LabEx1: Contain Questions from experiment 1-8

Question 1

factors that affects resolution, shorter the wavelength of light used, ___________.
-white light used in compound microscope limits resolution of structures smaller then 0.2mm

Answer 1

higher resolution

Question 2

higher magnification inverse relationship to _________.

Answer 2

lower resolution

Question 3

the objective lens magnifies the specimen to produce ____1_____ that is projected to ocular lens to produce the _____2_____.

Answer 3

1. real image

2. virtual image

Question 4

list 4 points regarding proper use and storage of microscopes. “just remember”

Answer 4

1. use both hands when you carry a microscope to your table.
2. plug in the lamp cord into electrical outlet, then turn on the main switch of microscope
3. before storing microscope back, replace the low objective lens into working position
4. always check before change objective lens to avoid slide breakage.

Question 5

identify at least 4 differences between prokaryotes and eukaryotes.

Answer 5

prokarytoes:
-non membranous
-one circular chromosome
-divided by binary fission
-made of peptidoglycan
Eukaryotes:
-separated from cytoplasm
-both membranous & non-membranous
-no peptidoglycan
-divided by mitosis

Question 6

what is the biochemical basis of cheek cell staining process, are the cheek cells prokaryotes or eukaryotes?

Answer 6

methylene blue is used to stain animal/human cells to make nuclei more visible under a microscope.
-the cheek cell is a eukaryote, because eukaryotic cell contain a nucleus.

Question 7

Staining:

define primary stain

Answer 7

mainly stain all cells

Question 8

Staining:

define mordant

Answer 8

holds the dye down

Question 9

Staining:

define decolorizing

Answer 9

wash of primary stain

Question 10

Staining:

counterstain

Answer 10

color to cells that dont retain the primary stain

Question 11

describe the principle of gram’s staining process, include the role of each chemical reagent used in the staining process.

Answer 11

To distinquish between two cell wall gram positive and negative.

Question 12

advantages of the gram’s staining process

Answer 12

advantage:

• it’s a relatively rapid and an extremely useful tool
• the staining provides suggestive includes during the identification process
• it provide valuable information so as to initiate course of antimicrobial treatment

Question 13

disadvantages of the gram’s staining process

Answer 13

disadvantage:

• often, disease causing bacteria, does not have distinct stain characteristic
• the stain is not specific enough to diagnose the cause of most infection
• some bacterial cells stain poorly or not at all

Question 14

list 3 precaution for the gram’s stain

Answer 14

1. fixing
2. staining
3. timing

Question 15

identify the 2 bacteria’s which characteristically produce spores. name the bacteria you did for that experiment.

Answer 15

1.spore has a thick wall
2.is a metabolically inactive structure
Bacillus anthrasis or Clostridium tetanus

Question 16

what is 5 features of spores and list spore position inside vegetative cells

Answer 16

1. spore begin to isolate DNA replicate
2. plasma membrane surround DNA
3. spore septum surrounds isolated portion forming forespore
4. peptidoglycan layer forms between membrane
5. spore coat forms then endospore freed from cell

Question 17

what are functions of spore?

Answer 17

are reproductive cells that must fuse in pairs in order to give rise to a new individual.

Question 18

what are differentiate between spore and vegetative cells?

Answer 18

1. endospores is form from vegetative cell

2. vegetative cell response to environment signals

Question 19

what is sporulation and germination?

Answer 19

1. sporulation- process of spore formation in a sequential event
2. germination - bacterial spore transform into a vegetative cell upon return of favorable conditions by the metabolic process

Question 20

name 2 bacteria’s which are acid fast positive and the associated disease they cause in humans.

Answer 20

Mycobacterium nocardia>
Mycobacterium tuberculosis - causes chronic diseases
Mycobacterium leprae - hansen’s diseases

Question 21

describe the composition of the cell wall that is responsible for the acid fast properties of the cell.

Answer 21

Acid Fast Bacteria are Gram positve, peptidoglycan contain large amout of lipids (mycolic acid).

Question 22

What is sterile transfer technique?

Answer 22

they incorporate procedures that minimizes chance of other organisms being accidentally introduced.

Question 23

list 4 factors with regard to importance of the sterile transfer techniques.

Answer 23

1. free from containing you or others
2. prevent culture from contaminating you or others
3. to isolate pure culture of microbes not considered
4. prevents observing features of microbes

Question 24

name 2 methods for pure culture isolation.

Answer 24

1. spreading plating on solid agar medium with a glass spreader.
2. streaking plating with a loop

Question 25

list 3 common errors in colony isolation by the streak process

Answer 25

1. label all media, tubes and cultures
2. use a loop which is sufficiently cooled
3. avoid aerosols
4. disinfects work place

Question 26

why pour plate technique needs to be done at a faster pace compared to the streak plate method

Answer 26

pour plate needs to be cooled enough before it solidify while streak plate doesn’t

Question 27

what is peritrichous arrangement of flagella?

Answer 27

peritrichous - Multiple flagella may be randomly distributed over the entire bacterial cell

Question 28

what is amphitrichous arrangement of flagella?

Answer 28

amphitrichous - A single flagellum (or multiple flagella; see below) can extend from both ends of the cell

Question 29

what are spirochete?

Answer 29

are flexible, is a member of the phylum Spirochaetes, which contains distinctive diderm bacteria, most of which have long, helically coiled cells

Question 30

name the disease that caused by the spirochete Borrelia burgdorferri

Answer 30

predominant causative agent of Lyme disease

Question 31

Acid Fast Positive -

Answer 31

Clumped together “cord factor” virulence factor (red in color due to carbolfuschin)

Question 32

Non-Acid Fast (negative) -

Answer 32

blue in color due to methylene blue

Question 33

emb plate contain

Answer 33

lactose sugar, peptones, sodium deoxycholate, eosin, methylene blue, extracted best yeast