Chapter #8 - Transport In Plants

Question 1

What is the defenition of xylem?

Answer 1

A plant tissue made of dead empty cells, joined end to end with no walls between them (in the shape of a tube).

Question 2

Wheare are xylem cell located?

Answer 2

They run from roots through the stem and into every leaf.

Question 3

What are the purposes of xylem?

Answer 3

• Transport water and mineral ions for photosynthesis)
• Helps support the plants

Question 4

How do xylem help support plants?

Answer 4

• They have ligin
• Because of the preassure the water provides aginst the xylem walls which keeps the stem from wilting (blown up balloon)

Question 5

Draw a diagram of the transverse section of the root.

Answer 5

Question 6

Draw a diagram of the transverse section of a stem.

Answer 6

Question 7

What is the defenition of vascular bundles?

Answer 7

Colections of xylem tubes and phloem vessels running side by side, which form the veins of a leaf.

Question 8

What are the cell walls of xylem made of?

Answer 8

The cells walls of xylem are made of cellulose AND lignin

Question 9

What does lignin help the plant with?

Answer 9

• Lignin keeps vessels open to allow constant flow.
• In leaves, lignin helps keep leaves flat and open to absorb sunlight.

Question 10

What is the defenition of lignin?

Answer 10

A hard, strong, watreproof substance that forms the walls of xylem vessels.

Question 11

What are the two thing xylem must be to work?

Answer 11

• Narrow enough to keep column of water unbroken (no bubbles).
• Wide enough to allow plenty of water to flow through.

Question 12

What is the defenition of phloem?

Answer 12

A plant tissue made up of cells joined end to end; it transports substances made by the plant, such as sucrose and amino acids.

Question 13

What does the phloem do?

Answer 13

It transports substances made by the plant like sucrose and amino acids “food”,

Question 14

How do the substances go through the cell walls of the phloem?

Answer 14

Diffusion or active transport

Question 15

What are the three main parts of the root?

Answer 15

• The root cap
• The epidermis
• The root hair cells

Question 16

What do root caps do?

Answer 16

Protect the root as it grows (no root hair cells at this part of the root).

Question 17

What is are epidermis cells and where are they located?

Answer 17

They are cells which cover the whole root (except the root cap). The root hair cells are formed from some of the epidermis cells.

Question 18

What are root hsir cells made of?

Answer 18

The root hair cells are formed from some of the epidermis cells.

Question 19

What is the function of root hair cells?

Answer 19

Absorb water and mineral ions from soil.

Question 20

How does water move into root hair cells?

Answer 20

Water moves through osmosis. The cytoplasm and root hair cell is concentrated to adapt for this, so the water moves down the gradient.

Question 21

What are the parts of the root?

Answer 21

• Root cap
• The epidermis (covering)
• Root hair cells (no epidermis)

Question 22

What does the root cap do?

Answer 22

It protects the root as it grows and has no root hair cells.

Question 23

What is the function of root hair cells?

Answer 23

Amsorb water and mineral ions from soil.

Question 24

How does water get into the plant?

Answer 24

• Water moves through osmosis. The cytoplasm and sap inside the root hair cells concentrated to adapt for this, so water moves down the gradient.

Question 25

What are the adaptions of root hair cells.

Answer 25

• By having a concentrated cytoplasm.
• Large surface area
• Do not live very long (get damaged and replaced quickley)

Question 26

What is the process by which water passes through the plant.

Answer 26

1. Water enters root hair cells by osmosis.
2. Water passes across root, from cell to cell, by osmosis, it also seeps through cells.
3. Water is drawn up the xylem vessels, because transpiration is constantly moving water from the top of them. (reducing the preassure)

Question 27

What is transpiration?

Answer 27

The loss of water vapour from leaves.

Question 28

What causes water to constantley move up th xylem?

Answer 28

By transpiration pull, which is caused by the loss of water vapour through transpiration, which cause there to be a lower preassure at the top of the system.

Question 29

What is a potometer?

Answer 29

An instrument for measuring the volume of water a plant loses through tarnspiration.

Question 30

How does a potometer look (in general)?

Answer 30

Question 31

What conditions affect transpiration?

Answer 31

• Temperature
• Wind
• Humidity

Question 32

How does a higer temp. affect the rateof transperation?

Answer 32

Greater kinetic energy of particles which makes the water evaporate more quickly.

Question 33

How does a stronger wind affects transpiration?

Answer 33

water vapour is quickly moved away from leaf. This leaves a constant diffusion gradient, because there is less outside the leaf than ina the air spaces inside the leaf.

Question 34

How does increasing the humidity affect the rate of transpiration?

Answer 34

It decreases transpiration becausethere is not much of a diffusion gradient for the water between the air spaces inside the leaf and the wet air outside (The concentration of water molecules between the air outside and the air spaces in the leaf are closer together that they would be in a dry enviornment). The gradient of water vapourcould even be
higher outside the leaf (inversly proportional). The leaf might even have water going in.

Question 35

What happens if the rate of transpiration id higher than than the volum of water it can take in?

Answer 35

The plant will wilt.

Question 36

What is translocation?

Answer 36

The movement of sucrose and amino acids in the phloem from sources and sinks.

Question 37

What is a source?

Answer 37

Part of plant that releases sucrose/amino acids to the rest of the plant, usually the leaves.

Question 38

What is a sink?

Answer 38

The part of the plant that uses or stores sucrose/amino acids.