Chapter 2

Question 1

most common bacterial shapes

Answer 1

coccus
bacillus
coccobacillus
vibrio
spirillum
spirochete

Question 2

strepto..

Answer 2

bacteria are arranged in chains

Question 3

staphylo

Answer 3

refers to a cluster or grape-like arrangement of bacteria.

Question 4

sarcinae

Answer 4

bacteria arranged in groups of 8

Question 5

tetrad

Answer 5

group of four bacteria that are arranged in a square shape.

Question 6

wavelength

Answer 6

distance between two consecutive troughs of a wave

Question 7

frequency

Answer 7

number of wave peaks that pass a point in one second.

Question 7

high frequency

Answer 7

shorter wavelength

Question 8

low frequency

Answer 8

longer wavelength

Question 9

relationship between wavelength and resolution

Answer 9

shorter wavelengths provide greater resolution

Question 10

resolution

Answer 10

the ability to see two objects as discrete objects
at the smallest distance

Question 11

what are the conditions needed to resolve an object from its surroundings

Answer 11

contrast between the object and its surroundings
wavelength smaller than the object
detector with sufficient resolution for the given wavelength

Question 12

what are the 4 ways light interacts with an object

Answer 12

absorption
reflection
refraction
scattering

Question 13

absorption

Answer 13

photon energy absorbed by material

Question 14

reflection

Answer 14

light bounces off the object in the same angle as the incident angle

Question 15

refraction

Answer 15

bending of a light wave when light enters a different medium

Question 16

scattering

Answer 16

the process in which light bounces off particles or objects in many different directions, rather than being absorbed or transmitted.

Question 17

focal point

Answer 17

refers to the specific spot where light rays converge after passing through a lens.

In a microscope, the focal point is where the image of the object you’re observing comes into sharp focus.

Question 18

compound light microscopy

Answer 18

uses visible light to illuminate the sample
visible light has a large wavelength which leads to lower resolution
bright field
dark field
phase contrast
fluorescence

Question 19

bright field microscope

Answer 19

-the large wavelength can only increase the resolution by 1000x
-see the object against a bright background
- observing stained or naturally pigmented specimens.

Question 20

aberrations

Answer 20

distortions or imperfections in the image produced by the microscope. These distortions occur when light does not focus properly due to imperfections in the lens system.

Question 21

dark field microscope

Answer 21

Uses a special condenser to direct light at an angle, making the specimen appear bright against a dark background.
Good for observing live, unstained specimens like bacteria.

Question 22

how is magnification calculated

Answer 22

ocular lens x objective lens
ocular - 10x
objective - 10x 40x 100x

Question 23

oil immersion

Answer 23

in microscopes to increase the resolution and clarity of the image, especially at very high magnifications (like 100x).

Oil has a similar refractive index to glass, which helps light pass through the specimen more effectively. Oil helps focus more light onto the specimen, making the image clearer and sharper.

Question 24

phase contrast microscope

Answer 24

Enhances contrast in transparent specimens by changing the phase of the light waves microscope uses special optics to alter the speed or timing of the light waves as they pass through the specimen.

Question 25

Fluorescence microscope

Answer 25

uses special dyes and UV light to make parts of the sample glow, making it easier to study tiny or transparent things in detail

Question 26

electron microscopy

Answer 26

type of microscope that uses electron beams (instead of light) to view very small objects, like viruses, bacteria, or cell structures. It can magnify objects much more than regular light microscopes

Question 27

Transmission Electron Microscopy

Answer 27

electron beams penetrate a thin section of tissue (HIGH RESOLUTION) 2D image

Question 28

Scanning Electron Microscopy

Answer 28

electrons bounce off the surface of the sample 3D image high resolution but less than TEM

Question 29

Do compound light or electron microscopes have a higher resolution

Answer 29

electron microscopes

Question 30

Specimen preparation for light microscopy

Answer 30

wet mount smear heat fixation

Question 31

wet mount

Answer 31

drop of liquid placed on slide - match refractive index

Question 32

smear

Answer 32

dried preparation of bacterial cells on a glass slide

Question 33

heat fixation

Answer 33

smear is fixed (attached) to slide by heat or would be washed away during staining

Question 34

Staining

Answer 34

Staining is coloring the microbes with a dye that creates a contract between the bacteria and the background or emphasizes certain microbial structures

Question 35

positive stain (basic stain)

Answer 35

positively charged and attract to the negatively charged parts of the bacteria that allow the stain to bind to the bacteria BACTERIA BECOMES STAINED

Question 36

negative stain (acidic stain)

Answer 36

negatively charged don't interact well with bacterial structures so the background becomes stained to create a contrast with the specimen

Question 37

simple stains

Answer 37

use a single dye do not distinguish organisms and structures

Question 38

differential staining

Answer 38

use two or more dyes that react differently allowing various kinds or parts of bacteria to be distinguished

Question 39

gram staining

Answer 39

Hans Christian Gram distinguish between gram-positive and gram-negative bacteria gram (+) - purple gram (-) - pink

Question 40

steps of the gram stain

Answer 40

1. smear specimen and heat fix 2. Add crystal violet stain 3. add iodine which binds crystal violet to stain 4. wash with ethanol to decolorize 5. add safranin to counterstain gram-positive remains purple due to thick peptidoglycan gram-negative remains pink

Question 41

gram negative cells

Answer 41

single layer of peptidoglycan has outer membrain containing LPS/endotoxin

Question 42

gram positive cells

Answer 42

multiple layers of peptidoglycan no outer membrane so has no LPS/endotoxin

Question 43

Ziehl Nelson Stain - Acid fast stain

Answer 43

Gram-positive bacteria can be further differentiated into acid-fast and non acid-fast Acid-fast have a thick waxy mycolic acid layer

Question 44

Steps of the Ziehl-nelson acid fast stain

Answer 44

1. Add primary stain carbolfuchsin - both types will be red 2. heat up the smear to allow carbolfuchsin to properly adhere to the waxy mycolic acid layer 3. wash with an acid-alcohol wash acid-fast - red non acid fast - colorless 4. add counterstain methylene blue acid fast - red non acid fast - blue

Question 45

Schaeffer Fulton Method

Answer 45

identify bacterial species that produce spores primary stain - malachite green (stains spores) safranin (stains other parts of the cell)

Question 46

parts of the microscope

Answer 46

light source condensor specimen medium objective lens ocular lens