Micro Exam 2 Flashcards
Inducible operons
Inducible operons are turned on in reponse to a metabolite (a small molecule undergoing metabolism) that regulates the operon
Transduction requires a(n) ________ to move DNA from one bacterial cell to another.
bacteriaphage
What is the hallmark of all horizontal gene transfers?
Transfer of DNA between organisms of the same generation.
Which of the following is a method of vertical gene transmission
cell division
Which of the following genetic elements is transcribed into a single mRNA?
structural genes
here on the DNA strand does a repressor bind
the operator
Thymine dimers result from
nonionizing radiation
conjugation
cell to cell contact via pili
transduction
The process by which a virus transfers genetic material from one bacterium to another
operon
a functioning unit of DNA containing a cluster of genes under the control of a single promoter.
What are the two ways mutations can be repaired?
) Damage to DNA caused by UV radiation can be repaired by enzymes that cut out and replace the damaged portion of DNA.
2) Light-repair enzymes repair thymine dimers in the presence of visible light.
catabolite regression
a regulatory mechanism by which the expression of genes required for the utilization of secondary sources of carbon is prevented by the presence of a preferred substrate.
what is the function of a plasmid
used as a vector to amplify and replicate genes. A plasmid is a small, circular, double-stranded DNA molecule that is distinct from a cell’s chromosomal DNA.
how does radiation kill cells ?
he inhibition of cellular proliferation is the mechanism by which radiation kills most mammalian cells.
how is disk diffraction used ?
n diagnostic laboratories, the disk diffusion test is used to determine the susceptibility of clinical isolates of bacteria to different antibiotics.
How to tell if antibiotic is effective
large zone of inhibition
What are disinfectants?
Disinfectants are used on non-living things, such as countertops and handrails, to kill the microorganisms living on that inanimate surface
What are antiseptics ?
Antiseptics are used on living organisms, such as human skin, to kill any microorganisms living on the bodies surface
constitutive genes
expressed at a fixed rate always there
nonsense mutation
a mutation that introduces a stop codon into the genetic code and prevents the protein from being made completely.
frameshift mutation
single letter is inserted or deleted resulting in shift of reading frame
sillent mutation
a mutation in which a single nucleotide base is changed, but that change does not effect the amino acid sequence.
missense mutation
A missense mutation is a point mutation in which a single nucleotide is changed, resulting in a codon that codes for a different amino acid.
lytic cycle
The lytic cycle involves the reproduction of viruses using a host cell to manufacture more viruses; the viruses then burst out of the cell.
lysogenic cell
involves the incorporation of the viral genome into the host cell genome,
sterilization
destruction of all microbial life
bacteriostatic
inhibiting not killing microbes
Asepsis
absence of significant contamination
DNA helicase
unwinds DNA
DNA ligase
joins okasaki fragments together
What do gyrase and toprimase do
relax DNA strands
What doers RNA polymerase do?
remove RNA primers
What does DNA polymerase do?
adds nucleotides to DNA strand in 5 -3 direction.
Explain pre-transcriptional regulation of gene expression in bacteria.
wo genetic mechanisms known as repression and induction regulate the transcription of mRNA and consequently the synthesis of enzymes from them. These mechanisms control the formation and amounts of enzymes in the cell
lac operon
The lac operon is an example of inducible control because the presence of lactose turns on transcription of the genes for its own metabolism.
trp operon
The trp operon is an example of repressible control because it uses proteins bound to the operator sequence to physically prevent the binding of RNA polymerase.
Compare and contrast protein synthesis in prokaryotes and eukaryotes. Why are they different?
.In Prokaryotic cells, Transcription and Translation Can Occur at the Same Time(coupled)
2.Occurs in nucleus of eukaryotes and cytoplasm in prokaryotes
3.Eukaryotes have have variations in the number of chromosomes between species
First step of DNA replication
The first step is to unwind the double helix structure of the DNA molecule, and ‘unzip’ the strands
second step of DNA replication?
replication fork forms
