Midterm 1 Flashcards

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1
Q

Microbiology

A

the study of microbes

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2
Q

microbes

A

forms of life too small to be seen with the naked eye

ex:
Bacteria
Viruses
Protists
Fungi (two kinds, yeast & mold)
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3
Q

t or f: 10^14 bacteria in body 10^13 human cells in body

A

TRUE there are 10x more bacteria in the human body than human cells

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4
Q

amniotic fluid has ______

A

antimicrobial properties

cleanses birth canal but doesn’t get rid of bacteria completely

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5
Q

babies born _______ are healthier

A

through birth canal

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6
Q

bacteria help plants take up ______

A

nitrogen

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7
Q

what are the characteristics of a living object?

A
  • metabolism, growth, reproduction
  • genetic variation/evolution
  • response/adaptation to external environment
  • homeostasis

-a self organizing, self-replicating, non-equilibrium system

EMPHASIZE REPRODUCTION

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8
Q

key difference between bacteria and virus?

A

viruses ARE NOT MADE OF CELLS!!!!!!

viruses are have genetic material covered in capsid. cannot reproduce themselves don’t have enzymes. need a host.

OUTSIDE OF CELLS VIRUSES ARE NON-LIVING

INSIDE CELLS VIRUSES ARE LIVING

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9
Q

outside of host viruses are _______

inside host viruses are ________

A

non-living

living

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10
Q

life needs _____

A

genetic material

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11
Q

definition of life

A

self-organizing, self replicating, non-equilibrium system

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12
Q

life is made up of 4 macromolecules?

A

polypeptides, nucleic acids, lipids, polysaccharides

all are organic molecules

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13
Q

why do we have more RNA than DNA?

A

we need to continuously make protein whereas we only need one copy of DNA

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14
Q

RNA polymerase

A

uses DNA as template to make RNA

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15
Q

Glycogen phosphorylase

A

converts glycogen into glucose monomers

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16
Q

Glycogen phosphorylase

A

converts glycogen into glucose monomers

important because brain runs on glucose

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17
Q

flagellin

A

protein that are apart of flagella that help the movement of bacteria

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18
Q

FtsZ

A

key component of cell division machinery in bacteria

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19
Q

Most important role of cell membrane?

A

separate outside from inside of cell.

also in prokaryotes the etc to make atp is on the plasma membrane

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20
Q

up until 1970s, organisms were placed into two categories:

A

prokaryotes and eukaryotes

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21
Q

eukaryote v prokaryote

A

eukaryote: has membrane bound organelle structures (mitochondria, nucleus)
prokaryote: no membrane bound organelles. circular dna

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22
Q

how did scientists discover/define the three domains of life?

A

RIBOSOMAL SEQUENCING
ribosomal RNA. the amount of it varies significantly in the three domains

DNA sequencing was used to compare sequences of ribosomal RNA genes in different organisms

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23
Q

three domains:

A

bacteria, archaea, eukarya

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24
Q

what is the first branch between bacteria and archaea?

A

HISTONES!!!!!!

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25
Q
bacteria:
nuclear membrane?
membrane-bound organelles?
plasma membrane?
cell wall?
RNA polymerases?
Histones?
A

nuclear membrane = no
membrane bound organelles = rare only a few types found in a few species
plasma membrane = similar to eukarya
cell wall = found in nearly all species constructed of peptidoglycan
RNA polymerase: single polymerase
Histones = histone like proteins

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26
Q
archaea:
nuclear membrane?
membrane-bound organelles?
plasma membrane?
cell wall?
RNA polymerases?
Histones?
A

nuclear membrane = no
membrane bound organelles = rare only a few types found in a few species
plasma membrane = different from bacteria and eukarya
cell wall = found in nearly all species constructed of various materials
RNA polymerase: single polymerase. eukaryal-like RNA pol II
Histones = yes

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27
Q
eukarya:
nuclear membrane?
membrane-bound organelles?
plasma membrane?
cell wall?
RNA polymerases?
Histones?
A

nuclear membrane = yes
membrane bound organelles = multiple distinct types found in all species
plasma membrane = similar to bacteria
cell wall = found in somespecies constructed of various materials
RNA polymerase: three main (RNA pol 1,2,3)
Histones = yes

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28
Q

why do we study microbes?

A

they are very fast and easy to grow
they can produce enzymes and other molecules for industrial medical uses
most of them have small numbers of genes, making them simple to study
genetic manipulation of single celled bacteria is usually much easier than multicellular eukarya

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29
Q

early environment of earth:

A

very little oxygen
the surface of planet was a soup of chemicals in liquid form
initial synthesis led to the first forms of macromoleculues (and their use in primitive single-celled organisms)

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30
Q

early environment of earth:

A

very little oxygen
the surface of planet was a soup of chemicals in liquid form
initial synthesis led to the first forms of macromolecules (and their use in primitive single-celled organisms)

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31
Q

endosymbiotic theory:

A

symbiosis: interaction between two orgs one living inside the other

primitive prokaryotic microbes ingested other microbes starting a symbiotic relationship forming the first basic eukaryotes.
(mitochondria, chloroplasts)

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32
Q

commensalism

A

one org is benefited the other is neutral

type of symbiotic relationship

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33
Q

parasitism

A

one benefits other hurts

type of symbiotic relationship

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34
Q

mutualistic

A

both benefit

type of symbiotic relationship

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35
Q

how did the first microbial life arise?

STANLEY MILLER

A

used electric spark to simulate the spark that might have started forming organic molecules in the primordial soup.

spark needed to start forming organic molecules

however molecules alone aren’t life

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36
Q

how did early organic molecules change into the four macromolecules in cells today?

A

early iron containing surfaces may have helped turn the early organic molecules into the larger ones we know

how can they replicate?
ribozymes (a combination of ribonucleic acid and enzymes) can serve dual purpose. RNA could serve dual purpose as a genetic storage AND an enzyme.

micelles may have been an early form of the plasma membrane

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37
Q

t or f: micelles do NOT exist in nature

A

t

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38
Q

why is the bilayer required instead of a monolayer?

A

plasma membrane is semi permeable!!! would not be possible by monolayer.

size of micelle is more limited (much smaller) than bilayer so many things wouldn’t fit.

polar molecules that can kill cells easily cannot get into or out of the cell easily because of the nonpolar tails in the middle of the bilayer.

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39
Q

how did early microbial life form?

A

early conditions formed RNA + micelles.

these came together into primitive cell using RNA for storing genetic info and coding

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40
Q

WHY DID CELLS CHANGE FROM USING RNA TO DNA FOR STORING GENETIC INFO?

A

double stranded DNA provides better backup copy of genetic information and is more stable

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41
Q

t or f: rna is less stable than dna

A

t

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42
Q

why is rna less stable than dna?

A

While DNA contains deoxyribose, RNA contains ribose, characterised by the presence of the 2’-hydroxyl group on the pentose ring (Figure 5). This hydroxyl group make RNA less stable than DNA because it is more susceptible to hydrolysis

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43
Q

how are microbes associated with diseases?

A

people used to believe that disease was associated with angry gods or bad air.

the first microbes were observed from 1623-1673 by Anton van Leeuwenhoek

1665: Robert Hooke invented cell theory: all living things are composed of cells

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44
Q

Robert Hooke

A

INVENTED CELL THEORY THAT ALL LIVING THINGS ARE MADE FROM CELLS

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45
Q

spontaneous generation

A

the hypothesis that life arises from nonliving matter; a “vital force is necessary for life

John Needham- boiled chicken broth and saw growth (but it was contaminated)

NOT TRUE

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46
Q

biogenesis:

A

hypothesis that living cells arise only from preexisting cells

LAzzaro Spallanzani did the boiled chicken broth and covered the flask and sawno growth. people critiqued saying closing it prevented from opening

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47
Q

PASTEUR

A

S shaped flask experiment. made neck long but didn’t close it and no contamination happened.

microorganisms are present in the air but air itself does not giv e birth to microorganisms

pasteurization: application of high heat for a brief period of time!

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48
Q

pasteurization:

A

application of high heat for a brief period of time!

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49
Q

Robert Koch

A

discovered tuberculosis and anthrax bacteria as causes.

CREATED GERM THEORY “a specific microorganism causes a specific disease”

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50
Q

methods to prevent infection caused ______

A

a dramatic drop in us deaths from infectious diseases.

used antiseptics, sanitation improvements like sewage treatment, food/water safety (pasteurization), personal hygiene improvements, vaccination

also antibiotics

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51
Q

size of bacteria

A

0.5 to 5 micrometers

bigger than viruses, smaller than eukaryotic cells

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52
Q

mycoplasma gallicepticum

A

the smallest known organism capable of independent growth and reproduction

parasite in gut of primates

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53
Q

thiomargarita nambiensis

A

largest bacteria ever discovered

a gram negative proteobacterium
found in the ocean sediments of the continental shelf of Namibia

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54
Q

cocci

A

spherical

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55
Q

bacilli

A

rod-shaped

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56
Q

vibrios

A

curved rod

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57
Q

spirilla

A

spiral

syphillis example

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58
Q

pleiomorphic

A

varied shapes

h pylori example

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59
Q

barrelia burgedorferi

A

cause lyme disease

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60
Q

possible shapes of bacteria

A
cocci
bacilli
vibrios
spirilla
pleiomorphic
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61
Q

single arrangement

A

do not touch each other

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62
Q

diplo/tetra arrangement

A

bacteria go in twos or fours

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63
Q

strepto arrangement

A

bacteria make a chain

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64
Q

staphylo arrangement

A

bacteria cluster!

there may be some singles or diplos around but it couldn’t be all singles

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65
Q

“multicellular” organizations of bacteria

A

are single but look multicellular

hyphae (branching filaments of cells)
mycelia (tufts of hyphae)
trichomes (smooth unbranched chains of cells)

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66
Q

hyphae

A

branching filaments of cells

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67
Q

mycelia

A

tufts of hyphae

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68
Q

trichomes

A

smooth unbranched chains of cells

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69
Q

examples of bacteria with multicellular organizations

A

cyanobacteria- the cells adhere to each other through common cell wall forming long multicellular filaments

myxobacteria are dramatic example of multicellular bacteria

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70
Q

nucleiod

A

nuclear area where the DNA in bacteria chill

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71
Q

breakdown of cytoplasm

A

80% water, 20% protein

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72
Q

plasmid

A

small dna molecule in cell that is physically separated from chromosomal dna and can replicate independently.

usually small circular double stranded DNA

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73
Q

why are plasmids considered a genetic advantage for bacteria?

A

can have antibiotic resistance genes

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74
Q

bacteria contain ______ chromosome

A

one circular

75
Q

inclusion bodies

A

(also called elementary bodies)

sites of wild multiplication
consist of wild capsid proteins

76
Q

carboxysomes

A

have rubisco. used for carbon fixation in the calvin cycle. they do carbon fixation rxns

77
Q

magnetosomes

A

store magnetic material. composed of lipid membrane and magnetic materials.

organelle associated with DIRECTION FINDING. organisms that have these look for a specific environment of microaerophilic environment

78
Q

FtsZ and MreB

A

cytoskeletal proteins in bacteria

79
Q

MreB

A

homologue of actin

helps shape bacteria because MreB polymerizes to form actin-like helical bands next to plasma membrane

80
Q

FtsZ

A

homologue of tubulin

FtsZ aids in cell division by helping the formation of the Z ring

81
Q

ParM and ParR

A

ParM ParR and ParC come together to form a complex and help in the segregation of plasmid when a cell replicates.

Plasmids replicate when the cell divides and whenever they want to just have many copies of it

ParM polymerizes and depolymerizes to help with segreation and direction of plasmid movement

82
Q

hopanoids

A

sterol-like molecules in plasma membrane that helps with stability across a range of temperatures

83
Q

__ and __ are small and can diffuse across the pm readily

A

O2 and CO2

84
Q

_____ is helped across the pm by _____

A

water; aquaporins

85
Q

osmosis

A

the movement of water across pm toward the side with a higher solute (particle) concentration

osmosis can cause a cell to swell with water or shrivel as water leaves but a strong cell wall can help keep bacterial cell alive during these hardships

86
Q

facilitated diffusion

A

using protein channel to move particles with concentration gradient

87
Q

active transport

A

using energy to move particles against a concentration gradient

ex. amino acids, glucose, na k pump

88
Q

primary active transport

A

uses ATP

P-type ATPase: sodium potassium pump, calcium pump, proton pump

ABC (ATP binding cassette) transporter: MDR, CFTR, etc.

89
Q

secondary active transport

A

uses other sources of energy such as co-transport or coupled transport

one molecule goes with its gradient to allow something else to go against its gradient

90
Q

ABC transporter

A

substrate binds protein interacts with solute. complex interacts with channel. channel undergoes conformation change. atp hydrolysis provides energy for opening channel and moving solute

91
Q

antiport

A

na k pump

cotransport in opposite directions

92
Q

symport

A

go in same direction.

cotransport of sodium and glucose

93
Q

plasma membrane methods for capturing energy. what is that energy used for?

A

embedded electron transport chains can help create proton motive force

can be used for respiration/photosynthesis

can be used to derive motion (flagella)

94
Q

how does the plasma membrane hold sensory systems?

A

proteins in the pm can be used to detect environment changes

the cell can use the detected changes to alter gene expression to respond

95
Q

protein secretion in the pm

SecG,SecE etc.

A

making proteins and shipping them outside the cell

SecG, SecE, SecY act as a transport system. SecA functions like a doorman deciding when things can cross the membrane. A signal peptide tells the protein where to go and SecB binds it so that it won’t fold and atp hydrolysis occurs. SecE, SecG, and Sec Y form the channel that lets the protein out and then the signal peptide is removed by a peptidase

96
Q

cell wall

A

not all bacteria have but 90% do. composed of cross linked strands of peptidoglycan subunits forming a matrix. increases structural strength.

provides protection from osmotic lysis/mechanical forces

involved in binary fission

97
Q

peptidoglycan makeup

A

disaccharide

NAG and NAM connected by beta 1 4 glycosidic bond. arranged nag nam nag nam. a peptide chain with a few amino acids are attached.

the amino acids are attached only to NAM and vary from species to species. all are d amino acids. can crosslink in various ways.

98
Q

amino acids only attach to ______

A

NAM

99
Q

how does the cell wall form?

A

outside of plasma membrane.

bactoprenol is a lipid that is amphipathic. It spans entire plasma membrane. it serves as a conduit to transport new peptidoglycans from the plasma membrane to the periplasmic space

step 1: f6p and glutamine

at step 5 nag and nam are synthesized, the nag reacts with utp –> udp + nag. some of this is converted to udp-nam. this combines with a peptide. this attacks bactoprenol. udp-nag comes back and and attaches to nam causing a flip

100
Q

transglycosylation

A

hydroxyl group of nag will attack

101
Q

___ and ___ can degrade cell wall

A

lysozyme (attacks beta 1,4) and lysostaphin secretions (acts on the crossbridge)

102
Q

b-lactam antibiotics

A

break cell wall. prevent peptidoglycan crosslinking which

weakens the cell wall structure

103
Q

antibiotic resistance & b-lactam antibiotics

A

some bacteria can produce an enzyme (beta lactamase) that destroys the b-lactam ring structure

addition of a second drug to inhibit that enzyme restores the drugs efficiency

tldr the bacteria can’t inactivate the antibiotic because we are distracting the enzyme it uses to do so

104
Q

what happens when you weaken the cell wall?

A

the cell cant resist osmotic pressure changes and will likely rupture (hypotonic conditions)

105
Q

protoplast v spheroplast

A

protoplast have two membranes and come from gram - bacteria

spheroplasts have one membrane and come from gram + bacteria

106
Q

Hans Christian Gram

A

bacteria are stained crystal violet, iodine stabilizes the crystal violet in the cell material, alcohol can extract crystal violet from the cell and the stain complex gets removed from gram negative and remains in gram positive

so gram negative cells stain pink and gram positive cells appear purple

107
Q

gram negative cells stain _____

gram positive cells stain ______

A

pink

purple

108
Q

gram positive cells have

A

thicker outer layer of peptidoglycan

a very narrow periplasmic space

teichoic acids in the peptidoglycan (that are negatively charged)

109
Q

gram negative cells have

A

a varying width periplasmic space containing a very thin layer of peptidoglycan

an outer membrane composed of lipopolysaccharide

110
Q

why did professor graham see a different staining for + and -?

A

gram positive retained stain because alcohol reacts with sugar thick layer in peptidoglycan and it shrunk the layer and it held the violet

111
Q

how does techoic acid make the cell wall stronger?

A

the negative acids interact with positive ions

112
Q

LPS from gram-negative cells can be ____________

A

harmful.

113
Q

LPS structure

A

lipid a (endotoxin) portion induces a strong inflammatory response

o outer side chain of polysaccharides can vary dramatically and even be changed by the microbe to evade host immune response

114
Q

t or f gram - infections are harder to treat than gram +

A

true

115
Q

how can nutrients get through gram positive cell walls?

A

the gram positive peptidoglycan layer has large pores throughout its matrix

116
Q

how can nutrients get through gram negative cell walls?

A

the gram negative cell has porin and TonB proteins in its outer membrane to transfer molecules to the periplasmic space

117
Q

S layer (surface layer)

A

part of cell envelope found in many types of bacteria

composed of identical proteins and glycoproteins

bound to rigid peptidoglycan containing layer via secondary cell wall polymers of gram positive bacteria

closely associated with the lipopolysaccharide of the outer membrane of gram negative bacteria

118
Q

flagellum

A

motility from flagella: spiral, hollow, rigid filaments extending from cell surface

-locations and number vary from species to species

locomotion and sensory!!!!!
15-20nm

function rather than structure

119
Q

structure of flagella

A

filament of multiple flagellin proteins 5-10 micro meter long

hook protein portion that connects filament to basal body

basal body = disk like structure that produces torque on the filament to turn it like a propeller
-gets energy from plasma membrane (proton motive force)

120
Q

energy to spin flagella is derived from _____

A

proton motive force

121
Q

_____ give flagella direction

A

basal body

122
Q

when flagella change direction, their movement changes from _____ to ______

A

directional to nondirectional (tumble)

123
Q

axial flagella

A

attached in periplasmic space. when it moves inside it creates a corkscrew and we can seethe entire cell body rotate

124
Q

pili

A

adherence molecules to stick to surface

fibers of pilin protein possess
other proteins on their tips for sticking

a sex pilus is a different structure used for conjugation

125
Q

conjugation

A

sex pilus

126
Q

pili v fimbriae

A
pili = conjugation
fimbraie = adherence (thinner and shorter than flagella)
127
Q

capsules

A

have k antigen

made up of polysaccharides surrounding some cells

provide defense against host immunity, protection against drying out (dessication)

MAJOR VIRULENCE FACTOR because body can’t recognize the capsule as foreign

help make biofilms

128
Q

biofilms

A

provide protection and enhanced survivability in harsh environments

example of biofilms include dental plaque and mold on bathroom surfaces

129
Q

t or f most microbes cant be cultured

A

true

130
Q

archaea

A

prokaryotes that have distinct properties. look like bacteria but are different. some live in inhospitable places.

131
Q

extremophiles

A

can live in inhospitable environment

first archaea discovered fit this bill

132
Q

how do we know archaea is distinct?

A

comparison of rRNA gene sequences helped to establish phylogenic trees

133
Q

methanogens

A

a poorly characterized group of microbes capable of producing methane as a byproduct

134
Q

t or f: ch4 traps more radiation than co2

A

t

135
Q

halobacterium salinarium growth req

A

3.0-5.0 M NaCl

136
Q

pyrococcus furiosus growth req

A

100 degrees C

137
Q

picrophilus ashimae growth req

A

0.7 pH

138
Q

methanogenium frigidum growth req

A

15 degrees C

139
Q

genetic sequence analyses indicate that the branching point occurs when ____________

A

occurs when archaea and eukarya branch off from bacteria.

140
Q

WHAT IS THE BRANCHING POINT?

A

development of histones !!!

141
Q

Size of archaeal cells

A

0.5-5 micrometers

can vary greatly

142
Q

shapes of archaeal cells

A

vary similar to bacteria

143
Q

genetic material of archaea

A

usually a singular circular chromosome and lack a membrane bound nucleus

however many of the DNA replication enzymes of archaea look like those of eukarya

144
Q

archaeal histones

A

archaeal dna is complexed with histones (like eukarya) in the nucleoid

histones form structures that dna wraps around

HISTONE STRUCTURE IS DIFFERENT IN ARCHAEA AND EUKARYA

145
Q

histones can allow DNA to be ______

A

stabilized

146
Q

archaea histone structure

A

contain h3 and h4 types histones in a tetramer of histone proteins

eukaryotic histones make octamer of h2a h2b h3 and h4

147
Q

archaeal cytoskeleton

A

cytoskeleton homologues are found in both bacteria and archaea

Ta0583 is an actin homolog that resembles eukaryal actin (equivalent to MreB)

148
Q

what is ta0583 equivalent to in bacteria and eukarya?

A

MreB in bacteria

actin in eukarya

149
Q

cytoskeletal proteins from M.thermoautotrophicum and M. kandleri more closely resemble ________ cytsokeletal proteins

A

bacterial

150
Q

archaea have ____ and _____ but these structures are different than their equivalents in bacteria and eukarya

A

plasma membrane and (sometimes) cell wall

151
Q

how does the archaeal plasma membrane differ from bacteria/eukarya?

A

different bilayers construction

instead of glycerol 3 phosphate with fatty acid and a ester linkage

we have glycerol 1 phosphate and phytanyl and the linkage is an ether

ALSO THE PLASMA MEMBRANE CAN BE A MONOLAYER INSTEAD OF A BILAYER

152
Q

why can the archaeal plasma membrane be a monolayer?

A

it has glycerol 1 phosphate on both sides which make it like a bilayer

monolayer is likely more stable at higher temperature because of this.

153
Q

ignicoccus membrane

A

have an outer membrane and periplasm

the atp synthase enzymes are housed in this main outer membrane rather than the main plasma membrane of the cell

WE CAN EXPLOIT THIS FOR DRUG DELIVERY

154
Q

cell wall functions

A

physical and osmotic protection

155
Q

in archaea the cell wall is composed of mostly __________

A

pseudomurein

(slightly different peptidoglycan structure)

NAG-NAT instead of NAG-NAM

156
Q

t or f: some archaea lack a cell wall

A

true

157
Q

pseudomurein is different in three ways from peptidoglycan, what are they?

A

beta 1,3 linkage instead of beta 1,4

NAG-NAT instead of NAG-NAM

THEY ARE L AMINO ACIDS INSTEAD OF D

158
Q

thermoplasma acidophilum

A

DO NOT HAVE A CELL WALL AND CANT MAINTAIN SHAPE

159
Q

how are flagella similar and different in bacteria versus flagella

A

similar: rotate to move cell
different: they are much thinner in archaea and in archaea it attaches at the based of the cell membrane rather than the tip like bacteria

160
Q

archaeonics

A

use chemicals in the archae for antibiotics

haloarchae and sulfolobus are used archaeonics

161
Q

pfu DNA polymerase

A

PCR: heat DNA, separate the strands.

problem was heating killed the enzyme dna polymerase so youd have to add more became tedious

SOOOOOOO we used dna polymerase from archaea that are stable at 95 deg celsius – taq dna polymerase

pfu - heat stable moreso than taq dna polymerase. it has 3’ to 5’ exonuclease activity

162
Q

exonuclease activity in pfu

A

makes pfu better than taq polymerase because the 3’ to 5’ exonuclease activity proof reads the DNA polymerase that works in the 5’ to 3’
direction

163
Q

are archaea pathogenic?

A

NO KNOWN EXAMPLES.

however some methanogens are associated with infection in mice.

164
Q

two major phyla of archaeons:

A
  • euryarchaeota

- crenarcheota

165
Q

two less major phyla of archaeons that have been proposed:

A

nanoarchaeota (only one current member the symbiotic archaeon nanoarchaem equitans)

korarchaeota (thermophilic ones that don’t fit well in the two major)

166
Q

recently detected species of archaea

A

ARMAN

archaeal richmond mine acidophilic nanoorganisms

167
Q

crenarcheota

A

most abundant marine archaea could be important to biogeochemical cycling of carbon and nitrogen

thermophiles/hyperthermophiles (growing at temps greater than 55-80 deg respectively)

many are acidophiles, some are barophiles

ex. sulfolobus solfataricus

168
Q

sulfolobus solfataricus

A

a type of crenarcheote

opt temp 80 opt ph 2-4

169
Q

adaptations for crenarcheota to survive in extreme environment

A
  • tetraether lipids/lipid monolayers
  • more alpha helical regions in proteins
  • more salt bridges/side chain interactions in proteins
  • more arginine/tyrosine less cysteine/serine
  • strong chaperone protein complexes
  • thermostable dna-binding proteins
  • reverse dna gyrase enzyme to increase dna supercoiling
170
Q

mesophile temperature range

A

15-40 degress celsius

171
Q

psychrophiles temperature range

A

< 15 degrees celsius

172
Q

euryachaeota: methanogens

A

methanogens

they reduce co2 with h2 to produce methane ch4 and water h2o in an unusual reaction

energy released can be used to fix carbon

all identified methanogens are strict anaerobes

ex. m smithii

173
Q

m smithii

A

predominant archaeon in our gut. plays role in digestion of polysaccharides by reducing co2 with h2 to produce methane and water

in animals free from bacteria and then we give them a lot of m smithii they become very fat

174
Q

euryarchaeota: halophiles

A

require NaCl concentration greater than 1.5 M

high salt environments are fairly rare–these areas vary between 5 to 34% salinity

the ocean is typically 3.5% salinity

175
Q

how do halophiles deal with osmotic shock and loss of water?

A

they maintain high intracellular potassium concentration to offset high Na concentration in the envrionment

however this solution can cause its own problems denaturing proteins and splitting dsDNA

176
Q

what are the problems that arise from halophiles maintaining high intracellular potassium levels and how do cells overcome these problems?

A

DNA denaturing –> higher GC content (stronger bonds)

Protein denaturing –>highly acidic proteins that remain more stable in high salt environment

177
Q

halobacterium

A

type of halophile. A TYPE OF ARCHAEA NOT BACTERIA THE NAMING IS UNFORTUNATE

produce energy through odd form of phototrophy

do not use chlorophyll or etc

use bacteriorhodopsin to harness light energy and produce a proton motive force that is used to make atp

bacteriorhodopsin gives off a reddish hue

178
Q

anton van leeuwenhoek

A

father of microbio observed first microbes by making microscope

179
Q

robert hooke

A

invents cell theory

180
Q

john needham

A

spontaneous generation theory (proven wrong) put boiled nutrient broth into covered flasks (contamination allowed for growth inside because flasks weren’t sealed)

181
Q

lazzarro spallazani

A

biogenesis he did same experiment has needham but sealed the flasks and nothing grew. critics said that cutting off the flasks from the environment might preclude growth though

182
Q

louis pasteur

A

fixed the chicken brother scenario with his s shaped flasks that allowed the broth to be open to the environment

183
Q

robert koch

A

GERM THEORY’

specific org causes specific disease