BIOL1025 - Signalling pathways induced in cells (1)

Question 1

2 types of signals

Answer 1

mechanical

biochemical

Question 2

mechanotransduction

Answer 2

transducing signals to chemical

Question 3

mechanic stimuli - pressure applied

Answer 3

cell passed against matrix

changes in actin and cytoskeleton - reorganised

Question 4

signal ligand

Answer 4

small molecule of complex with macromolecules

receptor protein - conformation change to generate signals

Question 5

form of signals

Answer 5

contact-dependent signals
cell-matrix signals
soluble signals

Question 6

contact-dependent signals (Juxtracrine)

Answer 6

target adjacent touching cells

transmitted through membrane vis protein/lipid components integral to membrane of emitting cell

Question 7

example of contact-dependent signals

Answer 7

Delta-Notch

Question 8

cell-matrix signal

Answer 8

makes up to half of body
from insoluble extracellular matrix
largely mediated by intergrins

Question 9

integrin

Answer 9

receptors covering cell surface

Question 10

example of cell-matrix signals

Answer 10

collagen

Question 11

soluble signals

Answer 11

autocrine(intracrine)
paracrine
endocrine

Question 12

autocrine signals

Answer 12

signal secreted and act via receptors by same cell bind = signal transduction event causing response within cell

Question 13

paracrine

Answer 13

signal escape
release local mediator
released into interstitial fluid

Question 14

example of intracrine

Answer 14

steroid

Question 15

endocrine

Answer 15

distant

concentration in blood - low therefore has great affinity

Question 16

interleukin 1

Answer 16

by macrophage - activated

Question 17

interleukin 2

Answer 17

by T lymphocyte - proliferate - amplified

Question 18

1pg

Answer 18

1X10(-12) g

Question 19

example of mechanical

Answer 19

muscle contraction

Question 20

example of biochemical

Answer 20

light, heat sensing

Question 21

molecular form of signal

Answer 21

gas, nucleic acid, FA and cholesterol derivates, amino acids and derivatives, peptide (<50) and protein (>50)

Question 22

gas

Answer 22

NO, CO, H2S, CO2

Question 23

nucleic acid

Answer 23

ATP, ADP and adenosine

Question 24

FA derivatives

Answer 24

eicosanoid e.g. prostaglandin

Question 25

cholesterol derivates

Answer 25

steroids

Question 26

amino acids and derivatives

Answer 26

glycine, glutamine etc

Question 27

peptide

Answer 27

TRH-thyrotropin releasing hormone

Question 28

protein

Answer 28

insulin

Question 29

function of form signal

Answer 29

able to define cell signal - look at bio/biochem of molecule and tell its pathways and change

Question 30

lipophilic molecule

Answer 30

can enter cells - receptor can be anywhere

Question 31

lipophilic example

Answer 31

steroids (cortisol)

gases (NO)

Question 32

hydrophilic molecule

Answer 32

can’t cross cell membrane - receptor at cell surface

Question 33

Hydrophilic example

Answer 33

amines(serotonin)
A.A (glycine)
peptide and protein

Question 34

Thyroid hormone

Answer 34

HP but has carrier - bring ligand into cell with receptor in cytoplasm - a.a derivative

Question 35

signal transduction

Answer 35

how chemical/physical signals - transported through cell as sense of molecular event

Question 36

increase signalling cascade

Answer 36

change by ligand binding to receptor

Question 37

cellular responses by signalling pathways interaction - network

Answer 37

change in transcription/ translation of genes
post-translational and conformation change in protein
change in protein location and ion concentration

Question 38

signal transduction can alter:

Answer 38

cell growth 
proliferation
metabolism
movement
secretion etc

Question 39

first messenger

Answer 39

signalling molecules - released from extracellular fluid and bind to specific receptor

Question 40

second messenger

Answer 40

relaying message from membrane to cytoplasm = response triggered
cell surface receptors need second messenger

Question 41

example of second messenger

Answer 41

cAMP, cGMP, IP3, DAG and Ca2+

Question 42

turning off signals 4 ways

Answer 42

spontaneous breakdown
enzymatic breakdown
reuptake
receptor/ligand internalisation

Question 43

longer signals

Answer 43

wider area affect

length(?strength) of effect in paracrine signal - removal of signal impacts area of effect

Question 44

spontaneous breakdown e.g. NO

Answer 44

very liable - free radical and unpaired e-
converted into NO3- quickly without catabolising enzyme
very local effect

Question 45

enzymatic breakdown e.g. acetyl cholinesterase

Answer 45

breaks acetyl choline at synapse

enzyme at high concentration - very local effect therefore short acting

Question 46

enzymatic breakdown e.g. protease

Answer 46

cleaves peptide/protein in hormones

at lower concentration therefore produce long term effect

Question 47

reuptake

Answer 47

many neurotransmitters transferred back into secreting cell

Question 48

reuptake examples

Answer 48

GABA
glycine
serotonin

Question 49

receptor/ligand internalisation

Answer 49

some ligands and receptors are brought back into cell following binding
both endocytosed into cell then broken down
some cases - ligands is released and receptor is recycled back to the surface

Question 50

neostigmine

Answer 50

blocks acetylcholinesterase - increase effectiveness of acetylcholine
treat myasthenia gravis

Question 51

fluoxetine

Answer 51

block serotonin uptake at synapse - has prolonged effect

used to treat depression