Topic 2- plant tissues, organs and systems

Question 1

How is epidermal tissue adapted fr 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 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

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

Made up 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-allows 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 tubes cells have a 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

What is the function of guard cells

Answer 8

Guard cells 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

Stomata 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

Root hair cells allow uptake of water and mineral ions from the soil
-large surface area- maximises rate of absorption
-contain lots of mitochondria- release energy for active transport of mineral ions

Question 11

What is translocation?

Answer 11

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

Question 12

What is transpiration?

Answer 12

Transpiration is the 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 the 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 continuous transpiration stream

Question 14

How does temperature affect the rate of transpiration

Answer 14

increasing the temperature increases the rate of transpiration
-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 relative humidity will 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 16

How does wind speed affect the rate of transpiration?

Answer 16

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

Question 17

How does light intensity affect the rate of transpiration

Answer 17

increasing the light intensity increases 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