Week 1

Question 1

Define resolution

Answer 1

Ability to distinguish between two objects; dependent on wavelength of energy source (not strength)

Question 2

Fixative for:
A) light microscope (LM)
B) electron microscope (EM)

Answer 2

A) formalin (formaldehyde & water)

B) osmium tetroxide or gluteraldehyde

Question 3

Steps of tissue preparation

Answer 3

1. Fixation
2. Dehydration
3. Embedding
4. Sectioning
5. Staining

Question 4

Objective of fixation:

Answer 4

1. End cellular processes
2. Preserve protein components
3. Micro organisms destroyed
4. Tissue hardening

Question 5

Hematoxylin & Eosin dye

Answer 5

Hematoxylin: blue/purple, basic dye; net positive charge; binds an anionic (net negative charge)

Eosin: pink/red, acidic dye; net negative charge; binds cationic (net positive charge)

Question 6

What stain is used on carbohydrates?

Answer 6

PAS (periodic acid -Schiff)

Question 7

What stain is used for reticular fibers?

Answer 7

Silver impregnating

Question 8

Two types of EM

Answer 8

TEM: transmission electron microscopy: beam passes through material

SEM: scanning electron microscopy: beam reflects off metal-coated sample

Question 9

What are artifacts?

Answer 9

Abnormalities of slides due to human error

Question 10

Define epithelium:

Answer 10

Continuous layer of cells that sit on a basement membrane

Question 11

When enzymatically transferred to outer leaflet, signals programmed cell death

Answer 11

Phosphatidylserine

Question 12

What is a lipid raft?

Answer 12

Specialized cholesterol enriched micro domains; functions to signal transduction and endocytosis

Question 13

What Ian glycocalyx?

Answer 13

Carbohydrate rich zone covering the cell’s surface’ made up of glycolipids, glycoproteins, and proteoglycans. Established micro environment, protection, cell recognition, and cell to cell interactions

Question 14

What is a Lectin?

Answer 14

Used for cell to cell integration; binds to carbohydrates and causes agglutination

Question 15

Permeable vs highly impermeable molecules

Answer 15

Permeable: hydrophobic, non-polar, uncharged, gases (O2, CO2)

Highly impermeable: charged (ions: H+, Na+, K+), polar, charged

Question 16

What is the function of channel and transporters?

Answer 16

To increase the permeability of the membrane to molecules

Question 17

3 types of endocytosis

Answer 17

1. Receptor-mediated: specific; clathrin dependent
2. Pinocytosis: non-specific;
3. Phagocytosis: actin dependent; very specific (Ab)

Question 18

Purpose of adaptin and dynamin in receptor-mediated endocytosis

Answer 18

Adaptin: interacts with clathrin and cargo receptors that then leads to basket-like cage formation

Dynamin: mediate vesicles pinching off from the plasma membrane; requires GTPase

Question 19

What is required for accurate vesicle targeting?

Answer 19

V-SNARE & t-SNARE

Question 20

What is an endosome?

Answer 20

Membrane enclosed structure that is associated with the endocytotic pathway.

Early endosome: sort and recycle proteins
Late endosome: receives proteins for degradation and newly synthesized lysosomal enzymes -> matures into lysosomes

Question 21

The indigestible substances remaining after phagosome and lysosomes digest particles

Answer 21

Residual body