IGBio 8.1&8.2 Transport in Plants: Xylem and Phloem

Recall what is dissolved in the water in the xylem.

• Glucose

• Amino acids

• Mineral ions

• Starch

Answer explanation

In the xylem, water primarily carries dissolved mineral ions, which are essential for plant growth and development. Glucose and amino acids are transported in the phloem, while starch is not dissolved in water.

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-3

Select which of the following statements are true for phloem.

• Bi-directional movement (up and down stem).

• Elongated, tubular shape with thin walled sieve tubes.

• Transportation of feed and nutrients.

• Occupy the centre of the vascular bundle.

• Water and mineral transport from roots to aerial parts of the plant.

Answer explanation

Phloem is responsible for bi-directional movement of nutrients, has elongated sieve tubes, and transports food. It does not occupy the center of the vascular bundle, nor does it transport water and minerals, which is the role of xylem.

Recall what substance is used to thicken and strengthen xylem walls in woody plants.

• Protein

• Mineral ions

• Lignin

• Glucose

Answer explanation

Lignin is the substance that thickens and strengthens the walls of xylem in woody plants, providing structural support and rigidity, which is essential for their growth and stability.

Phloem tubes are made of...

• Dead cells

• Living cells

Answer explanation

Phloem tubes are composed of living cells, which are responsible for transporting nutrients and sugars throughout the plant. In contrast, xylem tubes are made of dead cells that transport water.

Xylem tubes are made of...

• Dead cells

• Living cells

Answer explanation

Xylem tubes are primarily composed of dead cells, which form hollow structures that efficiently transport water and nutrients from the roots to the rest of the plant. This is why the correct answer is 'Dead cells'.

What is the role of companion cells in phloem tissue?

• They help in the transport of water

• They assist in the transport of sugars and organic compounds

• They provide structural support to the plant

• They produce oxygen for the plant

Answer explanation

Companion cells play a crucial role in the phloem by assisting in the transport of sugars and organic compounds. They are closely associated with sieve tube elements, providing them with the necessary metabolic support for efficient transport.

Which of the following sentence shows correct relation between xylem structure and function?

• xylem transport water up and down so that every plant organ get enough water

• xylem consists of living cell so water transport can be faster

• xylem cell wall is lignified so that it will not easily collapse

• xylem located outside of the phloem so that water can enter it in shorter way

Answer explanation

The correct choice highlights that xylem cell walls are lignified, providing structural support to prevent collapse under pressure, which is essential for efficient water transport in plants.

What is the difference between the transport direction of xylem and phloem tissue?

• Xylem transports upward, phloem transports downward

• Xylem transports downward, phloem transports upward

• Both xylem and phloem transport in the same direction

• Both xylem and phloem transport in opposite directions

Answer explanation

Xylem transports water and nutrients upward from the roots to the leaves, while phloem transports sugars and other metabolic products downward from the leaves to other parts of the plant. Thus, xylem goes up and phloem goes down.

What is the role of xylem fibers in xylem tissue?

• They help in the transport of sugars and organic compounds

• They assist in the transport of water and minerals

• They provide structural support to the plant

• They produce oxygen for the plant

Answer explanation

Xylem fibers provide structural support to the plant, helping it maintain its shape and withstand various stresses. They do not transport water, minerals, or sugars, nor do they produce oxygen.

What is the process called when sugars move from the leaves to other parts of the plant through phloem?

• respiration

• photosynthesis

• translocation

• transpiration

Answer explanation

The process of moving sugars from the leaves to other parts of the plant through phloem is called translocation. This is essential for distributing energy throughout the plant.