Cellular Communication

Question 1

4 Types of communication via chemical messengers

Answer 1

• Gap Junctions
• Paracrine (comm. btwn nearby cells)
• Autocrine (comm. btwn a cell and itself)
• Hormonal (long distance comm. btwn cells)

Question 2

2 Types of chemical messengers

Answer 2

1. Sterol based (hydrophobic)
   
   • bind intracellularly
2. Protein based (hydrophilic)
   
   • bind to membrane receptors

Question 3

3 types of membrane-bound receptors

Answer 3

1. Ligand-gated channel operators -e.g. neurotransmitters
2. Enzyme-linked receptors - e.g. tetanus toxin
3. G-protein-linked receptors - e.g. insulin

Question 4

Glycoproteins

Answer 4

Cell surface markers that identify a cell to it’s neighbors

-Proteins attached to carbohydrates

Question 5

Ligands

Answer 5

Ligands are molecules that bind to plasma membrane receptors

Question 6

Examples of Ligands

Answer 6

hormones
neurotransmitters
antigens
complement components
lipoproteins
infectious agents
drugs
metabolites

Question 7

7 cellular responses to a messenger

Answer 7

A stimulus can cause a cell to change it’s:

• permeability
• electrical state of plasma membrane
• transport proteins
• metabolism
• contractile activity
• rate of proliferation and differentiation
• secratory activity

Question 8

Signal Transduction Pathway

Answer 8

The cascade of events btwn receptor activation and the cell’s responses.

signal = receptor activation
transduction = transformation of stimulus into cellular response

Question 9

Kinase

Answer 9

phosphorylates another moluecule

• removes a phosphate group
• i.e. ATP > ADP + P

Question 10

Phosphatase

Answer 10

Adds a phosphate group to to another molecule

- i.e. ADP + P > ATP

Question 11

Homeostasis for proteins depends on…

Answer 11

1. pH

2. Tempurature