B2 - SPECIFICALLY : PLANTS

Question 1

What does the epidermal tissue do?

Answer 1

Covers the whole plant

Question 2

What does the palisade mesophyll tissue do?

Answer 2

Most photosynthesis happens here

Question 3

What does the spongy mesophyll tissue do?

Answer 3

Contains big air spaces to allow gases to diffuse in and out of cells.

Question 4

What do xylem and phloem do?

Answer 4

Transport food and water around the plant.

Question 5

What is the meristem tissue?

Answer 5

Found at the growing tips of roots and shoots and is able to change into lots of different types of plant cells.

Question 6

Epidermal tissues are covered with..

Answer 6

A waxy cuticle which helps to reduce water loss by evaporation.

Question 7

Upper epidermis is…

Answer 7

Transparent so the light can pass through it to the palisade layer

Question 8

Palisade layer has…

Answer 8

Lots of chloroplasts. Near to the top of the leaf so they can get the most light.

Question 9

Xylem and phloem form…

Answer 9

A network of vascular bundles which deliver water and other nutrients and take away glucose produced by photosynthesis.

Question 10

The tissues of leaves are adapted for…

Answer 10

Gas Exchange. Lower epidermis is full of stomata which let CO2 diffuse directly into leaf.

Question 11

Phloem tubes transport…

Answer 11

Food for immediate use or for storage. This process is called TRANSLOCATION.

Question 12

Phloem tubes are made of…

Answer 12

Elongated living cells with small pores in the end walls to allow cell sap to flow through.

Question 13

Xylem tubes transport…

Answer 13

Water and mineral ions from the roots to the stem and leaves.

Question 14

Xylem tubes are made of…

Answer 14

Dead cells joined end to end with no end walls between them and a hole down the middle. Strengthened with a material called lignin.

Question 15

The movement of water from roots through Xylem is called…

Answer 15

The transpiration stream.

Question 16

Transpiration is caused by…

This evaporation creates…

Answer 16

The evaporation and diffusion of water from a plants surface. This evaporation creates a slight shortage of water so more water is drawn up through xylem. Constant transpiration stream of water.

Question 17

Transpiration rate is affected by:

Answer 17

Light intensity - brighter = more stomata close when it’s darker

Temperature - warmer = faster

Air flow - better the air flow the greater. Water vapour is slept away maintaining a low concentration of water in the air outside the leaf.

Humidity - the drier the air around a leaf, the faster transpiration happens.

Question 18

You can estimate the rate of transpiration by…

Answer 18

Measuring the uptake of water by a plant - because you can assume the water update is directly related to water loss by the leaves.

Question 19

How to measure the rate of transpiration?

Answer 19

Set up a photometer and record the starting position of the air bubble - start a stopwatch and record the distance moved by the bubble per unit time.

Question 20

How are guard cells adapted?

Answer 20

They have a kidney shape which opens and closed the stomata.

Thin outer walls and thickened inner walls makes the opening and closing work.

Sensitive to light = close at night to save water without losing photosynthesis.

Question 21

What happens when a plant is short for water?

Or has lots of water?

Answer 21

When plant is short of water, guard cells lose water and become flaccid making stomata close - prevents too much water vapour escaping.

When the plant has lots of water, the guard cells fill with it and go plump and turgid . Makes stomata open so gases can be exchanged.