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microbio > lecture 1 > Flashcards

lecture 1 Flashcards

1
Q

what are some examples of acellular and cellular organisms?

A
  • Cellular: Fungi/ Protists /Bacteria /Archea
  • Acellular: Viruses, Viroids, Satellites, Prions
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2
Q

What are the types of microbial cells?

A

bacteria archaea and eukerya

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3
Q

how was the orgins of life identified?

A

Carbon dating
Fossils
Molecular fossils - hopanes

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4
Q

what was the oxygen revolution?

A
  • Caused the extinction of some prokaryotes
    Some groups survived anaerobic environments
    Others adapted using cellular respiration to harvest energy - endosymbiosis
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5
Q

how do the three domains increase diversity?

A
  • Eukaryotes increase diversity through sexual reproduction
  • Bacteria and archaea increase the gene pool through horizontal gene transfer
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6
Q

what was endosymbioisis?

A
  • Endosymbiosis is when one organism lives inside another, which leads to the formation of mitochondria, chloroplasts, and hydrogenosomes
  • These organelles have DNA and ribosomes similar to bacteria, showing they evolved from bacteria that were absorbed by larger cells.
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7
Q

What are characteristics of Domain bacteria?
- single or multi celled?
- what structire do most bacteria have?
- what cellular feature do bacteria lak?
- what enviornmnet do they live in ?
- effects?
- typical structure of chromosme?
- common lipid found ?

A
  • usually single celled
  • Most have cell walls with peptidoglycan
  • Most lack a membrane-bound nucleus
  • Live in extreme environments (including our bodies - microbiome)
  • Both disease-causing and non-disease causing exist
  • Chromones - usually one circular chromosomes that have a single origin of replication, some are polyploid
  • ester linked phospholipids
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8
Q

What are charchteristics of Archea?
- What distinguishes this group from bacteria at the molecular level?
- What type of environments do many organisms in this group inhabit?
- Do organisms in this group cause diseases in humans?
- What is the structure of the chromosomes found in these organisms?
- What is one unusual characteristic of the metabolism of some organisms in this group?
- plasma membrane?
-

A
  • Distinguished from bacteria by unique rRNA sequences
  • Have unique membrane lipids
  • Some have unusual metabolic characteristics
  • Many live in extreme environments
  • Do not directly cause disease in humans
  • One circular chromosome, some have chromosomes with multiple origins of relocations, some are polyploid
  • Plasma membrane lipids: glycerol diethers and diglycerol tetraethers
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9
Q

what are characteristics of Eureka ? two types?

A
  • membrane-enclosed nucleus
  • Larger and more morphologically complex
  • Protists
    unicellular, generally larger than bacteria and archaea
    Protoza- animal-like metabolism
    Algae - photosynthetic
  • Fungi
    Unicellular (yeast)
    Or multicellular (molds and mushrooms)
  • Chromosome: multiple and linear with multiple origins of replication - usually a dipoid
  • Plasma membranes - ester-linked phospholipids and sterols
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10
Q

what is the use of 16s rRNA gene sequence analysis?

A
  • It is responsible for the initiation of protein synthesis and stabilization of correct codon to anticodon pairing
  • Carl Woese pioneered the use of RNA nucleotide sequences to classify and identify organisms
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11
Q

why do we use 16s rRNA?

A
  • It is a highly conserved genetic sequence in bacteria and archaea and is present in all strains
  • Can find where certain species have diverged by aligning sequences and finding small differences
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12
Q

what did robert hooke do?

A
  • made a compound microscope and illumination system
  • made the word cell
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13
Q

Dutch biologist Antin van Leeuwenhoek

A
  • first to observe and describe single-cell organisms
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14
Q

what is sponentenous generation?

A
  • that living organisms can develop from nonliving or decomposing matte
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15
Q

Francesco Redi

A
  • discredited spontaneous generation
  • Showed maggots on decaying meat came from fly eggs
    He had an open container that formed maggots
    Cork sealed - no maggots
    The gauze covered no formation only on the gauze
  • meat must be exposed to get contaminated
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16
Q

John Needham

A
  • Based on observations that boiled hay gave rise to microorganisms he stated that some extracts have what it takes to confer life from nonliving material
  • spontaneous generation did occur
17
Q

Lazzaro Spallanzani

A
  • Proved that the hay itself did not make microorganisms if in a sealed environment
  • disproved spontaneous generation
18
Q

Louis Pasteur

A
  • Disproved spontaneous generation by the swan neck flask experiments
  • He made a swan neck flask and heated up the flask which made the broth sterile
    He broke the the neck of the flask and growth occurred
    Neck intact - broth remained sterile
  • Discovered that microorganisms cause fermentation and disease
  • Originated the process of pasteurization
  • Developed vaccine against anthrax and rabies
19
Q

Pasteur’s Germ Theory

A
  • States infectious diseases are
    caused by microbes
  • Each microbe causes a particular
    disease in susceptible individuals
    Susceptibility depends on:
  • Infecting Agent (variant, how it
    mutates?)
  • Environmental factors
  • Factors involving host (e.g.
    immune system, genetics)
20
Q

what was kochs experiment?

A

The microorganism must be present in all
cases of disease and absent from healthy
organisms.
2) The microorganism must be able to be isolated
from the diseased host and grown in pure
culture.
3) The microorganism must cause same disease
when inoculated in the healthy host.
4) The same microorganism must be isolated
from diseased host again and identified as
identical to what was inoculated.

21
Q

what were limitations of koch experiment?

A
  • Some organisms cannot be grown in pure culture because they rely on host cells
  • Possible lack of an animal model - can’t use human subjects
22
Q

edward jenner

A

Used vaccination procedure to protect against smallpox

23
Q

Joseph lister

A
  • said microorganisms were the causal agent of disease
  • Developed an antiseptic surgery system
  • A study of lactic acid fermentation deminstratd the specific cause of milk souring
24
Q

Alexandr fleming

A

pencilin

25
Q

what were the first microscopes created? how did they work? magnification? resolution?

A

Light microscopes were the first microscopes to be invented
The image is magnified through lenses - bending light
Magnification: see how much bigger the image is from the sample
Resolution: the ability to see objects that are small and close together as separating objects

26
Q

bright-field microscope

A

Dark image on a light background
Used to examine both stained and unstained species

27
Q

dark field microscope

A

Light image on dark background
For living, unstained preparations. Used to observe internal structures of eukaryotic cells

28
Q

Phase contrast microscope

A
  • Deviated and undeviated light are combined in a condenser to generate a more detailed image
  • Can see microbial movement and detect structures
  • Can observe living cells no fixing or staining required
29
Q

Differential interference contrast (DIC) microscope

A
  • Creates images by detecting differences in refractive indices and thickness of different parts of the specimen
  • Adds contrast
30
Q

fluorescence microscope

A
  • Labeled probes are added to specific cell constituents
  • Produced image by exciting a specimen with a wavelength of light that triggers the object to emit fluorescence light
  • Can show localization of specific proteins in cells
31
Q

Confocal microscope

A
  • Uses a laser beam to illuminate a fluorescently labeled specimen
  • Creates a sharp composite 3D image of specimens’ special aperture that eliminates stray light
  • Can be used to study biofilms
32
Q

what is fixiation in terms of Preparation of specimens ?
heat fixation?
chemical fixation?

A
  • Preserves internal and external structures by inactivating enzymes that can disturb cell morphology
  • Heat fixation - preserves overall morphology bt destroys subcellular structures
  • Chemical fixation - protects fine cellular substructures and morphology
33
Q

what is Staining?
simple staining?

A
  • Increases visibility of specimen for better contrast background
  • Used to detect the presence or absence of structures
  • Simple staining, a single stain is used t help determine size, shape and arrangement of bacteria
34
Q

Electron microscopy

A

Uses electrons as a beam to see very small organisms
The wavelength is 100,000 shorter than visible light making a higher resolute image
Allows for microbial morphology to be studied

35
Q

Scanning electron microscopy

A
  • Uses a stream of electrons excited from the surface of a specimen p to create a details image and it makes a realistic image in 3D form of a surface image
  • gives informatio about the samples surface and its compostion
36
Q

transmission electron microscopy

A
  • A focused beam of electrons passes through the specimen to form the image
  • Denser regions scatter electrons and appear darker
    -clearer image
  • uses transmitted electrons, the electrons which are passing through teh sample before they are collected
  • infomation on the inner structure of the sample
37
Q

Cyro-electron microscopy

A

Samples are rapidly frozen and images are captured at different angles sto make a 3D image

38
Q

Scanning probe microscopy

A
  • Measures surface features of an object by moving a sharp probe over the surface of an object
  • Can view atoms on the surface of a solid
39
Q

Atomic force microscopy

A
  • Up and down movement of the sharp probe as it maintains constraint distance from the specimen
  • The deflection of a laser beam that strikes the level holding the probe is measured

microbio (5 decks)

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