Transport System in Organisms

Question 1

Very small or single-celled organisms move substances mainly by

Accepted Answer

Diffusion — In tiny organisms every cell is close to the surface, so diffusion is enough.

Question 2

Large multicellular organisms need a transport system because

Accepted Answer

Diffusion alone is too slow over long distances — In a big body diffusion cannot supply every cell quickly enough.

Question 3

In plants, water and dissolved minerals are transported by the

Accepted Answer

Xylem — Xylem carries water and minerals upward from roots to leaves.

Question 4

Dissolved food such as sucrose is transported in the plant by the

Accepted Answer

Phloem — Phloem transports sugars made in the leaves to the rest of the plant.

Question 5

The upward movement of water in the xylem is driven by

Accepted Answer

Transpiration — Water evaporating from leaves pulls more water up the xylem.

Question 6

The transport of food in the phloem is called

Accepted Answer

Translocation — Translocation is the movement of dissolved food through the phloem.

Question 7

Water is absorbed from the soil mainly by the

Accepted Answer

Root hair cells — Root hair cells have a large surface area for absorbing water.

Question 8

The main transport system in humans is the

Accepted Answer

Blood circulatory system — The blood circulatory system carries oxygen, food and wastes around the body.

Question 9

In which direction does the xylem mainly transport water?

Accepted Answer

Upward from roots to leaves — Xylem moves water and minerals upward from the roots to the leaves.

Question 10

Which plant tissue is made of dead, hollow cells?

Accepted Answer

Xylem — Mature xylem cells are dead and hollow, forming continuous tubes.