Microscopy Flashcards

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1
Q

development of microscopy

A

Robert Hooke (1665) constructed the first LM, observed dead cork tissue and other plant and animal tissue - introduced the term “cell” from monk cells

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2
Q

magnification

A
  • number of times an object is magnified
  • how much smaller/larger is the image than the real specimen
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3
Q

resolution

A
  • the ability of a microscope to show two close objects separately
  • depends on the wavelength of the rays that pass through the spectrum (e- have much shorter wavelength so EM has much higher resolution)
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4
Q

LM vs EM
- what passes through specimen?
- FOV (field of view)?
- magnification?
- resolution?
- colors?
- type of specimen?

A
  • beam of light/beam of electrons
  • larger/smaller
  • up to 500x/up to 500 000x
  • 0.25 microm apart/0.25 nanom apart
  • visible/black-white
  • alive/dead
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5
Q
  • as magnification increases, FOV…
A

…decreases

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6
Q

magnification =

A

image size/actual size

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7
Q

scale bar

A
  • a line added to the micrograph to show the actual size of the structure
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8
Q

freeze-fracture EM

A
  • physically breaking apart frozen biological sample through the weakest piint of the cell
  • structural details exposed by the fracture plane is visualized by deposition of Pt-C to make a replica for examination in the EM
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9
Q

cryogenic EM

A
  • structures of proteins, nucleic acids and other biomolecules
  • studying how they move around and change as they perform their functions (alive)
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10
Q

cell theory

A

1) cells are the basic units of life (nothing smaller than the cell can survive independently)
2) all living things consist of cells
3) new cells come from pre-existing cells by the process of cell division

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11
Q

1) cells are the basic units of life (nothing smaller than the cell can survive independently) - evidence

A
  • sub-cellular components have never been seen to perform functions of life whereas full cells have
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12
Q

2) all living things consist of cells - evidence

A
  • biologists examined tissues from all kingdoms, each specimen had at least one cell
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13
Q

3) new cells come from pre-existing cells by the process of cell division - evidence

A
  • we have observed cells coming from other cells but never observed spontaneous generation
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14
Q

discrepancies (exceptions) to the cell theory

A

1) Striated (skeletal) muscles
- more than 1 nucleus per cell
- long cells, around 30 mm
2) Giant algae, Actabularia
- single-celled organism but up to 20 cm long
3) Aseptate Funghi
- fungal hyphae (narrow thread-like structures) are made up of rows of cells usually separated with septa but some funghi lack this septa -> each hyphae is a continuous multinucleated tube-like structure

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15
Q

unicellular organisms…
(example)

A

…carry out all functions of life. Amoeba

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16
Q

functions of life

A

1) metabolism
2) response
3) nutrition
4) excretion
5) reproduction
6) growth
7) homeostasis
8) movement

17
Q

metabolism

A

all chemical reactions in a cell (catalyzed)

18
Q

response

A

ability to react to stimuli from the environment

19
Q

nutrition

A

obtaining food to get energy

20
Q

excretion

A

removal of waste products

21
Q

reproduction

A

production of offspring sexually or asexually

22
Q

growth

A

irreversible increase in size

23
Q

homeostasis

A

regulating internal conditions (keeping them within limits)

24
Q

all cells (prokaryotic and eukaryotic) have some basic features in common:

A
  • plasma membrane
  • cytoplasm
  • DNA
  • present ribosomes
25
Q

differences between euk. and pro.

A
  • size (pro - 0.2-10 microm, euk - 10-100 microm)
  • complexity - eukaryotic cells are compartmentalized (many differences arise from this fact like type of cell division, DNA structure…)
26
Q

pro, eu, karyon

A

before, real, nucleus

27
Q

TEM and SEM

A

transmission electron microscope (for the interior) and scanning electron microscope (for the surface)

28
Q

structure of a cell seen from a microscope

A

ultrastructure of cells

29
Q

anucleate cells vs multinucleate cells

A

don’t have a nucleus - cannot transcribe DNA to make mRNA and synthesized proteins - red blood cytes (erythrocytes)
have multiple nuclei (more mRNA and proteins) - skeletal muscle/aseptate fungi