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Unit 1 Flashcards

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1
Q

Flagella and Archaella

A

Tiny rotating machines that function to push or pull the cell through a liquid - anchored in the cytoplasmic membrane and cell wall

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2
Q

Polar flagellation

A

Flagella are attached at one or both ends of a cell - move more rapidly and continuously, and some are able to reverse their direction

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3
Q

Peritrichous flagellation

A

Flagella are inserted around the cell surface - move slowly in a straight line, stop and then head off in a new direction

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4
Q

Two main components of flagellum motor

A
  • rotor and the stator
  • rotor consists of the central rod and the L, P, C, and MS rings
  • stator is comprised of Mot proteins, which surround the rotor and function to generate torque
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5
Q

Flagellar basal body

A

Made up of rotor and stator

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6
Q

Surface Motility

A

Motile microbes that are unable to swim and instead crawl over surfaces in various ways

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7
Q

Twitching motility

A

Requires type IV pili, which extend from one pole of the cell, attach to a surface, and then retract to pull the cell forward - allows cells to move together in groups

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8
Q

Gliding motility

A

Smooth motion along the long axis of a cell without the aid of external propulsive structures (such as pili or attachment organelles) - no gliding Archaea are known - continuous form of movement

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9
Q

Chemotaxis

A

Response to chemicals - ability of a cell to move toward or away from various stimuli

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10
Q

Phototaxis

A

Response to light - the ability of a cell to move toward or away from various stimuli

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11
Q

Chemoreceptors

A

Sense the concentration of particular chemicals and transduce this information to flagella, causing them to alter their rotation

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12
Q

Nucleus

A

Contains the chromosomes of the eukaryotic cell - only in eukaryotic - contains cell DNA genome - enclosed by a pair of membranes with it own function

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13
Q

Histones

A

DNA within the nucleus is wound around basic proteins

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14
Q

Nucleolus

A

Within the nucleus - site of ribosomal RNA (rRNA) synthesis

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15
Q

Mitosis

A

Eukaryotic cell division - chromosomes are replicated, and the chromosomes are segregated into two sets, and a nucleus is reassembled in each daughter cell

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16
Q

Meiosis

A

Converts a diploid cell into several haploid cells - form a total of four haploid cells called gametes. This form of cell division is typically used in organisms that reproduce sexually.

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17
Q

Mitochondria

A

In eukaryotic cells, respiration occurs here

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18
Q

Chloroplasts

A

Chlorophyll-containing organelles are found in plants and algae and are the site of photosynthesis

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19
Q

Endosymbiotic theory

A

The idea mitochondria and chloroplast originated from bacteria

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20
Q

Microbial communities

A

2+ populations of cells that coexist and interact in the same habitat

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21
Q

Three major domains

A

Bacteria, Archaea, or Eukarya

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22
Q

Bacteria

A

Have a prokaryotic cell structure - undifferentiated single cells- unicellular or multicellular

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23
Q

Archaea

A

Prokaryotic cell structure - associated with extreme environments

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24
Q

Eukarya

A

Plants, animals, and fungi - eukaryotes

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25
Viruses
Viruses are not cells, and they lack the cytoplasmic membrane, cytoplasm, and ribosomes found in all forms of cellular life - infect cells from all three domains of life
26
Pathogen
Disease-causing microorganism
27
Louis Pasteur
Demonstrates that microbes do not generate spontaneously - used sawn necks to prove after boiling contents remained free of microbes - had some development of vaccines for anthrax, fowl cholera, and rabies.
28
Robert Koch
Demonstrated the link between bacteria and infectious diseases - developed pure culture techniques
29
Koch’s postulates
Formulated a set of rigorous criteria for definitively linking cause and effect in an infectious disease
30
Carl Woese
DNA sequences change over time - used to record evolutionary history with polygenic tree
31
Robert Hooke
Built the first compound microscope - and used it to study mold
32
Refraction
The bending of a ray of light as it passes from one medium to another
33
Resolution
The ability to separate or distinguish between adjacent objects
34
Bright-field microscopy
Visualize organisms based on a difference in color or density from the surrounding medium (light microscopy)
35
Gram stain
Differentiates cells based on their cell wall properties - Gram-negative vs. Gram-positive cells
36
Dark-field microscopy
Visualize organisms due to the light that they reflect (the light is introduced from the side)
37
Phase contrast microscopy
Visualize organisms based on a difference in the refractive index from the surrounding medium - the background is bright due to undeviated light; the organism is dark due to a change in phase as light passes through
38
Differential stain
Differentiates cells into groups based on their staining properties
39
Fluorescence microscopy
Visualize organisms based on the ability of the organisms to emit light (naturally or due to a fluorescent stain or fluorescent protein)
40
Differential interference contrast microscopy
generate a 3D image of cells -visualize differences among structures within organisms based on differences in their refractive index
41
Confocal Scanning Laser Microscopy
Generates a 3D image of cells - florescent
42
Scanning electron microscopy
Generate 3D image of the external features of a cell - Coat sample with a thin film of metal (often gold)
43
Transmission electron microscopy
Visualize viruses and internal features of cells - Electrons do not penetrate cells well, so cells are thinly sliced
44
Cytoplasmic membrane - Cell membrane - Plasma membrane
Separates cell from environment - thin layer that surrounds all cells is a molecular gatekeeper - if it breaks, the cell dies
45
Complex lipids
Simple lipids that contain additional elements such as phosphate, nitrogen, or sulfur
46
Simple lipids
Fatty acids linked to a glycerol by ester linkage
47
Bacterial cytoplasmic membranes contain
Phospholipids and associated cations, glycolipids, integral and peripheral membrane proteins, hopanoids
48
Functions of the cytoplasmic membrane
To regulate the flow of material into and out of the cell, permeability barrier, protein anchor, maintain proton-motive force
49
Cell wall
semi-rigid, corset-like layer around the cell, often called a Sacculus - a single, interlinked molecule that encloses the cell
50
Peptidoglycan
The major structural component of Bacterial cell walls
51
Glycosidic bonds within cell walls
Provides strength, but not rigidity
52
Cross-linking
provides rigidity - the more cross-links, the greater the strength - the resulting “sack” can hold its own shape but is porous and lets molecules through
53
Cell wall-less Bacteria
Closely related to Gram-positive bacteria - includes mycoplasmas that infect animals - includes phytoplasmas that infect plants
54
Gram-negative cell wall
More complex - contains periplasm, braun lipoprotein, outer membrane, porins, LPS -lipid A, core polysaccharide, and O-antigen
55
Functions of cell walls
Restrict the flow of very large molecules and provide protection from osmotic lysis
56
Archaeal cell walls
Do not have peptidoglycan - can stain Gm+ or Gm-, but the stain doesn’t indicate particular wall types
57
S-layers
Cell surface layers outside the cell wall – when present, they form the outermost structured layer of a cell - formed of interlocking proteins or glycoproteins - general role may be in protection
58
Capsule
A well-organized layer of material that is not easily washed off - visible by India ink staining
59
Slime layer
An unorganized layer of material that is easily removed
60
Functions of Capsules and Slime layers
Attachment to surfaces - supports the development of biofilms - Protection against bacterial viruses, toxic materials like detergents, Destruction by the host immune system
61
Isotonic
The same solute concentrations out and in
62
Hypertonic
More solute concentration outside
63
Hypotonic
More solute concentration inside
64
Cell shape - coccus
Spherical
65
Cell shape - rod/bacillus
Cylinder
66
Cell shape - spirillum
spiral
67
Cell shape - vibrio
Curved (comma-shaped)
68
Integral membrane proteins
Proteins embedded in the membrane
69
Transmembrane Proteins
Proteins extend completely across the membrane
70
Peripheral Proteins
Loosely attached proteins
71
Pili (s. pilus)
Appendages that are much shorter than flagella - can only be seen with EM
72
Type IV pilus
Retractable pilus involved in twitching motility
73
T pilus
Helps transfer DNA from a bacterial plant pathogen to a plant
74
Hrp pilus
Helps transfer proteins from bacterial plant pathogens to their plant host and cause disease
75
Cytoplasm
The fluid and cell constituents inside the cytoplasmic membrane
76
Genome
Total DNA content of a cell
77
Plasmids
DNA elements that replicate independently of the chromosome
78
Ribosomes
Up to 10,000 ribosomes per cell- carry out protein synthesis - Composed of 40% protein and 60% RNA
79
Gas vesicles
Protein-enclosed vesicles that promote buoyancy
80
Magnetosomes
Membrane-bound structures comprised of iron oxides
81
Endospores
Dormant structures that are extremely resistant to stresses - low water content
82
Aerotaxis
movement in response to oxygen - allows movement to the optimal oxygen concentration
83
Medium
the nutrient solution used to grow a microbe
84
Macronutrients
Nutrients required in large amounts
85
Passive Transport
Transport that enables molecules to travel across a membrane down a concentration gradient
86
Active Transport
Transport that requires energy to move compounds against a gradient
87
Forms of active transport - Simple transport
Transport in which one molecule moves down its gradient, and this drives the movement of another up its gradient; this is usually fueled by proton motive force.
88
Forms of active transport - group Translocation
Nutrients are chemically altered during transport into the cell - a concentration gradient is not produced- energy is used for the chemical alteration
89
Forms of active transport - ABC transporters (ATP-binding cassette transporters)
ABC transporters have three components: (a) Binding protein (b) Membrane-spanning transporter protein (c) ATPase protein in the cytoplasm, which provides energy for transport
90
Forms of active transport - Iron uptake systems
Cells need a lot of iron for electron transport proteins and many enzymes - Microbes make special scavenging compounds to extract iron from precipitates and transport it back to, and into, the cell
91
Methods of measuring microbial growth - Microscopy count
Relatively rapid (no waiting for cells to grow) - Laborious - Can’t be done if cells are motile!
92
Methods of measuring microbial growth - Viable counts using serial dilutions
Have to wait for colonies to grow before you can determine the cell density - The counts reflect only living cells
93
Methods of measuring microbial growth - Turbity
Measured with a spec - doesn't distinguish living from dead - need a standard curve
94
Binary fission
The division of a cell to create two equal cells - this is asexual reproduction; all reproduction in prokaryotes is asexual
95
Batch culture
The growth of a population in a closed system where the nutrients are limited
96
Planktonic Growth
Bacterial growth in a liquid medium
97
Biofilms
Structure containing bacterial cells encased in organic polymers on the surface

Micro (5 decks)

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