1.4 Communication and Signalling Flashcards
What is a division of labour?
Different cells carry out different functions within defined areas of the body.
How is coordination of communication achieved?
Extracellular Signalling Molecules
What are examples of extracellular signalling molecule?
Steroid hormones, peptide hormones and neurotransmitters
What is a tissue-specific response?
Different cell types show different response to the same signal
Can hydrophobic signalling molecules diffuse directly through the bilayer
Yes
Why can hydrophobic molecules diffuse directly?
Because the tails of the phospholipids are also hydrophobic
What are examples of steroid hormones?
oestrogen and Testosterone
How is a hormone receptor complex formed?
A steroid hormone enters the cell, binds to and activates a specific receptor in the cytosol or nucleus
What does the hormone receptor complex bind to?
Specific sites on DNA called hormone response elements HREs
What does the hormone receptor complex binding influence?
The rate of transcription
What are transcription factors?
The receptor proteins for steroid hormones.
What do transcription factor receptor proteins do?
Bind to DNA and constimulate or inhibit initiation of transcriptiomn
Can hydrophilic signalling molecules pass through the bilayer?
They cannot pass through the hydrophobic part.
What are hydrophilic signalling molecules?
Peptide hormones and neurotransmitters
