Payne Csf Ultrastructure 1

Front 1

Inclusions

Back 1

Components of the cytoplasm with characteristic staining properties; can be membrane-bound or not.
-Secretory vesicles (memb-bound)
-Neutral fat (found in adipocytes)
-Glycogen (granules 25-30 nm in diameter, often in clusters)
-Crystalline inclusions (e.g. in Sertoli and Leydig cells)
-Pigments (melanin, hemoglobin)
-Stored waste products

Front 2

Glycocalyx

Back 2

Extracellular coating of plasma membrane formed from carbohydrate groups attached to:
-Proteins --> glycoproteins
-Lipids --> glycolipids

Front 3

Lipid rafts have (higher/lower) concentration of cholesterol and contain (longer/shorter) fatty acids

Back 3

higher, longer

Front 4

When a freeze fracture is done of a plasma membrane, separating the E (extracellular) and the P (protoplasmic) faces, which contains the majority of the transmembrane proteins?

Back 4

P face

Front 5

Functions of the plasma membrane

Back 5

-pumps
-channels
-gap junctions
-receptor proteins
-linker proteins (anchor intracellular cytoskeleton to ECM)
-enzymes (catalyze metabolic rxns)
-structural proteins

Front 6

Three variables which can potentially cause the opening/closing of gated channels in plasma membrane

Back 6

voltage, ligand, mechanical stimuli

Front 7

Three types of endocytosis:

Back 7

-Pinocytosis
-Phagocytosis
-Receptor-mediated endocytosis

Front 8

Pinocytosis

Back 8

-no clatharin, constitutive
-pinched off by dynamin (a GTPase)
-abundant in endothelial and smooth muscle cells

Front 9

Phagocytosis

Back 9

-no clatharin
-cellular debris, bacteria
-Fc receptor on cell surface recognizes Ab
-Can also occur without Fc receptor
-Actin dependent; requires depolimerization and repolimerization of cytoskeleton

Front 10

Receptor-mediated endocytosis

Back 10

-Clatharin-mediated
-Cargo receptors gather in well-defined places on cell surface
-Clatharin is recruited to the inner surface where these receptors gather, creating clatharin-coated wells
-Dynamin (a GTPase) pinches the vesicle off
-Clatharin is recycled to cell surface

Front 11

Exocytosis: two pathways

Back 11

-constitutive
-regulated secretory pathway

Front 12

Constitutive exocytosis

Back 12

-continuous delivery of proteins to plasma membrane
-Proteins exported after production
-occurs in all cells

Front 13

Regulated secretory pathway

Back 13

-occurs only in specialized cells (endocrine, exocrine, neurons)
-concentrate proteins and store them in secretory vesicles
-regulatory event induces Ca++ influx, stimulating vesicles to fuse with plasma membrane, secreting contents

Front 14

Which membranous compartments have mannose-6-phosphate receptors (M-6-P targets enzymes to serve in the lysosome)?

Back 14

Early and late endosomes, lysosomes, and golgi

Front 15

Two models to explain endosomal compartments in cells:

Back 15

Maturation model (early endosome develops into a late endosome)

Stable compartment model (early and late endosomes are distinct and form stable compartments)

Front 16

Multivesicular bodies

Back 16

Transport substances between early and late endosomes

Front 17

Function of early endosomes

Back 17

sort and recycle proteins internalized by endocytic processes

Front 18

Four fates of internalized receptor-ligand complexes

Back 18

-receptor recycled, ligand degraded (they separate in the acidic pH of endosome)
-receptor and ligand both recycled
-receptor and ligand both degraded
-transcytosis (both are transported across the cell)