Plant tissues, organs and organ systems

Question 1

What is the function of the palisade mesophyll and how is it adapted (3 ways)

Answer 1

1) absorbing light to be used for photosynthesis
2)
-packed with many chloroplasts
-column shaped + close together arrangement
-towards upper surface of leaf

Question 2

Why are spongy mesophyll cells covered by a thin layer of water

Answer 2

So that gases dissolve in the water as they move in/out of cell

Question 3

What goes into spongy mesophyll cells, out of spongy mesophyll cells and by what processes

Answer 3

Carbon dioxide diffuses into the cells, oxygen diffuses out of them, both by diffusion

Question 4

How do gases enter a leaf

Answer 4

Through small pores on the base called stomata

Question 5

What is the process of water movement through a plant and evaporation from aerial parts called

Answer 5

Transpiration

Question 6

Why is spongy mesophyll tissue packed loosely

Answer 6

For efficient gas exchange

Question 7

How is transpiration reduced in plants

Answer 7

Closing the stomata

Question 8

What is the function of the xylem

Answer 8

It transports WATER and MINERALS from roots to stem/ leaves of plant

Question 9

What are vessels

Answer 9

Specialised cells that make up the xylem in mature plant/tree

Question 10

Why do vessels lose their end walls

Answer 10

So that the xylem forms a long and continuous tube

Question 11

What is used to strengthen vessels

Answer 11

A chemical called lignin

Question 12

Why isn’t energy required for transport in the xylem

Answer 12

It is a physical process

Question 13

What is the function of the phloem

Answer 13

moves food produced by photosynthesis to where it is needed

Question 14

Give 3 functions carried out by the plant that require food

Answer 14

1) growing parts for immediate usage
2) as storage organs (tubers)
3) developing seeds

Question 15

What is the transport of substances through the phloem called

Answer 15

Translocation

Question 16

Why is transport in the phloem both up and down

Answer 16

The food is needed all throughout the plant

Question 17

What is a sieve plate’s function + adaptations

Answer 17

1) Separate neighbouring sieve cells help with transport throughout phloem
2)
- have no nucleus
- perforated end so cytoplasm connects cells

Question 18

What is a companion cell’s function + adaptations

Answer 18

1) provide energy for translocation
2)
- one or more attached to each sieve tube

Question 19

What is the function of the epidermal tissue and adaptations

Answer 19

1) protects surface of leaf
2)
- transparent —> allows light to pass through
- waxy cuticle —> reduces evaporation from surface

Question 20

Where is meristem tissue found

Answer 20

At the growing tips of shoots and roots

Question 21

What does meristem tissue contain

Answer 21

Stem cells

Question 22

Why are stem cells useful

Answer 22

They can differentiate into different types of plant tissue

Question 23

What is a root hair cell’s function and adaptations

Answer 23

1) the uptake of water and nutrients from the soil
2)
- large surface are to increase uptake
- thin walls so that water movement isn’t restricted

Question 24

What 4 factors affect the rate of transpiration

Answer 24

1) temp
2) humidity
3) air movement
4) light intensity

Question 25

What change in temperature increases transpiration rate and explanation

Answer 25

1) increase
2) increases kinetic energy of molecules so more evaporate from cell surfaces. Rate of water molecule diffusion from leaf surface increases

Question 26

What change in humidity increases the rate of diffusion and explanation

Answer 26

1) decrease

2) reduces concentration of water molecules outside of leaf so more diffusion off of leaf

Question 27

What change in air movement increases the rate of diffusion and explanation

Answer 27

1) increase

2) removes water vapour from leaf surface so more diffusion

Question 28

What change in light intensity increases the rate of diffusion and explanation

Answer 28

1) increase

2) increases rate of photosynthesis so stomata open so more water loss via diffusion

Question 29

What 3 plant organs form an organ system for transport of substances around the plant

Answer 29

Roots, stem and leaves

Question 30

What is the function of the stomata and adaptations

Answer 30

1) they control gas exchange in the leaf and water loss
2)
- can be opened closed depending on how turgid guard cells are
-

Question 31

How can cell sap move between phloem cells

Answer 31

Through pores in the end walls