Lecture 10-11

Question 1

4 types of cell communication

Answer 1

1. autocrine
2. paracrine
3. Neural
   4 endocrine

Question 2

autocrine signaling

Answer 2

the chemical signal from on cell that alters the function of the same cell

Question 3

paracrine signaling

Answer 3

the chemical signal from on cell to next that alters a closely located cell

Question 4

neural signaling

Answer 4

from signal cell crossing the synaptic cleft to reach target cell (synaptic signaling)
- signals operate over short distances

Question 5

endocrine signaling

Answer 5

hormone travels through blood stream
- long distance hormonal signaling

Question 6

what types of molecules act as signals

Answer 6

amino acids and their derivatives
steroids’
peptides
proteins

Question 7

2 major receptor types

Answer 7

1. Those located in the membrane that interact with hydrophilic signals that cannot cross the plasma membrane
   ex: amino acids and their derivatives, peptides
2. Those found in the cytoplasm that bind to hydrophobic signals that can cross the plasma membrane
   ex: Steroids

Question 8

cell communication process

Answer 8

ligand binds to receptor
triggers second messenger
which triggers transduction cascade
which triggers response molecules

Question 9

second messengers

Answer 9

trigger transduction cascades and activated by receptor
- is an intermediate b/w cascade and receptor
3 types:
1. Cyclic adenosine monophosphate (cyclic AMP)
2. Calcium ions (Ca2+)
3. Inositol Trisphosphate (IP3)

Question 10

3 advantages of signal transduction pathways (cascades)

Answer 10

1. allows signal to be amplified. (way more efficient than a one to one activation ratio)
   2) It allows one signal to diverge and control a whole range of cellular processes.
   3) it allows other signals to control the cascade.

Question 11

kinase

Answer 11

is an enzyme that adds a Ph group onto another molecule which changes its shape and there fore function

Question 12

phosphate groups

Answer 12

• can be thought of as switches turned on by kinase
• Ph groups can be removed by phosphatase which would reduce enzyme activity

Question 13

cyclic AMP (cAMP)

Answer 13

ATP to cAMP to ADP

Question 14

Tyrosine Kinase Receptors To Function they have ……

Answer 14

2 components
a) a kinase (which is actually part of the receptor itself)
b) a target (or ‘relay’) protein, which is separate from the receptor

Question 15

Calcium increases in what 2 ways

Answer 15

Increases in intracellular calcium can occur in two ways:
1) facilitated diffusion through ion channels.
2) the release of calcium from intracellular stores. This can be controlled by yet another signal transduction cascade that uses inositol trisphosphate (IP3).

Question 16

Places Ca2+ can be pumped

Answer 16

1) Out of the cell
2) Into mitochondria
3) Into smooth endoplasmic reticulum