1 - Cell Ultrastructure & Light Microscopy Flashcards
(149 cards)
1
Q
What advantage is conferred by fluorescent microscopy?
A
Multiple fluorescent stains can be used to tag one specimen
2
Q
What happens to nucleoli during cell division?
A
Disappear
3
Q
What is immunohistochemistry?
A
Identifying specific proteins by introducing relevant antibodies linked to a dye
4
Q
Describe the structure of the SER.
A
Network of relatively round cisternae; no ribosomes
5
Q
Two self-replicating organelles are peroxisomes and mitochondria. What distinguishes them?
A
Peroxisome: no genetic information
Mitochondria: own genetic information
6
Q
H2O2 oxidizes half the alcohol we drink to form ___.
A
Acetaldehyde
7
Q
What is the function of ribosomes?
A
Protein synthesis
8
Q
Describe the structure of intermediate filaments.
A
Rods of protein twisted together (visualize: rope)
9
Q
What is the most commonly used clearing agent?
A
Xylene
10
Q
Describe the structure of microfilaments.
A
Two strings of actin twisted together
11
Q
What is the function of lysosomes?
A
Digestion
12
Q
List 3 areas where you would perform a direct incision biopsy.
A
- Skin
- Mouth
- Larynx
13
Q
What color does eosin stain basic substances?
A
Pink
14
Q
What is the function of mitochondria?
A
Produce ATP
15
Q
What is the function of microfilaments?
A
Contraction
16
Q
What is an endoscopic biopsy?
A
Removal of tissue via instruments on an endoscope
17
Q
What is the name for the convex face of the Golgi apparatus?
A
Cis face
18
Q
Which dye predominantly identifies proteins?
A
Eosin
19
Q
What is the limit of resolution?
A
Minimum distance at which two objects can be distinguished
20
Q
Describe the structure of the RER.
A
Network of relatively flat cisternae; embedded with ribosomes
21
Q
How do lysosomal membranes protect themselves from the powerful acidic hydrolases within?
A
They are highly glycosylated
22
Q
Why must you stain histological sections to reveal structure?
A
Tissues are otherwise translucent
23
Q
What is the fate of proteins synthesized by free ribosomes?
A
Remain in the cytosol
24
Q
What is a direct incision biopsy?
A
Cutting directly into the tissue of interest to remove it
25
Why must you use a clearing agent before embedding tissue with wax?
Dehydrated cells contain alcohol, which doesn’t mix with wax
26
What is autolysis?
Destruction of a cell by its own enzymes (a.k.a. self-digestion)
27
When would you use periodic acid-Schiff (PAS) stain?
Stain areas rich in carbohydrates (e.g., glycogen, glycoproteins, and proteoglycans)
28
Describe the structure of the nucleolus.
Dense region inside the nucleus (note: no membrane)
29
What advantage is conferred by phase contrast microscopy?
Enhanced image of unstained cells
30
In which type of cells are lysosomes generally most abundant?
Phagocytes
31
What is the most commonly used acidic dye?
Hematoxylin
32
Describe the appearance of peroxisomes.
Membrane-bound spheres containing granular matrix
33
Why is it difficult to infuse fresh tissue with wax?
Cells are mainly water, which doesn’t mix with wax
34
How does dark field microscopy work?
Excludes unscattered beam from the image
35
List 3 functions of the nuclear envelope.
1. Separate contents of the nucleus from the cytoplasm
2. Allow selective permeability via nuclear pores
3. Attach to the endoplasmic reticulum
36
What is an organ?
Collection of tissues grouped to perform a particular function
37
When would you use Giemsa stain?
Identify immune cells
38
Why are peroxisomes more abundant in kidney tubules and liver parenchymal cells?
These areas detoxify molecules that enter the bloodstream
39
What color does hematoxylin stain acidic substances?
Blue
40
Compare milli-, micro-, and nanometers.
Millimeters: 10^-3 m
Micrometers: 10^-6 m
Nanometers: 10^-9 m
41
How does fluorescent microscopy work?
Targets molecule of interest with fluorescent dye
42
What is a biopsy?
Removal of a small piece of tissue for microscopic examination
43
When would you use van Gieson stain?
Examine elastic fibres
44
What 2 advantages are conferred by dark field microscopy?
1. Enhanced image of unstained cells
2. Enhanced image of live cells
45
List 2 reasons why tissue needs to be fixed.
1. Prevent autolysis
2. Prevent putrefaction
46
Describe the structure of the plasma membrane.
Phospholipid bilayer with proteins embedded (i.e., fluid mosaic model)
47
What is the purpose of the glycocalyx?
Gives the cell specificity
48
What is Breslow thickness?
Depth of malignant melanocyte invasion
49
List 3 final destinations of the secretory pathway.
1. Cell membrane
2. Cell exterior
3. Lysosomes
50
Hematoxylin stains which substances blue?
Acidic
51
List 2 functions of the SER.
1. Synthesize fats
2. Synthesize steroids
52
Describe the structure of mitochondria.
Double membrane with inner membrane thrown into cristae
53
How do proteins get from the RER to the Golgi apparatus?
Membrane-bound vesicles
54
Compare transverse, longitudinal, and oblique cuts.
Transverse: width-wise
Longitudinal: length-wise
Oblique: at an angle
55
Define histology
The study of the structure of tissues via stains and microscopy
56
What type of microscopy would you use to generate 3D images from a series of 2D images?
Confocal
57
Compare euchromatin and heterochromatin.
Euchromatin: loose, actively synthesizing RNA
Heterochromatin: tightly packed, not synthesizing RNA
58
What is the most commonly used dehydrating agent?
Alcohol
59
Which dye would stain the nucleus?
Hematoxylin
60
What is the function of microtubules?
Movement
61
Describe the structure of the glycocalyx.
A cell “coat” made up of carbohydrate side chains
62
What is the first line of treatment for non-small cell carcinoma?
Surgery
63
Describe needle biopsies.
Needle gathers cells from tissue
64
List 5 structures that stain well with PAS.
1. Glycocalyx
2. Mucus
3. Brush borders
4. Reticular fibres
5. Basement membranes
65
Compare eukaryotic and prokaryotic cells.
Eukaryote cells: internal membranes
Prokaryotic cells: no internal membranes
66
List 3 functions of the RER.
1. Synthesize proteins destined for the secretory pathway
2. Make lysosomes
3. Glycosylation
67
Which organelle is responsible for maintaining cell shape?
Cytoskeleton
68
What are the 2 major functions of the nucleus?
1. Store DNA
2. Coordinate cell activities (e.g., metabolism, growth, protein synthesis, mitosis)
69
The phospholipid bilayer of the plasma membrane forms a barrier. What component performs most other functions?
Proteins embedded in the bilayer
70
Which substance is produced in peroxisomes?
Hydrogen peroxide (H2O2)
71
Describe the structure of the nuclear envelop.
Double-layered membrane interspersed with nuclear pores
72
Where would vesicles from the RER fuse with the Golgi apparatus?
Cis face
73
What is the best stain for revealing muscle and different types of connective tissue?
Masson’s trichome
74
What is the function of nuclear pores?
Allow specific molecules to travel between the nucleus and cytoplasm
75
Why are electron microscopes capable of finer resolution than light microscopes?
Limit of resolution is proportional to wavelength, and electrons have a shorter wavelength
76
List 3 types of cells that lack nuclei.
1. Erythrocytes
2. Stratum corneum cells
3. Lens fiber cells
77
Describe how a smear is taken.
Cells are exfoliated and smeared on a slide
78
What are the 3 components of the nucleus?
1. Nuclear envelope
2. Nucleolus
3. Genetic material (i.e., DNA, RNA, and nucleoproteins)
79
Which process confers stability upon biopsied tissue?
Fixation
80
List 5 functions of the cytoskeleton.
1. Maintaining cell shape
2. Structural support for membrane and organelles
3. Means of movement for cytosol constituents
4. Locomotor mechanisms for amoeboid movements, cilia, and flagella
5. Contractility (e.g., in muscle)
81
What is confocal microscopy?
Fluorescent microscopy with improved image resolution by means of using a pinhole to block out-of-focus light
82
Describe the pathological effects of lysosomal storage disorders.
Molecules normally broken down by lysosomes accumulate within the cell, causing dysfunction
83
List 5 areas that are abundant in SER.
1. Liver
2. Mammary glands
3. Ovaries
4. Testes
5. Adrenal glands
84
Proteins within the plasma membrane can either a) move or b) are fixed in place by the \_\_\_.
Cytoskeleton
85
When would you use silver stain?
Examine reticular fibres
86
How do fixatives work?
Arrest cell activity by cross-linking proteins
87
Why don’t fat droplets stain in H&E?
Washed away during preparation
88
List 2 areas where you would perform a transvascular biopsy.
1. Heart
2. Liver
89
What is the function of the Golgi apparatus?
Modify, package, and sort proteins from the RER
90
What is the most effective treatment for malignant melanoma?
Early diagnosis and excision
91
What is the function of the nucleolus?
Synthesize ribosomes
92
What is a microtome?
Device used to slice tissues for histological slides
93
How many mitochondria would you find in a liver cell?
2000
94
Which dye would stain the cytoplasm?
Eosin
95
What 3 advantages are conferred by confocal microscopy?
1. Multiple fluorescent stains can be used on one specimen
2. Improved focus
3. 3D images from a series of 2D images
96
What is the perinuclear cisterna?
Space between the inner and outer nuclear membranes
97
What is the function of SER in the mammary glands?
Synthetize fats
98
By what process do secretory vesicles release their contents at the cell surface?
Exocytosis
99
What do lysosomes contain?
Powerful hydrolytic enzymes
100
Period acid-Schiff stains carbohydrate-rich areas what color?
Purple
101
List 5 areas where you would perform a needle biopsy.
1. Brain
2. Breast
3. Liver
4. Kidney
5. Muscle
102
Why do proteins entering the Golgi body migrate from the cis face to the trans face?
Differences in polarity
103
List 3 common tissue fixatives.
1. Glutaraldehyde
2. Formaldehyde
3. Alcohol
104
List 7 functions of the plasma membrane.
1. Selective permeability
2. Transport of material along the cell surface
3. Endocytosis
4. Exocytosis
5. Intercellular recognition
6. Intercellular adhesion
7. Signal transduction
105
Which organelle is the site of translation?
Ribosomes
106
Which organelle has a female lineage?
Mitochondria
107
Explain the value of histology in diagnosis.
A biopsy and histology is the final proof of disease (nb doctors may not administer treatment until histopathologists have given a diagnosis)
108
What is the function of SER in the liver?
Synthesize fats
109
Compare primary and secondary lysosomes.
Primary: free lysosome
Secondary: lysosome fused with a phagosome
110
What are the 2 main substrates of the mitochondria?
1. Glucose
2. Fatty acids
111
What are the 2 major components of ribosomes?
4. RNA
5. Proteins
112
When would you use Picro-Sirius Red dye?
Stain collagen bright red
113
What is the most common embedding agent?
Paraffin wax
114
What is autophagy?
The process by which malfunctioning cellular components are broken down for reuse
115
Why Is it difficult to cut thin section of fresh tissue?
Fresh tissue is soft and loses its integrity as the microtome passes through it
116
What is the name for the concave face of the Golgi apparatus?
Trans face
117
Compare the diameter of microfilaments, intermediate filaments, and microtubules.
Microfilaments: 5 nm
Intermediate filaments: 10-12 nm
Microtubules: 25 nm
118
Describe the structure of phospholipids.
Amphipathic; have a hydrophilic head and hydrophobic tail
119
Where are ribosomes synthesized?
Nucleolus
120
Eosin stains which substances pink?
Basic
121
Describe curettage.
Tissue is removed by scraping
122
Describe the structure of the Golgi apparatus.
Saucer-shaped stacks of cisternae
123
List 3 areas where you would perform an endoscopic biopsy.
1. Lungs
2. Intestine
3. Bladder
124
What are the 3 components of the cytoskeleton?
1. Microfilaments
2. Intermediate filaments
3. Microtubules
125
List 5 substances you would find in the mitochondrial matrix.
1. Enzymes
2. DNA
3. RNA
4. Ribosomes
5. Calcium granules
126
What is the fate of proteins leaving the Golgi?
Secretory pathway (i.e., leave cell, implant in membrane, or engulfed by lysosomes)
127
List 2 areas that you would perform a smear.
1. Cervix
2. Buccal cavity
128
What is the first line of treatment for small cell carcinoma?
Chemotherapy
129
Why are there large numbers of mitochondria in the liver and skeletal muscle?
Areas require a lot of energy
130
What is the structure of lysosomes?
Membrane-bound vesicle filled with hydrolytic enzymes
131
Where do proteins entering the cis face of the Golgi body migrate?
Trans face
132
What is chromatin?
Fibers of DNA and protein; precursor for chromosomes
133
Explain the endosymbiosis theory re: mitochondria.
Mitochondria were originally prokaryotic cells that developed a symbiotic relationship with primordial eukaryotic cells
134
Describe the structure of microtubules.
Hollowed cylinder consisting of dimers of alpha and beta tubulin
135
What is the function of SER in the ovaries, testes, and adrenal glands?
Synthesize steroids
136
What is the function of intermediate filaments?
Anchoring
137
What is a tissue?
Collection of cells specialized to perform a particular function
138
What is the centrosome?
Site of microtubule organization
139
How can tissue professing lead to the formation of artefacts?
During slide preparation, tissue is dehydrated and rehydrated, which can lead to abnormalities in the final slide
140
What are lamins?
Intermediate filaments that support the nuclear membrane
141
What is putrefaction?
Decay
142
What are residual bodies?
Lysosomes that have digested their contents, but contain indigestible remains
143
Compare the limit of resolution of scanning electron microscopes (SEM) and transmission electron microscopes (TEM).
SEM: higher
TEM: lower
144
What is the function of peroxisomes?
Detoxification
145
How does phase contrast microscopy work?
Uses interference effect of two combining light waves
146
Which dye predominantly identifies nucleic acids?
Hematoxylin
147
Where would you perform curettage?
Lining of uterus
148
What is the basic structure of all cell membranes?
Phospholipid bilayer
149
What happens to the nuclear envelope during cell division?
Breaks down during prophase and is reconstituted around the two daughter cells at telophase
