Bio Chapter 8 (Transport in Plants)

Question 1

What materials do plants exchange and transport

Answer 1

1. carvin dioxide
2. Oxygen
3. Water
4. Glucose
5. Mineral ions

Question 2

Which cells in plants transport nutrients

Answer 2

Xylem and phloem

Question 3

Function of xylem

Answer 3

Transports water and mineral up the roots and into the leaves

Question 4

function of phloem

Answer 4

Transports sugars produced by the leaves up and down the stem

Question 5

Structure of xylem

Answer 5

1. End walls removes- cells join to form long tubes called xylem vessels
2. Walls are thickened with lignin to prevent the cells from collapsing inwards
3. Cells are dead- No cytoplasm or organelles

Question 6

Why are the end walls in Xylems removed?

Answer 6

In order to have a rapid water and mineral transportation

Question 7

The diameter of xylem vessels

Answer 7

Around 15 to 200 micro meter

Question 8

Structure of phloem tissues

Answer 8

1. They contain sieve tubes and companion cells.
2. Thin cytoplasm- cells must remain alive or sugar transportation stops
3. No nucleus or organelles so sugar flow is not impeded
4. Companion cell does not transport sugars but carries out some live process in the sieve tube

Question 9

What are arranged in vascular bundles

Answer 9

Xylems, Phloems and the cambium tissue (responsible for secondary growth of stem and root)

Question 10

Function of cambium tissue in plants

Answer 10

Responsible for secondary growth of stem and root

Question 11

How are Vascular bundles arranged in the stem

Answer 11

Vascular bundles are arranged in a ring with soft cortex in the centre

Question 12

Vascular bundles in roots

Answer 12

Vascular bundles form a strong central rod with the epidermis protecting it from fungi.

Question 13

How do plants get mineral ions

Answer 13

From the soil

Question 14

How guard cells open stomata’s

Answer 14

When there is little carbon dioxide, the stomata become turgid and open the stomata.

Question 15

How do cells close stomata’s

Answer 15

When there is a high concentration of carbon dioxide, it causes the cells to lose water and hence close the stomata to prevent more water loss.

Question 16

Where are stomata placed and why

Answer 16

They are placed at the bottom of the leaves, in the shade to prevent excess water evaporation.

Question 17

Define transpiration

Answer 17

The loss of water from plants by evaporation

Question 18

What is the Dilemma for plants

Answer 18

1. When stomata are open, there is more gas exchange but more water evaporation
2. when they are closed, they loose less water but also have less gas exchange

Question 19

What does the rate of transpiration depend on

Answer 19

temperature, Humidity, Air movement and light

Question 20

what can be used to measure transpiration

Answer 20

Potometer

Question 21

Describe the cohesion-Tension theory

Answer 21

Water in the xylem vessels is pulled (the Tension) towards the leaves because of the transpiration (transpiration pull)

Question 22

Define root pressure theory

Answer 22

In the roots, the endodermis cells actively transport mineral ions into the xylem, reducing its water potential, water is drawn in, hydrostatic pressure increases, water is pushed upwards

Question 23

Define the capillarity theory

Answer 23

Water molecules climb up in narrow tubes because they are attracted to polar molecules of the tube. The narrower the tube the higher the water goes

Question 24

Define translocation

Answer 24

Phloem tissues transporting substances made in the leaves to all other parts of the plant.

Question 25

What does phloem transport

Answer 25

1. Sucrose
2. Amino acids
3. Hormones
4. Minerals

Question 26

When does transpiration occur

Answer 26

During Day time

Question 27

When does Translocation occur

Answer 27

During night time