microbiology exams 1
What is this structure of a virus ?
The nucleic acid in a protein coat
When do viruses display property of living organisms?
When they have invade host cell
What is the functions of the viral envelope?
What are the type of microorganism mension?
Virus, fungi, protist, bacteria
What is the size of virus in relationship to lie microscope?
Too small to be seen with the light microscope
How are virus classified?
By type of nucleic acid, shape and envelope
What are cytopathic effect?
Change in cell due to viral infections
What is teratogenesis?
Inductions of defect in embryonic development
Which viruses or associate with teratogenesis ?
cytomegalovirus, HIV, Rubella
What is carcinogenesis?
Inductions off change leading to cancer
Which virus are linked to carcinogenesis ?
Hepatitis b c and hpv
What is viroid?
An infectious RNA particle without a capsid
How does viroid rna behave in host cell?
It is copied in the host cell nucleus
What are prions?
Misfold protein that cause diseases
What do prions do to normal proteins?
They caused them to fold incorrectly
What disease are caused by prions?
kuru and creutzfeldt- jakob disease
What is the significance of fungi?
The compose organism and recycle nutrient
How do fungi obtain food?
From other organisms, chemoheterotrophic
What is the cell wall compositions of fungi?
Chitin
What is dimorphism in fungi?
Ability to exist in both yeast and mold form
What are the role of fungi in the ecosystems?
Decompose, help plants, produce antibiotics
What are the characteristic of protozoa?
Single eukaryotic cell with locomotions
What are the form of locomotion in protozoa?
Pseudopod, cilia, and Flagella
What are the characteristics of algae?
Plant like, photosynthetic, eukaryotic
Why study micro organism?
Inside into history, health, and manufacturing
What are the benefit of studying microorganisms?
Better understanding of the human body and vaccine
What is historical theories existed about disease causation?
Magic, spirits, miasma, and bad deeds
Who first observed cells in a microscope?
Robert Hooke
Why did Van Leewenhoek contribute to micro-organisms?
Observe animacules in the environment
What is spontaneous generations?
Micro-organisms arises from nonliving things
What is the Germ theory of disease?
micro-organism invade and cause diseases
What was Needham conclusion from his experiment?
air contain a life force for organism
What was Redi's hypothesis about maggot?
Fly lay egg on meat causing maggot
What was the role of gauze in Redi experiment?
Prevented fly from laying eggs on meat
What was the conclusions of Redi experiment?
What does miasma refer to?
Particle in bad air
What was the single most important contribution to medical science?
The germ theory of disease
What concept did the germ theory need to dispel?
spontaneous generation
what did needham's experiment in the mid- 1700s involved?
flask with sterilized broth left open
what argument was made for spontaneous generation?
Life arose from non living thing
who criticized Needham's conclusion?
Spallanzani
what did pasteur's swan- necked flask demonstrate?
air contains microbes
what did pasteur argue about microbes in air ?
Microbes exist in the air and do not arise spontaneously and cannot reach the experimental broth
what did pasteur work on wine involve?
pasteurization to kill unwanted organism
what temperature and time did pasteur use for pasterurization?
56 C for 30 minutes
what is attenuation in context of vaccines?
weakening a pathogen for vaccination
who administered the first vaccine to a human?
Louis pasteur
what did Edward Jenner observe about milkmaids?
they did not get smallpox infection
what does vaccination derive from?
latin for cor vacca
what did Robert Koch discover?
what did Semmelweis notice about maternal mortality rates?
lower rates with midwives delivering babies
what is the role of E.coli in the digestive system?
aids digestion and biosynthesis
what is the harmful strain of E.coli?
1. coli O157:H7
what does candida albicans cause ?
truth and vaginal yeast infections
what was Lister know for in surgery?
Aseptic surgical technique
what did Paul Ehrlich develop?
the idea of chemotherapy
what is seletive toxicity?
targeting structure specific to microbes
what was the first treatment for syphilis?
salvarsan
who discover lysozyme?
Alexander fleming
what did fleming recognize about ?
it inhibited the growth of bacteria
what is the binomial nomenclature ?
Genus species naming system developed by Carl Linnaeus
how do bacteria replicate ?
via binary fusion
what is found in the bacteria cell wall?
Peptidoglycon
what is unique about bacterial plasma membranes ?
they do not have cholesterol
what are the key structure of prokaryote ?
what is the significance of bacterial cell structures?
they are target for antibiotics and immunity
what does pathogenicity refer to?
the ability to cause disease
what are the similarities between prokaryote and eukaryote cell?
what are the difference between the prokaryote and eukaryotic cells?
what is the structure of prokaryotic genetic materials?
circular DNA and plasmid
what is the function of the bacterial cell wall?
prevents osmotic layer and shape the cell
what is peptidoglycan composed of ?
repeating disaccharides and polypeptide
what distinguish Gram positive from gram negative bacteria?
Gram negative has thick peptidoglycan layers while gram negative have thin layer
what is the role of teichoic acids in gram positive bacteria ?
provide negative charge and help sherpher ions
what is the function of the outer membrane in gram negative bacteria ?
protect against penicillin and phagocytosis
what is lipopolysaccharide and its significant?
it is an endotoxin causing fever and shock
what are the function of the glycocalyx ?
what are fimbriae and pili used for ?
attachment and genetic material transfer
how do flagella help bacteria?
they proper bacteria through environment
what are the different arrange of flagella ?
what is chemotaxis?
movement toward or away from substances
what is the composition of the plasma membrane in bacteria?
phospholipid bilayer with no sterols
what is the role of ribosome in bacteria?
sites for protein synthesis
what is the structure of the nucleoid in bacteria?
location of the circular DNa without histones
what are the characteristics of acid- fast bacteria ?
what is the function of the cell membrane in bacteria?
selective permeability and nutrient breakdown
what is the role of inclusion in bacteria cells?
store nutrients or important substances
what is this significance of the knowledge of cell wall structure?
determine antibiotic therapy
what does penicillin target in bacteria ?
final stage of peptidoglycan synthesis
what is the role of the cytoplasm in bacteria cells?
aqueous environment for chemical reactions
what is the function of the gas vesicles in bacteria ?
regulate dept in aquatic environments
what is the role of plasmid in bacteria?
carry antibiotic resistance and virulence factors?
what is the significance of the endospore resistance ?
what happens during germination of an endospore?
conversion to an actively dividing vegetative cell
what are the different shapes of bacteria?
what are the arrangement of bacterial cells?
what is the function of the ribosomes in prokaryotes ?
protein synthesis occurs simultaneously with transcription
what is the role of the nucleoid- associated protein (NAP)
help organize the DNA in the nucleiod
how do bacteria utilize their glycocalyx for survival?
helps in adherence and evasion of the immune system
what is the role of the capsule in pathogenicity?
inhibits phagocytosis by immune cells
what is the function of the slime layer in bacteria
helps in adherence and wash off easily
what is the role of the axial filaments in spirochetes?
provide motility through twisting movement
what is the function of the poly-B- hydroxybutyrate in bacteria ?
energy source for bacteria
how do bacteria utilize their flagella for movement?
proper through aqueous environment via rotation
what is the significance of the capsule in bacteria infection?
enhance virulence by evading immune response
what is the significance of the ribosomes size in bacteria?
70s ribosomes are targeted by antibiotics
what is the function of the cytoplasm in bacteria ?
aqueous environment for metabolic reaction
how do bacterial structures contribute to their pathogenicity?
facilitate adherence, evasion, and survival
who was the first sciences to pursue a magical bullet that could be used to treat infection disease ( question from home test)
Ehrlich
spirochete bacteria with filament with axial filaments have ?( question from home test)
endoflagella
osmosis most directly involves? ( question from home test)
water moving down a concentration gradient
rRNA signature sequences can be used to place microorganism in the correct
true
prions consist of protein and have no apparent nucleic acid genome? ( question from home test)
true
which of the following cellular structures are found only one e( eukaryote cells ( question from home test)
paired of chromosomes
when a DNA molecule is replicate the daughter molecule contain one strand of parental DNA and one strand of newly synthesized DNA; this is called ------------------------ replication ( question from home test)
semiconservative
wen a recipient cell acquires a piece of naked DNA from the environment, it is called ------------- ( question from home test)
transformation
which organelles likely to resemble a prokaryotic cell? ( question from home test)
mitochondrion
A bacteria population grow most rapidly during ---------------- phase ( question from home test)
log
eukaryotic cell have a peptidoglycan layer and simple morphology( question home test )
false
small circular DNA molecules capable of replicating and containing genes that useful but not necessary to the bacterium are called -------------------- ( question from homes test)
plasmids
microbiology is the study of bacteria, algae, fungi, viruses and protozoa. most of these are single-celled, except for which two: ( question orm home test)
algae and fungi ( some have many cells)
the process of conjugation in bacteria require that( question from home test)
there be contact between donor and recipient cells
structure only find in prokaryotic ( question from home test)
pili
the difference between simple diffusion and facilitate diffusion ( question home test)
require transporter proteins
What is a genome?
All DNA present in a cell or a virus
What does ploidy Bacteria and Archaea generally have?
Haploid (1N)
What does ploidy Eukaryotes generally have?
Diploid (2n)
What does genotype refer to?
The genetic makeup of an organism
What does phenotype refer to?
Expression of the genes
Who observed transformation in bacteria in 1928?
Griffins
What did Griffin experiment demonstrate?
Change of non-virus to virulence organism
Who showed that the transforming principle was DNA?
Avery, MacLeod, McCarty
What model did Hershey and Chase use in their experiments?
Bacteriophage T2 infection
What was used to label DNA in Hershey and Chase's experiment?
32P
What was used to label the protein coat in Hershey and Chase's experiment?
35S
What did Hershey and Chase conclude about DNA?
DNA carried genetics information
What are DNA and RNA composed of?
Pylomers of nucleotides
How are nucleotides linked in DNA and RNA?
By phosphodiester bonds
How do DNA and RNA differ?
By nitrogenous bases, sugars, and strand
What are the bases found in DNA?
Adenine, guanine, cytosine, thymine
What sugar is found in DNA?
Deoxyribose
What forms the sugar-phosphate backbone of DNA?
Covalent bonds between sugar and phosphate
What is the structure of DNA?
Double-stranded helix
How do adenine and thymine pair in DNA?
By 2 hydrogen bonds
How do guanine and cytosine pair in DNA?
By 3 hydrogen bonds
What forms when the two strands of DNA twist around each other?
Major and minor grooves
What bases are found in RNA?
Adenine, guanine, cytosine, uracil
What sugar is found in RNA?
Ribose
What is the typical flow of genetic information described by the central dogma?
DNA, mRNA, protein, function
How do mutations alter a genome?
Mutate DNA, mRNA, protein, function
What is genetics the study of?
Genes and their information transfer
What are chromosomes?
Structures containing DNA that carry heredity
What are genes?
Segments of DNA that encode proteins
What is a polymer of amino acids linked by?
Peptide bonds
How does DNA replication occur?
One strand serves as a template for another
What enzymes relax the strands during DNA replication?
Topoisomerase and gyrase
What enzyme separates the strands during DNA replication?
Helicase
What is created during DNA replication
A replication fork
How do eukaryotes transfer genes?
Vertical gene transfer
What is the method of gene transfer in prokaryotes?
Horizontal (lateral) gene transfer
What is vertical gene transfer?
Replication and transfer to descendants
What occurs during genetic recombination in eukaryotes?
Exchange of nucleotide sequences between homologous sequences
What are recombinants?
Cells with new DNA sequences
What are the three types of horizontal gene transfer in prokaryotes?
What is transduction?
Transfer of DNA via bacteriophages
What are transposons?
DNA segments that move locations
What is the result of transposition?
Frameshift insertion in DNA
What do transposons contain at each end?
Palindromic sequences
What are hybridomas used for?
Producing monoclonal antibodies
What must occur before bacterial and archaeal division?
Genome replication and segregation
What are the three phases of the bacterial cell cycle?
Growth, chromosome replication, cytokinesis
What is the first step in the cell cycle of E. coli?
Initiation mass reached
What begins when the z ring forms in E. coli?
Septum formation
What is septation?
Formation of cross wall between daughter cells
What are the steps in Septation?
Site selection, machinery assembly, cell constriction
How do archaeal cell cycles resemble eukaryal cell cycles?
Similar to mitotic cycle except for segregation
What does growth in prokaryotes refer to?
Population growth rather than individual cells
What is a microbial growth curve?
Plot of cell number vs. time in culture
What are the five distinct phases of a microbial growth curve?
Lag, log, stationary, death, decline
What is generation time?
Time for population to double in size
How does generation time vary?
Depends on species and environmental conditions
What is the range of generation time for microorganisms?
10 minutes to days
What are extremophiles?
Organisms that grow in harsh conditions
How do microbes adapt to hypertonic solutions?
Increase internal solute concentration with compatible solutes
What do halophiles require for optimal growth?
High salt concentrations above 0.2 M
What do extreme halophiles require for growth?
Salt concentrations between 3 M and 6.2 M
What do microbes do in hypotonic solutions?
Reduce osmotic concentration of cytoplasm
What do mechanosensitive (MS) channels in plasma membranes allow?
Solutes to leave the cell
How do microbes adapt in hypertonic solutions?
Increase internal solute concentration
What are halophiles?
Microbes that grow optimally in salt
What salt concentration do extreme halophiles require?
Between 3 M and 6.2 M
What does pH measure?
Relative acidity of a solution
What is the growth optimum pH for acidophiles?
Between pH 0 and 5.5
What is the growth optimum pH for neutrophiles?
Between pH 5.5 and 8
What is the growth optimum pH for alkaliphiles?
Between pH 8 and 11.5
What do most bacteria and protists prefer in terms of pH?
Neutral pH
What pH do most fungi prefer?
About pH 4 to 6
How do microorganisms respond to external pH changes?
Maintain a neutral cytoplasmic pH
What do neutrophiles exchange to maintain pH?
Potassium for protons
What is the acidic tolerance response in microorganisms?
Pumping protons out of the cell
What happens to many microorganisms' habitats due to their waste products?
Change the pH of their habitat
Can microbes regulate their internal temperature?
No, they cannot
What do enzymes have in relation to temperature?
Optimal temperature for functioning
What are the cardinal growth temperatures for organisms
Minimal, maximal, optimal
What temperature range do psychrophiles grow in?
0°C to 20°C
What temperature range do psychrotrophs grow in?
0°C to 35°C
What temperature range do mesophiles grow in?
20°C to 45°C
What temperature range do thermophiles grow in?
45°C to 85°C
What temperature range do hyperthermophiles grow in?
85°C to 113°C
How does oxygen concentration affect microbial growth?
Depends on metabolic processes and ETC
What is an aerobe?
Grows in presence of atmospheric oxygen
What is an obligate aerobe?
Requires oxygen to grow
What is an anaerobe?
Grows in absence of oxygen
What is a microaerophile?
Requires 2 to 10% oxygen
What are facultative anaerobes?
Do not require oxygen but grow better with it