Section 3 Flashcards

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1
Q

How do single-celled organisms carry out all life processes? What happens if it gets too large?

A

They maintain an efficient surface area to volume ratio. If a cell becomes to large, it will usually divide to produce two new cells.

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2
Q

What are 3 advantages of multicellular organisms? Explain your points.

A

1) Division of labour; cells perform their specialized purposes more efficiently than a single-celled organism that would have to perform all needed functions at once.
2) Size; in multicellular organisms, internal transport systems allow efficient exchange of materials, letting the organism grow to a larger size.
3) Interdependence of cells; life of a multicellular organism does not depend on a single cell.

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3
Q

What’s a disadvantage of a multicellular organism?

A

Cells cannot survive alone as they depend on others for certain tasks.

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4
Q

What is a tissue?

A

A group of similar cells performing the same function.

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5
Q

What is an organ?

A

Tissues contributing to the same function in a structured and functional unit.

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6
Q

What is an organ system?

A

A group of organs working together for a specialized task.

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7
Q

What is the shoot system? Name the organs apart of it.

A

The shoot system is generally everything that is above ground; includes stem, leaves, buds, flower, fruits. It also includes tubers even though they are underground.

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8
Q

What are tubers?

A

Swollen stems that store food (eg. potatoes).

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9
Q

What is the root system? Name the organs apart of it.

A

It’s generally everything underground, like the roots.

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10
Q

What are meristems?

A

These are sites of rapid cell division. These areas are found a the end of growing leaves and roots and is where growth and development occur. Different meristems produce root and shoot tissue.

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11
Q

How are the cells of a meristem different from a regular cell?

A

Meristems have less specialized cells and cell division occurs much faster

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12
Q

What is dermal tissue/epidermis? What is its role in leaves and stems? What about roots?

A

It’s a very thin outer layer of cells that covers all parts of herbaceous plants (in woody plants, it’s replaced by cork and bark). On leaves and stems, it’s main function is to facilitate gas exchange. In roots, it’s responsible for the uptake of water and mineral salts from the soil.

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13
Q

What is the cuticle?

A

Dermal cells create the cuticle that helps protect the plant from diseases and microorganisms, and prevent water loss.

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14
Q

What is the ground tissue? What’s it’s role in the stem? the roots? The leaves?

A

It’s beneath the epidermis and makes up majority of the plant.
Roles:
Stem: provides strength and support
Root: food and water storage
Leaf: site for photosynthesis (contains chloroplasts)

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15
Q

What is a herbaceous plant?

A

A non-woody plant.

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16
Q

True or False: the cells of ground tissue are tightly packed to allow gases to diffuse easily around the cells.

A

False; they are loosely packed.

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17
Q

What is the role of vascular tissue?

A

Transport of materials throughout the plant.

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18
Q

What does xylem tissue do?

A

It moves water and dissolved minerals from the roots up the stem to the leaves for photosynthesis

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19
Q

Explain how xylem vessels are formed.

A

Cells fuse together and end walls become perforated. The cytoplasm then breaks down and cells die, leaving the non-living cell walls attached like a long straw.

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20
Q

What does phloem tissue do? What can the substance it transports be converted into?

A

It transports the products of photosynthesis (dissolves sugars) from the leaves to the rest of the plant. It can be converted into cellulose or stored as starch in the roots/leaves.

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21
Q

What is phloem formed from?

A

Sieve tube cells.

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22
Q

Which is larger: xylem or phloem?

A

Xylem

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23
Q

What are sieve tube cells?

A
  • Remain alive but lose their nuclei
  • In many plants, they are controlled by companion cells
  • Allow cytoplasm to stream between cells
  • Pushes water and sugars through phloem
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24
Q

Cells no longer apart of the ___________ show the characteristics of only certain parts of their genetic code. They become _________________.

A

Meristems; specialized

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25
Q

What are root hairs responsible for?

A

They increase the surface area of the root to maximize the rate of water absorption into the plant.

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26
Q

True or false: the epidermis is responsible for creating the cuticle.

A

True

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27
Q

What are guard cells?

A

Specialized cells that swell and contract to allow gas exchange. They regulate stomata size. They are the only cells in the epidermis that contain chloroplasts.

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28
Q

What are stomata?

A

They are tiny pores on the underside of leaves that facilitate gas exchange. Found mainly on the lower epidermis.

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29
Q

Why are stomata found mainly on the lower epidermis?

A

Direct sunlight absorbed in upper epidermis would cause evaporation of water.

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30
Q

Humid areas: ___________ (more/less) stomata.
Dry areas: ___________ (more/less) stomata.

A

More; less

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31
Q

True or false: Cells apart of the xylem do not need to specialize to be able to conduct water.

A

False.

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32
Q

Is the leaf a tissue, organ, or system?

A

An organ.

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33
Q

The leaf’s main role is to?

A

Carry out photosynthesis.

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34
Q

What special organelle is responsible for photosynthesis? Where are they found?

A

The chloroplasts; they are found in the ground tissue of leaves and sometimes the stem.

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35
Q

What is the word equation for photosynthesis?

A

water + carbon dioxide —> (with light and chlorophyll) glucose + oxygen

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36
Q

Chloroplasts contain the green pigment called?

A

Chlorophyll

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37
Q

What does chlorophyll do? Where is it found?

A
  • Reflects + transmits green light
  • absorbs light energy
  • stores it as chemical energy in glucose
  • found in the thylakoids of the chloroplast (stacks of these are grana)
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38
Q

What are stacks of thylakoids called?

A

Grana

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39
Q

Does photosynthesis occur day and night?

A

NO; it needs light to function so it only works in the day.

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40
Q

What is cellular respiration used for?

A

It’s the process by which animals and plants convert the stored energy in their food (glucose) to usable energy.

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41
Q

Cellular respiration begins in the _____________ but ends in the _____________.

A

Cytoplasm; mitochondria

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42
Q

The movement of chloroplasts within cells has given indirect evidence of?

A

Cytoplasmic streaming

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43
Q

What is the word equation for cellular respiration?

A

glucose + oxygen —> carbon dioxide + water + energy

44
Q

In the balanced equations for photosynthesis/cellular respiration, 3/4 compounds are balanced by the number 6. Which one is not?

A

Glucose (C6H12O6)

45
Q

Does cellular respiration occur day and night?

A

Yes; during the day it is less evident in plants but it continues when it’s dark. For animals, breathing is a necessity at all times so it occurs at all times.

46
Q

True or false: the rate of photosynthesis increases as more carbon dioxide or light is available.

A

True

47
Q

Why can’t air enter cells by passive diffusion?

A

It can. but would take a long time to get the needed volume of air into the plant that way, especially with the cuticle covering most of the plant’s surface.

48
Q

What is an apical meristem?

A

They are specialized zones of growth found at the tips of plants. They are responsible for the extension of shoots and roots.

49
Q

How does a stoma open?

A

Light striking a leaf makes the guard cells accumulate potassium ions by active transport. The number of particles present in the guard cells increases, water enters by osmosis and the swell up due to turgor pressure. The cell under pressure bulges outward and is drawn into a crescent shape and the stoma opens.

50
Q

Explain the process of transpiration.

A

The process of water vapour leaving the leaf through the stomata (plant would be dehydrated with out the control system operated by guard cells).

51
Q

What happens to stomata if there is a short supply of carbon dioxide? What about if there’s more carbon dioxide?

A

Less CO2: Stomata will be open to the maximum.
Normal level: stomata will be less stressed.

52
Q

What are specialized ground tissue called?

A

Mesophyll

53
Q

What are palisade tissue cells responsible for?

A

They are found just below the upper epidermis. They are responsible for photosynthesis and there are many chloroplasts in this layer of tissue.

54
Q

What does the spongy mesophyll tissue do and where are they found?

A

They are under the palisade tissue and above the lower epidermis. They are responsible for gas exchange by diffusion throughout the leaf. It moves oxygen towards stomata and carbon dioxide toward the palisade cells.

55
Q

Name two environmental stresses that would cause the stomata to close because of excess evaporation of water.

A

Dryness and heat.

56
Q

How goes gas exchange occur?

A

diffusion

57
Q

Why are palisade tissues tightly packed?

A

To increase the number of cells exposed to sun rays so the sugars produced in them can be transported across the cell membrane.

58
Q

Why is spongy mesophyll tissue loosely packed?

A

Loosely organized because space allows gas to diffuse easily (its primary function is gas exchange).

59
Q

What is an advantage of having the palisade tissue directly below the upper epidermis?

A

It will be closer/have more access to sunlight, which is needs for photosynthesis.

60
Q

Why do greenhouse plants often struggle to survive when placed in a natural environment?

A

They are used to higher temperatures and more rapid chemical reactions (due to temp.) They are also used to controlled humidity.

61
Q

What are lenticels and their function?

A

They are pores along woody stems and mature roots.
- Provide a pathway for gas exchange
- Provide an opening for transpiration

62
Q

How are lenticels and stomata different and similar?

A

Lenticels operate in a similar way (allow gas exchange) but don’t have a control mechanism like the guard cells to moderate gas exchange.

63
Q

What are the ribs containing the the vascular tissue of the leaf called?

A

Leaf veins.

64
Q

What four processes move materials in plants?

A
  • Osmosis
  • Diffusion
  • Active transport
  • Transpiration
65
Q

Where in a plant can sugar be stored?

A

Sugar can be stored in roots, stems, and on leaves.

66
Q

What is cohesion?

A

The attraction of water molecules to other water molecules.

67
Q

How is water polar?

A

A molecules has a slightly positive end and a slightly negative end. These ends are attracted to another and other substances.

68
Q

How does water inch up capillary tubes?

A

Partly due to cohesion and also become the particles adhere to the tubing (sides) (adhesion)

69
Q

What is adhesion? Give an example.

A

The attraction of water molecules to molecules of other substances. Eg. water adheres to the xylem walls.

70
Q

What are cohesion and adhesion used for?

A

It’s used for water to enter roots and move around the plant.

71
Q

What brings water up from the roots to the stem?

A

Root pressure

72
Q

What is root pressure? Explain it.

A

The water in the roots builds up pressure and this brings water up to the stem. Through osmosis, water is drawn into the cells, creating positive pressure that forces fluid up the xylem. Water is forced from a higher pressure in the roots to the lower pressure in the leaves.

73
Q

During root pressure, does the root become hypo or hypertonic to its surroundings? Explain.

A

The root become hypertonic. Dissolved minerals are present in the cells of the root as a result of active transport, producing a higher solute concentration inside the cell.

74
Q

When does root pressure occur? Where is it created?

A

At night when the rate of transpiration is low, but root cells are still accumulating minerals. It is created in the xylem.

75
Q

True or false: root pressure can sometimes push water up to a maximum of 100m.

A

True

76
Q

True or false: substances like gases, minerals, and sugars can be transported in plants in their original composition.

A

False; they must be dissolved in a film of water.

77
Q

The evaporation of water through the stomata and lenticels through the process of transpiration creates…?

A

A transpiration pull/tension

78
Q

Explain transpiration pull.

A
  • Draws water from the stem to the leaf
  • As water molecules evaporate, they pull on on the adjacent water molecules
  • With cohesion and adhesion, this pull is enough to draw water from the xylem to the ground tissue
79
Q

What happens to the rate of transpiration when the temperature is high?

A

The rate of transpiration and evaporation will increase.

80
Q

What does the leftover water from transpiration pull used for?

A

The rest of the water in the leaf is used to manufacture sugars during photosynthesis.

81
Q

What is plasmolysis? What tonicity corresponds to the solution?

A

Plasmolysis occurs when the cell membrane and vacuole is not pushing against the cell wall and the leaf wilts. The higher solute concentration on the outside of the cell (hypertonic solution) causes water to pass by osmosis from the cell into the surroundings. The water leaves the cell.

82
Q

Explain turgor pressure/turgidity. What tonicity corresponds to the solution?

A

The opposite of plasmolysis (swelling rather than wilting). Water enters the cell and the vacuole swells. It occurs when the solution is hypotonic.

83
Q

Why his turgor pressure important?

A

The pressure in all of the cells combines to hold the green parts of the plant up to the sunlight. It allows a plant to hold itself up.

84
Q

What is the source?

A

Sugar produced in leaves.

85
Q

What is the sink?

A

Sugar must move in the plant to where it’ll be used.

86
Q

What is pressure-flow theory?

A
  • Movement of materials in and out of the phloem
  • has holes called sieve tubes that sugar can enter through
87
Q

If the cell is flaccid, what tonicity is the solution?

A

Isotonic

88
Q

What is stimuli?

A

A change in the environment that causes a reaction by the organism.

89
Q

What is a tropism?

A

The movement of the plant in response to the stimulus. They are important control systems.

90
Q

What is phototropism?

A

Plants growing away/toward light as a response to the stimulus of light.

91
Q

What is positive phototropism?

A

The plants grow towards light (eg. stems and shoot system)

92
Q

What is negative phototropism?

A

The plants grow away from the light (eg. roots and shoot system)

93
Q

What is gravitropism?

A

Plants responding to Earth’s gravitational force through growth movement.

94
Q

What is positive gravitropism?

A

Plants growing toward gravitational force (eg. roots)

95
Q

What is negative gravitropism?

A

Plants growing against gravitational force (eg. stems)

96
Q

What did Charles Darwin and his son conclude through their experiment? Briefly explain the experiment.

A

Conclusion: the tip of the stem is responsible for light detection, but not where the response is carried out.
- Seedlings with the tips covered did not respond to light
- plants with everything but the tip buried still responded to light

97
Q

What did Peter Boysen-Jensen conclude through his experiment? Briefly explain the experiment.

A
  • The thing responsible for communicating to the area of elongation could diffuse through the gelatin but not the mica
  • Growth response as a result of a chemical moving from the tip to the area of elongation
  • He covered grass seedling stumps with gelatin (phototropism continued) and then with mica (did not continue)
98
Q

What is the area of elongation?

A

The shaded side of the stem in which the cells elongate.

99
Q

What conclusion did F.W. Went come to?

A

He isolated the substance that Boysen-Jensen mentioned.
It’s a chemical substance called auxin, which is a hormone (it’s manufactured in one area, transported to another, where, in low concentrations it can initiate a physiological response–in this case, cell elongation)

100
Q

Scientists believe that if a plant is tipped, the _________ __________ shift and settle in a new location (why plants can differentiate between up and down)

A

Starch grains

101
Q

Name four other tropic responses in plants.

A
  • touch
  • temperature
  • chemicals
  • water
102
Q

True or false: there are plants who need 12+ hours of darkness to flower, 12+ hours of light to flower, or no particular amount of light/dark.

A

True

103
Q

Some scientists believe that __________ __________ is affecting the blooming of plant species.

A

Climate change

104
Q

In the fall, what direction does phloem matter flow?

A

Down

105
Q

Name three examples of a sink.

A

A meristem, a tuber, or a root

106
Q

Are stomata open or closed when light is present? Why?

A

Open; they take in potassium ions from surrounding cells.

107
Q

Are stomata open or closed when in darkness?

A

Closed