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Biology > Unit 6 - Plant Structures And Their Functions > Flashcards

Unit 6 - Plant Structures And Their Functions Flashcards

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1
Q

What is photosynthesis?

A

The process of plants converting energy into a sugar called glucose

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2
Q

What is the biomass of an organism?

A

The materials in an organism

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3
Q

Why do plants and algae produce food for almost all other life on Earth?

A

They produce their own biomass

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4
Q

What part of the food change are plants?

A

The producers

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5
Q

What is the word equation for photosynthesis?

A

Carbon dioxide + water —> glucose + oxygen (energy transferred by light)

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6
Q

Where does photosynthesis occur?

A

In chloroplasts in chlorophyll

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7
Q

What is a endothermic reaction.

A

When the reaction absorbs the energy from the surroundings

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8
Q

What is an exothermic reaction?

A

When energy is released from the reaction

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9
Q

What is starch?

A

A polymer made from glucose molecules

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10
Q

What happens to the starch produced from then

A

It is broken down into smaller substances and moved to the cytoplasm where it is used to make sucrose

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11
Q

What is sucrose used to make in plants?

A

Starch
Glucose (respiration)
Other molecules such as lipids and proteins

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12
Q

What cells contain the chloroplasts?

A

Palisade cells

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13
Q

Give 3 adaptations of a leaf

A

Broad and flat to give it a large surface area
Palisade cells are near the go to absorb light easily,
Very thin so carbon dioxide doesn’t have to diffuse very far

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14
Q

What is the role of the stomata

A

To allow carbon dioxide to enter the lead by diffusion

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15
Q

What are guard cells?

A

Specialised cells that open and close the stomata

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16
Q

What causes the stomata to open and close?

A

When it is light, water flows into pairs of guard cells and make them rigid and open, at night, water flows out of and the stomata shuts

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17
Q

What does the stomata allow to leave

A

Oxygen and water vapour

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18
Q

What is gas exchange?

A

The flow of different gasses in and out

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19
Q

Why is the rate of photosynthesis lower in the mountains than at sea level? (2)

A

The concentration of air molecules is less in the mountains

Higher mountains are colder which make the enzymes for photosynthesis work slower

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20
Q

What is a limiting factor?

A

A factor that prevents a rate increasing.

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21
Q

What are the 3 limiting factors for photosynthesis?

A

CO2 concentration, light intensity, temperature

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22
Q

For a graph showing a limiting factor and rate of photosynthesis, why does the line become horizontal after some time?

A

Something else becomes the limiting factor

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23
Q

What does a straight line on a graph show?

A

A linear relationship

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24
Q

What must the line do on a graph to show that two variables are in direct proportion?

A

It must

go through 0,0

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25
Q

What does the inverse square law calculate?

A

The new light intensity when the distance of a light source changes

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26
Q

What is the equation for new light intensity?

A

New LI = Original LI x original d^2 / new d^2

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27
Q

If you double the distance from the light source, what happens to the light intensity

A

It halves from the original

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28
Q

Explain the core practical - Light intensity and photosynthesis

A

Place different glass bottles at different distances from light
Add 20 algal balls to each bottle and indicator, put on bottle caps
Compare colours of tubes with a pH range at the start
Set up water tank between light and bottles
Cover a bottle in kitchen foil and place next to the closest one to the lamp
Turn on lamp and wait for obvious changes
Compare colours to pH range and calculate ‘change in pH/hour’

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29
Q

How are some trees adapted to living in rainforests?

A

They have huge buttress roots to stop tall trees falling over and trap dead vegetation for minerals

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30
Q

What is the water absorbed by plant roots used for? (4)

A

Carrying dissolved mineral ions
Keeping cells rigid (not wilting)
Cooling leaves (evaporation)
Photosynthesis

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31
Q

How are root hair cells well adapted? (2)

A

Provide large surface area, faster absorption of mineral ions
Thin walls so flow of water is not slowed

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32
Q

What is diffusion

A

When particles move down a concentration gradient

33
Q

What adaptation do plant roots have for diffusion?

A

The cell walls have an open structure allowing water particles to diffuse towards the middle of the root.

34
Q

What is osmosis?

A

When solvent particles diffuse through a semi-permeable membrane

35
Q

Where does osmosis occur in plants?

A

Water passes into the cytoplasm of root hair cells by osmosis

36
Q

Give an example of how plants use mineral salts

A

Nitrate ions to make proteins

37
Q

Why is active transport needed to pump ions into the root hair cells?

A

The concentration of ions inside a root hair cell is greater

38
Q

How does water keep plants cool?

A

When it evaporates, it transfers the heat energy

39
Q

What is transpiration?

A

The flow of water into a root, up the stem and out of the leaves

40
Q

Why is there an unbroken chain of water in the xylem vessels?

A

The weak forces of attraction between the water molecules

41
Q

Describe what happens in the xylem vessels to stop the flow breaking?

A

Water is pulled up the xylem vessels in the stem as water evaporates from the xylem vessels in the leaves. As water vapour diffuses out of a leaf, more evaporates from the xylem inside the leaf

42
Q

What type of factors would cause water to be evaporated quicker?

A

Making a bigger difference between the concentrations so diffusion occurs faster

43
Q

Give 2 factors which increase water evaporation

A

Wind

Low humidity

44
Q

Give 2 factors that increase transpiration

A

Higher temperature, particles move faster

Greater light intensity, makes stomata wider

45
Q

What causes the stomata to open?

A

Light

46
Q

Give 3 adaptations for xylem vessels

A

Thick side walls of lignin to it won’t burst or collapse
Dead cells, no cytoplasm so forms an empty tube for water to flow
Lack of cells walls on top and bottom of cells

47
Q

Give 3 adaptations of phloem vessels

A

Holes in ends of cell walls to allow liquids to flow through
Pores which sucrose solution can be pumped
Small amount of cytoplasm, more room for central channel

48
Q

Where do plants make sucrose from?

A

The glucose and starch made by photosynthesis

49
Q

How is sucrose transported?

A

It is translocated in the sieve tubes and phloem tissue

50
Q

What is the role of companion cells?

A

They actively pump sucrose into or out of sieve cells that form the sieve tubes

51
Q

Why do leaves have large surface areas?

A

To ensure they collect enough sunlight

52
Q

What part of the plant traps sunlight

A

Chlorophyll

53
Q

Where does CO2 diffuse into the plant

A

Through an open stomata

54
Q

What are epidermis cells

A

They form the outer layers of a lead and hold it together, protecting the cells inside

55
Q

Give 2 adaptations of epidermis cell’s

A

Transparent, allow light through

Waxy waterproof cuticle, prevent water loss

56
Q

Why do many deciduous plants lose their leaves in the winter

A

Prevents water loss when soil water may be frozen

57
Q

Why do conifers have needle-shaped leaves

A

Creates less wind resistance so they can withstand high winds

58
Q

Why is the stomata of conifers located in small pits

A

Reduces water loss because water vapour collects there and is less exposed to environment

59
Q

Why do some plants in the desert have hairs

A

To trap water

60
Q

Give 3 adaptations of plants in the desert

A

Thick cuticle (prevent water loss)
Some have hairs
Spines instead of leaves (minimise surface area)

61
Q

What is a stimulus

A

A change in environment that causes a response by an organism

62
Q

What is phototropism

A

Responding to a stimulus which is light by growing towards or away from it

63
Q

What hormones cause positive phototropism

A

Auxins

64
Q

Where are auxins found for phototropism

A

In the tip of the shoot

65
Q

How do auxins cause phototropism

A

They elongate the cells so they move to the shaded side to make it grow towards the light

66
Q

What was Darwin’s experiment?

A

6 different shoot tips: 1. Intact shoot, 2. Covered with place paper, 3. Covered with transparent cap, 4. Tip removed, 5. Tip removed and replaced on an impermeable block 5. Tip removed and placed on agar block

67
Q

What hormones cause gravitropism

A

Auxins

68
Q

Where are aiding found for gravitropism

A

In the root tips

69
Q

What do auxins do for gravitropism

A

They stop the elongation of cell so they move to the most downward side

70
Q

What is the hormone to help seeds germinate?

A

Gibberellins

71
Q

What hormones help fruit to ripen

A

Ethene

72
Q

What do selective weed killers contain

A

Artificial auxins to kill plants with broad leaves but not with narrow leaves

73
Q

What do auxins in root powders cause

A

Plant cuttings to develop roots quickly

74
Q

What is a positive of gibberellins

A

It can make the seeds germinate faster (some only germinate at certain times)

75
Q

What is photoperiodism

A

The response of an organism to the number of daylight hours in a day

76
Q

How can farmers override photoperiodism?

A

By spraying plants with gibberellins

77
Q

How are seedless fruits formed?

A

Gibberellins can cause the plant to produce the fruit without seeds being formed

78
Q

Why do fruit producers use ethene?

A

They can transport the fruits while they are unripe and use the ethene to ripen them when they need them

Biology (9 decks)

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