Biochemistry of Cellular Receptors Flashcards Preview

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Flashcards in Biochemistry of Cellular Receptors Deck (45):
1

For each signaling system, give its messenger
nervous system
endocrine system
immune system

NT; hormones; cytokines

2

The Eicosanoids: Prostaglandins, thromboxjnes and leukotrienes control cellular functions in response to what?

injury

3

Almost every cell in the body produces Eicosanoids. True or false?

true

4

Eicosanoids affect what cells?

the cells that produce them or their neighboring cells

5

What are growth factors

polypeptides that function through stimulation of cellular proliferation e.g EGF, FGF

6

Define signal transduction

chemical messenger binds to receptor, signal it's carrying must be converted into an intracellular response

7

Tyrosine kinase receptors are an example of what type of receptor

enzyme-linked receptor

8

Jak-Stat receptors are what type of receptor

cytokine receptor

9

In regards to the ion-channel receptor: Nicotinic acetylcholine receptor, ___ is the NT at neuromuscular junctions

acetylcholine

10

Nicotinic acetylcholine receptor are found where?

plasma membrane of muscle cells

11

As acetylcholine binds to the receptor, describe what happens

conformation change opens the narrow portion of the channel (the gate), allowing Na+ to diffuse in and K+ to diffuse out.

12

Tyrosine Kinase receptors generally exist in the ____ as ___ with a single membrane-spanning helix

membrane; monomers

13

In regards to the tyrosine kinase receptor, one molecule of ___ generally binds two molecules of the receptor and promotes their ___

GF; dimerization

14

In regards to the tyrosine kinase receptor, once the receptor dimer has formed, the intracellular tyrosine kinase domains of the receptor ___ each other on certain tyrosine residues

phosphorylate

15

In regards to the tyrosine kinase receptor, the phosphotyrosine residues form specific binding sites for what?

signal transducer proteins

16

Serine-Threonine kinase receptors are used by proteins in what superfamily?

transforming growth factor (TGF)

17

Serine-threonine kinase receptors associate with proteins from the sad family which are ___ ___ transcription actors

gene specific

18

The superfamily of TGF is involved in what?

tissue repair, immune regulation, and cell proliferation

19

The Jak-STAT receptor is used by cytokines to regulate what?

proliferation of certain cells

20

True or false? The Jak-STAT receptor has no intrinsic kinase activity, but it binds the tyrosine kinase Jak

true

21

STAT is phosphorylated by Jak which causes what?

STAT's dimerize and move to nucleus where they activate transcription

22

____ is the guanosine analogue of ATP and is involved in G-protein coupled receptors

GTP

23

Small G-protiens related to the ___ oncogene are involved in vesicle transport in cells, interactions between the cytoskeleton and cell membrane and cell growth

ras

24

All the heterotrimeric G protein-coupled receptors are proteins that span the cell membrane ___ times

7

25

When the signal reaches a G-protein, the protein exchanges GDP for ___

GTP

26

The resting state of a G-coupled receptor is achieved when GTPase converts GTP to ___

GDP

27

Messengers that use intracellular receptors must be ___ molecules that are able to diffuse through the plasma membrane

hydrophobic

28

Lipophilic hormones that use intracellular gene-specific transcription factors include the ____ hormones, ___ hormone, ____ acid and vitamin ___

steroid; thyroid; retinoic; D

29

In regards to lipophilic hormone receptors, cytosolic (subclass-1) receptors are in the cytosol bound to ___ ___ proteins

heat shock

30

When a hormone binds to a cytosolic receptor, the heat shock protein is displaced. What happens now?

hormone-receptor complex moves to nucleus and alters transcription

31

Sex steroids generally fall into the category of ___ receptors

cytosolic

32

These receptors are a type lipophilic hormone receptors found within the nucleus, not bound to hsps.

Nuclear (subclass-2) receptors

33

Binding of the hormones to nuclear receptors induces a conformation change (activation). What happens next? Give some examples

transcription is altered; thyroid hormone, retinoids, vitamin-D

34

Define down-regulation

when a hormone or NT is present in excess, the number of active receptors generally decreases

35

Define up-regulation

in the presence of a deficiency of the chemical messenger, there is an increase in the number of active receptors

36

Define internalization

in the case of receptors in the membrane, ligands bind to their receptors, and the ligand-receptor complexes move laterally in the membrane to coated pits, where they are taken into the cell by endocytosis

37

This is a type of down regulation in which receptors are chemically modified in ways to make them less responsive

desensitization

38

Ligands that bind to receptors and cause a maximal response are often termed full ____

agonists

39

Ligands that evoke a sub maximal response, even when filling all the receptors are termed ___ ___

partial agonists

40

Define antagonist

some ligands bind to receptors with high affinity, yet elicit no response ex: tamoxifen

41

The affinity of a ligand to the receptor is measured using ___

RRA (radio receptor assay)

42

____ analysis will give the affinity of a ligand

scatchard

43

A disease in which antibodies produced attack thyroid stimulating hormone receptors is called what?

grave's disease

44

A disease in which antibodies attack nicotinic acetylcholine receptors is called what?

myasthenia gravis

45

What are the symptoms of myasthenia gravis?

muscle weakness, fatigue