Micro Lec test 1
Cellular growth can be visualized by:
*an increase in cellular components *an increase in cell size *an increase in cell number
Transposons (jumping genes)
*mobile genetic elements *move from place to place in the genome, plasmid and viral genomes *disrupt genes when they land *may mobilize other genes (like antibiotic resistance)
How many cells or colony-forming units (CFUs) are presumed to result in a single colony using the variable plate method?
1
which of the following describes the primary "function" of the cell membrane?
a barrier between the internal and external contents of the cell.
another term for the cell membrane (or plasma membrane) in the __________________ membrane.
cytoplasmic
the cell membrane may also be referred to as the
cytoplasmic membrane
the taxonomic categories from top to bottom are:
domain kingdom phylum/division class order family genus species
The theory of ________ states that living things change gradually over time through natural selection.
evolution
which of the following bacterial growth phases correlates to the acute stages of a bacterial infection?
exponential
which term describes the length of time of a microbial species needs to divide?
generation time
what technology involves the deliberate modification of the genetic structure of an organism to create novel products?
genetic engineering
All bacteria possess a cell ________ but not all bacteria possess a cell ________.
membrane wall
During translation initiation, the ribosomes bind to the __________ RNA transcript.
messenger
the sum total of all the microbes in a certain environment is its ___________.
microbiome
in the 1600s, van Leeuwenhoek developed a large collection of single-lens _________.
microscope
Organisms that are only visible with the aid of a microscope are __________.
microscopic
________ microbes that are associated with humans cause no harm.
most
the ___________ bacteria have no cell wall, but have a cytoplasmic membrane that is stabilized by sterois.
mycoplasma
illustrate the scientific method by putting these statements in order, starting with the first process at the top.
1. A phenomenon is observed in the natural world. 2. The scientist develops an explanation known as a hypothesis. 3. An experiment is conducted to test the hypothesis. 4. Analysis leads to either rejection or support of hypothesis.
Phases or Order of normal bacterial growth curve.
1. Lag 2. Exponential 3. Stationary 4. Death
The human Microbiome Project began in
2008
What is the function of rRNA?
comprises ribosomal subunits
The genetic transfer of material through pili is termed
conjugation
cellular growth
is stimulated by nutrients and environmental factors
all of the following are true statements about the human microbiome EXCEPT ____________.
it regularly causes disease
The ___________ of the genetic code results in several codons encoding the same amino acid.
redundancy
older diseases that are experiencing recent increases in prevalence are referred to as ___________.
reemerging diseases
Bacteriophage
"middle man" transfers small pieces of DNA during infection process
Which three of the following events in protein synthesis occur post-transitionally.
*addition of cofactor *removal of the formyl methionine *protein folding
The anticodon of the tRNA carrying the codon GUU is ______.
CAA
Transformation Griffith and avery
Dead pathogenic Streptococcus pneumoniae (Pneumococci) were able to "transform" live non pathege
which 2 of the following statements regarding genome size are correct?
Eukaryotes generally have more genes than viruses. Genomes vary greatly in size
Is the transcriptional process shown in the image from a prokaryotic cell, a eukaryotic cell or both?
Eukaryotic
In eukaryotes, coding regions of DNA that will be translated into protein are called ___________.
Exons
____________ is the light-fueled conversion of carbon dioxide to organic material.
Photosynthesis
Which were the five kingdoms in the earlier Whittaker system of classification?
Plantae monera protista fungi animalia
RNA polymerase binds to which region of DNA to begin transcription?
Promoter
which of the following is the genetic pattern of viral genomes?
Single or double stranded DNA or RNA
A rigid helical bacterial cell twisted twice or more along its axis is described as a:
Spirillum
chose the prefix that may be used to describe arrangements of bacilli:
Strepto- diplo-
Infectious disease are among the top ten causes of death by disease both in the U.S. and worldwide.
True
Microbiology involves the study of microscopic organisms or agents, including ___________.
bacteria helminths fungi viruses protozoa archaea
________ diseases are those which are newly identified and becoming more prominent.
emerging
The transcriptional process shown in this image is from a _________ cell.
eukaryote
the microbe depicted in this image is an example of a
fungi
In binary fission, the doubling time of a particular microbial species is also known as its ____________ time.
generation
for the organism Staphylococcus aureus, Staphylococcus represents the _________ level of classification.
genus
Which is the main event of translation initiation?
mRNA binds to the ribosome
The __________ bacteria naturally have no cell wall, but have a cytoplasmic membrane that is stabilized by sterols.
mycoplasma
Which two macromolecules are the major component of cell membranes?
proteins lipids
The five kingdoms in the Whittaker system include Kingdoms Animalia, Plantae, Myceteae (fungi), ___________, and ___________.
protista monera
________ and proteins compose ribosome subunits.
rRNA
The deliberate manipulation of organisms by transferring genetic material from one organism to another, a type of genetic engineering, is known as ______________ DNA technology.
recombinant
The _____________ is a particle composed of two subunits of rRNA that is of protein synthesis.
ribosomes
A coccus is a _________ -shaped bacterial cell.
spherical
a ________ is a flexible, spiral-shaped bacterium.
spirochete
the prefix "___________" means "in grape-like clusters."
staphylo
The _________ phase of bacterial growth is when there is an equal number of cells dividing as there are dying.
stationary
The __________ phase of bacterial cell growth is when there is an equal number of cells dividing as there are dying.
stationary
During which phase of growth does the number of new cells balance the number of declining cells?
stationary phase
A curved rod (comma-shaped bacterium) is specifically described as a:
vibrio
A __________ is a microscopic agent, which is not cellular (acellular) and is composed of nucleic acids surrounded by a protein coat.
virus
Horizontal gene transfer
Transfer of DNA from a source other than the parent organisms.
Hfr Strains
*High Frequency of recombination *Integrated F factor (episome) *Conjugal transfer *chromosomal gene introduced *incorporation of new genes into the chromosome *these were used to "map" the relative positions of genes before DNA sequencing became so easy
Generalized Transduction
*Involves a lytic phage *infection as usual *Mistaken packaging of a host gene *defective phage *one in a million odds
Specialized Transduction
*Lysogenic phage *inserts as prophage *aberrant excision *pick up adjacent gene *defective phage *one in a million odds
Which two of the following statements regarding eukaryotic transcription are correct?
*Splicing to remove introns occurs in the nucleus. *A series of adenosines is added to the mRNA
In a stratified biofilm, :
*aerobes are found near the surface *anaerobes are found near the bottom
cellular growth can be visualized by:
*an increase in cell number *an increase in cell size *an increase in cellular component
A codon contains how many nucleotides?
3
What is the length of a typical tRNA molecule?
75-95 bases
Escherichia Coli generation time of 20 minutes. if 1 million parent cells where placed in a flask of sterile nutrient broth and incubated under optimal conditions, how many cells would be present in the broth after 1 hour?
8 million
which is the main event of translation termination?
A nonsense codon is reached and the peptide is released from the ribosome
which of the following can be measured or analyzed in an uncultured environment or tissue sample in order to qualify cell numbers present?
ATP
The Dutch linen merchant who developed a large collection of single-lens microscope in the late 1600s that used to view microbes was _________.
Antonie van Leeuwenhoek
The three domains of the Woese-fox system include the rure bacteria in Domain Bacteria, the extreme microbes in Domain ___________, and the eukaryotic organisms in Domain _____________.
Archaea Eukarya
which are the three domains of the Woese-Fox system of classification?
Archaea Eukarya Bacteria
__________ is the area of taxonomy that involves grouping similar organisms into a hierarchy of taxonomic categories.
Classification
What is the correct term for describing very short, ovoid, rod-shaped bacterial cells.
Coccobacilli
What are the three most common shapes of bacterial cells?
Bacillus Coccus Spirillum
typical bacteria, such as Bacillus or Streptococcus, belong to which domain?
Bacteria
In eukaryotes, which DNA sequences encode functional protein?
Exons
A person shedding bacteria in the late stages of infection is more likely to spread in to others than a person in the early or middle stages.
False
A sterile environment is free of actively growing cells and microorganisms, but may contain viruses or dormant life forms such as endospores.
False
Plasmids are insertion sequences that can lead to changes in genotype within a cell or between cells.
False
The different coccal arrangement are a consequence of growth in broth solid media.
False
Viral genomes are always composed of either single or double stranded DNA
False
based on research, microbes have been recently associated with which four of the following diseases that were once considered noninfectious?
Gastric Ulcers Cancer Diabetes Multiple sclerosis
which microbes have a true nucleus?
Protists yeast
Which term describes the length of time of a microbial species needs to divide?
Generation time
human, bacterium, virus
Human= tens of thousands of genes Bacterium= a few thousand genes Virus= a few dozen genes
_________ is the term applied to the method of assigning a scientific name to an organism, whereas taxonomy involves the organization of these named organisms.
Nomenclature
The viable colony count is based on the principle that each colony isolated represents ____________ cell or colony-forming unit from the original sample.
One
only gram-negative bacteria posses an
Outer membrane
which process can be used to quantify cell numbers in a sample without culturing the actual microb?
PCR
out of the answers given, choose the most general and the most specific level in the hierarchy of classification.
Species kingdom
A _________ is a flexible, spiral-shaped bacterium.
Spirochete
_________ is the science of organizing, classifying and naming living things.
Taxonomy
which two of the following statement regarding tRNA structure are correct?
The overall structure is termed a cloverleaf tRNA has regions that are double-stranded RNA
What is biotechnology?
The use of microbes or their products for commercial or industrial purposes.
Several codons code for the same amino acid, which is called the redundancy of the code.
True
when writing a binomial name, the initial letter of the genus is capitalized and the species is in lower case.
True
The structures seen in this figure are representatives of different types of _________.
Viruses
During translation elongation, peptide bonds form between:
amino acids
what is classification?
arranging organisms into a hierarchy
For the organism Staphylococcus aureus, what is the species name?
aureus
the proper term for a rod-shaped bacterial cell is a
bacillus
which two of the following group of organisms arguably play the greatest role in biological decomposition?
bacteria fungi
Transduction
bacteriophage transfers from cell to cell
In the __________ system of nomenclature, organisms are assigned and identified by a two-word name representing the genus and species names.
binomial
Conjugation Plasmid direct transfer
cell contact
Conjugation
cell contract-Fertility pilus-allows transfer of large amounts DNA from donor to recipient. *Requires physical contact between donor and recipient cells *Fertility plasmid codes for Fertility pilus *large amount of DNA transfer may occur
the prefix "strepto-" is used to indicate that the cells are arranged in
chains
Taxonomy involves ______________ living things.
classifying
the prefix "staphylo-" is used to indicate that the cells are arranged in:
clusters
The term used for a short, plump bacterial rod is __________.
coccobacilli
A ____________ is the specific sequence of 3 mRNA nucleotides, based n a DNA triplet, that encodes a particular amino acid.
codon
the genetic transfer of material through pili is termed _________.
conjugation
Lipopolysaccharide (LPS) is found on the outer membrane of Gram-negative cells. Within the outer membrane it is located:
on the outer surface
what is a helminth?
parasitic work
Louis _______ developed methods of making dairy products safer and the formation of beer and wine using microbes.
pasteur
in general, disease-causing organisms are referred to as
pathogens
A major structural component, ___________ are found within the lipid bilayer in a cell membrane and comprise 30-40% of the membrane mass.
phospholipids
"Finishing touches" on proteins are termed ____ modification.
posttranslational
The arrow is pointing to a ______ cell type.
prokaryotic
RNA polymerase bind to the ___________ region to initiate transcription.
promoter
rRNA composes ________ subunits together with protein.
ribosomes
A bacillus is a ________- shaped bacterial cell.
rod
the exocytosis or the transport of metabolic materials from a cell into the extracellular environment is referred to as ________.
secretion
what term refers to the discharge of a metabolic product to the extracellular environment?
secretion
Natural _________ is a process in which the environment places pressure on organisms to adapt and survive; traits best suited to the environment tend to spread in the population over time.
selection
the cell membrane is a _______ permeable barrier of the cell.
semi
What is the function of mRNA
serves as a transcript of a gene sequence of template DNA
an environment or material that is completely free of all life forms (including spores) and viruses particles is referred to as
sterile
which event helped establish the science of microbiology?
the development of the microscope
Enumeration of bacteria can be achieved by the _________ cell count, in which a cell suspension in a chamber is viewed under the microscope.
total
Which 2 statements regarding eukaryotic are correct?
transcription occurs before splicing the exon-intron junction is recognized by a spliceosome.
Vertical gene transfer
transfer of DNA from parent organisms during reproduction
Transformation
transfer of small segments of DNA from a dead cell
