Micro Exam 3
An organism with a mutation that affects its ability to synthesize a biochemical essential for its growth is known as a(n)
Auxotroph
In bacteria, conjugation refers to the transfer of DNA by
Cell-to-cell contact
Vertical gene transfer is observed in
all organisms
Alternative forms of a gene are called
allele
DNA polymerase catalyzes the formation of a phosphodiester bond between an existing DNA strand and
an incoming nucleoside triphosphate
Which two of these missense mutations would be predicted to have the most severe effects on the function of the protein encoded by the mutated gene?
substitution of an amino acid located at the active site of an enzyme; replacement of a nonpolar amino acid with a polar amino acid
If a bacterial cell is competent, that means it can
take up DNA and become transformed
Since DNA is double-stranded, either strand could serve as template for the production of a messenger RNA molecule. The strand that is used to direct mRNA synthesis is known as the ______ strand.
template
A mutation that leads to a change from wild type to a mutant form is called a(n) ______ mutation
Forward
The most common type of DNA recombination (e.g., during meiosis or bacterial horizontal gene transfer) is _______ recombination between similar or identical DNA strands.
Homologous
Mechanisms that result in the transfer of genes from one independent, mature organism to another are collectively called _____ gene transfer
Horizontal
Mutations that result from exposure to a physical or chemical agent (mutagen) are known as _______ mutations
Induced
Transition mutations, which result in purine for purine substitution or pyrimidine for pyrimidine substitution, are ______ common than transversion mutations.
More
A tautomeric form is an isomer of a nucleotide in which the ______ is changed.
Nitrogenous base
Which approach would be used to screen for revertants from a lysine auxotroph?
Plate a large number of lysine auxotrophs on a minimal medium lacking lysine.
Silent, missense, nonsense, and frameshift are all common types of _______ mutations
Point
The enzyme that catalyzes transcription is
RNA polymerase
Fill in the blank question. Proteins responsible for preventing DNA from re-annealing until the DNA replication machinery passes are called
SSB (single-stranded binding proteins)
A mutation that caused the codon CGU to change to CGC, which does not affect the amino acid encoded, could be described by which two of these terms?
Silent: point
Mutations that arise in the absence of any added agent are ____ mutations
Spontaneous
Which phrase best describes the form of a gene designated the "wild type?
The more prevalent form of the gene
UV radiation can cause mutations by inducing ______
Thymine dimers
The process of taking up DNA from the surroundings, and maintenance of the DNA in a heritable form, is called
Transformation
Nucleotide substitutions that result in purine for purine or pyrimidine for pyrimidine mutations are known as _______ mutations
Transition
A genetic selection differs from a genetic screen in that
a genetic selection adjusts the environment so that only mutants of the desired phenotype can grow
Fill in the blank question. After DNA replication, the two daughter chromosomes may be topologically linked, like two links in a chain. These linked chromosomes are called
catenanes
The term ______ base pairing refers to the manner in which the bases found on one strand of DNA match up with those of the opposite strand according to specific base-pairing rules.
complementary
Ultraviolet radiation may generate a thymine dimer, which is
covalent bonding between two adjacent thymines in a single strand
Polyribosomes increase the rate of protein production and are found ______.
in all three domains of life
The coding region of a gene
is between the start and stop codons
A polyribosome occurs when
multiple ribosomes assemble as separate but complete units on one mRNA molecule
DNA polymerase catalyzes the formation of a(n) ______ bond between an existing DNA strand and an incoming nucleoside triphosphate
phosphodiester
Ribose in RNA is different from deoxyribose in DNA because
ribose has a hydroxyl group attached to the 2' carbon
The ______ factor subunit of bacterial RNA polymerase recognizes two sequences of six bases each about 35 base pairs and about 10 base pairs before the transcription start point.
sigma
The proteins that keep the two parental template strands apart during DNA replication are
single-stranded DNA binding proteins
The template strand of a gene is
the strand copied for the mRNA transcript
In bacterial genetics, transformation is
the uptake of free DNA by a bacterial cell
Complementary base pairing in DNA refers to
the way that bases on opposing strands match up and hydrogen bond according to specific base-pairing rules