Support and transport systems (Plants)

Question 1

What are the two types of root systems?

Answer 1

Tap (easily see the main root) and adventitious (roots go everywhere, cant distinguish main root from others)

Question 2

Function of roots

Answer 2

Anchor the plant into the ground and absorb minerals salts and water

Question 3

What is the root cap?

Answer 3

It is made a parenchyma cells. It protects the inner layers of the root (when the root forces its way through the soil)

Question 4

What is the growing point?

Answer 4

It is made of meristematic cells which help replace the damaged parenchyma cells in the root cap. The rest is pushed to the region of elongation as more cells are made in the growing point

Question 5

What is the region of elongation?

Answer 5

This where the cells that have come from the growing point start to pile up (elongating the root)

Question 6

What is the root hair region?

Answer 6

(aka the region of differentiation) This is where the root hairs are, they increase the surface area, so they help absorb water and mineral salts

Question 7

What is the mature region?

Answer 7

Has side roots and fully differentiated tissues but some meristematic tissues still exist here

Question 8

What does the internal structure of a root look like?

Answer 8

A single layer of thin-walled epidermis cells (no cuticle). Inside that the cortex (many layers of parenchyma cells and one layer of endodermal cells) which surrounds the stele. The stele is made up of the xylem, phloem, cambium and pericycle.

The xylem is in the middle with arms going out, the phloem is in between these arms and the cambium is in between these two tissues. The pericycle surrounds all of these.

Question 9

Functions of stems

Answer 9

Hold leaves and flowers in good positions, contain chlorophyll, store water and food, transport water and food

Question 10

What does the internal structure of a stem look like?

Answer 10

A single layer of thin-walled epidermis cells (with cuticle). Inside that is the cortex (many layers of parenchyma cells) It may have a hypodermis made up of collenchyma (thick corners) / sclerenchyma (no stone cells, only fibre). Then there’s the vascular bundles around the central pith (parenchyma cells). They have the phloem on the outside, xylem on the inside, vascular cambium between these and a cap of sclerenchyma cells for protection

Question 11

Functions of some stem tissues

Answer 11

Parenchyma stores food
Hypodermis strengthens stem
Intercellular spaces transport water and gases
Endodermal cells store starch

Question 12

How do guard cells open and close?

Answer 12

Photosynthesis occurs in them and glucose builds up and water potential goes down. The cell becomes turgid and opens. At night there is no photosynthesis happening and the water potential goes up and water stops moving causing the cell to become flaccid and close

Question 13

Absorption in plants

Answer 13

Water is absorbed into the roots via osmosis. However mineral salts have to go against the concentration gradient and move via active transport

Question 14

How does water move up through the plant?

Answer 14

1. Root pressure - as more water is absorbed the ater above it is pushed up
2. Capillarity - natural tendency of water to move up through tiny openings like the ones in xylem and tracheids
3. Transpiration pull - main force responsible, when water evaporates the mesophyll draw more water from the xylem.

Question 15

What is cohesion and adhesion?

Answer 15

Cohesion is the forces between water molecules and adhesion is the forces between water molecules and the walls of the xylem