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6- Plant Structure And Function Flashcards

1
Q

Where does photosynthesis take place?

A

Chloroplasts on plants and algae

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2
Q

What type of reaction is photosynthesis?

A

Endothermic

Needs energy

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3
Q

What chemical inside chloroplasts is sunlight energy trapped inside?

A

Chlorophyll

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4
Q

Because photosynthesis is endothermic- what is the energy needed?

A

Sunlight

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5
Q

Where are plants and algae on a food chain?

A

1st

They are producers

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6
Q

What is the photosynthesis equation?

A

6CO 2 + 6H 2 O ——- C6 H12 O6 + 6O 2

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7
Q

What are the 4 key factors affecting the rate of photosynthesis?

A

chlorophyll concentration
- high means high rate of photo…
Carbon dioxide concentration
- +C02 = + rate of photo…
- above a threshold more C02 doesn’t increase rate because of another limiting factor (e.g. light intensity
Temperature
- increase = faster rate because more energy
- if temp over 45 degrees, enzymes start to denature
- rate of reaction drops
Light intensity
- increase = faster rate, more energy
- increase over threshold another factor is the limiting reactant

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8
Q

What does a limiting factor do?

A

Restricts the rate of reaction

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9
Q

What are some limiting factors faced by the plant?

A

Night
Winter
Warm and bright conditions
Mineral deficient soil

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10
Q

What is the limiting factor in night time?

A

Light intensity

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11
Q

What is the limiting factor in winter?

A

Temperature

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12
Q

What is the limiting factor in warm and bright conditions?

A

CO2 concentration

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13
Q

What is the limiting factor in mineral deficient soil?

A

Chlorophyll concentration

- plants may not absorb enough minerals to produce lots of chlorophyll

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14
Q

How can you test the effect of light intensity on the rate of photosynthesis?

A
  • aquatic plant
  • change distance between lamp and pondweed
  • count number of bubbles

Independent variable = light intensity
Dependant variable = no. Of bubbles

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15
Q

What is the light intensity equation?

A

Light intensity (L) = 1 / distance squared

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16
Q

What restricts the rate of a reaction?

A

A limiting factor

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17
Q

What is accuracy?

A

How close a measured value is to the true value

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18
Q

What is reliability?

A

The ability of an experiment to produce consistent results

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19
Q

What is validity?

A

How appropriate an experimental method is to achieving the aim of the experiment

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20
Q

What is an easy way to increase the reliability of an experiment?

A

Repeating the experiment

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21
Q

What reduces the validity of the pondweed light experiment?

A

Assume that all the bubbles are oxygen

- plants respire which produces CO2

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22
Q

Why is the pondweed light experiment not accurate?

A

Might not count all the bubbles

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23
Q

What does a root hair cell do?

A

Increase efficiency of a plants water absorption and uptake of minerals

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24
Q

What makes a root hair cell specific to its function?

A 
Long projections (hairs)
No chloroplasts
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25
How do long projections on a root hair cell help its function?
Increase surface area to Absorb water and minerals
26
Why does a root hair cell not have chloroplasts?
- cells underground | - no chloroplasts because there is no light for photosynthesis
27
What is a Xylem cell specialised to do?
Transport water up stem of plant to leaves
28
What is lignin?
A substance that strengthens the cell walls of xylem cells - can withstand pressure changes - waterproofing
29
What is the xylem made from?
Series of dead xylem cells | - the end walls are broken to allow water through
30
What are the long projections on a root hair cell also known as?
Hair
31
What is a stomata?
Gaps in the lower epidermis of leaves
32
What do stomata do?
Facilitate diffusion of gasses in and out of leaf
33
What opens and closes the stomata?
Guard cells
34
How do guard cells close the stomata?
Lose water and return to limp state
35
How do guard cells open the stomata?
Take up lots of water causing them to swell
36
When can a plant afford to lose water?
When water is abundant
37
What does the state of the stomata ( open or closed) achieve?
Balance between - allowing gasses into leaves for photosynthesis - conserving water
38
When can a plant allow gasses to move freely in and out of leaf?
When water is abundant
39
What do the stomata do when water is scarce? Why?
Stomata close | - prevents further water loss
40
What do the stomata do at night?
Close
41
Why do stay at a close at night?
No sunlight so CO2 is not needed for photosynthesis.
42
What is transpiration?
Water transport
43
What direction does water move?
Roots to the leaves
44
Where dose transpiration occur? What does it transport?
Water and minerals dissolved in it | - trough plant
45
How are mineral ions taken up in a plant?
Active transport
46
How do root hair chess absorb water from the soil?
Osmosis
47
What happens to the water and minerals after being absorbed by root hair cells?
Water and minerals transported in xylem vessels up stem and into leaves
48
What happens to water once it reaches the leaves?
majority evaporates & vapour diffuses through open stomata
49
What is water being evaporated from leaves known as?
Transpiration
50
What does transpiration do for the plant?
Helps pull water up from roots
51
What does transpiration in plants transport?
Water | Minerals
52
What factors affect the rate of transpiration?
Light intensity Air flow (wind) Humidity Temperature
53
How does light intensity affect the rate of transpiration?
Increased light intensity= water evaporates faster - increases rate of transpiration
54
How does air flow affect the rate of transpiration?
Increased airflow= carry’s water away from plants leaves - encourages more water to evaporate Increases rate of transpiration
55
How does humidity affect the rate of transpiration?
Increased humidity = increased amount of water in air - more difficult for water to evaporate - decreases rate of transpiration
56
How does temperature affect the rate of transpiration?
Increase temp = Makes water evaporate faster - increases rate of transpiration
57
How do you measure the rate of transpiration?
- potometer - water lost through plants leaves - air bubble moves - speed of bubbles movement = rate of water uptake - only an estimated
58
When measuring the rate of transpiration with a potometer, why is the calculation only an estimate?
A small amount of the water taken up by the shoot is used in the leaves and is not transpired.
59
What apparatus is used to calculate the rate of transpiration?
Potometer
60
What does the phloem specialised to do?
Transport food products to parts of plant that needs it
61
What is the phloem made of?
Phloem vellsels are made up of columns of living cells.
62
How does food move through phloem cells?
The end walls of phloem cells contain small holes | - allows food to flow through phloem vessels
63
What is translocation?
Process by which food is transported - from leaves - to growing regions - storage
64
How is food produced in a plant?
Photosynthesis
65
Where does translocation happen?
Phloem tubes
66
What is in cell sap?
Liquid in plants - stores sugars - salts - amino acids
67
How is sap transported?
Through translocation in phloem tubes
68
What does bidirectional mean?
Movement up and down the plant
69
What is bidirectional?
Translocation
70
What are examples of the different types of tissues in leaves?
- spongy mesophyll - stomata - epidermal tissue - palisade mesophyll
71
What is spongy mesophyll?
- contains many air spaces | - helps gas exchange throughout leaf
72
What is the stomata?
- gaps - facilitate diffusion of gas in and out of leaf - can open and close
73
Where is the stomata found?
Lower epidermis
74
What is the epidermal tissue?
Covers outer surface of leaves (And plant ) - has waxy cuticle for protection
75
What does the waxy cuticle do?
Protective barrier - mechanical injury - water loss - infection
76
What is the palisade mesophyll?
- row of cells - exposed to lots of sunlight - contain lots of chloroplasts - maximises energy created by photosynthesis
77
Where is the palisade mesophyll?
Bellow the upper epidermis
78
Why do pans produce hormones?
Let’s them respond to changes in the external environment
79
What are the key plant hormones?
Auxins Gibberellins Ethene
80
What are auxins?
change growth patterns | - allows shoots or roots to move either towards or away from stimulus
81
What are responses to stimuli that involve directional growth called?
Tropisms
82
What do gibberellins do?
Starting off seed germination process
83
What does ethene do?
- gas - controls cell division - leaf fall - ripening of fruits
84
What are tropisms controlled by?
Auxins
85
What can tropisms be split into?
- phototropisms | - gravitropisms
86
What does positive phototropism involve?
Growth towards light source
87
What does negative phototropism involve?
Growth away from light source
88
What does positive gravitropism involve?
Growth towards direction of gravity
89
What does negative gravitropism involve?
Growth away from direction of gravity
90
What do auxins promote in shoots?
Elongation of cells | More auxins on one side of plant = grow longer on that side
91
What do auxins prevent in shoots?
Elongation of cells
92
What do people use plant hormones for?
Agricultural (farming) | Horticulture (gardening)
93
How are auxins used in agriculture and horticulture?
Weed killers - selectively kills weed (not grasses like wheat) Rooting powders - promotes root growth in tissue culture
94
How do auxins work as weed killers?
- start rapid growth | - weed uses up resources
95
How is ethene used in agriculture and horticulture?
Speeds up ripening of fruit during transport
96
How are gibberellins used in agriculture and horticulture?
- Promote flowering - Increase fruit size - Start seed germination - can trigger production of seedless fruit (e.g. grapes and bananas) - fruit produced without fertilisation of plants ovules
97
What are the harshest conditions for a plant?
High heat | Low water
98
What is the name of the type of plant that is adapted for heat and low water?
Xerophyte
99
What adaptions does a xerophyte have to help it survive?
- waxy cuticle - sunken stomata - small leaves
100
Why does having a waxy cuticle help a xerophyte?
Waterproof | - reduces water evaporation
101
Why does having sunken stomata help a xerophyte?
- Reduces amount of water vapour that can diffuse out of stomata - stomata close during day & night if low on water or temp too high
102
Why do xerophytes often have small leaves?
- reduces surface area - fewer stomata - less water loss through transpiration

Biology (9 decks)

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