1.4a Co-ordination

Question 1

How do multicellular organisms signal between cells?

Answer 1

Using extracellular signalling molecules

Question 2

Give 3 examples of extracellular signalling molecules

Answer 2

• Peptide hormones
• Neurotransmitters
• steroid hormones

Question 3

What are receptor molecules of target cells?

Answer 3

proteins with a binding site for a specific signal molecule

Question 4

What does binding do to the receptor?

Answer 4

• It changes the conformation of the receptor
• Which initiates a response within the cell

Question 5

Explain the differences between cell types and signalling molecules

Answer 5

• Different cell types produce specific signals that can only be detected and responded to by cells with the specific receptor
• Signalling molecules may have different effects on different target cells due to the differences in the intracellular signalling molecules and pathways that are involved

Question 6

Explain cell signalling in multicellular organisms

Answer 6

different cell types may show a tissue specific response to the same signal