Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Physiology 2410 > Lecture 6- Biochemistry of signaling pathways > Flashcards

Lecture 6- Biochemistry of signaling pathways Flashcards

1
Q

minus gap junction signaling, what does cell to cell signaling require? (3)

A

signal (ligand)
receptor
way to get the message across (intracellular signaling pathways)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is a signal transduction pathway?

A

information from secreted signals is converted to intracellular signal pathways, therefore, converts one form of signal to another

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

explain signal transduction (5)

A

signal molecule –> binds to receptor protein –> activates intracellular signal molecules –> causes alterations of target proteins –> creates a biological response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

are signal pathways ubiquitous/ everywhere?

A

all cells have some pathways and only certain cells have specific pathways

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

why are signal pathways important?

A

they amplify signals to cause a large biological effect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what are the two main categories based on receptor location?

A

intracellular receptors
cell membrane receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what state are ligands in with intracellular receptors?

A

lipophilic (hydrophobic), therefore fat soluble

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

with intracellular receptors can ligands diffuse through cell membrane? what do they bind to?

A

yes, then they bind to receptors in the nucleus or cytosol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what do intracellular receptors alter?

A

gene expression (happens slowly but its long lasting)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

with intracellular signal receptors is the response fast?

A

no, theyre slower responses that are related to changes in gene activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what state are ligands in with cell membrane receptors?

A

lipophobic (hydrophilic) water soluble

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

with cell membrane receptors can ligands diffuse through cell membrane? what do they bind to?

A

no, they bind to membrane receptors which cause intracellular cascade

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

with cell membrane receptors is the response fast?

A

yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what are the 4 cell membrane receptors?

A

integrin receptor
receptor channel
receptor- enzyme
G protein- coupled receptor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what does the integrin receptor do?

A

binds extracellular matrix proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

binding of the ligand with integrin receptor stimulates what change?

A

changes in the cytoskeleton

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what can changes in the cytoskeleton affect?

A

cell movement
growth
wound healing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

how do receptor channels work?

A

ligand binds to the receptor channel protein and a channel gate either opens or closes (allowing ions to ener and leave).
this alters the cells permeability to an ion and membrane potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

how do receptor channels have an electrical effect?

A

when activated ions cross cell membrane they are charged which causes an electrical signal/ effect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what ligand normally binds to a receptor channel?

A

neurotransmitter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what ion is always allowed into cells through receptor channels?

A

Calcium!!! (important for intracellular signal)
recall: Ca++ inside the cell is low

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what are receptor channels often called?

A

ligand- gated ion channels
neurotransmitter gated ion channels
ionotropic receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what do receptor enzymes and GPCR have in common?

A

activate amplifier enzymes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

how does signal amplification work?

A

receptor- ligand complex activates an amplifier enzyme
1 ligand is amplified into many intracellular molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
what is the takeaway message about the ligand from signal amplification?
a small amount of ligand creates a large effect
26
what is an example of a receptor enzyme pathway?
tyrosine kinase receptor
27
what is the general goal of tyrosine kinase receptors?
to transfer a phosphate group from ATP to a tyrosine residue (amino acid) of a protein which phosphorylates tyrosine residues
28
what is a specific example of tyrosine kinase receptor?
insulin receptor
29
what does a complete insulin receptor contain?
alpha receptor (contains ligand binding domain) beta subunit (is transmembrane and contains the signaling domain
30
how does the insulin receptor work in tyrosine kinase receptor? (7)
1. insulin binds to alpha subunit of receptor 2. causes activation in beta subunit of the receptor 3. which causes them to dimerize (combine 2 identical units together) and automatically phosphorylate (auto phosphorylate themselves) 4. beta subunit send the signal of the insulin to the cytoplasm 5. kinase domain in the cytoplasm is activated 6. kinase domains on the receptor phosphorylate insulin receptor substrate 7. other responses in the cell are triggered
31
what are orphan receptors?
there are hundreds of known GPCR but many have unknown function
32
what are GPCRs also called?
metabotropic receptors 7 transmembrane domain receptor serpentine receptor
33
why might GPCRs be called 7 transmembrane domain receptor?
they have 7 transmembrane proteins
34
what does teh activation of GPCR do?
leads to generation/ release of second messengers
35
what are second messengers?
signaling molecule synthesized or released by a cell in response to an extracellular signaling molecule like a hormone
36
what are different paths of a second messenger?
synthesized released from a storage compartment
37
what form are second messengers in? hydrophobic, hydrophilic?
can be hydrophobic, hydrophilic or a gas
38
what does GPCR stand for?
G- protein coupled receptor
39
why are GPCRs called G- proteins?
because they bind GDP and GTP (guanosine diphosphate, guanosine triphosphate)
40
what is the inactive configuration of G- proteins?
bind GDP
41
what is the active configuration of G- proteins?
exchange GDP and GTP
42
what are 3 examples of GPCR?
adenylyl cyclase phospholipase C arachadonic acid
43
what is the process of Andenylyl cyclase?
1.ligand binds to G protein receptor 2. activates the G protein 3. once activated, the G- protein can diffuse along the inside leaf of the membrane 4. G- protein diffuses along the inside of the membrane 5. the amplifier enzyme Adenylyl Cyclase is now activated 6. Adenylyl cyclase converts hundreds of ATP into cAMP 7. cAMP activates protein kinase A (PKA) 8. PKA diffuses within cell to phosphorylate many other proteins
44
what can the activated receptor stimulate in Andenylyl cyclase?
several G- proteins
45
what does each G- protein activate in Andenylyl cyclase?
each G- protein activates one Andenylyl cyclase
46
what is cAMP in Adenylyl cyclase pathway?
second messenger can diffuse throughout the cell
47
in Andenylyl cyclase does PKA only phosphorylate one type of protein?
no, many types of proteins can be phosphorylated, giving rise to complex cellular responses
48
what is the process of phospholipase C in GPCR?
1. ligand binds to and activates G protein receptor 2. G- protein activates the phospholipase- C (amplifier enzyme) 3. PLC degrades membrane phospholipids (PIP2) into TWO second messengers (diacylglycerol + inositol tri- phosphate), DAG in the membrane stays associated with phospholipid, IP3 is small and polar so it diffuses through the cytoplasm 4. DAG activates protein kinase C (PKC) 5. PKC diffuses within the cell and phosphorylates other proteins 6. IP3 binds to the IP3 receptor on the endoplasmic reticulum 7. IP3 receptor is activated and allows stores of Ca++ to be released into the cytoplasm
49
what does Ca++ become in phospholipase C?
another second messanger
50
what are common second messengers?
cAMP cGMP IP3 DAG Ca++
51
what are the 5 different things calcium can do as a second messenger?
Ca binds to the calcium- binding protein calmodulin to activate other proteins Ca binds to motor proteins and allows action of cytoskeleton and motor proteins (muscle contraction) Ca binds to synaptic proteins to trigger exocytosis Ca binds to ion channels to modulate their gating (channels can be open all the time or gated (sometimes open, sometimes closed) Ca in fertilized eggs initiates development
52
how are gases second messengers?
only soluble gasses are second messengers however they do bend the definition of second messenger
53
NO is an example of a soluble gas, what is unique about it?
has a life of 2- 30 seconds
54
explain the process of the gas nitric oxide (NO) in viagra cialis
1. synthesized by endothelial cell of arteries or neurons of parasympathetic nervous system 2. diffuse into adjacent arterial smooth muscle 3. this activates guanylyl cyclase 4. which produces cGMP 5. which activates protein kinase G (PKG) 6. which leads to relaxation of smooth muscle
55
what are two other molecules that do similar things to NO?
CO (carbon monoxide) H2S (hydrogen sulfide)
56
what pathway is the arachidonic acid pathway similar to?
phospholipase C (PL-C pathway)
57
how does the arachidonic acid pathway work?
1. G- proteins activate phospholipase A2 (amplifier enzyme) 2. PLA2 degrades phospholipids into arachidonic acid
58
what are the two major groups of arachidonic acid- derived paracrine molecules to be aware of?
leukotrienes prostaglandins thromboxanes (prostanoids)
59
what are leukotrienes, how did they come about?
arachidonic acid --> lipoxygenase --> leukotrienes singulair tablets are a leukotriene receptor antagonist
60
what are prostaglandins, how did they come about?
arachidonic acid --> cycloxygenase --> prostaglandins thromboxanes aspirin is an anti-inflammatory that binds to cycloxygenase
61
why does the hormone epinephrine (adrenaline) cause some blood vessels to constrict and others to dilate?
presence of receptor isoforms
62
what receptor isoform causes the blood vessel to constrict? on what type of blood vessel?
alpha receptor intestinal blood vessel
63
what receptor isoform causes the blood vessel to dilate? on what type of blood vessel?
beta receptor skeletal muscle blood vessel
64
what is the takeaway message about target response?
target response depends on the target receptor. thus the same hormone causes different effects of the hormone. some ligands can activate multiple receptors
65
what does it mean that some receptors are promiscuous?
activated by more than one ligand ex. alpha receptors may be activated by either epinephrine or norepinephrine. beta receptors may be activated by either epinephrine or norepinephrine
66
how many receptors might a cell contain?
hundreds or thousands of receptor proteins
67
what does it mean that the numbers of receptors can change over time?
need more receptors when developing at a young age
68
receptors can be desensitized, what does that mean?
receptors can become over stimulated ex. people that overuse hard drugs, their tolerance wears off after a while because they over stimulated their receptors causing them to have desensitized receptors
69
what does the phosphorylation of alpha and beta receptors do?
causes them to have a lower affinity for ligands

Physiology 2410 (21 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions