5. Cell communication

Question 1

types of cell communication

Answer 1

1. direct communication
   (immune cells)
2. indirect communication

Question 2

types of indirect cell communication

Answer 2

1. paracrine signaling- MAST cells
2. synaptic signaling- nerve cells
3. endocrine signaling

Question 3

What are the 3 stages of cell signaling?

Answer 3

1. signal reception
2. signal transduction
3. cellular response

Question 4

Ligands

Answer 4

refers to signaling molecules which usually bind to other larger molecules

Question 5

the 3 types of receptors in the plasma membrane are:

Answer 5

1. GPCRs
2. RTKs
3. Ion Channel Receptors

Question 6

GPCRs

Answer 6

G protein-coupled receptors

Question 7

RTKs

Answer 7

receptor tyrosine kinases

Question 8

GTP

Answer 8

guanosine triphosphate (similar to ATP)

Question 9

the difference between GPCRs and RTKs

Answer 9

GPCRs activate one single transduction pathway, while RTKs activate more than one

Question 10

structure of G proteins in GPCRs

Answer 10

they have a secondary protein structure
have 7 alpha-helixes

Question 11

what is the difference between GPCRs in different cells?

Answer 11

1. the type of G protein making them
2. the binding site of the signaling molecules

Question 12

the protein kinase in the plasma membrane transfers phosphate groups to which aa?

Answer 12

tyrosines/ found in the tail of RTKs

Question 13

in which one of the 3 types of plasma membrane receptors do vision, smell, and taste depend?

Answer 13

GPCRs

Question 14

which infections can occur due to the malfunctioning of GPCRs?

Answer 14

bacterial infections
-cholera
-pertussis
-botulism

Question 15

with what are malfunctioning RTKs associated?

Answer 15

many kinds of cancers

Question 16

where are intracellular receptors found?

Answer 16

in the nucleus or the cytoplasm of the target cells

Question 17

which molecules can pass through the plasma membrane to bind to an intracellular receptor?

Answer 17

1. hydrophobic molecules- steroid hormones and thyroid hormones
2. small molecules- nitrogen oxide (NO) gas

Question 18

which are the 2 pathways of signal transduction?

Answer 18

1. protein phosphorylation and dephosphorylation
2. second messenger- nonprotein molecules

Question 19

protein kinase function

Answer 19

enzyme that catalyzes the transfer of phosphate groups to an inactive protein

Question 20

to which aa do cytoplasmatic protein kinases bind?

Answer 20

serine or threonine

Question 21

to which aa do plasma membrane protein kinases bind?

Answer 21

tyrosines

Question 22

which protein catalyzes the removal of the phosphate groups from proteins, making them inactive again?

Answer 22

Protein Phosphatases (PP)

Question 23

which molecules act as secondary messengers?

Answer 23

Ca+2
cAMP

Question 24

cAMP meaning

Answer 24

cyclic adenosine monophosphate

Question 25

which enzyme catalyzes the conversion of ATP to cAMP?

Answer 25

Adenylul cyclase (also known as adenylate cyclase)

Question 26

which enzyme catalyzes the conversion of cAMP to AMP?

Answer 26

phosphodiesterase

Question 27

which molecules does cAMP activate after broadcasting the signal to the cytoplasm?

Answer 27

activates protein kinase A (serine/threonine kinases) which phosphorylates other proteins

Question 28

where does the cellular response occur?

Answer 28

in the cytoplasm or the nucleus of the target cell

Question 29

IP3

Answer 29

inositol triphosphate

Question 30

DAG

Answer 30

diacyl glycerol

Question 31

the function of DAG and IP3

Answer 31

they act as secondary messengers that bind to the calcium channel in the ER, causing it to open, allowing Ca2+ ions flow out of the ER so as to activate other molecules