T2 plant tissues, organs and systems

Question 1

how is epidermal tissue adapted for their function

Answer 1

epidermal tissue covers the entire plant

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

contain lots of chloroplasts which allows photosynthesis to progress at a rapid rate

Question 3

how is spongy mesophyll tissue adapted for its function

Answer 3

has lots of air spaces which allow gases to diffuse in and out

Question 4

how is xylem adapted for its function

Answer 4

made up of dead cells which form a continuous hollow tube - allows the movement of water and mineral ions from the roots to the leaves

strengthened by lignin - makes the vessel strong and waterproof

has bordered pits - allow minerals to be transported to specific places

Question 5

how is the phloem adapted for its function

Answer 5

made up of elongated living cells

cells have sieve plates that connect them together - cell sap can move through plates into other cells

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 tissues does the leaf organ contain

Answer 7

epidermis
palisade mesophyll
spongy mesophyll
xylem
phloem
guard cells

Question 8

function of guard cells

Answer 8

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

Question 9

how are stomata adapted for their function

Answer 9

allow the control of gaseous exchange and water loss from the leaf

more stomata on the base of the leaf - minimises water loss as this side is cooler and shaded

have guard cells which control their opening and closing

Question 10

how are root hair cells adapted for their function

Answer 10

allow the uptake of water and mineral ions from the soil

large SA - maximises rate of absorption

contain lots of mitochondria - release energy for active transport of mineral ions

Question 11

what is translocation

Answer 11

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

Question 12

what is transpiration

Answer 12

evaporation of water vapour from the surface of a plant

Question 13

how does transpiration work

Answer 13

water evaporates from the leaf surface via stomata

water molecules cohere together - more water is pulled up the xylem in an unbroken column

more water is taken up from the soil - creating a continuous transpiration stream

Question 14

how does temperature affect the rate of transpiration

Answer 14

increasing temp, increases rate

higher rate of evaporation and diffusion of water - therefore rate of transpiration is increased

Question 15

how does humidity affect the rate of transpiration

Answer 15

increasing decreases

high relative humidity will reduce the water vapour concentration gradient.

Rate of evaporation will decrease, and so will the rate of transpiration

Question 16

how does wind speed affect the rate of transpiration

Answer 16

increasing increases

increased air movement lowers water vapour conc outside of the leaf.

this increases the water vapour conc gradient, thereby increasing the rate of evaporation and transpiration

Question 17

how does light intensity affect the rate of transpiration

Answer 17

increasing increases

rate of photosynthesis increases, so more stomata open

this allows the rate of evaporation to increase, increasing the rate