week 2: microscopy & cell structure

Question 1

describe the size of both prokaryotic and eukaryotic cell

Answer 1

prokaryotic - smaller size which gives high surface area to low volume
eukaryotic - larger, more complex and many cellular processes takes place

Question 2

what does having smaller size in prokaryotic cells do?

Answer 2

• facilitates rapid uptake of nutrients, excretion of wastes

- allows rapid growth

Question 3

what are the 3 key concepts of microscopes?

Answer 3

magnification, resolution, contract

Question 4

describe magnification

Answer 4

-

Question 5

what is resolution?

Answer 5

-

Question 6

describe contract

Answer 6

-

Question 7

contract - what does stain do?

Answer 7

• increases contrast but kill microbes

Question 8

what are the 2 light microscopes that increase contrast?

Answer 8

dark-field microscope and fluorescence microscope

Question 9

describe dark-field microscope

Answer 9

-

Question 10

describe fluorescence microscope

Answer 10

-

Question 11

what are the 2 types of electron microscope?

Answer 11

Transmission Electron MIcroscope & Scanning Electron Microscope

Question 12

what is differential staining used for?

Answer 12

used to distinguish different types of bacteria

Question 13

what is acid-fast staining used for?

Answer 13

• used to detect mycobacterium

- used to presumptively identify agents in clinical specimens

Question 14

what are the 3 special stains to observe cell structures?

Answer 14

capsule, endospore, flagella stain

Question 15

how does capsule stain work?

Answer 15

• stains poorly, so negative stain is often used

- india ink added to wet mount is a common method

Question 16

how does endospore stain work?

Answer 16

• resists gram stain often appears as clear object
• uses heat to facilitate uptake of primary due malachite green by endospore
• counterstain used to visualise other cells

Question 17

how does flagella stain work?

Answer 17

• coats flagella to thicken & make visible

- presence & distribution can help in identification

Question 18

what are the specimens used to prepare for light microscopy?

Answer 18

• fluorescent dyes & tags

- immunofluorescence

Question 19

what is immunofluorescence?

Answer 19

uses fluorescent dye-antibody labels to tag unique microbe protein

Question 20

what are the 2 common types of shapes in prokaryotic cells?

Answer 20

cocus (spherical), rod (cylindrical)

Question 21

what are the 4 characteristic grouping for prokaryotes during binary fission?

Answer 21

• neisseria gonorrnoeae
• streptococcus
• sarcina
• staphylococcus