes
This joins ADP + energy + P = ATP

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36
Q

Describe light stage pathway two

A

The Suns light energy is trapped by chlorophyll
The energy is passed to a reaction centre chlorophyll
The electrons become excited/energised and are picked up by an electron acceptor
This releases electrons and together with NADP+ form NADPH
The Suns energy is used to split water = photolysis
Electrons move via enzymes back to the reaction centre chlorophyll

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37
Q

What is photolysis?

A

Splitting of water into three products

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38
Q

What are the three products of photolysis and their functions

A

Oxygen - released or used in respiration
Hydrogen - used to make NADPH
Electrons - replenish chlorophyll

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39
Q

Describe the dark stage

A

Co2 diffuses into the chloroplasts and joins up with a 5 carbon acceptor molecule to produce a 6 carbon molecule
This 6C molecule is unstable and breaks up into 3C molecules
Some of the 3c molecules are used to replace the 5C carbon molecule, but most are reduced to from glucose
This reduction involves ATP and NADPH from rah light stage

40
Q

What does ATP provide glucose with

A

It provides energy for glucose formation in dark stage

41
Q

What does NADPH provide glucose with

A

Electrons
Protons
NADP+

42
Q

What happens to what remains after the dark stage? [ADP and NADP+]

A

ADP + P = recycled in pathway one
NADP+ = recycled in pathway two

of lightstage!

43
Q

Why is photosynthesis affected by temperature?

A

Because it depends on the activity of enzyme in both the light and dark stage

44
Q

What is the dark stage also known as and why?

A

The light independent stage as it can occur in the light but does not need to use it

45
Q

Where does the dark stage take place?

A

Stoma of chloroplasts

46
Q

What is CO2 reduced to?

A

Glucose

47
Q

In which pathway of the light stage is oxygen produced?

A

Pathway two

48
Q

Outline how oxygen is produced

A

Photolysis, which water is split into hydrogen, oxygen and electrons

49
Q

Give both fates of oxygen

A

Respiration

Released into atmosphere

50
Q

What is the fate of the carbon from carbon dioxide in the dark stage?

A

Most - reduces to glucose

Some - used to replenish the C5 acceptor molecule

51
Q

Aquatic plants such as elodea are particularly suitable for investigating photosynthesis, suggest a reason for this?

A

Bubbles of oxygen are visible for counting

52
Q

What is the energy source for the dark stage?

A

ATP

53
Q

Give two main uses of the main product of the dark stage

A

Glucose
Respiration [broken down]
Converted to starch [storage]

54
Q

Give one reason why the second stage cannot happen without the first stage

A

The second stage needs ATP to supply energy [from pathway one] and NADPH which provides glucose with electrons protons and NADP+ [formed in pathway two]

55
Q

Suggest one possible benefit to plants of having more than one chlorophyll pigment

A

Absorb more colours

56
Q

What is the main source of carbon dioxide used by plants in the dark stage?

A

Atmosphere

57
Q

To investigate the influence of light intensity or carbon dioxide on the rate of photosynthesis -
Suggest a suitable plant for such an investigation

A

Eleoda

58
Q

To investigate the influence of light intensity or carbon dioxide on the rate of photosynthesis -
How was the rate of photosynthesis measured?

A

Amount of bubbles per minute

59
Q

To investigate the influence of light intensity or carbon dioxide on the rate of photosynthesis -
What factor must be kept constant?

A

Temperature

60
Q

To investigate the influence of light intensity or carbon dioxide on the rate of photosynthesis -
Explain how you would keep temperature constant?

A

Using water bath

61
Q

To investigate the influence of light intensity or carbon dioxide on the rate of photosynthesis -
Why is it necessary to keep temperature constant?

A

Enzymes - optimum temp

62
Q

To investigate the influence of light intensity or carbon dioxide on the rate of photosynthesis -
Why would photosynthesis stop?

A

Too Saturated with light concentration

63
Q

Describe - investigate the influence of light intensity or carbon dioxide on the rate of photosynthesis

A
  • add sodium hydrogen carbonate to water in test tube until becomes saturated
  • cut section of eleoda and place in test tube [upwards]
  • place test tube and thermometer in water bath with a lamp one metre from apparatus
  • allow eleoda to stabilise for 5 mins
  • count number of bubbles of oxygen coming from stem per minute
  • repeat three times and work out average
  • increase light intensity by moving lamp closer and repeat steps
64
Q

To investigate the influence of light intensity or carbon dioxide on the rate of photosynthesis - diagram and explain the trend

A

Page 110
As light inc, rate of bubbles per minute inc [photosythesis inc] however it levels off when plant becomes too saturated with light

65
Q

To investigate the influence of light intensity or carbon dioxide on the rate of photosynthesis - result?

A

As lamp is moved closer to the apparatus, the rate of bubble production increases. However at some point it will cease to increase because it is saturated with light

66
Q

How do u calculate light intensity

A

10,000
———
[distance]^2

67
Q

To investigate the influence of light intensity or carbon dioxide on the rate of photosynthesis - why is sodium hydrogen carbonate added?

A

Ensure water is saturated with carbon dioxide

68
Q

Name the simple compound that provides the necessary energy for the second stage reactions

A

ATP

69
Q

To investigate the influence of light intensity or carbon dioxide on the rate of photosynthesis - how measured rate of photosynthesis

A

By counting bubbles produced per minute

70
Q

To investigate the influence of light intensity or carbon dioxide on the rate of photosynthesis - explain how varied light intensity

A

Moving lamp closer or further or away from test tube

71
Q

State a precise role of carbon dioxide in photosynthesis

A

Supplies carbon for conversion to glucose

72
Q

Give the specific site of a plant fell where photosynthesis takes place

A

Chloroplast

73
Q

Where do these energised electrons come from?

A

Chlorophyll

74
Q

Name the simple compound from which a plant obtains the H used to make glucose

A

H20

75
Q

How can photosynthesis be accelerated in horticulture and explain

A

Inc cO2 concentration
Inc temperature
Temperature - increase enzyme activity
CO2 - inc supply of carbon atoms

76
Q

Is the dark stage of photosynthesis anabolic or catabolic and explain

A

Anabolic - small molecules [co2 and h20] form larger molecules [glucose]

77
Q

Name the two types of particle transferred from NADPH to CO2 in the dark stage?

A

Electrons

Protons

78
Q

Name a substance which absorbs light energy for photosynthesis

A

Chlorophyll

79
Q

What does NAD stand for and name two types of particle that it transfers

A

Nicotinamide Adenine Dinucleotide

  • Electrons
  • Protons
80
Q

Name two environmental factors on which the rate of photosynthesis depends

A

Temperature

CO2 concentration

81
Q

Explain what happens to electrons in pathway I

A

When chlorophyll gets energy from sun, electrons become excited or energised and pick up an electron acceptor molecule
The electrons spin out of control and to chlorophyll via enzymes

82
Q

Explain what happens to electrons in pathway two

A

The electrons become excited/energised and are picked up by an electron acceptor
This releases electrons and together with NADP+ form NADPH
Electrons return back to chlorophyll

83
Q

Graph on colour pigments

A

Page 108 exam papers

84
Q

Each time light intensity or carbon dioxide concentration is varied a precaution is necessary. What is this precaution and why is it necessary?​​

A
Allow time (before counting bubbles)
Reason: Plant adjusting
84
Q

What happens to water molecules when they reach the sites of photosynthesis?

A

photolysis or split

Protons or H+ / electrons / oxygen

85
Q

From what substance is oxygen produced?

A

Water

87
Q

In which stage of photosynthesis is oxygen produced?

A

Light stage

87
Q

State a precise role for carbon dioxide in photosynthesis

A

Supplies carbon required to reduce to glucose

88
Q

Give an account of the role of NADP?

A

Accepts electrons and hydrogen carrier in dark stage

89
Q

State a precise role for water in photosynthesis

A

It is split by light and supplies hydrogen, oxygen and electrons

90
Q

What is the primary role of chlorophyll in photosythesis

A

Traps light as energy

91
Q

Name a gas that is essential for the dark stage

A

CO2

92
Q

To what group of biomolecules do the main products of the dark stage belong?

A

Carbohydrates

93
Q

What are the two products of the light stage are vital for the dark stage and state the precise role in the dark stage

A

ATP -> energy store

NADPH -> electrons, protons, NADP+

94
Q

Give two sources of the carbon dioxide that is found in the atmosphere

A

Respiration

Combustion

95
Q

Rate of photosythesis graph questions

A

Page 181