Chapter 1,2,3 Flashcards
What is a microbial community
2 or more ppns of cells that coexist and interact in a habitat
What is a culture
collection of microbial cells grown using nutrient medium
What is a medium
(l) or (s) nutrient mixtures used to grow microorganisms
What is a colony
microscopically visible ppn of cells growing on a solid medium ariing from a single cel
Carl Woose
Phylogenic tree based on rRna sequences, divide microbes into 3 domains (RNA World)
Stanly Miller
produce amino acids and biological cmps in lab
Louis Pasteur
Disapproved spontaneous generation theory (1800s)
Robert Koch
established rules for determining which microbes caused which diseases
but in some cases it is difficult to isolate/culture the suspected pathogen
FtsZ
found in plasma membrane for cell division
Does bacteria contain histones?
No
they contain histone-like . Topoisomerases
found in Eukarya and Archaea
Endosymbiotic theory says — was the first microbe on earth . Where is the the proof of this found in?(2)
Prokaryotes
Proof in mitochondria and chloroplast
How do microbes get energy?
Autotroph - produce organic molecules from inorganic materials such as
1. Photoautotroph - light
2. Lithoautotroph - oxidized reduced mineral cmpds
Heterotroph - ingest pre-formed organic molecules
What is a ppn?
grp of org of same species in the same place at the same time
What is a ecosystem
a dynamic complex of org and their physical environment interacting as a functioning unit
MreB
provides structure (rod shape) if not present bacteria is spherical
In plasmids (in Bacteria) what is the purpose of ParM and ParR proteins ?
ParM - directs plasmid mvt in rod shaped bacteria (bind to ATP)
ParR - nucleoprotein tht bind to ParM to prevent disassembly
What are the parts that make up the cell envelope of a bacteria?
capsule
cell wall
cell membrane
what makes up the cell membrane bilayer
phospholipids
What bond is associated with phospholipids in the cell membrane
Ester linkages
What is the use of hopanoids in bilayers of some bacteria?
temperature stability
Roles of plasma membranes
capture E
hold sensory systems
How do items cross the plasma membrane?
O2 and CO2 - diffusion
Water - Aquaporins Protein Channels ( osmosis)
Purpose of the cell wall in bacteria and what does it have?
shape
and has peptidoglycan aka Murein
Cell wall of bacteria can be damaged by— (3+1)
Penicillin - kills cells in a growing state
lysozyme - cleaves backbone of cell wall forming a Protoplast (cell w/out cell wall)
lysostaphin - acts on the cross bridge of some Staphylococcus species only.
b-lactam antibiotics (with beta-lactam ring) - inhibit Ftsl transpeptidation therefore impacting growing org
What happens during antibiotic resistance in bacteria?
Some bacteria produce an enzyme that can destroy beta-lactam ring structure
Gram - elicit a inflammatory response
T
Gram - elicit a robust inflammatory response in humans due to the Lipid A portion in the lipopolysaccharide (LPS)
Gram + elicit an inflammatory response due to lipoteichoic acids (LTA) in Staphylococcus aureus only
when do endospores form in gram + bacteria?
harsh cnds
Does the gram + have peptidoglycan layer which has large pores hence nutrients pass easily?
T
Once molecules enter the periplasmic space of gram - cells via Porins and Ton B how so molecules move into the cytoplasm?
Via Active Transport
How do molecules leave gram - cells’ periplasmic space?
use of transfer molecules
Autotransporters (type 5 systems) - from periplasm directly to the cytoplasm
Type 3 secretion system
Flagellar system
Flagella arrangements
Monotrichous
single flagellum
Flagella arrangements
Lophotrichous
tuft of flagella
Flagella arrangements
Amphitrichous
single or multiple flagella extending two ends of the cell
Flagella arrangements
Peritrichous
multiple flagella randomly distributed over the entire bacterial cell
Flagella arrangements
Atrichous
no flagella
What powers the flagella of bacteria?
Proton motive force generates spins (tht create runs and tumbles) no steering
What is chemotaxis?
directed movement of an organism toward or away from a chemical gradient
Are there any archaeal human pathogens known, if so are there harmful to the human species?
There are no known archaeal human pathogens
What are some non-flagellar motility used by bacteria?
4
Gliding motility
Twitching motility
pili
holdfast - extension of cell envelope wc also increases S/A and for nutrition
Function of the pili/pilus
adhesive pili = fimbriae
or sex pilus for conjugation
where do you find gram cells in bacteria?
cell wall
first archaeons were Methanogens?
T
originally called Archaebacteria
Archaea and Eukarya branched off from bacteria?
T
histone development may have been the branched point
many groups of archaea are –
Extremophiles
differences in histones btw Eukarya and Archaea
Eukarya longer DNA length (160 nucleotide) Bigger octamer of histone
Archaea shorter DNA length (60 nucleotide) smaller tetramer of histone
Is the nucleus of archaea membrane bound
No
just like in bacteria
Archaea has two distinct types of plasma membranes in different archeons
T
Monolayer Plasma membrane - Biphytanyl tails and glycerol-1-phosphate (more stable and joined by Ether linkages) seen in Extremophiles
Bilayer - Phytanyl (side chains) and glycerol-1-phosphate ( joined by Ether linkages)
Does all Archaea have cell walls
F
Do lysosomes attack Archaeon cell walls
f
bcoZ of the NAG-NAT (BETA-1,3 LINKAGE)
bacteria has NAG-NAM LINKAGES wc are attacked by lysosomes
differences in flagella in bacteria and archaea
Archaea Flagella - thinner/solid/composed of 2 versions/ used as attachments & mobility/grows form base (cytoplasm) not from the tip
Bacteria grows from tip out
how do halophiles deal with the osmotic shock and loss of water ?
High intracellular K+ offsets high extracellular Na+ therefore ions balance out , thus no net gain or loss of h2o
high intracellular K+ can cause denaturing of proteins and split dsDNA in halophiles
T
Halobacterium uses chlorophyll or an electron transport chain to produce E?
F
Which domain of life uses Bacteriorhodopsin to harness light E and produce a proton motive force that generates ATP
Archaea - Halobacterium
Do methanogens require O2 for growth
F
they are strict Anaerobes
What are facultative aerobes
A facultative anaerobe is an organism that makes ATP by aerobic respiration if oxygen is present, but is capable of switching to fermentation or anaerobic respiration if oxygen is absent.
What are obligate aerobes
An obligate aerobe cannot make ATP in the absence of oxygen
What are obligate anaerobes
obligate anaerobes die in the presence of oxygen
Alessandro Volta discovered
methane
what is an example of an obligate parasite (archaea)
Nanoarchaeum is an obligate parasite of Ignicoccus
relies on Nanoarchaeum for E/biosynthesis.
what is a Aminochondriate
Eukaryote w/out mitochondrial organelle
contain hydrogenosome - double membrane remnant of mitochondria/ produce H2 during anaerobic synthesis
do all eukaryotes have mitochondrial organelles
F
Flagella of eurkaya is powered by
E from ATP hydrolysis
Eurkaya has liner or circular chromosomes?
liner
Bacteria and chloroplast and mitochondria have circular or linear chromosomes ?
circular
Archaea has circular or linear chromosome?
single, Circular
Characteristics of Giardia lamblia
It is a Eukaryal microbe From the genus Protozoa genetically old lacks mitochondria cause human disease
Flelix D’Herelle
discovered bacteriophages coined the term “plaque”
Viruses are acellular
T
Do viruses contain ribosomes
F
Is a virus a intracellular obligate parasite
T
Is a virus dsDNA or dsRNA
both ds/ssDNA and ds/ssRNA (linear and circular)
Are all viruses small
F
some exceptions
capsids in viruses are what shape
icosahedral and helical or irregular or complex
Do viruses all have a Viral envelope
F
some are naked (no plasma membrane) poliovirus
some are enveloped with a plasma membrane surrounding the nucleocapsid HIV/influenza
can a virus enter a plant cell
Only if the plant cell has an open spot on the cell wall
Virus found in tree of life
F
Virus posses own genome
T
therefore independent of host’s genome
Are viruses cells
F
What is a virion
A virion is an entire virus particle consisting of an outer protein shell called a capsid and an inner core of nucleic acid (either ribonucleic or deoxyribonucleic acid—RNA or DNA).
Once inside the host cell, a viral genome orchestrates one of two quite different events.
- lytic pathway (replication and destroying host cell)- virus may replicate and destroy the host in a virulent infection
Phage enters → Replicates → lyse host cell with mature phage - lysogenic infection the host cell is not destroyed, and the viral genome becomes part of the host genome and replicates
Phage genome →into host cell → Phage genome replicates along with hosts
What inhibits the growth of the Gram positive bacteria in MacConkey agar?
Crystal violet dye and bile salts halt the growth of gram-positive bacteria
