MCM 2-5 Signaling I Flashcards Preview

MSI Unit II > MCM 2-5 Signaling I > Flashcards

Flashcards in MCM 2-5 Signaling I Deck (34)
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1

Ligands bind to receptors via what type of interaction?

what effect can this binding have on the receptor?

ligands bind receptors non-covalently which allows for interaction to be reversible

this binding can induce a conformation change in the receptor which can change its activity or affinity for another molecule

2

if the ligand binds a receptor on the outside of the cell....

secondary messengers will carry the message through the cell.

These allow for signal relay and subsequent amplification

3

benefits of secondary messengers?

allow for signal relay and subsequent amplification


amplification of signals allows for
-smaller number of receptors and signal molecules to be needed.
-shorter response time

4

steps leading up to signal transduction

1. ligand receptor binds
2. signal is amplified by secondary messenger
3. amplification causes the signal to be transduced more quickly


the activation of a single receptor can lead to

5

the activation of a single receptor can lead to

formation of MANY secondary messenger molecules ---> multiple coordinated responses or a single/amplified response.

6

what will generally cause the signal to be stronger?

greater concentration of signal molecules and greater density of receptors

7

what factors contribute to the exact reactions observed with individual receptors and their ligands?

signal molecule half life and receptor affinity for ligand

short half life means the molecule may need to be synthesized at a faster rate to adequately interact with receptor

if receptor affinity is low, the ligand again may need to be produced more rapidly for sufficient interaction to occur

8

signal molecule concentration is controleld by

how fast molecule is produced and degraded

typically degredation rate is constant, but synthesis rate can vary

9

fast synthesis + fast degredation

strong signal

10

slow synthesis + fast degredation

weak signal

11

degredation speed of hormones

hormones are degraded slowly, signal takes a long time to decrease. hormones are long acting signals

12

if there are more receptors...

there are more spots for ligand to bind and illicit response

13

if a receptor has a higher affinity than another...

it will take less ligand to bind it

14

if a cell is being repeatedly exposed, it will show ______

adaptation via desensitizing receptors, degrading receptors, or regulating receptor synthesis

15

how do nuclear receptors regulate gene expression

nuclear receptors are intracellular receptors that bind steroid hormones

once hormone binds, inhibitor released and the DNA binding domain of the receptor is exposed, allowing for regulation of genes with matching promoter sequences

some genes will require addiitonal parter TF to be activated. Therefor, the partner TF that a cell produces will determine the genes that will be affected by a given signalling pathway.

16

signals may pass from ________, but ussually come from ________. example?

cell to cell directly (gap), but ussually come from outside of the cell, like in the endocrine system.

17

describe the signaling molecules and receptors of endocrine system

very low concentration signals, requiring high affinity receptors

18

describe the signaling molecules and receptors of neurotransmitter systems

very high concentration signals (neurotransmitters), with very low affinity receptors on post-synaptic cells

19

rank the affinity of receptors in the neurotranmitter, paracrine, and endocrine systems

highest affinity - endocrine
medium affinity - paracrine
lowest affinity - neurotransmitters (due to high levels of NT released)

20

steroid hormones must be able to...

diffuse across the membrane

21

affinity

the strength with which a receptor will bind its ligand

22

half-life

the amount of time it takes for the body to halve the amount of a particular signal molecule in circulation

23

adaptation

process of changing a cellular response to a signal of constant concentration (like reducing receptor density/affinity)

24

autocrine

cell secretes signal taken up by receptor on same cell

25

paracrine

cell secretes signal taken up by neighboring cell

26

synaptic

signal processing specific to nerve cells and postsynaptic cells. NT secreted by nerve cell, travels across synaptic cleft, taken up by receptors on post-synaptic cell

high concentration signal, low affinity receptor

27

endocrine

cell secretes signal into blood stream to be distributed systemically.

-very low concentration signal
-very high affinity receptor

28

ligand gated

membrane protein channel that opens in response to binding a ligand. can be on cytosolic or extracellular side of membrane

29

primary response gene

genes activated by intracellular signals from a hormone-occupied receptor. hormone turns these genes on

30

eicosinoid

hydrophobic signal subclass, made by fatty acids that bind surface receptors rather than cytoplasmic proteins

(steroid hormones all work by binding cytoplasmic proteins to be taken into the cell).

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