cells and microscopy Flashcards
1
Q
What does staining do?
What is a negative?
A
Gives more contrast between the cell structures and makes them easier to see.
However staining cells kills them so they cannot be used when observing live cells.
2
Q
Name 2 positive of using electron microscopes.
A
- produces images at a higher magnification
- produces images which are clearer and with greater detail they have greater resolution
3
Q
How many mm are in a micrometers?
A
1mm = 1000um
4
Q
What are the units for a light microscope and an election microscope?
A
light - micrometer
electron - nanometer
5
Q
Where is the eyepiece graticule?
A
on the eyepiece lens
6
Q
What are prokaryotic cells?
A
- single - cell organism whose cell lacks a nucleus or other membrane bound organelles
examples = bacteria and archaea
7
Q
What are eukaryotic cells?
A
- cells that possess a clearly defined nucleus
examples = fungi, animals, plants and protists
8
Q
What is epithelial tissue?
A
- cells that sit on the basement membrane
- found covering surfaces and are often the sites of absorption of substances
- have no blood vessels but have nerve endings
- protective or secretory function
- eczema, psoriasis, severe asthma are diseases caused by these tissues
9
Q
What is columnar epithelium?
A
- cells that are taller than they are wide and are found in many organs of the body
= small intestine (cells are covered in microvilli to increase surface area)
10
Q
What is cuboidal epithelium?
A
- cells that have some height and width
- found lining the proximal convoluted tubules in the kidney
- reabsorb useful substances that are filtered out of the blood
11
Q
What is squamous epithelium?
A
- very thin cells
- cells line the alveoli in the lungs
- very thin = reduces diffusion distance for exchange between of gas
12
Q
Explain why the virus is unable to synthesize its own capsid.
A
- Does not possess any ribosomes for protein synthesis
- It does not possess mitochondria so it cannot produce its own atp for the process
