Cell Signalling Flashcards

1
Q

Negative feedback

A

Move back towards comfortable homeostatic zone

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2
Q

Positive feedback

A

Move outside comfortable homeostatic zone (ex. HR in crisis)

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3
Q

Direct cell signalling

A

Signal passed directly from one cell to another through gap juntion

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4
Q

Indirect cell signalling

A

Signalling cell releases chemical messenger, which is carried in extracellular fluid and binds to receptor of target cell. This activates signal transduction pathway or ion channel.

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5
Q

Connexin

A

Specialized pore complex, which creates aqueous pore between adjacent cells

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6
Q

Structure of connexins

A

Two hemichannels, each with six proteins

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7
Q

Autocrine and paracrine signalling

A

Signalling cell releases chemical messenger which can act on target cell nearby (paracrine), or back on signalling cell (autocrine)

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8
Q

Endocrine signalling

A

Signalling cell releases chemical messenger/hormone into circulatory system to act on target cell that is very far away

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9
Q

Neural signalling

A

Chemical messenger/NT is releases from neuron, and NT acts of target cell

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10
Q

Seven classes of chemical messengers

A

Peptides, steroids, amines, lipids, purines, gasses, amino acids

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11
Q

Site of peptide/protein hormone synthesis

A

RER as preprohormones, and stored in vesicles as prohormones, then releases as active hormone via exocytosis

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12
Q

Preprohormone

A

Produced in RER

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13
Q

Prohormone

A

Preprohormones are processed in golgi, and stored in vesicles as prohormones

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14
Q

Site of steriod hormone synthesis

A

SER or mitochondria

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15
Q

Three classes of steroid hormones

A

Mineralocorticoids, glucocorticoids, and reproductive hormones
(also, molting hormone for insects that shed hard exoskeleton)

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16
Q

All hormones are synthesized from…

A

Cholesterol

17
Q

Steroid hormones are produced and…

A

Used immediately, they are produced on demand as they diffuse quickly

18
Q

Steroid hormones show slow effects on cell through

A

Genetranscription; binding to intracellular receptors/transcription factors

19
Q

Amine hormones chemical classification

A

Possess an amine group; these are usually derived from amino acids

20
Q

Four components of signal transduction pathways

A

Receiver, transducer, amplifier, and responder

21
Q

Intracellular receptors

A

Chemical messengers bind to hydrophobic ligands

22
Q

Ligand-gated ion channels

A

Binding leads to changes in membrane potential (ion efflux or influx)

23
Q

Receptor-enzyme receptors

A

Binding leads to changes in intracellular enzyme activity

24
Q

G-protein coupled receptors

A

Binding leads to activation of membrane bound G-proteins

25
Q

Types of ligand-gated ion channels

A

Glutamate receptors, GABA receptors, nicotinic acetylcholine receptors, and 5-HG3, P2X receptors

26
Q

Examples of glutamate receptors

A

AMPA, NMDA, kainate

27
Q

What activates nicotinic acetylcholine receptors?

A

Acetylcholine

28
Q

Binding of ligand to single transmembrane receptor in receptor-enzymes causes…

A

Phosphorylation cascade of specific intracellular proteins

29
Q

Receptor tyrosine kinases activation causes…

A

Conformational change resulting on dimerization, and autophosphorylation of tyrosines (also known as transautophosphorylation)

30
Q

Activity of receptor-gyanylyl cyclase

A

GTP–>cGMP
cGMP activates protein kinase G (PKG)
PKG phosphorylates target proteins and relaxes smooth muscles/lowers blood pressure by vasodialtion

31
Q

G-protein couples receptors

A

Ligand binds to 7 transmembrane receptor; subunits of G-protein dissociate and either activate ion channels or amplify signal via formation of secondary messenger

32
Q

Insositol-phospholipid pathway net rxn

A

G-protein coupled receptor

PIP2 –> DAG + IP3