Module 1: History of Microbiology and Microscopy

Question 1

what are Eukaryokes

Answer 1

large multicelluar microorganisms

Question 2

what is microbiome

Answer 2

coexisting vast number of colonizing microorganisms
- vast majority are not harmful to us but play essential roles in providing nutrients, carrying out essential transitions and cycling of nutrients

Question 3

what is the average size of microorganisms

Answer 3

0.2 mm and smaller

Question 4

are paracites considered microorganisms

Answer 4

yes

Question 5

what other entitities are considered micro organisms even though they cant live on their own

Answer 5

viruses and prions

Question 6

how do we know that cellular life on earth is all related to one another

Answer 6

DNA sequencing analysis allows for comparisons of the DNA sequence changes between each species
- many scienctists have worked to obtain sequences from the same gene From every known organism and shared it on a data base

Question 7

what is is called to obtain sequences from the same gene?

Answer 7

phylogenetic analysis

Question 8

what are the three domains of life

Answer 8

bacteria, archaea, and eukarya

Question 9

what are viruses

Answer 9

• the smallest of the microbs
• they cannot replicate on their own, they require host cells to replicate
• they can encode their own genetic DNA or RNA
• we cannot determine how related they are to cellular life becasue they do not share genes that are consistenly in other life forms
• viruses can cause a number of human diseases and cancers

Question 10

what are viroids

Answer 10

• require host cells to replicate
• they replicate their genomes (single stranded RNA)
• spread from cell to cell
• they are limited to plants

Question 11

what are satellites

Answer 11

• a defective virus
• they encode a nucliec acid enclosed in a protein shell and infect new cells on their own
• they cant replicate themselves unless the cell they are in is coeffected with a specific virus that provides enzymatic help to complete their life cycle

Question 12

what is a prion

Answer 12

• proteins encoded by the host
• infectious variants of this protein misfold to create a new form that has a tendency to bind to other copies of the normal protein and cause them to misfold
• this can cause normal copies to fold
• this can effect foods and if foods are consumed by humans it can begin the process in a human host

Question 13

what was a major player of early life

Answer 13

RNA - serving as both a genetic informer and carrying on essential catalytic functions

Question 14

all living cells have a collective set of atributes

Answer 14

• they are made up of cells
• ability to respond to environmental changes
• ability to grow and develop
• use energy and undergo metabolism
• regulate cellular metabolic activites
• reproduce
• undergo biological evolution

Question 15

which of the collective set of attributes is most important

Answer 15

biological evolution

Question 16

what can all life forms be traced back to?

Answer 16

LUCA
L last
U universal
C common
A ancestor

Question 17

what was the first domain to exsist

Answer 17

evidence points to Bacteria and Archaea
with eukaryotes developing later
- both cells are similar with lack of internal structure
lack defiend nucleus - prokaryotic cells

Question 18

what do eukaryotic cells contain

Answer 18

• membrane enclosed nuclei
• mitochondria and endoplasmic reticulum golgi apparatus chloroplasts
• evolved from common ancestor of archaea
• likely caused from relationship between archaea ancestors and bacteria
• protists, algae, slime, molds water molds and fungi

Question 19

what was the ealiest microscope able to see

Answer 19

single celled organisms

Question 20

what created the earliest microscop

Answer 20

Antony Van Leeuwenhoek
- not a trained scientist and took the world a long time to take him seriously

Question 21

what were two major milestones in microbiology

Answer 21

1. the development of a systematic set of proofs for determining whether a specific organism was responsible for specific disease - robert koch
2. development of a series of effective vaccines - Louis pateur

Question 22

what did the need to obtain pure culture do for microbiology

Answer 22

development of newer and more refined media growth tequnics

Question 23

what did louis Pasteur do

Answer 23

• disproved spontaneous generation
• created succeful anthrax vaccine
• described chirality of chemical bonds
• developed pasteurization to preserve french wine
• developed germ theory
• developed attenuated
• developed vaccine for rabies

Question 24

what is the light microscope

Answer 24

• the first created
• utilize lenses to bend light beams and focus and magnify samples
• different lenses will have different focuses and magnifications
• general sizes - 10x 40x and 100x

Question 25

what are bright field microscopes

Answer 25

most common light microscopes - source of light shines through the bottom through the sample and image is visible by contrast background

Question 26

what is resolution

Answer 26

the ability to distinguish a point from a neightbourhouring point - poor resolution means that objects bluur together - for light miscroscopes the resolution is indicatied wavelength of light - 0.2 um

Question 27

what is contrast

Answer 27

- distinguishing the object from surrounding ones - treat the sample with a stain or combination of stains - the stain needs to be able to bind to specific parts of the sample to make it stand out - one downside is it often kills the sample being stained

Question 28

what is dark feild microscopy

Answer 28

imaging on a dark feild microscope - dark background - light is shinning on the sample instead of up through the sample

Question 29

what is phase contrast microscopy

Answer 29

light passes through a living cell but will be slightly delayed - amplifies small differenced so that light passing through an object will not cancel out light that didnt pass through

Question 30

what is differential interference contrast microscope

Answer 30

uses differences in refractice indices and thickness of different parts of specimen to create an image - use two beamd with right angeled lights - one light passes through specimen while the other passes through delayed - goes through prism to create three d object

Question 31

flourescent microscopes

Answer 31

- some materials can absorb energy from one source and become excited and emit light - illuminate the object with defined wavelength light beam - flourescent dyes excite sample and they emit their own colour

Question 32

confocal microscopy

Answer 32

creates shape 3d images computer collects image data scanning laser produces an image - creates a series of flat images and stacks them to create 3d object

Question 33

fixation and staining

Answer 33

- often stuck on glass slides to allow flooding and washing steps - heat and chemical fixation are most common - heat dries the sugars and sticks cells to glass - chemicals imobolize samples (fermaldehyde)

Question 34

staining has two dyes

Answer 34

basics - positively charged groups - bind to negatives acidic dyes - negatively charged sticks to positive groups

Question 35

what is the most used stain

Answer 35

gram stain - used to differentiate gram positive and gram negative

Question 36

electronic microscopes

Answer 36

beams of electrons are used instead of light beams - electrons travel in waves - wavelength is shorter than visible light - 1000x better than light -

Question 37

transmission electron microscopes

Answer 37

shoot beams through the sample and image is viewed by its ability to block out electrons, much like bright feild light microscopes

Question 38

staining in electron microscopes

Answer 38

- uses heavy metals because they are sufficient at blocking electrons and are often sprayed into other sampled to show them better

Question 39

what are potential draw backs of electron microscopy

Answer 39

samples must be viewed in a vaccum as electrons do not travel through air so the samples need to be dehydrated -

Question 40

scanning electron microscopy

Answer 40

electrons are bounced off at an angle the electron beams scans focuse on beams of electrons along the samples and image is generated

Question 41

scanning probe microscopy

Answer 41

- small prob scans along the surface of the sample specimen - the prob is designed to move up or down in response to the contours or other properties on the surface - scans to create a contour map = atomic force microscope - does not require dehydrated samples or use of high vaccuum environement