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Cell Biology - Summer 2023 > Theme 1 > Flashcards

Theme 1 Flashcards

(58 cards)

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1
Q

what is a cell?

A

the fundamental unit of life

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2
Q

what is needed to grow/culture cells?

A

glucose and nutrients, insulin, growth factor (serum) –> for growth
trypsin –> to break cells apart
EDTA –> sponge
at 37 degrees in CO2 for pH balance

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3
Q

what are primary cells? adv and disadv.

A

cells directly from the body
more accurate for observing diseases/reactions etc.
cannot grow indefinitely

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4
Q

what are cell lines? adv and disadv.

A

transformed immortal cells
grow indefinitely and are more versatile
potentially cancerous (genetic differences to primary)

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5
Q

what are HeLa cells? adv and disadv.

A

immortal cells from henrietta lacks
first human cell line
good for research
but illegal/ethical reasons to not use

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6
Q

what are HeLa cells? adv and disadv.

A

immortal cells from henrietta lacks
first human cell line
good for research
but illegal/ethical reasons to not use

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7
Q

what is contact inhibition?

A

when cells stop dividing due to lack of space (not cell line)

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8
Q

what is the role of trypsin?

A

break apart cells so you can replate them

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9
Q

what is the hayflick limit?

A

how many times cells can divide before senescence
determined by the telomere length

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10
Q

what is a fibroblast?

A

connective tissue cells

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11
Q

what does it mean for a cell to be transformed?

A

behaves differently because of mutations to the cell

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12
Q

what are the differences between normal and transformed fibroblasts?

A

hair-like processes, larger, overlap, rounded, no pattern to growth, no contact inhibition

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13
Q

what is the difference between symmetrical and asymmetrical cell division? importance of each.

A

symmetric = 1 cell –> 2 identical cells
asymmetric = 1 cell –> 2 diff cells or 1 same 1 diff cells
symmetric important for renewal, by primary/ immortalized cells.
asymmetric important for differentiation, by adult stem cells.

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14
Q

what are stem cells?

A

cells that can divide into any cell in the body

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15
Q

what are adult stem cells?

A

cells that can divide into any cell for a specific organ/function (progenitor or functional cells)

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16
Q

what are embryonic stem cells?

A

stem cells from the embryo, used to create organelles

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17
Q

what is stem cell renewal?

A

during symmetric and asymmetric division, divide into a cell identical to the “mother” cell

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18
Q

what are differentiated cells?

A

during asymmetric division, divide into a cell different to the “mother”.
in its final stage of division/ready for job/function

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19
Q

what is the difference between multipotent and pluripotent?

A

pluripotent = can divide into all cell types (germ layers)
multipotent = can divide into some but not all cell types

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20
Q

what is necessary for culturing ESC’s?

A

embryos –> inner cell mass (aka blastocyst) –> fibroblast feeder –> trypsin –> sieve –> feeder cells (again, re-plated)

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21
Q

what is the purpose of culturing ESC’s?

A

induced to create pluripotency/precursors for various cell types

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22
Q

why do we use adult stem cells instead of embryonic stem cells?

A

maintain/repair tissues, embryonic can only create organelles (not actual organs)

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23
Q

what is the pathway of adult stem cell differentiation?

A

adult stem cell (crypt) –> migrate (out crypt) –> differentiated cell (villi) –> death (top of villi)

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24
Q

what is the distinction between a stem cell and a differentiated cell?

Study These Flashcards
A

differentiated cell is at the last stage, stem cells continue to divide

25
what is a stem cell niche?
the few cells surrounding (adjacent to) stem cells, used to alert stem cells to differentiate or renew
26
do all tissues have stem cells?
yes, except for neurons and nerves. (this is why when they are damaged, they do not repair themselves)
27
how can you go backwards from differentiated cells to pluripotent stem cells?
induced pluripotency (done by reprogramming)
28
what are Oct4, Sox2, Lkf4 and c-Myc? What do they do?
- Yamanaka/transcription factors - introduced to induce pluripotency (artificial overexpression in differentiated cells) - c-Myc = cancerous and may disrupt the cell cycle
29
what are induced pluripotent stem cells?
iPS cells adult stem cells that have been changed to be pluripotent --> reprogrammed fibroblasts
30
what is the medical application of iPS?
use for transplantation, won't be rejected because it's your own cells, and will not have ethical concerns.
31
what are the basics of a compound microscope lens?
contains 3 lenses to help focus 1. condenser 2. objective 3. ocular
32
how does the size of an object correspond to which microscopy technique should be used?
animal/plant cells = brightfield atoms and intracellular components = electron
33
what is resolution? how is it derived?
D = 0.61 gamma/ Nsin alpha how close things can be together where the are still differentiable as 2 things.
34
what is numerical aperture?
bottom (N sin alpha). 1/2 angle and refractive index of light.
35
what changes D?
any of the variables, D is smaller when the top is decreased or the bottom is increased.
36
what are the refractive properties?
oil/glass = refractive. how light bounces off that surface, of the medium between specimen and objective lens.
37
what is phase contrast microscopy?
better quality than brightfield (for intracellular, outside will have a halo). for live, unstained cells. changes light phases, out of sync/has interference.
38
what is fluorescence?
a specific colour/wavelength excites electrons to express a different colour. uses dichroic mirrors, and in immunofluorescence, uses antibodies.
39
what is a stoke shift?
the difference between the peak of the excitation wave and the emission wave. the bigger the stoke shift, the more different the colour is.
40
what is the relationship between energy of a photon, wavelength and colour?
increased energy = short wavelength = more purple (UV)
41
what is the light path of a fluorescent microscope compared to normal?
light --> excitation light --> dichroic mirror --> objective lens --> specimen. specimen --> emission light --> objective lens --> dichroic mirror --> emission filter --> emitted light --> ocular lens --> detector.
42
what is an antibody?
made of proteins, bind to proteins they were designed to recognize
43
how are antibodies made?
from primary cells (spleen) that fought antigens
44
how can antibodies be used for research?
detect disease (immunobiology) --> detect and show (immunofluorescence)
45
monoclonal vs polyclonal antibodies?
detects 1 vs detects >1 disease.
46
how do you make monoclonal antibodies?
myeloma (cancer) + spleen (with antigens) = immortalized antibodies (in HAT medium). myeloma alone will die in HAT medium. spleen alone will die due to hayflick limit.
47
what are antigens?
disease cells
48
what are epitopes?
attachment sites for specific antibodies on antigens
49
what is dual labelling microscopy?
uses 2 antibodies (with 2 fluorochromes) --> 2 microscopy filters (one for each fluorochrome) --> digitally overlay images
50
what is green fluorescent protein? how is it used?
GFP = fluorescence from jellyfish. bioluminescence with a chromophore (excited with blue light, emits green light) (beta-barrel). transfected into live cells to fluoresce/image them.
51
what is confocal microscopy? what does confocal mean?
laser scanning, 3D reconstruction + clarity, focuses in-focus light through pinhole (higher intensity), rejects out-of-focus light from the image. confocal = same foci (aka block's out out-of-focus light with pinhole)
52
what is conventional fluorescence vs confocal?
changes intensity/focus of light for better/sharper quality. eliminates out-of-focus light to make a clearer image.
53
what is FRET? How does it work?
fluorescence resonance energy transfer (uses CFP and YFP), excitation from one fluoro --> emission excites #2. shows/measures protein interactions, if interaction is present, colour #2 will be expressed.
54
what is two-photon excitation microscopy?
two photons fired almost instantaneously --> no cone of excitation light but emits the same. for thicker samples without the need for pinholes.
55
what are the two basic types of electron microscopy?
TEM (transmission) and SEM (scanning/scattered) TEM = detailed interior sections of the cell SEM = detailed overview, surface details (3D)
56
why does electron microscopy have increased resolution?
uses electrons/energy, instead of light. D = 0.61 gamma / alpha no Nsin so D is increased.
57
how does immunoelectron microscopy work?
antibody to detect changes in charge. detects specific proteins using antibodies.
58
when would you use each microscopy technique over others?
brightfield = cheap and can be done on live cells confocal = for sharper images fluorescence = more than 1 protein/cell structure electron = whole cell/more detail FRET = detect protein interactions

Cell Biology - Summer 2023 (1 decks)

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