Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Histology (Emily) > Lecture 1 - Microscopy, Staining, Cell Membrane Organelles > Flashcards

Lecture 1 - Microscopy, Staining, Cell Membrane Organelles Flashcards

1
Q

Resolution

A

measurable distance b/t 2 points at which they can still be seen as separate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the resolution of the human eye?

A

0.2 mm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

____ wavelength = better resolution

A

Shorter wavelength = better resolution (light < UV < EM)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Light Microscope

A

light, condenser lens condenses light on specimen, passes through to objective lens, ocular lens enlarges virtual image.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

TEM (Transmission Electron Microscopy)

A

same as light except cathode emits electrons through sample (done in vacuum)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

SEM (Scanning Electron Microscope)

A

electrons reflect off specimen (coat in metal). Get a 3D view of the specimen, shows what’s on the surface of membrane not what’s inside. Resolution is not as good as TEM.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Atomic Force Microscope (AFM)

A

non-optical, cantilever w/ sharp tip dragged along specimen, laser pointed at tip of cantilever and reflect to photodiode (stationary, the stand moves to hit the it)

  • bumpy images, very high resolution (can see single DNA molecule, nuclear pore etc.)
  • No fixation, can look at living cells; examine dynamic changes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the six steps to preparation of samples?

A
  1. Fixation: stop metabolism, cross-link proteins to make them inactive, prevents enzymatic degradation, kills pathogens.
  2. Dehydration: alcohol up to 100%, 70% common; removes fat, mucosa, golgi etc.
  3. Embedding: allows specimen to be thinly sliced
  4. Sectioning
  5. Mounting
  6. Staining
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Fixation for FM v. EM

A

LM: Formaldehyde

EM: Glutaraldehyde

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Embedding for LM v. EM

A

LM: Paraffin

EM: Epoxy resins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Sectioning LM v. EM

A

LM: Microtome (metal knife)

EM: Ultra-microtome (diamond/glass)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Mounting LM v. EM

A

LM: Glass Slide

EM: Copper grid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Staining LM v. EM

A

LM: Hematoxylin and Eosin

EM: Heavy Metals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What type of dye is Hematoxylin? Types of structures stained?

A

Basic dye (acidophilic stain)

Stains acidic structures BLUE

Stains DNA, ribosomes, nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What type of dye is Eosin? Types of structures?

A

Acidic dye (Basophilic stain)

Stains basic structures PINK

Stains cytoplasmic stuff, proteins, protein-filled vesicles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Acidophilic

A

Loves acid, therefore basic and positively charged (BLUE)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Basophilic

A

loves base, therefore acidic and negatively charged

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

PAS (Periodic Acid-Shiff Reaction)

A

Carbohydrates stain purple. Used to demonstrated glycogen in cells, mucus (goblet cells), basement membrane, and reticular fibers.

  1. Periodic acid cleaves bond between adjacent carbon atoms to make aldehydes.
  2. Aldehyde groups react with Schiff reagent.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Mallory’s Trichome

A

stains connective tissue (collagen – blue)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Toludine Blue

A

stains mast cells dark blue/purple

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Mucicarmine

A

Stains mucus (pink)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Silver Stain

A

Stains for reticular fibers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Immunocytochemistry

A

Using antibody with specific marker to bind specifically to molecule of interest or specific cell/tissue type (like melanocytes).

Usually used with enzymes.

24
Q

Autoradiography

A

Radioactive labeled molecules can be injected into animals/tissues and traced to localize the larger molecules in cells and tissues.

25
Q

Enzyme Histochemistry

A

Using capture agent to precipitate reaction product of the enzyme, not the enzyme itself.

e.g. lysosome was identified by precipitating lead ions derived from acid phosphatase activity.

26
Q

Hybridization Techniques

A

Localizing mRNA or DNA by hybridizing the sequence of interest to a complementary strand of a nucleotide probe.

Ex. FISH (gene testing by probing chromosomes)

27
Q

Plasma Membrane

A
  • asymmetric, dynamic fluid structure of amphipathic lipids, cholestorol, proteins, glycoproteins and glycolipids
  • held together by non-covalent interaction between lipids.
  • more proteins on inner P-face (covered more in cell membrane!)
28
Q

Lipid Rafts

A

Multiple signaling platform; enriched in glycosphingomyelins (stick out above surface w/ long lipid tails) & cholesterol, thus more dense area of glycogen & protein on “ocean” of lipids

29
Q

Integral Membrane Proteins

A

Imbedded in membrane (pumps, receptors, channels, enzymes, structural, linkers)

30
Q

Peripheral Membrane Proteins

A

Not attached to membrane, but attached to membrane proteins.

E.g. glycocalyx and microvilli

31
Q

Rough Endoplasmic Reticulum (rER)

A
  • protein synthesis w/ ribosomes for secretion, cell membrane, and internal needs (acidic = basophilic! BLUE)
  • volume occupied by rER – best LM indication of cell activity; if large, cell is producing lots of protein
32
Q

Smooth Endoplasmic Reticulum

A

Synthesize steroid hormones, degrade and detox alongside lysosomes and peroxisomes (alcohol abuse shows a lot of sER in liver cells), glycogen metabolism in liver cells, and regulate Ca2+ release into cytoplasm for muscle contraction.

33
Q

Golgi Apparatus

A
  • cisternae layers, vesicles bud from rER and go to cis-face (first layer) of Golgi
  • trans-face towards cell membrane
  • complete synthesis of lipids and proteins through post-translational modification: trim off singal peptides from sequence, hydroxylation of a.a. residues, and glycosylation to make polysaccharides

- sorts/packages proteins into secretory vesicles for export

  • Often washed away during stain process b/c contains lots of lipids = negative staining of where golgi used to be!
34
Q

What are the two types of pathways for protein secretion?

A
  1. Regulated
  2. Constitutive
35
Q

What is regulated protein secretion?

A

Some sort of regulatory event triggers secretion. Ex. Clathrin-coated vesicles accumulate and wait in cytoplasm, influx of Ca2+ regulates secretion.

If regulated secretion is common in cell, see presence of clathrin-coated vesicles (very pink stored protein).

36
Q

What is constitutive protein secretion?

A

Immediate/constant secretion of synthesize proteins, ie. collagen in fibroblasts, plasma cell antibodies. Not all have regulated secretion.

37
Q

Endosomes and Transport Vesicles - How are they formed?

A

Formed folling budding from plasma membrane or Golgi, coated by clathrin.

  1. cargo protein reaches cargo receptor at plasma membrane
  2. adaptin binds to receptor allowing clathrin to interact with receptor
  3. dynamin cuts the vesicle from the membrane
  4. vesicle uncoats and goes to specified location in cell
38
Q

Early Endosome

A

Sorting of vesicles, those not sent to other places go to late endosome

39
Q

Late Endosome

A

Acidifying, become lysosomes. Found near Golgi and nucleus.

40
Q

Lysosomes

A
  • Formed from late endosome by delivery of hydrolytic enzymes.
  • hydrolysis of molecules & organelles – how cell gets nutrients; recycling of amino acids/monosaccharides; destroy foreign organisms; bone reabsorption
  • has unique membrane that is resistant to hydrolytic enzymes à membrane contains cholesterol and lipids that are highly glycosylated. pH decreases as the lysosomes mature (more acidic)
41
Q

What role does Mannose-6-phosphate play in lysosomes?

A

M6P directs enzymes to late endosomes.

42
Q

What is I-Cell disease?

A

No M6P, lots of vescicles with lysosomal enzymes! Eventually unsustainable.

43
Q

Mitochondria

A
  • mobile power generators (ATP) with highest ATP synthase and protein pump concentrations in inner mitochondrial membrane; very distincted membrane covered “bean” shape and cristae.
  • own genome and complete system of protein synthesis
  • can initiate apoptosis via release of cytochrome C from intermembrane space = caspases cascade
44
Q

Nucleus - LM and EM features

A

LM: Largest organelle, distinct dark color

EM: Double membrane, dark nucleolus, nuclear pores, dark heterochrom/light euchromatin

45
Q

Nucleolus - LM and EM Features

A

LM: Not visible unless in living cells

EM: Very dense and granular within nucleus

46
Q

Plasma membrane - LM and EM Features

A

LM: Not visible; can see outline but not the bilayer structure; PAS staining

EM: Inner and outer electron dense layers separated by electron lucent layer

47
Q

rER - LM and EM Features

A

LM: A basophilic region of cytoplasm

EM: Flattened sheets and sacs with ribosomes!

48
Q

sER - LM and EM Features

A

LM: Not visible

EM: Flattened sheets

49
Q

Golgi - LM and EM Features

A

LM: Negative staining; washed away

EM: Flattened membrane sheets next to nucleus

50
Q

Mitochondria - LM and EM Features

A

LM: Not visible

EM: Double membrane, cristae

51
Q

Endosome - LM and EM Features

A

LM: Not visible

EM: Tubulovesicular with subdivided lumen

52
Q

Lysosome - LM and EM Features

A

LM: Only with histochemical staining

EM: Membrane bound vesicle, electron dense

53
Q

Peroxisome - LM and EM Features

A

LM: Only with histochemical staining
EM: Membrane bound, electron dense, crystalloid inclusions

54
Q

Cytoskeleton - LM and EM Features

A

LM: Not visible unless in large fibrils

EM: Long linear staining pattern with each type

55
Q

Ribosomes - LM and EM Features

A

LM: Not visible

EM: Small dark dots, often by rER

56
Q

Lipid Droplets - LM and EM Features

A

LM: Washed out holes, peripheral nuclei

EM: Nonmembranous, void

Histology (Emily) (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions