Lecture 16

Question 1

why do cells need to communicate?

Answer 1

to adapt their behaviour to environmental changes
to coordinate the actions of adjacent, but also, distant cells

Question 2

signalling by cell to cell contact

Answer 2

no release of secreted molecules
cells make direct contact - signals are in plasma membrane of signalling cell

Question 3

signalling by free diffusion of ligands

Answer 3

signals that can cross the plasma membrane
these types of signals are hydrophobic small molecules that diffuse across plasma membrane and bind receptors inside the cell

Question 4

DNA binding domain - how is specificity achieved?

Answer 4

specific target genes contain specific DNA sequences in their regulatory gene regions
the DNA binding domains differ in different receptors

Question 5

steroid binding domain - how is specificity achieved?

Answer 5

specific hormones bind to specific ligand binding domains
the ligand binding domains differ in different receptors

Question 6

locally paracrine

Answer 6

paracrine signalling occurs mostly within one tissue
diffusion of signals over a short distance to target neighbouring cells

Question 7

locally neuronal

Answer 7

neurotransmitters are signals release by neuronal cells
signal is released strictly local between two cells into snyaptic cleft

Question 8

remote endocrine

Answer 8

endocrine cells produce hormones (secretory proteins)
remote signals act over the whole body via the blood stream to target cells

Question 9

signals can act over a long or a short range - which range are the following ?
paracrine signalling occurs over a ______ distance
neuronal signalling occurs in the ________
endocrine signalling via the ______
contact signalling has no _______

Answer 9

short
synaptic cleft
bloodstream
contact signalling

Question 10

an example of 1 signal with 2 responses

Answer 10

ligand - acetylcholine
different in skeletal muscle cells and heart muscle cells
skeletal - contraction
heart muscle - decreased rate and force of contraction

Question 11

an example of 1 signal 1 receptor but dif response

Answer 11

muscarinic ACh receptor
heart muscle cell - decreased rate and force of contraction
salivary gland cell - secretion
cells interpret the signal in different manners

Question 12

signal molecs mediate their effect upon binding to _____

Answer 12

specific receptors in the cell

Question 13

one signal molec can bind to _______

Answer 13

several dif receptors

Question 14

the response to the signal depends on how the cell ____ the signal

Answer 14

interprets

Question 15

3 families of cell surface receptors

Answer 15

ion channel coupled receptors
g protein coupled receptors
enzyme coupled receptors

Question 16

ion channel coupled receptors

Answer 16

open or close as response

Question 17

g protein coupled receptors

Answer 17

activate guanine nucleotide binding protein (g protein) as response - then leads to activation of effector

Question 18

enzyme coupled receptors

Answer 18

activate catalytic activity of intrinsic or associated enzyme
increase catalytic activity - intrinsic and directly related to binding of ligan

Question 19

different types of receptors (2)

Answer 19

signal molecs that can pass the plasma membrane bind intracellular receptors
signal molecs that cannot pass the plasma membrane bind transmembrane receptors

Question 20

signal conversion - signal transduction (explain)

Answer 20

signal
receptor
signal transduction
response

Question 21

how can signal transduction be achieved?

Answer 21

molecular switches