Exam 2

Question 1

How do you prepare a smear

Answer 1

1. aseptically a thin film of a specimen is spread on a slide
2. Film is air dried
3. then heat fixed (adhere and kills things on slide)

Question 2

what is staining?

Answer 2

procedure that use dyes to add color to microbes or cellular structures

Question 3

what are dyes?

Answer 3

chemicals added to microbes

Question 4

what are basic dyes?

Answer 4

have positivity charged ions that help them adhere to negatively charged bacteria
Ex. Crystal Violet, Methylene Blue, and Safranin

Question 5

What are acidic dyes?

Answer 5

have negative charged ions that are attracted to background
bacteria appears colorless against a stained background
Ex. Nigrosin

Question 6

What is a simple stain?

Answer 6

use 1 dye

determine shape and arrangement

Question 7

what is differential stain

Answer 7

places bacteria into categories

Question 8

what are special stains?

Answer 8

stains specific part of microbes

Ex. ENDOSPORE STAIN, Negative Stain, and Flagellar Stain

Question 9

how do you make a gram stain?

Answer 9

1. make smear
2. Crystal Violet –> 1 min
3. Rinse with water
4. Iodine –> 1 min
5. Decolorize with ethyl alcohol
6. rinse with water
7. Safarrin –> 1 min
   8 rinse with water
8. blot dry

Question 10

Gram positive bacteria appears

Why?

Answer 10

purple
Ex. bacillus
have many peptiodglycan and they retain primary dye

Question 11

gram negative bacteria appears

why?

Answer 11

red/pink
Ex. E. Coli
have few peptidoglycan that allow decolorization of primary dye and adherance to the counterstain

Question 12

how do you make an acid fast stain?

Answer 12

1. make smear
2. carbolfucshin –> microwave –> 1 min
3. cool and decolorize with acid alcohol
4. rinse with water
5. methylene blue – 30 seconds
6. rinse with water
7. blot dry

Question 13

Acid Fast positive bacteria appears

why?

Answer 13

bright red
waxy material called mycolic acid
Once heated carbolfuchsin are applied and not decolorized with alcohol and appear read

Question 14

Acid Fast negative bacteria appears

whY?

Answer 14

blue

if bacteria doesnt contain mycolic acid carbolfuchsin is decolorized with acid alcohol and methylene blue adheres

Question 15

What are the steps for endospore stain?

Answer 15

1. make smear
2. Malachite green –> microwave –> 1 min
3. cool rinse with water
4. Safranin –> 45 seconds
5. Rinse with water
6. blot dry
   * view on oil immersion lens

Question 16

What are the results of spore stain?

Answer 16

if spore present –> green ( can be inside or out of cell)
bacteria cell –> red
Ex. of positive Bacillus and Clostridum

Question 17

what are the reasons for the spore stain results?

Answer 17

spore are resistant to mild heat but heating in the microwave allows them to open –> absorb malicite green stain

bacteria cells are decolorized with water and counter stain adheres (red) to cell

Question 18

what are the steps for a negative stain?

Answer 18

1. mix bacteria with Nigrosin on one end of slide
2. Use second slide, spread suspension over entire slide
3. Air dry

Question 19

what are the results for Negative Stain?

Answer 19

used to determine capsules (structures that surround cell wall)

if capsule is not present it wont accept the stain and will appear as light spots against a dark background

Question 20

prokaryotic characteristics

Answer 20

DNA not in a membrane (no nucleous)
very small
cell wall have peptidoglycan
no membrane bound organelles
Ex. bacteria

Question 21

eukaryotic characteristics

Answer 21

DNA in a membrane (nucleous)
larger and more complex
not all have cell wall bu most
membrane bound organelles
Ex. Human, plant , and fungi

Question 22

what are some similarities in prokaryotic and eukaryotic cells?

Answer 22

contain carbohydrates, protein, lipids, and nucleic acids
use chemical reaction to metabolize food build protien and store energy
contain cells

Question 23

what is the size of prokaryotes?

Answer 23

0.1 um ( 10 ^ -6) to 50 um in diameter

Question 24

why is the size significant in prokaryotes?

Answer 24

all less space and food so can reproduce and adapt quickly

Question 25

what is coccus shape?

Answer 25

spherical

Question 26

what is bacillus shape?

Answer 26

rod

Question 27

what is spirillum shape?

Answer 27

spiral

Question 28

what is the plemorphic shape?

Answer 28

many shapes

Question 29

what is strepto shape?

Answer 29

chain

Question 30

what is the staphylo shape?

Answer 30

grape- like clusters

Question 31

what is the diplo shape?

Answer 31

two (pair)

Question 32

what is tetrad shape?

Answer 32

group of four

Question 33

what is flagellum?

Answer 33

structure used for motility

Question 34

what are monotrichous?

Answer 34

one flagellum at one end

Question 35

what is amiphitrichous?

Answer 35

one flagellum on each end

Question 36

what is lophotrichous?

Answer 36

turf of flagella at one or more ends

Question 37

what is peritrichous?

Answer 37

flagella around entire surface

Question 38

what is the movement of using flagellum? run tumble

Answer 38

rotation of flagella is clockwise or counterclockwise move in one direction stop and change directions

Question 39

what is taxis? positive negative

Answer 39

movement toward or away from a stimulus towards away

Question 40

what is chemotaxis?

Answer 40

movement involving chemical

Question 41

what is phototaxis?

Answer 41

movement involving light

Question 42

what is geotaxis?

Answer 42

movement involving gravity

Question 43

what is fimbriae?

Answer 43

appendage that is shorter and straighter thatn glagella 2 to 100's per cell used for attachement

Question 44

what is pili?

Answer 44

longer than fimbriae 1 to 2 per cell used in conjugation

Question 45

what is glycocalyx?

Answer 45

made of polysaccharides found outside cell well cell protection

Question 46

what are types of glycocalyx?

Answer 46

capsule | sime layer

Question 47

what is a capsule?

Answer 47

glycocalyx firmly attached to cell wall | protects bacteria from phagocytosis

Question 48

what is slime layer?

Answer 48

glycocalyx loosely attached to cell wall | protects from water loss

Question 49

what is the prokarytoic cell wall like?

Answer 49

semiridgid structures outside cell membrane

Question 50

what is the function of prokaryotic cell wall?

Answer 50

protection and give shape

Question 51

what are things to know aobut prokaryotic cell walls?

Answer 51

can only be seen clearly with an electron microscope | site where many antibiotics damage bacteria

Question 52

what is peptidoglycan?

Answer 52

``` main component of cell wall it contains 2 monosaccharides NAG ( N-acetylglucosamines) NAM ( N-acetylmuramic) amino acid for crossbridge ```

Question 53

what is gram positive cell wall consist of?

Answer 53

25 - 30 layers of peptidoglycan | teichoic acid

Question 54

what is teichoic acid?

Answer 54

acidic polysaccharide give cell surgace a negative charge prevents lyse

Question 55

what is the gram negative cell wall consist of?

Answer 55

10 layers of peptidoglycan no teichoic acid contain additional wall layer called LPS outside peptidoglycan

Question 56

what is LPS?

Answer 56

LipoPolySaccharide | layer is toxic to humans, is responsible for symptoms of infections and is resistant to many antibiotics

Question 57

what is the cell membrane?

Answer 57

structure below cell wall | forms a phospholipid bilayer similar to eukaryotic cells

Question 58

what is the function of cell membrane?

Answer 58

acts as selective barrier | site of ATP production

Question 59

What is simple diffusion ?

Answer 59

movement of molecules from areas of high to low

Question 60

what is osmosis?

Answer 60

diffusion of water across cell membrane high to low

Question 61

what is a solute?

Answer 61

substance dissolved in a solvent | Ex. salt

Question 62

what is a solvent

Answer 62

a liquid | Ex. water

Question 63

what is solution

Answer 63

mixture of the two or more substance | Ex. Salt water

Question 64

lower concentration of solutes ouside the wall would be?

Answer 64

hypotonic solution

Question 65

what does hypotonic solution consist of?

Answer 65

higher concentration of water outside celle water moves into the cell Lysis could happen

Question 66

higher concentration of solutes outside the cell is?

Answer 66

hypertonic

Question 67

what does a hypertonic solution consist of?

Answer 67

higher concentration of water inside the cell water moves out crenation could happen

Question 68

what is isotonic solution?

Answer 68

equal concentration of both solutes | cells remain intact

Question 69

what is cytoplasm?

Answer 69

jelly-like substance found inside cell 80% is water contains carb., proteins, lipids, and genetic material

Question 70

what is a nucleoid?

Answer 70

cluster of genetic material

Question 71

what are ribosomes?

Answer 71

structures directs protein synthesis composed of 2 sub units smaller than eukaryotic very numerous in cells that are actively growing

Question 72

what are inclusions?

Answer 72

``` large storage molecules made of C N S P formed when these elements are abundant not always present ```

Question 73

what are endospore?

Answer 73

structure formed when nutrient are limited contain thick cell walls able to survive extreme environments conditions (heat, lack of water, or exposure to chemicals) can live for 25 million years

Question 74

what happens to endospores when conditions are favorable again?

Answer 74

convert back to vegetative state

Question 75

what is sporulation?

Answer 75

process of making spores

Question 76

who has spores?

Answer 76

bacillus and clostridium

Question 77

how are spores killed?

Answer 77

autoclave --> heat under pressure for 20 min