plant tissues, organs and systems

Question 1

how is epidermal tissue adapted for its function?

Answer 1

epidermal tissue covers the entire plant. it has a waxy cuticle which helps reduce water loss from the leaf surface

Question 2

how is palisade mesophyll tissue adapted for its function?

Answer 2

palisade mesophyll tissue contains lost of chloroplasts which allows photosynthesis to progress at a rapid rate

Question 3

how is spongy mesophyll tissue adapted for its function?

Answer 3

spongy mesophyll tissue has lots of air spaces which allow gases (including oxygen and carbon dioxide) to diffuse in and out

Question 4

how is the xylem adapted for its function?

Answer 4

1. made up of dead cells which forms a continuous hollow tube which allows the movement of water and mineral ions from the roots to the leaves
2. strengthened by lignin which means the vessel strong and waterproof
3. has bordered pits which allows minerals to be transported to specific places

Question 5

how is the phloem adapted for its functions?

Answer 5

1. made up of elongated living cells
2. cells have sieve plates that connect them together - cell sap can move through plates into other cells
3. sieve tube cells have few organelles to allow the efficient transport of substances

Question 6

how is meristem tissue adapted for its function?

Answer 6

made up of stem cells which can differentiate into many different cell types, allowing the plant to grow

Question 7

what 6 tissues does the leaf organ contain?

Answer 7

1. epidermis
2. palisade mesophyll
3. spongy mesophyll
4. xylem
5. phloem
6. guard cells

Question 8

what is the function of guard cells?

Answer 8

control the opening and closing of the stomata, according to the water content of the plant

Question 9

what do stomata allow?

Answer 9

the control of gaseous exchange and water loss from the leaf

Question 10

how are stomata adapted for their function?

Answer 10

1. more stomata on the base of the leaf - minimises water loss as this side is cooler and shades
2. have guard cells which control their opening and closing

Question 11

what do root hair cells allow (in plants?)

Answer 11

allow the uptake of water and mineral ions from the soil

Question 12

how are root hair cells adapted for the function?

Answer 12

1. large surface area - maximises rate of absorption
2. contain lost of mitochondria - release energy for active transport of mineral ions

Question 13

what is translocation?

Answer 13

the movement of dissolved sugars from the leaves to other parts of the plant

Question 14

what is transpiration?

Answer 14

the evaporation of water vapour from the surface of a plant

Question 15

how does transpiration work?

Answer 15

1. water evaporates from the leaf surface via the stomata
2. water molecules cohere together - more water is pulled up the xylem in an unbroken column
3. more water is taken up from the soil - creating a continuous transpiration stream

Question 16

how does temperature affect the rate of transpiration?

Answer 16

increasing the temperature increased the rate of transpiration
- higher rate of evaporation and diffusion of water, therefore rate of transpiration is increased.

Question 17

how does humidity affect the rate of transpiration?

Answer 17

increasing relative humidity decreases the rate of transpiration
- high relative humidity will reduce the water vapour concentration gradient. the rate of evaporation will decrease, and so will the rate of transpiration

Question 18

how does wind speed affect the rate of transpiration?

Answer 18

increasing wind speed/ air movement increases the rate of transpiration
- increased air movement lowers water vapour concentration outside the leaf. this increased the water vapour concentration gradient, thereby increasing the rate of evaporation and transpiration

Question 19

how does light intensity affect the rate of transpiration?

Answer 19

increasing the light intensity increased the rate of transpiration
- the rate of photosynthesis increases, so more stomata open. this allows the rate of evaporation to increase, increasing the rate of transpiration