Paper 1: Topic 2 Organisation - Plant tissues, organs and systems (IV form) Flashcards Preview

Mrs P's GCSE Biology > Paper 1: Topic 2 Organisation - Plant tissues, organs and systems (IV form) > Flashcards

Flashcards in Paper 1: Topic 2 Organisation - Plant tissues, organs and systems (IV form) Deck (54)
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1

Why do plants need a transport system?

They are too large for materials to simply diffuse in and out and meet the demand of the plant

2

Give three examples of a plant organ

  1. Leaf
  2. Stem
  3. Root

3

Where is sucrose transported to?

The sinks e.g. roots

This is where the sucrose is converted to starch or other molecules for storage

4

What causes the stomata to open?

The guard cells absorb water

By osmosis

This causes the guard cells to become turgid

This causes the stomata to open and widen

5

What is the role/function of the palisade mesophyll layer in the leaf?

These cells are specialised to contain many chloroplasts

Hence they carry out photosynthesis

6

What is the role/function of the stoma in the leaf?

  1. Stomata can widen and narrow to control how much gas exchange occurs i.e. intake of carbon dioxide and loss of oxygen 
  2. and to control how much water vapour is lost from the leaf during transpiration

Summary: Control gas exchange and water vapour loss

7

Which direction does xylem transport materials?

ONLY up the plant i.e. one way movement

From the roots to the stem and the leaves

8

What is the role/function of the air spaces in the leaf?

Site for gas exchange:

a) oxygen diffuses out of the mesophyll cells into the air spaces

b) carbon dioxide diffuses from the air spaces into the mesophyll cells

9

Which process of transport uses phloem tissue?

Translocation

10

How does transpiration take place?

 

Hint: there are 3 key stages

1. Water vapour evaporates out of the leaf through the stomata

2. This generates a transpiration pull - which pulls water up through the plant in the xylem

3. The water that is lost from the base of the plant is then replaced as root hair cells absorb more water from the soil by osmosis

11

What is the role/function of the guard cell in the leaf?

Specialised cells that can take in water or lose water by osmosis

Depending on how much water they contain they can open and close pores (stomata)

Control gas exchange and water vapour loss

12

What assumption is made when using a potometer to measure the rate of transpiration?

That the rate of water vapour loss from the plant is the SAME as the rate of the water uptake by the plant

13

What causes transpiration?

Transpiration is a side effect of photosynthesis

When the plant is photosynthesising it opens its stomata to allow carbon dioxide to diffuse in

This then allows the water vapour in the air spaces of the leaf to diffuse out causing the transpiration stream

14

What materials does xylem transport?

Water and dissolved mineral ions

15

How does the water vapour exit the leaf?

By diffusion

 

Remember water vapour is a gas!

16

Describe and explain how root hair cells adapted for the uptake of mineral ions

Many mitochondria are present in each root hair cell

The mitochondria produce ATP

The ATP can then be used/broken down to release energy

Thsi energy is used for the active transport of mineral ions into the cell

17

What conditions cause the rate of transpiration to INCREASE?

Higher temperature

Faster wind speed

Lower air humidity (dier air)

18

What materials does phloem transport?

Sucrose (a specialised carbohydrate made from glucose)

19

Where is the xylem and phloem located in plants?

In vascular bundles

20

What is the role/function of the phloem in the leaf?

Specialised cells forming a tissue responsible for transporting dissolved sugars up and down the plant

Located in the vascular bundles (veins)

21

What causes the stomata to close?

The guard cells lose water

By osmosis

This causes the guard cells to become plasmolysed

This causes the stomata to narrow and close

22

What is the main role of stomata?

To allow gas exchange between the leaf the atmosphere

23

How is the rate of transpiration usually investigated in a laboratory?

Using a potometer

24

Give 4 key features of xylem

  1. The cells are dead
  2. The cells are hollow (no cytoplasm)
  3. The cells have lignin around them (to make them waterproof and strengthen the cell)
  4. The cells are joined end to end to form continuous hollow columns

25

Where is sucrose transported from?

The source i.e. the leaves (where the sucrose is made)

26

What is the role/function of the upper epidermis in the leaf?

Specialised cells which are thin and flat It is transparent to enable light to pass through them easily to reach the palisade mesophyll tissue

27

What 3 gases diffuse in and out of the leaf? For each gas state which direction it diffuses.

Oxygen - diffuses out of the leaf

Carbon dioxide - diffuses in to the leaf

Water VAPOUR - diffuses out of the leaf

28

Why is it incorrect to say a potometer measures the rate of transpiration?

The potometer doesn't actually measure the amount of water vapour that is lost from the plant

Instead it actually measure the volume of water taken up by the plant

29

How do water molecules move through the xylem during transpiration?

As a continuous column of water molecules

30

What is the role/function of the chloroplast in the leaf?

Site where photosynthesis occurs

Chloroplast contain a special pigment called chlorophyll that is essential for photosynthesis

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