Microscopy

Question 1

What 3 types of cell exist in single cell form?

Answer 1

Spermatozoa, Ovum & Blood Cells

Question 2

What is used to preserve tissue and prevent rotting before light microscopy?

Answer 2

Formalin

Question 3

What substance is the tissue embedded in to allow very thin slicing in light microscopy? To what typical thickness is the tissue cut?

Answer 3

Melted Paraffin.

5 micrometres.

Question 4

What stain is commonly used to make the nucleus of cells look clearer and to show more detail in the cytoplasm? What colour does it give?

Answer 4

Haemotoxylin + Eosin (H + E Stain)

Purple

Question 5

What does a haemotoxylin stain do to a cell?

Answer 5

Stains the nucleus most strongly blue

Question 6

What does Eosin stain do to a cell?

Answer 6

Stains the extracellular matrix and cytoplasm most strongly pink

Question 7

When taking a frozen section what temperature is the specimen reduced to? What is an advantage and disadvantage of this technique?

Answer 7

-20 to -30 degrees Celsius.
Much faster than traditional techniques.
Lower technical quality of the sections.

Question 8

What causes gout? What is a common place for gout to be seen?

Answer 8

Too much uric acid. Formation of monosodium urate crystals especially at joints.
Big toe.

Question 9

What is analgesia?

Answer 9

Rapid pain relief

Question 10

What types of drugs can be used to treat the pain as a result of gout?

Answer 10

Non-steroidal anti-inflammatory drugs

Question 11

What type of microscopy can be used to study living cells?

Answer 11

Confocal Microscopy

Question 12

What is the common magnification of a light microscope?

Answer 12

1000x

Question 13

What is the difference between resolvable points when using a light microscope?

Answer 13

0.2 micrometres

Question 14

Do you get a higher resolution with a shorter or longer wavelength in microscopy? What is the wavelength used in light and TE microscopy?

Answer 14

Shorter wavelength
Light = 400nm
TEM = 1nm
TEM has a 400x greater resolution

Question 15

What is the typical magnification of a TEM?

Answer 15

250,000x

Question 16

Why can’t TEM be used to examine living structures?

Answer 16

Electron beam is fired in a VACUUM

Question 17

How does the electron beam fired in TEM produce an image?

Answer 17

Fired at tissue. Portions that the beam passes through will appear brighter. Portions that absorb/scatter the electrons will appear darker.

Question 18

What is used to fix a sample in TEM? What is the sample embedded in?

Answer 18

Glutaraldehyde.

Epoxy Resin.

Question 19

What tool is used to slice samples extremely thinly?

Answer 19

Microtome

Question 20

How does freeze fracture EM work?

Answer 20

Tissue frozen to -160 degrees Celsius.

Fractured with a knife - sample interior exposed.

Question 21

How does SEM work?

Answer 21

Electrons fired at sample, reflected back from the surface of sample and received by cathode ray tube.

Question 22

What is a cyrostat?

Answer 22

Microtome in a freezer. Used to produce a frozen section.

Question 23

What is autoradiography?

Answer 23

Photographic emulsion is used to visualise molecules that are labelled with a radioactive marker.
Marker injected into live animal/cell culture.