Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MICROBIOLOGY > LECTURE 1 > Flashcards

LECTURE 1 Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

What is Microbiology?

A

A great complex of biological sciences about micro-organisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the major groups of microorganisms?

A
  • Bacteria
  • Archaea
  • Fungi
  • Algae
  • Protozoa
  • Viruses
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the different types of Human pathogens?

A

SUBCELLULAR BIOLOGICAL ENTITIES:
- Prions (infection proteins)
- Viruses

PROKARYOTIC MICROORGANISMS:
- Chlamydiae
- Rickettsiae
- Mycoplasmas
- Classic bacteria

EUKARYOTIC MICROORGANISMS:
- Fungi
- Protozoa

ANIMALS:
- Helminths
- Arthropods

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What did Antony van Leeuwenhoek do?

A
  • First person who observed and described microorganisms
  • Constructed first microscope (magnification 50-300X)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What did Louis Pasteur do?

A
  • Established that fermentation was the result of microbial activity
  • Introduced techniques of sterilisation
  • Showed that microorganisms DO NOT arise by spontaneous generation
  • Elaborated methods of pathogenic microorganisms attenuation
  • Developed rabies vaccine and anthrax one
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the key concepts of Koch’s postulates?

A
  • A specific infectious disease is caused by a specific microbe
  • Postulates help determine the ETIOLOGY of disease (first step in treatment + prevention)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What did Robert Koch do?

A
  • Elaborated methods of staining and cultivation of microorganisms
  • Discovered what caused anthrax, cholera and tubercle bacillus
  • Proposed techniques for pure culture isolation
  • Elaborated criteria for proving relationship between a microorganism and specific diseases (Koch’s postulates)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are Koch’s postulates?

A
  • Microorganisms must be present in every case of the disease but absent in healthy organism
  • Suspected microorganism must be isolated and grown in pure culture
  • Same disease must result when the isolated microorganism is inoculated into a healthy host
  • Same microorganism must be isolated again from the diseased host
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the different characteristics of the different Bacterial forms?

A
  • COCCI: occur in clusters, chains, pairs and packets
  • STRAIGHT RODS: uniform thickness, rounded/pointed ends
  • CURVED RODS: comma shaped, spiral, screw shaped
  • MYCOPLASMAS: bacteria without a rigid cell wall, coccoid cells, long threads
  • CHLAMYDIAE: either spherical/oval elementary bodies or spherical/oval reticulate bodies
  • RICKETTSIAE: short coccoid rods
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Which structures are found in all bacteria?

A
  • Plasma membrane
  • Cytoplasm
  • 70S Ribosomes
  • Nucleoid containing DNA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

____________ of bacterial flagella propel the cell through an aqueous environment

A

Rotation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the difference between a Nucleoid and a Plasmid?

A

Nucleoid = Double-stranded DNA localised in the cytoplasm

Plasmid = Genetic structure with circular DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe the formation of endospores by sporulation

A

1) Spore septum isolates newly replicated DNA and a small portion of cytoplasm + Plasma membrane surrounds isolated DNA and cytoplasm
2) Spore septum surrounds isolated portion forming FORESPORE
3) Petidoglycan layer forms between membranes, spore coat forms and Endospore is freed from cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does the cytoplasm contain?

A
  • A large number of solute low and high molecular weight substances
  • RNA
  • 20000 ribosomes
  • Reserve substances (e.g glycogen depots, polymerised metaphosphate, lipids)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Bacteria have _____ ribosomes comprising 30S and 50S subunits

A

70S

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the Bacterial cell wall functions?

A
  • Protect the PROTOPLASTS from EXTERNAL NOXAE
  • Withstand and maintain the osmotic pressure gradient between the cell interior and the extracellular environment
  • Give cell its outer form + facilitate communication with its surroundings
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What gives the bacterial cell wall its strength?

A

A layer composed of a substance referred to as Murein, Mucopeptide or Peptidoglycan

Explanation: Consists of repeating units of N-ACETYLGLUCOSAMINE (NAG) and N-ACETYLMURAMIC ACID (NAM) crossed linked by peptide side chains. PENICILLIN-BINDING PROTEINS (PBP) cross-link these peptide side chains

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the characteristics of Gram-positive bacteria?

A
  • Thick murein layer
  • Proteins and trichroic acids anchored in the murrain
  • Lipoteichoic acid fixed to membrane by lipophilic anchor
  • No Porin proteins or Periplasm
  • More sensitive to penicillin and lysozyme
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the characteristics of Gram-negative bacteria?

A
  • Thin murein layer
  • Outer membrane connected to murein layer by proteins (OmpA, murein lipoprotein)
  • Outer layer made up of closely packed lipopolysaccharide complexes (aka “endotoxin”)
  • Porin proteins and Periplasm present
  • Not sensitive to penicillin and lysozyme
20
Q

What does the Lipopolysaccharide complex consist of?

A
  • Lipid (Diglucosamine, Fatty acids & phosphate)
  • Core polysaccharide (Inner & outer core region of different sugars)
  • O-specific polysaccharide chain (Repeating units consisting of 3-8 sugars)
21
Q

What colour do Gram-positive and Gram-negative bacteria stain?

A

Gram positive = Purple

Gram negative = Reddish-pink

22
Q

What are the factors that affect the growth of bacteria?

A
  • Nutrition
  • Oxygen
  • Carbon dioxide
  • Temperature
  • Moisture and drying
  • Light
  • H+ ion concentration
  • Osmotic effect
23
Q

Macrophages produce Hydrogen peroxide, Superoxide radicals and Hydroxyl radicals to pour over bacteria. What are the three enzymes bacteria possess to break down these oxygen products?

A
  • CATALASE (breaks down hydrogen peroxide into water + oxygen)
  • PEROXIDASE (breaks down hydrogen peroxide)
  • SUPEROXIDE DISMUTASE (breaks down superoxide dismutase into hydrogen peroxide + oxygen)
24
Q

What are the steps of Binary Fission?

A

1) DNA replication
2) Cell elongation
3) Septum formation
4) Completion of septum with formation of distinct walls
5) Cell separation

25
Q

What are the growth phases of Bacterial populations?

A

1) LAG PHASE (preparation for population growth + no increase)
2) LOG PHASE (exponential increase in population)
3) STATIONARY PHASE (microbial deaths balance production of new cells)
4) DEATH PHASE (exponential decrease)

26
Q

Define Prototrophic, Chemotrophic, Autotrophic and Heterotrophic

A

Prototrophic = deliver their energy from sunlight

Chemotrophic = obtain energy from chemical reaction

Autotrophic = synthesise all their organic compounds

Heterotrophic = unable to synthesise their own metabolites

27
Q

What are the different sterilisation techniques?

A
  • Heat
  • Filtration (cellulose-acetate membrane filters)
  • Chemicals (ethylene oxide = plastic dishes and pipettes, beta-propiolactone = living tissues)
  • Radiation

Explanation: Sterilisation is the killing of all microorganisms and viruses or their complete elimination from a material with the highest possible level of certainty

28
Q

What is the difference between disinfection, preservation and decontamination?

A

Disinfection = antimicrobial treatment that prevents transmission of microorganisms

Preservation = prevents microbes caused by spoilage of susceptible products

Decontamination = removal or count reduction of microorganisms contaminating an object

29
Q

What is the difference between Aseptic and Antiseptic measures?

A

Aseptic measures = prevents microbial contamination of materials or wounds

Antiseptic measures = chemical agents used to fight pathogens in or on living tissue

30
Q

What is the mechanism of action of ionising radiation, Uv light and chemical agents?

A
  • Ionising radiation = form reactive groups -> chemical reactions -> affect DNA and proteins
  • UV light = structural changes in DNA that prevent it from replicating
  • Chemical agents = attack cytoplasmic membrane
31
Q

What are the two types of Ionising radiation used?

A
  • Gamma radiation = electromagnetic waves produced by nuclear disintegration
  • Corpuscular radiation = electrons produced in generators and accelerated to raise their energy level
32
Q

Which disinfectants are considered “low level”?

A
  • Quaternary ammonium compounds (inactivates enzymes/denatures proteins + bacterial, fungicidal but not sporocidal)
  • Phenols (inactivates enzymes, leaks cell wall + fungicidal, bactericidal, but not sporocidal)
  • Guanidine derivatives (Protein denaturation, not sporocidal)
  • Alcohols (Protein denaturation + bactericidal, fungicidal, not sporocidal)
  • Chlorine/Hypochlorite (Protein denaturation, inactivates nucleic acids + fungicidal, bactericidal and sporicidal)
33
Q

Which disinfectants are considered “High level”?

A
  • Aldehydes (Alkylation of amino groups of proteins + bactericidal, fungicidal and sporocidal)
  • Glucoprotamin (Denaturation of proteins + bactericidal, fungicidal, virusidal, not sporicidal)
  • Peroxides/Paracetic acid (Effects DNA lipids + fungicidal, bactericidal, sporocidal)
34
Q

What are the different ways of verifying sterilisation?

A
  • Airsampling (ACTIVE, Quantitative, disruption of airflow)
  • Surface sampling/settle plates (PASSIVE, semi-quantitative, inexpensive, minimal disturbance)
  • Swabs
  • Indicator strips
35
Q

What happens in a compound microscope?

A

The image from the objective lens is magnified again by the ocular lens

TOTAL MAGNIFICATION = OBJECTIVE LENS X OCULAR LENS

36
Q

Describe Basic stains

A
  • DYES = Methylene blue, Crystal violet, Safranin
  • PURPOSE = Stain negatively charged molecules and structures (e.g nucleic acids + proteins)
  • OUTCOME = +ve stain
37
Q

Describe Acidic stains

A
  • DYES = Eosin, Rose Bengal, Acid fuchsin, Congo red
  • PURPOSE = Stain positively charged molecules and structures (e.g proteins)
  • OUTCOME = can either be a +ve or -ve stain depending on the cell’s chemistry
38
Q

Describe Negative stains

A
  • DYES = India ink, Nigrosin
  • PURPOSE = Stains background, not specimen
  • OUTCOME = Dark background with light specimen
39
Q

What are special stains used to colour?

A
  • Endospores
  • Flagella
  • Capsules
40
Q

What is the difference between Gram stain and Acid-Fast stain?

A

Gram Stain = Gram +ve vs Gram -ve

Acid-Fast Stain = Used to identify acid-fast bacteria with a waxy, lipid cell wall

41
Q

What happens in the Slide agglutination test?

A

1) Samples of an unknown bacteria are placed in a drop of saline on several slides + different known antiserum is added to each sample
2) Bacteria agglutinate when mixed with antibodies that were produced in response to that species or strain of bacteria
3) Positive test indicated by presence of agglutination

42
Q

What is Flow Cytometry and was does it entail?

A

Flow Cytometry = identifies bacteria in a sample without culturing bacteria

1) A moving fluid containing bacteria is forced through a small opening
2) Fluid passing through is illuminated by a laser
3) Scattering of light provides info about cell size, shape, density and surface -> analysed by computer

43
Q

What is DNA Fingerprinting?

A

A technique that chemically divides DNA into fragments which form unique patterns, used to determine specific organisms

44
Q

What is DNA Base Composition used for?

A

Gives conclusion about relatedness of the bases

45
Q

What is Nucleic Acid Amplification Tests?

A

Used to increase the amount of microbial DNA to levels that can be tested by gel electrophoresis

46
Q
A

MICROBIOLOGY (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions