2 - plants

Question 1

phloem tubes

Answer 1

• translocation - transport foods
• pores in walls to allow cell sap to flow through
• transport in both directions UP AND DOWN

Question 1

xylem tubes

Answer 1

• transpiration stream - transports water
• only UPWARDS - roots to the stems of leaves
• dead cells and strengthened with lignin

Question 2

epidermal tissue

Answer 2

• covers whole plant
• covered in waxy cuticle to reduce water lost by evaporation

Question 3

palisade mesophyll tissue

Answer 3

• where photosynthesis happens
• lots of chloroplasts
• top part of leaf to get most light

Question 4

spongy mesophyll tissue

Answer 4

air spaces to allow gas to diffuse

Question 5

meristem tissue

Answer 5

in the growing tips or roots and shoots and can differentiate into different types of plant cells

Question 6

upper epidermis

Answer 6

transparent so light can get through to palisade layer

Question 7

lower epidermis

Answer 7

loads of stomata which let co2 diffuse into leaf and controlled by guard cella

Question 8

4 factors affecting the transpiration rate

Answer 8

1. LIGHT intensity - brighter the greater the transpiration rate
   stomata close in dark bc photosynthesis cant happen - when closed little water can escape
2. TEMP - warmer the faster transpiration rate
3. AIR FLOW - better airflow the better the. transpiration rate
4. HUMIDITY - the drier the air the faster the transpiration rate

Question 9

guard cells

Answer 9

• kidney shape to open and close the stomata
• when the leaf has lots of water it fills the guard cells and they go plump
• this makes stomata open so gases can exchange for photosynthesis
• when the leaf is short of water the guard cells lose water and become flaccid and the stomata close to stop water from escaping