Pintar - Intro To Cell II

Question 1

Functions of membrane proteins

Answer 1

1) Link/anchor - interact with cytoskeleton (spectrin)
2) Transporters
3) Receptors- intracellular signaling (G-proteins)
4) Enzymes

Question 2

Glycocalyx

Answer 2

Fuzzy coat on microvilli - “enteric surface coat”. Made of many types of glycosylated molecules (glycolipids, glycoproteins, proteoglycans)

Question 3

Terminal Web

Answer 3

Filamentous complex where actin from microvilli terminates at base. Connects to intermediate filaments

Question 4

Types of Junctional Complexes

Answer 4

Tight Junctions (Zonula Occludens)
Belt Desmosomes (Zonula Adherens)
Spot Desmosomes (Macula Adherens)
Communicating (Gap) Junctions

Question 5

Microtubules

Answer 5

Made of tubulin subunits, found in centrioles, cilia, mitotic spindles

Question 6

Smooth ER

Answer 6

No ribosomes, lipid/steroid biosynthesis, detox, calcium storage.

Question 7

Rough ER

Answer 7

ribosome studded, produces secretory proteins/stuff for export

Question 8

Constitutive vs. Regulated Secretion

Answer 8

Constitutive: constant, no secretory vesicles built up in cell (i.e. for immunoglobulins, ECM material)

Regulatory: Secrete at distinct intervals, due to signal. Secretory vesicles stored in cell (i.e. digestive enzymes)

Question 9

Lyosomes

Answer 9

Intracellular digestion. Use acid hydrolases, low internal pH, to degrade endocytosis objects and organelles. H & E staining, trypan blue indicates lyosomes (or phagocytes, since contain many lysosomes)
-Lyosomes in Eosinophils have unique “hamburger” look

Question 10

Peroxisomes

Answer 10

Use H2O2 degradation. Denser than lyosomes (high [enzyme]), so look darker under EM.

Question 11

Hereditary Spherocytosis

Answer 11

Mutation in spectrum causes less biconcave RBCs (since less attachment of peripheral membrane proteins to cytoskeleton), shrivel more easily