PHIL 1000X Study Guide - Final Guide: Integrin, Cytoskeleton, Paracrine Signalling
10 May 2018
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BLOCK XA
MODULE X4 - CELLULAR COMMUNICATION & HOMEOSTASIS
UNIT 1
Target Cell Receptors
Unit Objectives
When you have finished this unit, you should be able to:
1. Describe basic methods of cell-to-cell communication. Identify if they use chemical or
electrical signals.
a. Local communication
i. Gap junctions (electrical and chemical) - they form direct cytoplasmic
connections
ii. Contact-dependent signals
iii. Chemicals that diffuse through ECF to act on cells close by (autocrine
and paracrine)
b. Paracrine (chemical)
c. Autocrine (chemical) - signal that acts on the cell that secreted it
2. Identify the classes of long distance chemical messengers.
a. Hormones
b. Neurotransmitters
c. Neurohormones (chemicals released into blood for action on distant targets)
3. Describe the common features of a signal pathway.
a. Signal molecule (LIGAND; FIRST MESSENGER) binds to protein receptor
b. Ligand-receptor binding activates receptor
c. Receptor then activates one or more intracellular signal molecules
d. last signal molecule in the pathway creates a response by modifying existing
proteins or initiating the synthesis of new proteins.
4. Differentiate between intracellular and cell membrane receptors.
5. Describe the 4 categories of membrane receptors.
a. Receptor-channel (ligand binding opens or closes it)
b. G-protein coupled receptor (ligand binding opens an ion channel or ALTERS
ENZYMATIC activity)
c. Receptor-enzyme (ligand binding activates intracellular enzyme)
d. Integrin receptor (binding alters enzymes or the cytoskeleton)
