Unit 2: Organisation - Plant tissues, organs, and organ systems

Question 1

how do specialised plant cells get formed?

Answer 1

they are formed from a process called differentiation

Question 2

draw and label a diagram of a root hair cell

Answer 2

Question 3

what is the function of a root hair cell

Answer 3

1. they help to absorb water by osmosis
2. they absorb mineral ions by active transport and diffusion

Question 4

what are the adaptations of a root hair cell

Answer 4

1. Root hair - increases surface area for osmosis and diffusion of mineral ions
2. Thin cell wall - short diffusion distance
3. Vacuole - contains cell sap which gives cell low water concentration (maintains gradient for osmosis)

Question 5

draw and label a diagram of a xylem cell

Answer 5

Question 6

what is the function of a xylem cell

Answer 6

1. transports water + mineral ions
2. UP the plant, roots to shoots/leaves
3. via the TRANSPIRATION STREAM

Question 7

what are the adaptations of a xylem cell

Answer 7

1. the cells are dead and hollow (empty)
2. cells are elongated
3. cell walls are strengthened by lignin

Question 8

draw and label a diagram of a phloem cell

Answer 8

Question 9

what is the function of a phloem cell

Answer 9

1. transports sugar solution
2. UP and DOWN plant (bidirectional)
3. via TRANSLOCATION

Question 10

what are the adaptations of a xylem cell

Answer 10

1. cells are living (sugars move by active transport)
2. sieve plate (pores) allow sugar solution to move from cell to cell
3. cells are elongated

Question 11

what do epidermal tissues do

Answer 11

they cover the plant

Question 12

what does the palisade mesophyll do

Answer 12

it is the main site of photosynthesis

Question 13

what does the spongy mesophyll do

Answer 13

it has air spaced for diffusion of gases and some photosynthesis

Question 14

what do the xylem and phloem do

Answer 14

they transport substances around the plant

Question 15

where is meristem tissue found

Answer 15

at growing tips of shoots and roots

Question 16

what happens in the meristem tissue

Answer 16

cells divide by mitosis and then differentiate into specialised cells

Question 17

what is the cuticle

Answer 17

a layer of wax (not a tissue)

Question 18

draw and label a diagram of leaf

Answer 18

Question 19

give an example of a plant organ

Answer 19

vascular system

Question 20

what is the vascular system made up of

Answer 20

phloem tissue and xylem tissue

Question 21

definition of transpiration

Answer 21

the loss of water vapour from the surface of plant leaves

Question 22

how does transpiration occur

Answer 22

water vapour is mainly lost via open stomata
some get lost via cuticle

Question 23

draw a diagram of an open and closed guard cell

Answer 23

Question 24

when is the stoma opened

Answer 24

in daylight

Question 25

when is the stoma closed

Answer 25

at night (no transpiration occurs)

Question 26

what is a bubble potometer used for

Answer 26

to measure the rate of transpiration

Question 27

why is the capillary of the potometer narrow

Answer 27

1. easier to see bubble move
2. bubble will move further

Question 28

formula for rate of transpiration

Answer 28

cross sectional area of capillary tube x distance travelled by the bubble = volume of water lost.

Question 29

what factors affect the rate of transpiration

Answer 29

temperature
humidity
air movement
light intensity

Question 30

what is the assumption for potometer

Answer 30

the water uptake = water lost in transpiration

Question 31

as temp increases, the rate of transpiration _____

Answer 31

increases

Question 32

as humidity increases, the rate of transpiration _________

Answer 32

decreases

Question 33

as air movement increases, the rate of transpiration __________

Answer 33

increases

Question 34

as light intensity increases, the rate of transpiration __________

Answer 34

increases

Question 35

which part of the leaf usually has the most stomata

Answer 35

on the lower surface the leaf

Question 36

rate of transpiration increases when:

Answer 36

• temp increases
• air movement increases
• light intensity increases
• humidity decreases
• more stomata (stomata density)
• more leaves/ bigger leaves