E/N Transport in plants

Which of these substances is/are transported by the xylem?

• water only

• water and sucrose

• water and mineral salts

• mineral salts and sucrose

In what direction does the xylem transport water?

• roots > stem > leaves

• roots > leaves > stem

• leaves > stem > roots

• leaves > roots > stem

True or false:

A xylem vessel is made of many dead cells fused together to form a long hollow tube.

• True

• False

True or false:

A xylem vessel has many cross-walls

• True

• False

True or false:

Cells in the xylem vessel have no protoplasm.

• True

• False

What is the function of lignin deposits in the walls of xylem vessels?

• Enable water to move more easily through the xylem.

• Enable mineral salts to move more easily through the xylem.

• Provide mechanical support to the xylem.

• Make the xylem bitter so animals don't eat it.

Which two cells form phloem tissue?

• sieve tube elements and companion cells

• phloem cells and tissue cells

• cross walls and lignin cells

• tube elements and sieve tissue cells

True or false:

Sieve tube cells have no nucleus.

• True

• False

Why do sieve tube cells have little protoplasm?

• To reduce resistance to the flow of substances in the phloem.

• To reduce energy required for transport of mineral salts.

• To increase the production of amino acids.

True or false:

Companion cells have few mitochondria.

• True

• False