Chapter 11 (Transport in Plant) Flashcards

1
Q

What is osmosis?

A

Movement of water from high water potential to low water potential across partially permeable membrane.

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2
Q

When does osmosis happen?

A

Osmosis happens when partially permeable membrane separates two solutions.

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3
Q

What is the name of an artificial partially permeable membrane?

A

Visking Tubing which has microscopic holes

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4
Q

Where is the visking tubing used?

A

In kidney dialysis machines

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5
Q

What is the relation between water concentration and water potential?

A

Directly proportional

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6
Q

Why water potential is low in sucrose solution?

A

Because water molecules are attracted to the sugar molecules.

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7
Q

What is water potential?

A

How free the water molecules are able to move.

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8
Q

Water in —– can move freely.

A

Pure water

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9
Q

The more concentrated solution, ——- the water potential.

A

Lower

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10
Q

Which keeps the shape of the cell?

A

Cell wall

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11
Q

What happens when cell absorb water?

A

The cell swells up, and becomes turgid.

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12
Q

What happens when the cell lost water?

A

The cell loosens up, and becomes flaccid.

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13
Q

What happens when a cell lost excessive water?

A

The membrane and cytoplasm split away from the cell wall, and become plasmolyzed.

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14
Q

What does the pressure inside the cell provide?

A

It supports the non-woody parts of a plant, such as leaves, and hold stems upright. so leaves can carry out photosynthesis properly.

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15
Q

Why is wilting protective action?

A

It cuts down water loss by reducing the exposed surface area of the leaves and closing the stoma.

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16
Q

Which increases the SA for root?

A

Root hairs

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17
Q

How does most water pass out of the leaves?

A

As water vapors

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18
Q

What is transpiration?

A

Loss of water vapor from the leaves.

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19
Q

What is the transpiration stream?

A

The flow of water from roots to leaves through xylem vessels in the plant.

20
Q

What are the functions of the transpiration stream?

A
  • Supplies water to the leaves cell for photosynthesis
  • Carries mineral ions dissolved in the water
  • Provide water to keep the plant cells turgid
  • Allows evaporation from the leaf surface, which cools the leaf
21
Q

Why do animal cells have low water potential?

A

Animals’ cells do not have strong walls to resist the changes in internal pressure caused by large movements of water.

22
Q

What does xylem transport?

A

Water and mineral ions

23
Q

What does xylem contain?

A

Xylem contains dead cells arranged end-to-end, forming a continuous vessels.

24
Q

What happen to vessels when they become matured?

A

They contain no cytoplasm, instead they form a lumen which the water passes.

25
Q

What does xylem contain that prevent the water leakage to sides?

A

Lignin

26
Q

What is lignin made by?

A

Cytoplasm

27
Q

What does lignification do?

A
  • It make xylem strong enabling them to carry water without collapsing
  • It make xylem impermeable to water
28
Q

What does phloem carry?

A

Sugar and amino acids

29
Q

How is end of each phloem formed?

A

Sieve plate

30
Q

What does sieve tube transport?

A

It transport the products of photosynthesis from the leaves to other parts of the plant.

31
Q

Contents of the phloem can travels up or down the plant.

A

True

32
Q

Where is the nucleus that control the phloem sieve tubes?

A

In the companion cells

33
Q

Where is xylem and phloem in young stem?

A

At vascular bundles arranged in a circle around the outer part of the stem.

34
Q

Where is vascular tissue in root?

A

In the central core

35
Q

Why stoma are mainly located in lower leaf surface?

A

To reduce water loss

  • Upper leaf surface is exposed to direct sunlight producing high rate of evaporation
  • There is less air movement on the underside of leaves
36
Q

What happen to stoma in light and dark?

A
  • In the light, water enters the guard cells by osmosis and become turgid, bending outwards and opening up the stoma.
  • In the dark, water leaves guard cells and become flaccid closing up the stoma
37
Q

Why stoma absorb water in the light?

A

Because guard cells use energy of accumulate solutes in their vacuoles.

38
Q

What are four main factors that affect the rate of transpiration?

A
  • Light intensity
  • Temperature
  • Humidity
  • Wind speed
39
Q

Why more light intensity increase the transpiration rate?

A

Because of the opening of the stomata

40
Q

Why does more temperature increase the transpiration rate?

A

Because of the increase rate of evaporation of water

41
Q

Why less humidity increase the transpiration rate?

A

Because it reduce the diffusion gradient between the air spaces in the leaf and the external air

42
Q

Why more wind speed increase the transpiration rate?

A

Because the moving air removes any water vapor which might remain near the stomata.

43
Q

What is used to measure the rate of transpiration?

A

Potometer

44
Q

What are two types of photometer?

A

Weight and volume

45
Q

How does a weight potometer measure the transpiration rate?

A

It measures the rate of mass loss from a potted plant or leafy shoot, over a period of time.

46
Q

How does the volume potometer measure the transpiration rate?

A

It is used to find the transpiration rate by a leafy shoot, by magnifying this uptake in a capillary tube.

47
Q

Mention the steps to measure the transpiration using simple potometer?

A
  • Cut the plant under water
  • Seal it on potometer
  • Introduce the bubble in capillary tube
  • Measure the distance move by bubble
  • Measure the time it take to move using stop watch
  • speed = distance / time
  • repeat the procedure