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18 Cards in this Set
- Front
- Back
What is the glycocalyx?
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polar oligosac. Side chains linked cov to most proteins and some lipids of plasmalemma (contains proteoglycans [GAGs bound to integral proteins]
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What is the function of the glycocalyx? (6x)
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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 |
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What are the heterotrimeric G proteins? (5x)
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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) |
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Stimulatory G protein (Gs): Function, Result, Examples
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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) |
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Inhibitory G protein (Gi): Function, Result, Examples
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Function: inhibits adenylate cyclase, preventing formation of cAMP
Result: protein kinase inactive Examples: Alpha 2 adrenergic receptors (dec. cAMP in cytosol) |
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phospholipase C activator G protein (Gp): Function, Result, Example
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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 |
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olfactory specific G protein (Golf): Function, Result, Example
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Function: activates AC in olfactory neuron
Result: opens cAMP gated Na channels in olfactory neuros Examples: initiates nerve impulse |
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Transducin (Gt): Function, Result, Example
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Function: act. cGMP phosphodiesterase; hydrolysis of cGMP
Result: hyperpolarization of rod cell membrane Examples: photon activation of rhodospin causes rod cells to fire |
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What is an integrin?
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proteins which associcate plasmalemma and cytoskeleton;
Most important: Band 3 |
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Red blood cell framework (5 components)
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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 |
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Cytoskeleton framework of nonerythroid cells (4)
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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) |
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Cystinuria: description and cause
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Description: kidney stones
Cause: abnormal carrier proteins unable to remopve cystine form urine |
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Cholera toxin: description and cause
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Description: diarrhea, severe electrolyte loss
Cause: alteration of G protein so unable to hydrolyze GTP, leading to high cAMP |
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Pertusis toxin: description and cause
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Description: death/irritation/damage of bronchial mucosa
Cause: ADP ribosylation of alpha portion of G protein: accumulation of inactive G proteins |
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Venoms: description and cause
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Description: relaxation of skeletal muscle
Cause: inactivate AcH receptors of skeletal muscle sarcolemma |
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Autoimmune diseases: description, cause
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Description: Ex: Grave's Disease
Cause: Ab stimulation and activation of plasma membrane receptors |
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Defective Gs proteins: description, cause
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Description: delay/inhibition of development
Cause: defect Gs protein: decreases responses to certain hormone |
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Hereditary sphereocytosis: description, cause
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Description: anemia, misshapen RBC
Cause: defective spectrin which cannot properly bind to band 4.1 proteins: fragile, misformed RBCS |