2.3 - Plant tissues, Organs and Systems

Question 1

How is palisade mesophyll tissue adapted for its function?

Answer 1

Tissue contains lots of chloroplasts which allows photosynthesis to progress at a rapid rate.

Question 2

How is epidermal tissue adapted for its function?

Answer 2

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

Question 3

How is spongy mesophyll tissues adapted for its function?

Answer 3

Tissue has lots of space 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 of dead cells which form continuous hollow tube - allows the movement of water and minerals ions from the root of the leaves.
• Strengthened by the lignin - makes the vessel strong and waterproof
• Has bordered pits - allow minerals to be transported to specific places

Question 5

How is 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 tubes
• 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

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

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

Allow the up take of water and minerals rate if absorption

Contains lots of mitochondria - release energy for active transport of mineral ions.

Question 11

What is translocation?

Answer 11

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

Question 12

What is transpiration?

Answer 12

Is the evaporation of water vapour form the surface of a plant.

Question 13

What 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 a continuous transpirations stream

Question 14

How does temperature affect the rate of transpiration?

Answer 14

Increasing the temperature issues 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 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 in wind speed increase 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

Increase in light increase 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.