Midterm 1 Flashcards
Microbiology
the study of microbes
microbes
forms of life too small to be seen with the naked eye
ex: Bacteria Viruses Protists Fungi (two kinds, yeast & mold)
t or f: 10^14 bacteria in body 10^13 human cells in body
TRUE there are 10x more bacteria in the human body than human cells
amniotic fluid has ______
antimicrobial properties
cleanses birth canal but doesn’t get rid of bacteria completely
babies born _______ are healthier
through birth canal
bacteria help plants take up ______
nitrogen
what are the characteristics of a living object?
- metabolism, growth, reproduction
- genetic variation/evolution
- response/adaptation to external environment
- homeostasis
-a self organizing, self-replicating, non-equilibrium system
EMPHASIZE REPRODUCTION
key difference between bacteria and virus?
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
outside of host viruses are _______
inside host viruses are ________
non-living
living
life needs _____
genetic material
definition of life
self-organizing, self replicating, non-equilibrium system
life is made up of 4 macromolecules?
polypeptides, nucleic acids, lipids, polysaccharides
all are organic molecules
why do we have more RNA than DNA?
we need to continuously make protein whereas we only need one copy of DNA
RNA polymerase
uses DNA as template to make RNA
Glycogen phosphorylase
converts glycogen into glucose monomers
Glycogen phosphorylase
converts glycogen into glucose monomers
important because brain runs on glucose
flagellin
protein that are apart of flagella that help the movement of bacteria
FtsZ
key component of cell division machinery in bacteria
Most important role of cell membrane?
separate outside from inside of cell.
also in prokaryotes the etc to make atp is on the plasma membrane
up until 1970s, organisms were placed into two categories:
prokaryotes and eukaryotes
eukaryote v prokaryote
eukaryote: has membrane bound organelle structures (mitochondria, nucleus)
prokaryote: no membrane bound organelles. circular dna
how did scientists discover/define the three domains of life?
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
three domains:
bacteria, archaea, eukarya
what is the first branch between bacteria and archaea?
HISTONES!!!!!!
bacteria: nuclear membrane? membrane-bound organelles? plasma membrane? cell wall? RNA polymerases? Histones?
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
archaea: nuclear membrane? membrane-bound organelles? plasma membrane? cell wall? RNA polymerases? Histones?
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
eukarya: nuclear membrane? membrane-bound organelles? plasma membrane? cell wall? RNA polymerases? Histones?
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
why do we study microbes?
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
early environment of earth:
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)
early environment of earth:
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)
endosymbiotic theory:
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)
commensalism
one org is benefited the other is neutral
type of symbiotic relationship
parasitism
one benefits other hurts
type of symbiotic relationship
mutualistic
both benefit
type of symbiotic relationship
how did the first microbial life arise?
STANLEY MILLER
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
how did early organic molecules change into the four macromolecules in cells today?
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
t or f: micelles do NOT exist in nature
t
why is the bilayer required instead of a monolayer?
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.
how did early microbial life form?
early conditions formed RNA + micelles.
these came together into primitive cell using RNA for storing genetic info and coding
WHY DID CELLS CHANGE FROM USING RNA TO DNA FOR STORING GENETIC INFO?
double stranded DNA provides better backup copy of genetic information and is more stable
t or f: rna is less stable than dna
t
why is rna less stable than dna?
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
how are microbes associated with diseases?
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
Robert Hooke
INVENTED CELL THEORY THAT ALL LIVING THINGS ARE MADE FROM CELLS
spontaneous generation
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
biogenesis:
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
PASTEUR
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!
pasteurization:
application of high heat for a brief period of time!
Robert Koch
discovered tuberculosis and anthrax bacteria as causes.
CREATED GERM THEORY “a specific microorganism causes a specific disease”
methods to prevent infection caused ______
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
size of bacteria
0.5 to 5 micrometers
bigger than viruses, smaller than eukaryotic cells
mycoplasma gallicepticum
the smallest known organism capable of independent growth and reproduction
parasite in gut of primates
thiomargarita nambiensis
largest bacteria ever discovered
a gram negative proteobacterium
found in the ocean sediments of the continental shelf of Namibia
cocci
spherical
bacilli
rod-shaped
vibrios
curved rod
spirilla
spiral
syphillis example
pleiomorphic
varied shapes
h pylori example
barrelia burgedorferi
cause lyme disease
possible shapes of bacteria
cocci bacilli vibrios spirilla pleiomorphic
single arrangement
do not touch each other
diplo/tetra arrangement
bacteria go in twos or fours
strepto arrangement
bacteria make a chain
staphylo arrangement
bacteria cluster!
there may be some singles or diplos around but it couldn’t be all singles
“multicellular” organizations of bacteria
are single but look multicellular
hyphae (branching filaments of cells)
mycelia (tufts of hyphae)
trichomes (smooth unbranched chains of cells)
hyphae
branching filaments of cells
mycelia
tufts of hyphae
trichomes
smooth unbranched chains of cells
examples of bacteria with multicellular organizations
cyanobacteria- the cells adhere to each other through common cell wall forming long multicellular filaments
myxobacteria are dramatic example of multicellular bacteria
nucleiod
nuclear area where the DNA in bacteria chill
breakdown of cytoplasm
80% water, 20% protein
plasmid
small dna molecule in cell that is physically separated from chromosomal dna and can replicate independently.
usually small circular double stranded DNA
why are plasmids considered a genetic advantage for bacteria?
can have antibiotic resistance genes