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Z OLD Tissues of the Body > Cell Ultrastructure > Flashcards

Cell Ultrastructure Flashcards

1
Q

How is the image viewed using a light microscope?

A

Directly

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2
Q

How is the image viewed using a transition electron microscope (TEM)?

A

On a fluorescent screen

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3
Q

What is the purpose of the heated filament in a TEM?

A

Source of electrons

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4
Q

What is used as the lenses in a TEM?

A

Electromagnets

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5
Q

Why is the specimen for a TEM not on glass?

A

Glass would disrupt the electrons

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6
Q

How is the image viewed using a scanning electron microscope (SEM)?

A

On a viewing screen

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7
Q

What is the specimen for a SEM treated with?

A

Gold or palladium

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8
Q

Why is the specimen for SEM treated with gold or palladium?

A

So it reflects electrons, giving a surface image

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9
Q

What is the limit of resolution?

A

The minimum distance at which two objects can be distinguished

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10
Q

What is the limit of resolution proportional too?

A

Wavelength

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11
Q

What happens to resolution as wavelength decreases?

A

It improves

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12
Q

What does the wavelength of electrons depend on?

A

Voltage

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13
Q

Is the theoretical limit of resolution ever reached?

A

No

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14
Q

What is the theoretical limit of resolution for light microscopes?

A

0.2µm

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15
Q

What is the theoretical limit of resolution for electron microscopes?

A

0.002nm

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16
Q

What membranes do prokaryotes have?

A

Have external membrane, but no internal membrane

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17
Q

Where do all biochemical processes of a prokaryotic cell occur?

A

All in same compartment

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18
Q

How are eukaryotic cells compartmentalised?

A

By internal membranes

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19
Q

Give 10 components of a eukaryotic cell

A
  • Endosome
  • Lysosome
  • Cytosol
  • Golgi apparatus
  • Peroxisome
  • Endoplasmic reticulum
  • Nucleus
  • Free polyribosomes
  • Mitochondria
  • Plasma membrane
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20
Q

How many proteins does a typical mammalian cell synthesise?

A

More than 100,000

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21
Q

What do phospholipids consist of?

A

NAME?

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22
Q

What does the head group of phospholipids consist of?

A

Choline-Phosphate-Glycerol

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23
Q

What does the hydrophobic tail of a phospholipid consist of?

A

2 fatty acids

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24
Q

What kind of molecules are phospholipids?

A

Amphipathic

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25
What do phospholipid molecules make up?
The cell membrane
26
What does the phospholipid bilayer form?
A relatively impermeable barrier to most water-soluble molecles
27
What mediates most other functions of the phospholipid bilayer?
Proteins ‘dissolved’ in the membrane
28
Are the proteins in the phospholipid bilayer free to move?
Some are attached to cytoskeletal elements, so can\t move as much, but some freely mobile
29
How can membrane proteins be associated with the bilayer?
#NAME?
30
What parts of proteins often sit in the membrane?
α-helical regions
31
What is the cell coat called?
Glycocalyx
32
What is the glycocalyx made up of?
Oligosaccaride and polysaccharide side chains on outside of plasma memebrane
33
What do sugars give to the cell membrane?
Specificity of action
34
What is the importance of the specificity of action of the glycocalyx?
It allows them to work as receptors or stimulators
35
What are the functions of the plasma membrane?
- Selective permeability  - Transport of materials along cell surface - Endocytosis  - Exocytosis  - Intercellular adhesion  - Intercellular recognition  - Signal transduction
36
What does the rough endoplasmic reticulum (RER) have?
Ribosomes
37
Do all cells have RER?
Yes
38
Where is RER more abundant?
In cells producing a lot of protein
39
Where are proteins made?
In the cisternae of RER
40
Does smooth endoplasmic reticulum (SER) have ribosomes?
No
41
Where is SER found?
#NAME?
42
What is the function of SER in the mammary glands?
Lipid biosynthesis
43
What is the function of SER in the adrenal glands?
Steriodogenesis
44
How does SER differ from RER?
More irregular
45
What is it thought of the ER membrane?
It is continuous and enclosed in a single lumen
46
What is the Golgi apparatus involved in?
Protein synthesis
47
What happens at the Golgi apparatus?
- Vesicles with proteins join at it’s cis face - Proteins move through various sacs - Vesicles pinch off
48
What are the functions of the Golgi apparatus?
Modify, sort, concentrate and package proteins synthesised in the ER
49
What modifications are made in the Golgi apparatus?
Glycocylation
50
What are lysosomes generated by?
Golgi apparatus
51
What do lysosomes contain?
Lots of acid hydrolytic enzymes
52
What hydrolytic enzymes do lysosomes contain?
#NAME?
53
What is the pH in lysosomes?
~5
54
What happens to anything defunct in a cell?
It can be wrapped in a membrane, fused with a lysosome and broken down
55
How is the membrane of a lysosome protected?
By a glycocalyx
56
What do lysosomes fuse with?
Any material requiring digestion
57
What material might require digestion?
- Bacterium  - Other molecules taken up by endocytosis  - Defunct cellular components
58
What happens when bacteria are taken up by phagocytosis?
They form phagosomes, which fuse with lysosomes
59
What happens to other molecules that are taken up by phagocytosis?
They form an early endosome, which changes to lysosome, which fuses with lysosome
60
What is the process of removal of defunct cellular components called?
Autophagy
61
What is formed in autophagy?
Autophagosome
62
Where are peroxisomes found?
#NAME?
63
What do peroxisomes do?
Detoxify a number of molecules
64
How do peroxisomes detoxify?
By oxidation
65
What molecules do peroxisomes detoxify?
- Alcohol - Phenols  - Formic acid - Formaldehyde
66
Give the equations for detoxification that occurs by peroxisomes
- RH 2 + O 2 →  R + H 2 O 2 | - R’H 2 + H 2 O 2 →  R’ + 2H 2 O
67
What do mitochondria consist of?
- Matrix  - Inner matrix in folds in cristae  - Outer membrane
68
What does the matrix contain?
100’s of enzymes and mitochondrial DNA genome
69
What does the inner membrane of mitochondria contain?
Enzymes for oxidation reactions of respiratory chain
70
What is an important feature of the inner mitochondrial membrane?
It is impermeable to small ions
71
Is the outer mitochondrial membrane permeable?
Yes, to molecules
72
What is the pH of the mitochondrial inner membrane space?
7
73
What is the pH of the matrix?
8
74
What are the mitochondria the site of?
A cells energy production
75
Where are the mitochondria cristae typically tubular?
In steriodogenic cells
76
Why are mitochondria unlike other organelles?
They contain their own genetic information and can divide
77
What is the primary function of mitochondria?
Generation of ATP by oxidative phosphorylation
78
What lineage to mitochondria have?
Female
79
What is meant by mitochondria having female lineage?
All mitochondria are inherited from mother
80
How big are actin filaments
5-9nm in diameter
81
How are actin filaments distributed?
Cortical
82
What are actin filaments made up of?
A coil of two strings
83
What are actin filaments able to do?
Get longer and shorter
84
What is the diameter of intermediate filaments?
~10nm
85
Where are intermediate filaments common?
In epithelial cells
86
What do intermediate filaments form?
A tough supporting meshwork in the cytoplasm.
87
Where are intermediate filaments found in the nucleus
Just beneath the inner nuclear membrane
88
What is formed by intermediate filaments beneath the inner nuclear membrane?
The nuclear lamina
89
What is the purpose of the nuclear lamina?
It helps bind cells together through plasmodesmata
90
What are microtubules?
Long hollow tubes
91
What are microtubules made of?
The protein tubulin
92
Where are microtubules found?
At sites where structures are moved
93
Give 4 places that microtubules are found
- Nerve fibres - Mitotic spindle  - Cilia  - Flagella
94
Where do microtubules originate from?
Centrosome
95
Where do microtubules show the 9+2 arrangement?
- Cilium  | - Flagellum

Z OLD Tissues of the Body (19 decks)

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