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Microbiology > Chapter 1: The microbial world > Flashcards

Chapter 1: The microbial world Flashcards

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Biology 101 flashcards
1
Q

Micro-organism (M)

A

They are life forms too small to be seen by the human eye
-diverse in function
-Inhabit every environment that supports life
-Many single-celledm some form complex structures and some mulitcellular
-Live in microbial communities

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2
Q

why are M NB

A

-Oldest forms of life
-Major fraction of Earth’s biomass
-Surround plants and animals
-Affect Human life

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3
Q

In what ways do M impact humans

A

-food
-industry
-biotechnology

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4
Q

culture

A

cells grown in/on nutrient medium

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5
Q

Medium

A

Liquid/solid mixture containing all required nutrients

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6
Q

Growth

A

Increase in cell number resulting from cell division

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7
Q

Colony

A

Visible, contains millions/billions of cells

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8
Q

Cell

A

A living compartment that interacts with the environment and other cells

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9
Q

Factors all cells have

A

-Cytoplasmic (cell membrane)
-Cytoplasm
-Ribisomes
-Cell wall

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10
Q

which structures distinguish Pro and Eu

A

Pro
-No organelles
-single circular chromosome
-Plasmid
-Small/compact
Eu
-Linear chromosome
-Much larger
-Organelles

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11
Q

properties of all microbial cells

A

Structure
-Cytoplasmic mebrane, cytpolasm, genome made of DNA
Metabolism
-Anabolism (build) and Catabolism (break)
Growth
-Proteins are used to convert nutrients into new cells
Evolution
-Chance mutations in DNA cause new cells to have new properties thereby promoting evolution

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12
Q

Properties of only some cells

A

Differentiation
-Some cells can for, new structures such as spores
Communication
-via chemical messengers
Motility
-Some cells are capable of self-propulsion
Horizonta gene transfer
-Cells can exchange genes with each other via several mechanisms

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13
Q

Morphology

A

Cell size and shape

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14
Q

Size of Pro

A

Most are between 0.5 to 10 micro meters

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15
Q

EU size

A

5 to 100 micro meters

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16
Q

surface area and volume

A

Advantages to being small is more surface area relative to volume relative to larger cells
-Supports greater nutrient and waste exchange per unit cell volume
-More efficient than larger cells

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17
Q

Cell morphologies (shapes)

A

-Coccus (circle)
-Rod
-spirillum (spiral)
-Spirochete
-Budding and appendaged
-Filamentous

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18
Q

Fungal cell structure

A

-Most have hyphae divided into cells by septa
-Pores allow cell-to-cell movement of organelles
-Cell wall contains chitin (fibrous substance consisting of polysaccharides and are major constituent in the exoskeleton of arthropods)
-No chloroplasts (no photosynthesis)
-Multiple vacuoles

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19
Q

Coenocytic fungi

A

Also known as Non-septate/Aseptate fungi
-Lack septa, continuos cytoplasmic mass with hundreds or thousands of nuclei

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20
Q

Different microbial life

A

-Bacteria
-Archae
-Eukarya
-Algae
-Fungi
-Protozoa
-Viruses

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21
Q

Bacteria

A

-Pro
-Usually undifferentiated single cells that are 0.5-10 micrometres long
-80+ phylogenetic lineages
-Cell walls contain peptidoglycan
-Reproduce via binary fission
-Movement achieved using appendages called flagella
-Nutrition derived from organic substances (some can photosynthesise and some can eat inorganic matter)

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22
Q

Archae

A

-Pro
-12+ phyla
-Associated with extreme environments, extremophiles
-Cell walls lack peptidoglycan
-Lack of known parasites or pathogens of plants and animals

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23
Q

Eukarya

A

-Plants, animals, fungi
-First were unicellular, and may have appeared 2 billion years ago
-At least 4 kingdoms
-Vary dramatically in size, shape, physiology

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24
Q

Fungi

A

-Can be uni/multi-cellular
-Cell walls contain chitin
-Reproduce asexually or sexually
-Majority are non-motile
-Nutrition derived from organic substances

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24
Q

Algae

A

-Not plants
-are able to photosynthesize
-Many conformations
-cell walls contain cellulose

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25
Q

Protozoa/Protists

A

-Several conformations
-Single celled
-reproduce asexually or sexually
-Movement achieved through the use of appendages called cilia, flagella, pseudopods
-Nutrition derived from organic substances

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26
Q

Viruses

A

-Obligate parasites that only replicate within host cell
-Not cells
-Do not carry out metabolism; take over infected cells to replicate
-Have small genomes of double-stranded or single-stranded DNA or RNA
-Classified based on structure, genome composition and host specificity (eg. bacteriophages)

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27
Q

History of life

A

-Atmosphere was anoxic (no O2) and so only anaerobic metabolisms
-first anoxygenic phototrophs
-Cyanobacteria (oxygenic phototrophs)
-Plants and animals

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28
Q

Micro-organisms and agriculture

A

-Nitrogen-fixing bacteria
-Cellulose-degrading rumen
-gut microbiome: digests complex carbohydrates in humans and synthesizes vitamins and other minerals

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29
Q

M and food

A

Negative
-Food spoilage and foodborne disease
-harvest, storage, safety and prevention of spoilage influenced by M
Positive
-Improve food safety, preservation
-dairy products
-other food products such as kimchi and pickles

30
Q

Industrial Microbiology

A

Use of M for major industries such as pharmaceuticals and brewing
-Biofuels
-Wastewater treatment
-Bioremediation
-Biofilms

31
Q

Biotechnology

A

-Genetically-engineered M making high value products in small amounts

32
Q

Fields of light Microscopy

A

Brightfield
Fluorescence

33
Q

Brightfield Microscopy

A

-Also called light microscopy
-Simplest of all light techniques
-Object illumination is via transmitted white light

34
Q

Refraction Index

A

Properties of light are dependent upon the material
Light passing through higher-density material will slow down

35
Q

Refraction

A

Change in direction of wave passing from one medium to another

36
Q

Types of lens used

A

Converging lens
-Biconvex

37
Q

Lens abberations

A

Spherical
Chromatic

38
Q

Spherical aberration

A

-Found in optical systems that use elements with spherical surfaces
-Light rays that strike a spherical surface off-center are refracted or reflected more or less than those that strike close to the center
-Manifests as a blurry image

39
Q

Chromatic abberation

A

caused by the dispersion of the lens material
-The variation of its refractive index with the wavelength of light
-RI can vary depending on the specific wavelength
Manifests as fringes of colour around the image (mainly green)

40
Q

Resolving power

A

The ability to measure the separation of images that are close together
-Determined by the numerical aperture
-As objective increases, numerical aperture increases

41
Q

Numerical aperature

A

NA is the ability of the objective to gather light and resolve fine specimen detail at a fixed object distance
-Higher NA = better resolution

42
Q

NA of air

A

Theoretical=1
Practical=0.95

43
Q

NA of oil

A

Theoretical=1.515
Practical=1.5

44
Q

Positive staining

A

Uses basic dyes thats attach to bacteria

45
Q

Negative staining

A

Uses negative dyes that are repelled by bacteria and so stain background instead
Nb for observing capsules, shape and size of living bacteria

46
Q

staining techniques

A

simple
differentail
complex

47
Q

simple stains

A

Made from a single basic dye
Purpose is to highlight the entire organisms so that shape and basic structures are visible
includes crystal violet and safranin

48
Q

Mordant

A

Additive that intesifies the stainn by increasing the affinity of stain for biological sample
Gram’s iodine forms complexes with crystal vioelt which causes it to clumo and stay contained by thick layers of peptidoglycan

49
Q

Differential stains

A

Different stains react with different kinds of M
used to differentiate between M
Eg. Grams stain

50
Q

steps of Grams stain

A
  1. Application of basic dye crystal violet
  2. Application of mordant iodine
  3. Decolourisation using alcohol
  4. Application of counter stain safranin
51
Q

Crystal violet stain process (P)

A

Gram + cellls have thick layers of peptidoglycan in cell wall that retains stain
Gram - cells have thinner pepti that allows stain to wash out during decolourisation

52
Q

Iodine P

A

Iodine forms a crystal violet-iodine complex that remains contained within the thick layers of peptidoglycan

53
Q

Decolorising agent p

A

Alcohol will remove the crystal violet from some of the cells but not from others

54
Q

safranin counterstain P

A

Safranin is a basic red dye
cells are first rinsed with water before stain is applied
Safranin stains the decolourised cells pink and is less noticeable in the cells that contain crystal violet dye

55
Q

Purpose of knowing gram positive/negatve

A

+ are more readily killed by cephalosporins and penicillins while - is more resistant to antibiotic treatment

56
Q

Phase contrast microscopes

A

Improves image contrast of unstained, live cells
Phase ring amplifies differences in refractive index of cells and surroundings
results in dark cells on light background

57
Q

Dark-field microscopy

A

Light reaches specimen from sides
only light scattered by specimen reaches the lens
image appears light on dark background
Better resolution than light microscopes
excellent for observing motility and flagella

58
Q

Fluoresence Microscopy

A

Visualise specimens that fluoresce
cells appear to glow due to filters
fluoresce naturally or after fluorescent dye such as DAPI
used in clinical microbiology and M ecology

59
Q

TEM

A

Transmission electron microscopy
greater resolving power (0.2nm) than light microscope
enables visualisation of structures on molecular level
speciman must be very thin and stained with high atomic weight substances that scatter electrons and improve contrast
Negative staining allows for direct observation of intact cells/components

60
Q

CryoET

A

electron cryotomography: TEM used to obtain #D images

61
Q

SEM

A

Scanning electron microscopy
speciman is covered with thin film of heavy metal such as gold
electron beam scans object
scattered e are collected and projected to produce image
magnification range up to 100,000x
only surface visualised

62
Q

Aseptic technique

A

Collection of practices that allow preperation and maintenance of sterile media and solutions

63
Q

Pure culture

A

cell from single type of M

64
Q

Enrichment culture

A

Isolate M having particular metabolic characterisitcs from nature

65
Q

Louis pasteur discovery

A

Organisms discriminate between optical isomers
alcoholic fermentation was a biological process
disproved theory of spontaneous generation

66
Q

Swan-necked flask experiment

A
67
Q

germ theory

A

Discovered by robert Koch
linked microbes to infectious disease
identified anthrax, tb and cholera
developed koch’s postulates

67
Q

Koch’s postulates

A

Link cause and effect to infectious disease

68
Q

Martinus Beijernick

A

Developed enrichment culture
selectively encourages growth of specific organisms

68
Q

Sergei Winogradsky

A

showed specific bacteria linked to specific biochemical transformations
Chemolithtrophy:
showed oxidation of only inorganic compounds to yield energy as chemolithotrophs use carbon from CO2
showed nitrogen fixing and nitrification

69
Q

Evidence DNA is molecular basis of hereditary

A
70
Q

Phylogenetic tree

A

Made from similarities in rDNA
shows 3 domains
root is LUCA (last common universal ancestor)

71
Q

Metagenomics

A

Microbia; genomes/fragments recovered from environmental DNA samples

Microbiology (4 decks)

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