Histology Chap 1: Plasma Membrane

Front 1

What is the glycocalyx?

Back 1

polar oligosac. Side chains linked cov to most proteins and some lipids of plasmalemma (contains proteoglycans [GAGs bound to integral proteins]

Front 2

What is the function of the glycocalyx? (6x)

Back 2

1. aids in attachment of some cells
2. binds antigens/enzymes to surface
3. facilliates cell-cell recognition and interaction
4. protects cell via preventing contact;
5. aligns T-cells and APC
6. prevents in approrp enzymatic cleavage

Front 3

What are the heterotrimeric G proteins? (5x)

Back 3

1. Stimulatory G Proteins (Gs)
2. Inhibitory G proteins (Gi)
3. phospholipase C activator G protein (Gp)
4. Olf-actory-specific G protein (Golf)
5. Transducin (Gt)

Front 4

Stimulatory G protein (Gs): Function, Result, Examples

Back 4

Function: Activates AC leading to formation of cAMP

Result: activation of protein kinases

Examples: epinephrine binding to B-adrenergic receptors (inc cAMP levels in cytosol)

Front 5

Inhibitory G protein (Gi): Function, Result, Examples

Back 5

Function: inhibits adenylate cyclase, preventing formation of cAMP

Result: protein kinase inactive

Examples: Alpha 2 adrenergic receptors (dec. cAMP in cytosol)

Front 6

phospholipase C activator G protein (Gp): Function, Result, Example

Back 6

Function: activates phospholipase C leading to IP3 and DAG formation
Result: influx of Ca into cytosol and activation of pKC
Examples: binding of antigen to membrane-bound IgE causes release of histamine by mast cells

Front 7

olfactory specific G protein (Golf): Function, Result, Example

Back 7

Function: activates AC in olfactory neuron
Result: opens cAMP gated Na channels in olfactory neuros
Examples: initiates nerve impulse

Front 8

Transducin (Gt): Function, Result, Example

Back 8

Function: act. cGMP phosphodiesterase; hydrolysis of cGMP
Result: hyperpolarization of rod cell membrane
Examples: photon activation of rhodospin causes rod cells to fire

Front 9

What is an integrin?

Back 9

proteins which associcate plasmalemma and cytoskeleton;

Most important: Band 3

Front 10

Red blood cell framework (5 components)

Back 10

Band 3: attached to plasma membrane
(integrin)

Spectrin: long flexible protein composed of alpha and B chains; forms tetramers and forms scaffold for strxl reinforcement

Actin: attaches to binding sites of spectrin tetramers and holds them together (aids in spec latticework)

Band 4.1: stabilizes spectrin-actin complexes

Ankyrin: links band 3 proteins and spectrin tetramers

Front 11

Cytoskeleton framework of nonerythroid cells (4)

Back 11

1. Band 3: integrin acts as connection between plasmalemma and cytoskeleton

2. Actin/fodrin: nonerythroid spectrin: scaffold for strxl stability

3. alpha-actinin: cross links actin filaments to form a meshwork

4. Vinculin: binds alpha actinin and talin (protein which binds integrin)

Front 12

Cystinuria: description and cause

Back 12

Description: kidney stones

Cause: abnormal carrier proteins unable to remopve cystine form urine

Front 13

Cholera toxin: description and cause

Back 13

Description: diarrhea, severe electrolyte loss

Cause: alteration of G protein so unable to hydrolyze GTP, leading to high cAMP

Front 14

Pertusis toxin: description and cause

Back 14

Description: death/irritation/damage of bronchial mucosa

Cause: ADP ribosylation of alpha portion of G protein: accumulation of inactive G proteins

Front 15

Venoms: description and cause

Back 15

Description: relaxation of skeletal muscle

Cause: inactivate AcH receptors of skeletal muscle sarcolemma

Front 16

Autoimmune diseases: description, cause

Back 16

Description: Ex: Grave's Disease

Cause: Ab stimulation and activation of plasma membrane receptors

Front 17

Defective Gs proteins: description, cause

Back 17

Description: delay/inhibition of development

Cause: defect Gs protein: decreases responses to certain hormone

Front 18

Hereditary sphereocytosis: description, cause

Back 18

Description: anemia, misshapen RBC

Cause: defective spectrin which cannot properly bind to band 4.1 proteins: fragile, misformed RBCS