13.2.3 Signal Transduction Pathways in Plants

Question 1

Signal Transduction Pathways in Plants

Answer 1

• Plants, like animals, make hormones that must be transported to cells where they will elicit a response.
• Fat-insoluble hormones bind to a receptor protein on the cell membrane and initiate a signal-transduction pathway. A signal-transduction pathway links a chemical stimulus to a cellular response.

Question 2

signal-transduction pathway and auxin

Answer 2

• In the diagram to the left, the hormone binds to a receptor on the surface of the target cell and triggers a signal-transduction pathway. A second messenger will
  signal the cell to respond in a number of ways.
• The plant growth hormone auxin can stimulate a number of cellular responses in a signal-transduction pathway. These responses include the activation of proton pumps, which will facilitate the softening of the cell wall. Activated transcription factors induce the transcription of genes encoding growth proteins. The Golgi apparatus will be stimulated to release vesicles that contain materials for cell wall maintenance.

Question 3

Water-soluble hormones enter cells by

Answer 3

• none of the above.

Question 4

The binding of hormones to their specific membrane receptors directly stimulates

Answer 4

• the release of second messengers inside the cell

Question 5

Why is it that fat-soluble hormones can easily pass into cells, whereas fat insoluble hormones must bind to a receptor?

Answer 5

• The cell membrane is composed mostly of fat.

Question 6

Which one of the following represents the correct sequence of events in a signal-transduction pathway involveing a water-soluble hormone?

Answer 6

• Hormone binds to receptor, secondary messenger, cellular response

Question 7

A common second messenger is

Answer 7

• cAMP

Question 8

Each hormone may

Answer 8

• stimulate many different types of second messengers that produce many different types of cellular responses.

Question 9

Which of the following apply to signal transduction?

Answer 9

• The process by which auxin stimulates plant growth involves signal transduction.
• Signal transduction involves the binding of a hormone to a membrane protein, which then stimulates a change in the behavior of the cell.
• Signal transduction is the process by which a chemical stimulus is linked to a cellular response.