Test 1 - Lecture 3

Question 1

What is a C/N ratio? Why is it important?

Answer 1

The amount of cytoplasm to nucleus ratio - it helps determine what cell type it is (squamous has small C/N and columnar has large C/N)

Question 2

What are 4 possible “inclusions” in the cytoplasm? How might they look with H&E stain?

Answer 2

Make the cytoplasm look odd
1. secretory granules
2. pigment
3. glycogen
4. stored waste products

Question 3

Describe the fluid mosaic model for a plasma membrane.

Answer 3

Not homogenous (things in membrane not evenly dispersed) - lipid rafts (percentage into areas that have specific functions

Question 4

What is the function of the plasma membrane (4)?

Answer 4

1. encloses the cell
2. ion/nutrient transport
3. recognition of environment or cell signals
4. cell-cell & cell-ECM adhesions (proteins that allow cell to attach to another cell)

Question 5

How does an endosome become a lysosome?

Answer 5

1. early endosome starts in cytoplasm near plasma membrane
2. the endosome begins migration towards nucleus where the pH starts to decrease
3. as the pH decreases protons begin to come into the cell
4. within an increase in protons another vesicle from the Golgi called the pre-lysosome fuses to the late- endosome
5. after fusion, the lysosome pumps more protons & destructive enzymes inside
6. these late endosomes then mature into lysosomes

Question 6

What does a lysosome do?

Answer 6

digestion of macromolecules derived from endocytotic pathways and autophagy

Question 7

Describe how a protein made in the rough ER is secreted by the cell.

Answer 7

RER -> Golgi -> plasma membrane = excretory pathway

Question 8

In general, what is necessary for a vesicle to fuse with another membrane?

Answer 8

match-up of proteins in order for a vesicle to meet-up and attach…. need the right SNARE protein

Question 9

Describe how a lysosome participates in the process of autophagy?

Answer 9

cell clean out process —- digestion by lysosome

Question 10

Compare electron densities of autophagosomes and lysosomes.

Answer 10

lysosomes - electron-rich, because they are digesting macromolecules

autophagosomes - have halo around what they are degrading

Question 11

What is a proteasome, and is its functioning random?

Answer 11

large cytoplasmic protein complexes that perform protein degradation without lysosomes - this isn’t random. proteins are specifically tagged for this pathway

Question 12

How would you distinguish whether a cell performed more detoxification versus protein production?

Answer 12

protein production - dark more e-rich

Question 13

Does the Golgi Apparatus stain with H&E?

Answer 13

No, because it is a very fatty structure

Question 14

Describe and compare the rER, sER, and Golfi using EM images

Answer 14

rER - lines/channels with dots (ribosomes) all over
sER - tubular with no ribosomes
Golgi - stacked, flat membrane stacks with tubular extensions (wider than sER)

Question 15

Describe the appearance of mitochondrion using TEM

Answer 15

Looks just like a cartoon image of a mitochondria

Question 16

Describe the appearance of peroxisome using TEM

Answer 16

basically looks just like vesicles

Question 17

How would you differentiate active filaments, microtubules, and intermediate filaments using TEM?

Answer 17

actin: look like wispy hairs
microtubules: look like smooth ER, but with bigger lumen and much more irregular
intermediate: scaffolding/basket-weave

Question 18

Are glycogen inclusions electron-dense?

Answer 18

Yes

Question 19

Compare and contrast the electron density of nucleus, heterochromatin, and euchromatin.

Answer 19

nucleolus (most dense)
heterochromatin
euchromatin (less dense)

Question 20

How would you identify a slide with necrosis and/or apoptosis?

Answer 20

necrosis: accidental cell death; pathological swelling + lysis

apoptosis: programmed cell death - cells maintain membrane, perform autodigestion (cleaner and more organized)