Ch1-2 Flashcards
1
Q
Eukaryotic DNA
A
- linear
- packed inside the nucleus (membrane bound organelle for storing DNA)
2
Q
Prokaryote DNA
A
- circular
- DNA packed in nucleiod
- most have one or 2 circles of DNA distinct from the chromosome called plasmids
- plasmids not vital but give cell special property (ex. Antibiotic resistance )
3
Q
Construction of Microbe tree
A
By looking at the ribosomal RNA of a cell
- genes record evolutionary history
4
Q
Prokaryotes Ribosomal Structure
A
- 70s -big unit
- 16s small unit (ssu) rRNA
5
Q
Eukaryotes ribosomal structure
A
- 80S
- 18S ssu rRNA
6
Q
Domain Bacteria
A
Prokaryotic
- pathogenic and non pathogenic
- genetically distinct from domain archea
7
Q
Domain Archaea
A
Prokaryotic
- non pathogenic
- live in extreme environments
- closed to domain Eukarya than bacteria
8
Q
Domain Eukarya
A
Eukaryotic
- pathogenic and non pathogenic
- closer to domain archaea than bacteria
9
Q
Ribosomal RNA genes
A
Genes used to classify micro organisms according to similarities
- all organisms have them
- work same function
- change slowly
- long enough to be studied
Ex. 16s and 18s - comparing lead to classification of 3 domains of life
10
Q
Species
A
A group of stains that share certain diagnostic traits, genetically cohesive and share a uniqe recent ancestor
- scientific not evolutionary based
11
Q
2 criteria for species classification
- DNA- DNA hybridization
- 97% rRNA sequence
A
- 70% genomic hybridization
- a strand of one microorganism DNA is taken out and marched with complementry strand of another microorganisms DNA. Then compare base pairs
12
Q
Taxonomy
A
Science of organizing organizing into domain, phylum, class Naming / Nomenaclarure
13
Q
Louis Pasteur
A
- fermentation not a chemical reaction but involved yeast microorganisms
- disproved spontaneous generation
- living things can’t arise from
No. Living things
- living things can’t arise from
- flasks filtration experiment
- beginning of control micro growth exp
- went on to make vaccines
14
Q
Robert Koch
A
A German physicist who studied anthrax. He devised for knowing if a micro is responsible for a certain disease
Kochs pastulates
1. Find a diseased animal
2. Take. Blood/ tissue sample from diseased animal
3. Find a suspected pathogen and grow it outside of animals in a pure culture
4. Inject suspected pathogen on a healthy animal
5. If healthy animal gets sick, the. Suspected pathogen is culprit
15
Q
Kochs micro techniques
A
- Agar
- Streak plate techniques
- Spread plate technique
- Pour plate technique
16
Q
Agar
A
A growth medium made of an algal polysaccharide
17
Q
Steak plate techniques
A
Used for isolating pure cultures of bacteria
18
Q
Spread plate
A
Sample of diluted Bactria is spread over the plate when a sterile pipettes. Plate medium is solid
19
Q
Pour plate technique
A
Like spread plate but molten agar instead of solid medium
- bacteria is embedded in agar
- spread and pour plate allow calculation of concentration of bacteria
- not I under 30 colonies but not more than 300
20
Q
6 types of light microscopy techniques
A
- Bright- field microscopy
- Phase- contrast microscopy
- Dark field microscopy
- Fluorescence microscopy
- Differential interference contrast microscopy
- Confocal scanning laser microscopy
21
Q
Cell staining
A
- Simple staining
2. Differential staining
22
Q
Simple staining
A
Stains all cells by due to make them all stand out
23
Q
Chromophore
A
Coloured portion of a dye molecule that makes staining possible
* staining always kills cells !
24
Q
Basic dye
A
A basic dye has positively charged chromophore. Since cell surface is negative, positive binds to it and stains cell (eg crystal violet )
25
Acid dye
Negatively charged chromophore it repels cell and stains the background
26
Differential staining
Renders different kinds of cells with different colours
| - 3 types
27
Gram positive
Retain primary stain and are coloured purple
28
Gram negative
Loose primary stain and are coloured pink
29
Procedure of gram staining
1. All cells are flooded with crystal cooler stain (primary stain )
- all cells purple
2. Iodine is added to stick crystal violet to cell surface . Gram positive will stick but not gram negative
3. Alcohol washes away crystal violet, except for gram Positive cells which are stick to stain
- gram negative are colourless
4. All cells are flooded with safrani ( secondary stain )
- will turn colourless gram negative cells positive
30
Acid fast stain
Targets any cell with mycolic acid in its cell wall
| - becomes pink every other cell becomes blue
31
Endospore stain
Targets endospores
| - endospores become green other cells become pink
32
Phase contrast microscopy
Light passes through a phase ring before the lenses. The phase ring takes advantage of the fact that light refracts through cells different
Than It refracts through air
- improved contrast between cells and surrounding
33
Dark field microscopy
Instead of a light new
Shooting from under the specimen, the light beam is shot at the side of specimen
- only light that reaches the lenses is the light refracted by the cells
- greater contrast than phase contrast
34
Fluorescence microscopy
Some cells fluoresce light on their own that can be used to contrast from the background . For cells that don't fluoresce, dyes can be added to contrast them from background
Ex . DAPI- fluorescent dye that binds to DNA
35
3D light microscopy
| 2 types
1. Differential interference
| 2. Confocal scanning laser microscopy
36
Differential interference
DIC uses a plaeizwe to polarize light into 2 distinct beams that pass through the specimen and reunite again at the lens
- gives 3D cellular structure
* can find a cell structure not seen by bright field microscopy
- doesn't require staining
37
Confocal scanning laser
CSLM uses a laser to focus on single layers of a specimen. When laser adjusted different layers can be viewed
- layers put together to create 3D image
- resolution enhanced to 0.1 im
38
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Electron microscopes
( 2 types )
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1. Transmission electron microscopy (TEM)
| 2. Scanning electron microscope (SEM)
39
TEM
Unlike photons, elections are poor at penetrating cells ( repulsion )
- to view internal stir ute cell must be fit into thin slices for electrons to pass through (20-60um)
- specimen stained with brave metals to better cater electrons and improve contrast
40
SEM
Externally image a specimen in 3D
- coated with thin film of Gold
- scatter electrons externally
41
Morphology (shape )
| Major types - name them
1. Coccus- spherical
2. Bacillus - rod shaped
3. Spirilla - spiral
4. Spirochete - tightly coiled
42
Clustering
1. Stephyl- grapes
| 2. strept - chain
43
Mechanism of transport
1. Simple transport
2. Group translocation
3. ABC - ATP binding cassette
44
Simple transport
A protein uses the proton motive force to move a solute against its concentration gradient
- sucrose pump
45
Group translocation
Instead of proton motive force, the protein uses the energy of an energy rich organic compound to transport solute against its gradient
- chemically modified as it is transported
- phosphotransferase system transports glucose. Fructose. Mannose in e Coli
46
ABC
3 components
1. Specific substrate binding protein
2. Membrane integrated transport protein
3. ATP hydrolizing protein on the inside
Gram negative - free protein- pariplasmic
Gram positive - membrane attached substrate protein
47
3 possible transport events
1. Uni port - one direction across membrane
2. Symport - 2 substrates across membrane in one direction
- simple transport relies on this
Ex. Sucrose pump
3.Antiport - one substance in one direction while another in opposite direction
48
Cell wall structure
| Gram positive
Single layered, thick cell wall made of generally a single type of molecule
- peptitogycan
49
Gram negative
Double layered think call wall made up of many different molecules
50
Peptitogycan
Polysaccharide made of N- acetylhlicosine acid and a few amino acids
- can create glycan tetra peptide
51
Gram negative bilayer
2 layers
- 2nd lipid layer called outer membrane
- too many polysaccharides to be considered phospholipid bilayer, therefore called
Lipopolysaccharide (LPS)
52
LPS structure
1. Core polysaccharide
2. O specific
3. Lipid A - toxic end
* area between cell
Wall and outer membrane is called a Periplasm
- trapped proteins
53
Mycoplasmas
Don't need a cell wall
- they have molecules embedded (sterols) in their cell Miranda
- > add rigidity to the cell membrane
- > similar structure in Archaea called lipoglycans
54
Archaeal cell wall structure
- no peptidoglycan,no outer membrane
- instead have pseudomurein
- N- acetyminuronic acid
- 1-3 instead of 1-4 glycosidic linkages
- all archaea have paracrsytalline surface layer (s-layer)
- lack of pep = no lysozyme or penicillin affect
- s layer made up of proteins and glyco proteins
55
Capsules
Many prokaryotes secrete extracellular slime around cell walls
- helps surface attachment
- > prevents white blood cell from recognizing and distorting cell
- > externally binds water protecting cell from dryness
56
Fimbriae
- short- threadlike proteins extending from
Cell surface
- pili assist in attaching 2 surfaces
-conjugation - bridge between 2 cells
57
Inclusions
Vacuoles found within the cell with substances inside used for energy storage
58
Carbon storage polymers
Most common
59
Poly phosphate (volutin) granules
Accumulation of phosphate groups (PO43-) in granules
| - synthesis of nucleic acids, phospholipids or ATP
60
Sulfur globules
Gram negative prokaryotes carry soulful globules for use in anaerobic respiration (instead of oxygen )
61
Magnetosomes
Intracellular particles containing granules of magnetic compounds
- Fe3O4 or Fe3S4
- allow cell to orient itself in a magnetic field
- > travel along magnetic field (magneto taxis)
62
Gas vesicles
Structures that give a cell buoyancy
- conical shaped has filled made up of protein
- only permeable to gas
63
Endospores
Highly differentiated cells resistant to heat, harsh chemicals and radiation
- dormant stage of a bacterial stage of a bacterial life cycle
- easily dispersed by wind
- gram negative
64
Acid calcium complexes
Bind water in the endospores to dehydrate it to make it heat resistant
65
Small a is soluble spore proteins (SASPs)
These bind to DNA and printer it against denaturation by radiation
- carbon storage source when endospores germinates back into vegitative cell
66
Flagella types (4 types )
1. Monotrichous flagellation
2. Lophotrichous flagellation
3. Amphitrichous flagellation
4. Peritrichous
1. A single flagellum attaches to the cell at a pole or subpole
2. A BUNDLE of flagella attach to the cell
3. Many flagella are inserted at different location
- grouping of strand in one direction when travelling
67
Components of flagellum
1. Filament- the filament makes up the bigger portion of a flagellum
- flagellin - it is made is a rigid, helical interlocking chains of protein
2. Hook- the hook connects the filament to the cell - made fe a different protein
3. Basal body - anchor of the flagellum in the cell
- rod passing through a series of anchored rings
A. L-rings (attached to LPS)
B. P- ring (to Peptidoglycan )
C. MS- ring (cytoplasm membrane )
MOT - c ring connected to MS
- H ions diffuse through this channel
68
Flagellum motion
Reversible Polar: turns counterclockwise to propel the cell forward - clockwise = backwards
Peritrichous: can only turn counter clockwise and propel forward
- tumbles to a random orientation
Unidirectional Polar: flagella can only turn clockwise and propel forward. Can stop to orient body.
69
Taxis
A biased and directed movement of a cell in response to chemical or physical gradients
