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MicroBio > Exam 1 > Flashcards

Exam 1 Flashcards

1
Q

Cellular organisms include

A
  • fungi
  • protists
  • bacteria
  • archaea
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2
Q

Acellular organisms include

A
  • viruses
  • viroids
  • satellites
  • prions
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3
Q

Viruses are composed of

A

protein and nucleic acid

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4
Q

Viroids are composed of

A

RNA

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5
Q

Satellites are composed of

A

nucleic acid, often RNA

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6
Q

Prions are composed of

A

protein

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7
Q

Prokaryotic cells lack what?

A

a true membrane

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8
Q

T / F: prokaryotic cells always lack a true membrane

A

F

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9
Q

What is true of eukaryotic cells?

A

eukaryotic cells have a membrane enclosed nucleus, are morphologically complex, and are usually larger than prokaryotic cells

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10
Q

The three domain system is based on a comparison of what?

A

ribosomal RNA genes

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11
Q

The 3 domains

A
  • bacteria
  • archaea
  • eukaryotes
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12
Q

Cyanobacteria produce significant amounts of

A

oxygen

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13
Q

Archaea are distinguished from bacteria by what?

A

unique rRNA gene sequences

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14
Q

Some Archaea have unique __________ and _________

A

metabolic characteristics, membrane lipids

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15
Q

Many Archaea live where?

A

in extreme conditions

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16
Q

Protists are generally _____ than Bacteria and Archaea

A

larger

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17
Q

Algae + cyanobacteria produce ____% of oxygen

A

75

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18
Q

Yeast are a ___cellular fungi

A

uni

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19
Q

Mold are _____cellular fungi

A

multi

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20
Q

What yeast is often used in labs?

A

Sacchromyces cervesiae

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21
Q

_____ are the smallest of all microbes

A

viruses

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22
Q

Viruses require ________ to replicate

A

host cell

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23
Q

T / F: some viruses can cause cancer

A

T

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24
Q

T / F: oldest fossils on earth are microbial fossils

A

T

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25
Q

How old is the oldest fossil?

A

3.5 billions years old

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26
Q

_______ were the first life forms on earth

A

bacteria

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27
Q

For how long were bacteria the only life form on earth?

A

4.6 bya

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28
Q

What was the earliest molecule?

A

RNA

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29
Q

Ribozymes

A

RNA molecules that perform cellular work

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30
Q

Ribozymes are functional as what?

A

RNA

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31
Q

Earliest cells may have been RNA surrounded by _____

A

liposomes

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32
Q

______ is the precursor to double stranded DNA

A

RNA

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33
Q

The endosymbiotic hypothesis

A

the theory that some of the organelles in eukaryotic cells were once highly efficient prokaryotic cells

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34
Q

Which organelles are thought to originate from endosymbiont?

A

mitochondria and chloroplasts

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35
Q

Why are mitochondria and chloroplasts thought to uphold the endosymbiont theory?

A

mitochondria and chloroplasts contain DNA/RNA

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36
Q

rRNA genes show bacterial ______

A

lineage

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37
Q

16S rRNA (length, role)

A
  • 1,500 nt RNA molecule
  • structural role in the ribosome
  • acts as a scaffold defining the positions of the ribosomal protein
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38
Q

Two regions of 16S rRNA

A
  • highly conserved regions
  • hyper variable regions
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39
Q

16S rRNA is ideal for what?

A

phylogenetic analysis due to the slow rate of evolution of the gene

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40
Q

Few differences in 16S rRNA indicates

A

close relation between species

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41
Q

Evolutionary distance

A

aligned rRNA sequences from diverse organisms are compared and differences counted to derive a value

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42
Q

T / F: time of divergence is determined by evolutionary distance

A

F

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43
Q

Archaea and Eukarya evolved ________ of Bacteria

A

independently

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44
Q

Archaea and Eukarya diverged from ________ ancestry

A

common

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45
Q

_________ of genetic material led to selected traits

A

mutation

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46
Q

Bacteria and Archaea increase genetic pool by _______ within the same generation

A

horizontal gene transfer

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47
Q

Who was the first person to observe and describe microorganisms accurately?

A

Antony van Leeuwenhoek

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48
Q

The idea that micro-organisms are the result of the process of decay is what theory

A

spontaneous generation

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49
Q

Who disproved spontaneous generation theory?

A

Louis Pasteur

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50
Q

Miasma theory

A

disease caused by foul air and bad smells

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51
Q

Louis Pasteur demonstrated that microorganisms carry out what process?

A

fermentations

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52
Q

Louis Pasteur developed what process to avoid wine spoilage by microbes?

A

pasteurization

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53
Q

Who provided indirect evidence that microorganisms were the causal agents of disease?

A

Joseph Lister

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54
Q

Joseph Lister developed what system and what did it result in?

A

aseptic surgery techniques, fewer postoperative infections

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55
Q

Who established the relationship between Bacillus anthracis and anthrax?

A

Robert Koch

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56
Q

Koch’s (4) Postulates

A
  1. the microorganism must be present in every case of the disease but absent from healthy organisms
  2. the suspected microorganisms must be isolated and grown in a pure culture
  3. the same disease must result when the isolated microorganism is inoculated into a healthy host
  4. the same microorganisms must be isolated again from the diseased host
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57
Q

What disease did Koch experiment on to test his postulates?

A

TB

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58
Q

Limitations of Koch’s Postulates

A
  • some organisms cannot be grown in pure culture
  • using humans in completing the postulates is unethical
  • asymptomatic carriage
  • co-infections
  • dysbiosis
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59
Q

Koch’s work led to discovery of development of

A
  • agar
  • petri dishes
  • nutrient broth and nutrient agar
  • methods for isolating microorganisms
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60
Q

Taxonomy

A

science of biological classification

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61
Q

Taxonomy consists of what 3 separate but interrelated parts

A
  • classification
  • nomenclature
  • identification
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62
Q

Highest taxonomic rank is ______

A

domain

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63
Q

Within domain

A

phylum, class, order, family, genus, species

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64
Q

Binomial system used 2 names, the first name is the ____ and the second is the ____

A

genus, species

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65
Q

Species

A

population of cells with similar characteristics

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66
Q

Genus name

A

italicized and capitalized

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67
Q

Species name

A

italicized but not capitalized

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68
Q

Gene nomencltaure

A
  • three lowercase letters followed by an uppercase fourth letter
  • italicized
  • / abcD /
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69
Q

Protein nomenclature

A
  • same four letters as gene name
  • not italicized
  • first and last letter capitalized
  • AbcD
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70
Q

Prokaryotes differ from eukaryotes in _____ and _____

A

size, simplicity

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71
Q

Most prokaryotes lack

A

internal membrane systems (nuclear membrane, r and s ER, mitochondria)

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72
Q

Prokaryotes = what two domains?

A

bacteria and archaea

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73
Q

Overarching characteristics of prokaryotic cells

A
  • no nucleus
  • one chromosome
  • usually unicellular
  • no organelles
  • 70S rRNA
  • plasma membrane
  • cell wall
  • 80-90% genome density CDS
  • cell size: 1-10 micro m
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74
Q

Most common bacterial shapes

A

cocci and rod

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75
Q

Arrangement of bacterial cells is determined by

A

plane of division

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76
Q

Diplococci

A

pairs

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77
Q

Streptococci

A

chains

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78
Q

Staphylococci

A

grape-like clusters (dividing in alternating planes)

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79
Q

Tetrads

A

4 cocci in a square

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80
Q

Sarcina

A

cubic configuration of 8 cocci

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81
Q

Coccobacilli

A

very short rods

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82
Q

Streptobacilli

A

chain of rods

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83
Q

Vibrios

A

resemble curved rods, comma shaped

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84
Q

Spirilla

A

rigid helices

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85
Q

Spirochetes

A

flexible helices

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86
Q

Mycelium

A

network of long, multinucleate filaments

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87
Q

Pleomorphic

A

organisms that are variable in shape

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88
Q

Smallest bacteria (name and size)

A

0.3 micro m, Mycoplasma

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89
Q

Average rod size

A

1.1-1.5 micro m wide x 2-6 micro m long

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90
Q

______ is one of the biggest viruses that infects humans

A

Pox virus

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91
Q

Bacterial genome size (range)

A

500,000 bp to 10 million bp

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92
Q

What increases S/V ratio?

A

corkscrew shape

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93
Q

_____ cell size increases S/V ratio

A

small

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94
Q

Bacterial cell organization (3) common features

A
  1. cell envelope
  2. cytoplasm
  3. external structures
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95
Q

Layers of cell envelope

A
  1. cell membrane
  2. wall
  3. S-layer
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96
Q

All bacteria must have

A

cell membrane, cell wall, cytoplasm

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97
Q

_____ and ______ are variable to bacteria

A

S-layer, external structures

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98
Q

Typical bacterial cell structure (describe)

A

plasma membrane is further in than cell wall which is further in than capsule

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99
Q

Layers outside cell wall

A

S-layer, capsule

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100
Q

__________ is an absolute requirement for all living organisms

A

plasma membrane

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101
Q

Plasma membrane functions

A
  • encompasses the cytoplasm
  • selectively permeable barrier
  • interaction with external environment
  • metabolic processes
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102
Q

Hydrophobic regions associate with each other (_____), hydrophilic regions exposed (______)

A

inside, outside

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103
Q

Peripheral = ________% total membrane protein

A

20-30

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104
Q

Peripheral protein characteristics

A
  • loosely attached to membrane
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105
Q

Integral protein = ____% of total membrane protein

A

70-80

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106
Q

Integral protein characteristics

A
  • amphipathic (embedded within membrane)
  • carry out important functions
  • may exist in microdomains
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107
Q

Saturated bacterial lipids = ___ fluid

A

less

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108
Q

Hopanoids

A

sterol-like molecules, stabilize membrane

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109
Q

Macronutrients

A
  • C, O, H, N, S, P
    - found in organic molecules such as proteins,
    lipids, carbohydrates, and nucleic acids
  • K, Ca, Mg and Fe
    - cations and serve in variety of roles including
    enzymes, biosynthesis
  • required in relatively large amounts
  • mostly needed as cofactors for enzymes
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110
Q

Micronutrients

A
  • trace elements
  • Mn, Zn, Co, Mo, Ni and Cu
  • often supplied in water or in media components
  • ubiquitous in nature
  • serve as enzymes and cofactors
  • passively enter the cell
111
Q

Growth factors

A
  • organic compounds
  • essential cell components (or their precursors) that the cell cannot synthesize
  • must be supplied by environment if cell is to survive
  • any organic compound that a cell must take up
112
Q

Amino acids are needed for _____ synthesis

A

protein

113
Q

Purines and pyrimidines are needed for ______ synthesis and are the basic building blocks for ____

A

nucleic acid, DNA

114
Q

Vitamins function as _______

A

enzyme cofactors

115
Q

Heme

A

iron

116
Q

An example of nutritional immunity

A

body keeps iron in a form that is inaccessible to bacteria

117
Q

What two transport mechanisms do all microorganisms use?

A

facilitated diffusion, active transport

118
Q

Group translocation is used by

A

bacteria and archaea

119
Q

Endocytosis is used by

A

Eukarya only

120
Q

H2o, O2 and CO2 often move across membrane by

A

passive diffusion

121
Q

Facilitated diffusion typically involves

A

carrier proteins

122
Q

In facilitated diffusion, direction of movement is from ______ to _____ and, ____ require energy

A

high concentration to low concentration, does not

123
Q

How does facilitated diffusion differ from passive diffusion?

A
  • uses permeases (membrane bound carrier molecules)
  • smaller concentration gradient is required for significant uptake of molecules
  • effectively transports glycerol, sugars, and amino acids
124
Q

Facilitated diffusion is more prominent in ____ than in

A

eukaryotic cells, bacteria or archaea

125
Q

Passive diffusion is

A

linear

126
Q

Active transport is a(n) ______-dependent process

A

energy

127
Q

Active transport movement

A
  • moves molecules against the concentration gradient
  • concentrates molecules inside cell
128
Q

3 types of active transport

A
  1. primary active transport
  2. secondary active transport
  3. group translocation
129
Q

Primary active transport (characteristics, what microorganisms it is observed in)

A
  • ABC transporters
  • use ATP
  • observed in bacteria, archaea and eukaryotes
  • consists of 2 hydrophobic membrane spanning domains, 2 cytoplasmic associated ATP-binding domains, substrate binding domains
130
Q

Secondary active transport

A
  • use ion gradients to cotransport substances (instead of ATP!)
  • symport
  • antiport
131
Q

Symport

A

two substances both move in the same direction

132
Q

Antiport

A

two substances move in opposite directions

133
Q

Group translocation

A
  • energy dependent transport that chemically modifies molecule as it is brought into cell
  • a variety of sugars can be transported by PTS systems
  • Enzyme I and Hpr are the same in all PTS systems
  • specificity lies with Enzyme II
134
Q

Siderophore

A

secreted by microorganisms to aid in iron uptake

135
Q

Cell wall functions

A
  • maintains shape of the bacterium
  • helps protect cell from osmotic lysis
  • helps protect from toxic materials
  • may contribute to pathogenicity
136
Q

T / F: a lot of bacteria can survive without cell wall (no osmotic pressure) but not without cell membrane

A

T

137
Q

Gram-positive bacteria stain

A

purple

138
Q

Gram-negative bacteria stain

A

pink

139
Q

T / F: peptidoglycan is found in bacterial cell wall and nowhere else

A

T

140
Q

Area between peptidoglycan and plasma membrane

A

periplasm

141
Q

Peptidoglycan (murein)

A

rigid polymer structure that lies just outside the cell plasma membrane

142
Q

Gram (+) peptidoglycan: _____ nm thick

A

20-80

143
Q

Gram (-) peptidoglycan: ______ nm thick

A

2-7

144
Q

Peptidoglycan structure

A
  • two alternating sugars: NAM and NAG
  • peptide strand (alternating D- and L- amino acids)
145
Q

L amino acid is connected to NAM or NAG?

A

NAM

146
Q

Chains in peptidoglycan are crosslinked to other chains via

A

peptides

147
Q

Crosslinking can be direct or

A

by a peptide inter-bridge

148
Q

Most common #3 amino acid is

A

DAP

149
Q

Most common type of linkage is

A

3 - 4 linkage

150
Q

Amino acid at #3 position can be

A
  • DAP
  • L-Lys
  • L-Hsr
151
Q

Linkage types

A

3 - 4
2 - 4

152
Q

Composition of linkage

A
  • direct
  • bridged
153
Q

Protein translation by ribosomes exclusively utilizes

A

L-amino acids

154
Q

T / F: D-amino acids are common

A

F

155
Q

The most common place in nature to find D-amino acids

A

bacterial cell wall

156
Q

Peptidoglycan backbone

A
  • alternating NAM-NAG sugars
  • beta-(1,4) linked
  • beta-(1,4) glyosidic bond
157
Q

Gram (+) cell walls

A
  • 20-80 nm thick peptidoglycan
  • may also contain teichoic acids
158
Q

Teichoic acids

A
  • polymer consisting of alternating phosphate/sugar groups
  • (-) charged
  • help maintain cell envelope
  • protect from environmental substances
  • may bind to host cells
  • covalently connected to peptidoglycan
  • may also be covalently connected to lipids in plasma membrane (LTA)
159
Q

TA: anchored to ____

A

cell wall

160
Q

LTA: anchored to/in _____

A

plasma membrane

161
Q

Sortase

A
  • periplasmic protein
  • anchors other proteins to cell wall
162
Q

Periplasmic space of Gram (+) bacteria is ____ than that of Gram (-)

A

smaller

163
Q

Gram (+) cell walls

A
  • important for virulence
  • covalently linked to peptidoglycan
  • proteins have protein sequence LPXTG
  • covalently linked to peptidoglycan through T residue by enzyme sortase
164
Q

Gram (-) cell walls are _____ complex than Gram (+) cell walls

A

more

165
Q

Gram (-) cell walls

A
  • consist of a thin layer of peptidoglycan surrounded by an outer membrane (OM)
  • outer membrane composed of lipids, lipoproteins and LPS
  • no teichoic acids
  • plasma membrane sometimes called inner membrane (IM)
166
Q

Important differences between Gram (-) and (+) cell walls

A
  • Gram (+) cell walls have no OM
  • Gram (+) cell walls have thicker peptidoglycan/cell wall
  • Gram (-) has LPS, no TA
167
Q

Periplasmic space of Gram (-) cell

A
  • 20-40% of cell volume
  • many enzymes present (hydrolytic enzymes, transport proteins, etc.)
168
Q

In Gram (-) cell walls, the OM lies

A

outside thin peptidoglycan layer

169
Q

OM is _____ bonded to peptidoglycan by

A

covalently, Braun’s lipoprotein

170
Q

Outer surface of OM consists of

A

LPS

171
Q

Inner layer of OM composed of

A

phospholipids

172
Q

T / F: LPS is only found in Gram (-) bacteria

A

T

173
Q

LPS structure

A
  1. O side chain (O antigen) (extended out from cell)
  2. core polysaccharide
  3. lipid A (embedded in OM)
174
Q

Importance of LPS

A
  • core polysaccharide contributes to (-) charge on cell surface
  • lipid A helps stabilize OM structure
  • creates a permeability barrier
  • O antigen protects from host defenses
  • lipid A can act as a toxin (endotoxin)
175
Q

Gram (-) OM permeability

A
  • more permeable than IM due to presence of porin proteins
  • porin proteins form channels to let small molecules pass
176
Q

One major function of the cell wall is to protect the bacterial cell from

A

osmotic stress

177
Q

Hypotonic environments

A
  • solute concentration is higher inside the cell
  • water moves into cell and cell swells
  • cell wall protects from lysis
178
Q

Hypertonic environments

A
  • solute concentration is higher outside the cell
  • water leaves the cell
  • plasmolysis occurs (shrinking of cytoplasm)
179
Q

If peptidoglycan cell wall is removed…

A
  • cells will lyse if they are in a hypotonic solution
  • survive in isotonic solution
180
Q

Gram (+) bacteria without peptidoglycan

A

protoplasts

181
Q

Gram (-) bacteria without peptidoglycan

A

spheroplasts

182
Q

3 most common types of components outside the cell wall

A
  • capsules
  • slime layers
  • S-layers
183
Q

Capsules

A
  • usually composed of polysaccharides
  • resistant to phagocytosis
  • protect from desiccation
  • exclude viruses and detergents
  • well organized, not easily removed from cell
184
Q

Slime layers

A
  • may aid in motility
  • similar to capsules except diffuse, unorganized and easily removed
185
Q

S-layers

A
  • regularly structured layers of protein or glycoprotein that self-assemble
  • Gram (-): S-layer adheres to OM
  • Gram (+): S-layer is associated with the peptidoglycan surface
186
Q

Cytoplasm

A

material bounded by the plasmid membrane

187
Q

Bacterial cytoplasmic structures (5)

A
  • cytoskeleton
  • intracytoplasmic membranes
  • ribosomes
  • nucleoid and plasmids
  • inclusions
188
Q

Cytoskeleton (3 eukaryotic cytoskeletal elements, role, homologs)

A
  • 3 eukaryotic cytoskeletal elements: actin, tubulin, intermediate filaments
  • plays role in cell shape and structure, internal organization, localization of components within the cell
  • homologs of all three have been identified in bacteria
189
Q

FtsZ

A
  • tubulin homolog
  • found in many bacteria
  • forms ring during septum formation in cell division
190
Q

MreB

A
  • actin homolog
  • maintains shape by positioning peptidoglycan synthesis machinery
  • found in rods
191
Q

CreS

A
  • IF homolog
  • rare
  • maintains shape in curved bacteria (prevents peptidoglycan synthesis on one side)
192
Q

Intracytoplasmic membranes

A
  • extension of the plasma membrane into cytoplasm
  • many metabolic reactions can only happen in/at a membrane, provides more surface area that can then provide space for reactions
  • observed in many photosynthetic bacteria and bacteria with high respiratory activity
193
Q

Ribosomes

A
  • complex protein/RNA structures
  • sites of protein synthesis
194
Q

Bacterial and archaeal ribosome

A

70S

195
Q

Eukaryotic ribosome

A

80S

196
Q

Bacterial rRNA

A
  • 16S small subunit
  • 23S and 5S in large subunit
197
Q

Ribosomes are found where in bacteria?

A

free floating in cytoplasm

198
Q

The nucleoid

A
  • genetic material of the cell
  • usually not membrane bound
  • consists of chromosome and associated proteins
  • usually 1 closed circular, DS DNA molecules
199
Q

______ condenses nucleoid

A

Supercoiling

200
Q

Plasmids

A
  • extrachromosomal DNA
  • exist and replicate independently of chromosome
  • contain non-essential genes
201
Q

Episomes

A

when plasmids integrate onto chromosomes

202
Q

Inclusions

A
  • granules or organic or inorganic material that are stockpiled by the cell for future use
  • general term for anything random found in cytoplasm
203
Q

External structures (functions)

A
  • attachment to surfaces
  • cell movement
  • protection
  • horizontal gene transfer
204
Q

3 best known examples of external structures

A
  • pili
  • fimbriae
  • flagella
205
Q

Pili and fimbriae

A
  • short, thin, hair-like appendages (up to 1,000 per cell)
  • proteinaceous
  • helical tubes
  • functions include attachment to surfaces, motility and DNA uptake
  • attachment to surfaces is main function
206
Q

Sex pilus

A
  • longer, thicker, less numerous
  • genes for formation found on plasmids
  • required for conjugation
  • forms between bacterial cells
207
Q

Flagella

A
  • long thread-like appendages extending outward from plasma membrane and cell wall
  • up to 20 micro m in length
  • functions include motility, attachment to surfaces, virulence factors
  • motility is main function, acts as a propeller
  • can be 4-5x larger than the cell
  • corkscrew shape
208
Q

Monotrichous

A

one flagellum

209
Q

Polar (flagella distribution)

A

flagellum at end of cell

210
Q

Amphitrichous

A

one flagellum at each end of cell

211
Q

Lophotrichous

A

cluster of flagella at one or both ends

212
Q

Peritrichous

A

spread over entire surface of cell

213
Q

3 parts of flagella

A
  1. filament
    - extends from cell surface to the tip
    - hollow, rigid cylinder of flagellin protein
  2. hook
    - links filament to basal body
  3. basal body
    - series of rings that drive flagellar motor
214
Q

Filament subunits self-assemble with help of filament cap at

A

tip, not base

215
Q

Chemotaxis

A

move toward chemical attractants such as nutrients, away from harmful substances

216
Q

4 common types of motility

A
  • flagellar movement
  • spirochete motility
  • twitching motility
  • gliding motility
217
Q

Flagellar movement

A
  • flagellum rotates like a propeller (very rapid rotation)
  • CCW: forward motion (run)
  • CW: cell spins around (tumble)
218
Q

Spirochete motility

A
  • flagella remain in periplasmic space inside OM (periplasmic flagella)
  • multiple flagella form axial fibril which winds around the cell
  • corkscrew shape exhibits flexing and spinning movements
219
Q

Twitching motility

A
  • pili at ends of cell
  • extend and contact surface
  • retract, pulling the cell forward
  • short, intermittent, jerky motions
220
Q

Gliding motility

A
  • not well-defined process
  • various proposed mechanisms
  • smooth movements
  • smile layers?
221
Q

In a graph of flagellar mediated chemotaxis:
- each corner indicates a _______
- in absence of attractant, flagella rotate CCW and CW with ______ frequency
- when concentration of attractant increases, the frequency of CW is _____, runs in direction of attractant are ______
- when concentration of attractant decreases, frequency of CW is ______, cell redirects until _______

A
  • tumble
  • equal
  • reduced, longer
  • increased, moving towards attractant
222
Q

The bacterial endospore

A
  • complex, dormant structure formed by some bacteria
  • various locations within the cell
  • resistant to numerous environmental conditions (heat, radiation, chemicals, desiccation)
223
Q

Sporulation

A
  • process of endospore formation
  • occurs in hours (up to 10)
  • normally commences when growth ceases because of lack of nutrients
  • complex, multistage process
224
Q

Purpose of sporulation

A

survival and preservation of the genetic matieral

225
Q

Formation of vegetative cell

A
  • activation (prepares spores for germination, often results from treatments like heating)
  • germination (environmental nutrients are detected, spore swelling and rupture of spore coat, increased metabolic activity)
  • outgrowth (emergence of actively growing cell)
226
Q

One thing Archaea are not known to do

A

cause disease in humans

227
Q

Archaeal size, shape, arrangement

A
  • cocci and rods are common shapes (others can exist)
  • no spirochetes or mycelial forms yet
  • branched/flat shapes
  • sizes vary (typically 1-2 x 1-5 micro m for rods, 1-5 micro m diameter for cocci)
  • smallest observed is 0.2 micro m in diameter
228
Q

Properties that bacteria and archaea have in common

A
  • inclusions
  • ribosomal size
  • chromosomal structure
  • plasmids
  • external strucutres
229
Q

Archaeal cell envelopes

A

cell envelope consists of
- plasma membrane
- no peptidoglycan
- cell wall (some lack one, however)
- additional external layers (S-layer may be only component outside plasma membrane, capsules and slime layers are rare)

230
Q

Archaeal envelopes differ from bacterial envelopes in

A

the molecular makeup and organization

231
Q

Archaeal membrane lipids (building block, composition)

A
  • composition is very different than that of bacteria
  • building block is 5 carbon branched molecule isoprene
  • lipid chains of isoprene are branched, unlike the chains of bacterial phospholipids
232
Q

Branching of membrane lipids affects

A

fluidity of membrane

233
Q

Archaeal lipids are attached to glyercol by

A

ether linkages

234
Q

Bacterial lipids are attached to glycerol by

A

ester linkages

235
Q

Some archaeal lipids and membranes have…

A
  • diglycerol tetraethers
  • pentacyclic rings (increases membrane rigidity)
236
Q

Archaeal lipid and membrane composition supports what idea?

A

that archaea evolved independently of bacteria

237
Q

Most common type of archaeal cell envelope is

A

S-layer outside plasma membrane

238
Q

Additional layer outside of the S layer may be composed of

A

polysaccharide

239
Q

Some archaeal cell walls contain a peptidoglycan-like polymer called

A

pseudomurein

240
Q

Differences between pseudomurein and peptidoglycan

A
  • beta,1-3 linkage
  • no D amino acids
  • NAT and NAG
241
Q

Protein translation by ribosomes exclusively utilizes

A

L-amino acids

242
Q

Archaeal cell walls have a thick _______ layer, and often stain

A

polysaccharide, Gram (+)

243
Q

Archaeal cells use what mechanisms for nutrient uptake

A
  • primary active transport
  • secondary active transport
244
Q

T / F : archaea have more proteins than bacteria

A

T

245
Q

5.8S suggests relationship between

A

eukaryotes and archaea

246
Q

_____ may be involved in archaeal adhesion mechanisms

A

pili

247
Q

Cannulae

A
  • hollow, tube-like structures on the surface of thermophilic archaea in the genus Pyrodictium
  • function is unknown
  • connects cells together, helps them adhere to each other and the surface around them
248
Q

Hami

A
  • not well understood
  • looks like a grappling hook
  • involvement in cell adhesion mechanisms (?)
249
Q

Archaeal flagella: growth occurs where?

A

at the base

250
Q

Differences of archaeal flagella

A
  • thinner than bacterial flagella
  • more than one type of flagellin protein
  • flagellum are not hollow
  • hook and basal body are difficult to distinguish
  • add subunits to base, not tip
251
Q

Two groups of eukaryotes commonly possess microbial members

A
  • protists
  • fungi
252
Q

T / F: protist is a taxonomic group

A

F

253
Q

Eukaryotic cell envelopes

A
  • plasma membrane is lipid bilayer
  • consists of plasma membrane and all coverings attached to it
  • usually don’t have cell wall (protists and fungi do)
  • sphingolipids and cholesterol contribute to strength of membrane
254
Q

Cell walls of photosynthetic algae commonly composed of

A

cellulose, pectin, and silica

255
Q

Cell walls of fungi consist of

A

cellulose, chitin or glucan

256
Q

T / F: cell wall of a eukaryotic cell is typically complex

A

F

257
Q

Cytoplasm of eukaryotes

A
  • consists of the cytosol and many organelles
  • cytoskeleton plays a role in cell shape and movement (microfilaments, microtubules, intermediate filaments)
258
Q

_____ cytoskeletal component is involved in cell motion and shape changes

A

actin filaments

259
Q

Intermediate filaments

A
  • heterogeneous elements of the cytoskeleton
  • role in cell is unclear
  • play a structural role
  • some shown to form nuclear lamina, others help link cells together to form tissues
260
Q

Microtubules

A
  • think cylinders
  • help maintain cell shape
  • involved with actin filaments in cell movements
  • participate in intracellular transport processes
261
Q

Lysosomes

A
  • intracellular digestion (important for clearing microbes from eukaryotic cells)
  • contain hydrolases (enzymes that hydrolyze molecules and function best under slightly acidic conditions)
  • maintain an acidic environment by pumping protons into their interior
262
Q

Endosytosis

A
  • used to bring materials into the cell
  • solutes or particles taken up and enclosed in vesicles pinched from plasma membrane
263
Q

Phagocytosis

A
  • cell surface protrusions surround and engulf particles
  • particles are taken up inside a membrane bound vesicle
264
Q

Receptor mediated endocytosis

A
  • external receptors on cell surface
  • specifically bind macromolecules
  • binding triggers endocytosis
  • receptor and bound molecule are taken up
265
Q

Eukaryotic ribosomes

A
  • may be attached to ER or free in cytoplasmic matrix
  • when present in ER: bound via 60S subunit
266
Q

ER ribosomes

A

secreted and membrane proteins

267
Q

Free ribosomes

A

cytoplasmic proteins

268
Q

External cell covering (eukaryotic cells) and what they are associated with

A
  • cilia, movement
  • flagella, movement
269
Q

______ may have lateral hair-like projections

A

flagella

270
Q

_______ move in an undulating fashion
- wave from base to tip, pushes cell
- wave from tip to base, pulls cell

A

flagella

271
Q

_______ beat with two phases, working like oars, and have highly coordinated movements

A

cilia

272
Q

In what type of cell are introns rare in?

A

archaeal and bacterial

273
Q

Describe the plasma membrane lipids of
- bacterial cells
- archaeal cells
- eukaryotic cells

A
  • bacterial cells: ester-linked phospholipids and hopanoids; some have sterols
  • archaeal cells: glycerol di-ethers and diglycerol tetraethers
  • eukaryotic cells: ester-linked phospholipids and sterols

MicroBio (4 decks)

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