Chapter 9 Microbial Genetics
Proteins that remove incorrect bases and replace them with correct ones are termed ... repair enzymes.
excision
The lactose repressor protein binds to the ... ...of the lac operon.
operator
The process of bacteria turning on or off a group of genes that changes its phenotype in a heritable manner is called......
phase variation
A mutation that affects only a single pair in DNA is termed a ... mutation
point
... mutations are generally most harmful to cells because they cause the greatest change in the amino acid sequence of a protein.
frameshift
Control of enzymes at the level of gene expression ensures that
genes are active only when their enzyme products are required
The .... is the genetic makeup of an organism that is ultimately responsible for an organism's expressed characteristics.
genotype
The corepressor of the histidine biosynthetic operon is
histidine
Viral mRNA is translated into viral protein on ... ribosomes using ...tRNA
host; host
The final sealing of nicks in a newly synthesized DNA strand is catalyzed by the enzyme...
ligase
A permanent inheritable alteration in the DNA sequence of a cell is a(n)
mutation
Genes are made up of building blocks called... ...
nucleic acids
The process of replication of the DNA molecule is described as being ... because the parent strands serve as templates for the production of two daughter strands of DNA.
semiconservative replication
What is the function of mRNA?
serves as a transcript of a gene sequence of template DNA
rRNA composes ... subunits together with protein
ribosomal
True or False: A RNA template is a strand of RNA made from DNA
False
True or false: A point mutation results from an insertion or deletion of nucleotides, and always leads to a shift of the triplet sequence from the point of mutation downstream.
False
Induced mutations are caused by
2-amino purine, and ultraviolet light
A codon contains how many nucleotides?
3
Which sequence of DNA nucleotides is complementary to the DNA triplet 5'-ATG-3'?
3'-TAC-5'
Which is the main event of transcription termination?
RNA polymerase reaches a terminator region
During transcription, RNA polymerase synthesizes ... from a(n) ... template
RNA; DNA
... refers to the transfer of genes from donor to recipient microorganisms, where the recipient strain shows a change in genetic makeup at the end.
Recombination
Which kind of gene encodes a protein?
Structural
The lactose repressor protein is allosteric, meaning that it has two binding sites, on for ... and another for ...
The operator DNA sequence, and lactose
.... involves the transfer of DNA via bacteriophages.
Transduction
... RNA is transcribed and then plays a role in translation by carrying amino acids to the ribosome
Transfer
Which gene transfer method involves the uptake of free DNA by competent bacterial cells?
Transformation
... is the process of decoding the mRNA into a polypeptide.
Translation
"Jumping genes" or _____, can lead to changes in genotype within a cell or between cells.
Transposons
True or false: Eukaryotic DNA is linear whereas bacterial DNA is circular.
True
A nitrogen-containing molecule found in DNA and RNA that provides the basis for the genetic code is a nitrogenous....
base
Binding of arginine to the arginine repressor protein causes the repressor to
bind to the operator sequence
DNA transfer between bacterial cells typically involves DNA in the form of ...
chromosomal fragments or plasmids
A ... is a discrete cellular structure composed of a neatly packaged DNA molecule
chromosome
A ... is a discrete cellular structure composed of a neatly packaged molecule
chromosome
Donor and recipient bacterial cells are connected by the cell sex pilus during ...
conjugation
During conjugation, the donor cell generally retains a copy of the genetic material being transferred. This is termed a ... process.
conservative
Biosynthesis of DNA, RNA, and protein ... energy.
consumes
A recombinant is defined as an organism that...
contains and expresses genes that originated in another organism.
Most DNA damage is resolved by...
enzymes
...are DNA sequences which encode for functional proteins.
exons
In Eukaryotes, which DNA sequences encode functional protein?
exons
The ability of Neisseria gonorrhoeae strains to produce attachment ... is an example of phase variation
fimbriae
Which DNA sequences are found within a gene but do not encode the protein specified by that gene?
introns
The newly forming DNA strand that is discontinuously replicated in segments (Okazaki fragments) is called the ... strand
lagging
A small number of ... are considered beneficial in that they provide the cell with a useful change in structure or physiology
mutations
A ... mutation results in early termination of the protein
nonsense
Building blocks of DNA, called .... , contain the same sugar and phosphate, but different nitrogenous bases.
nucleotides
In a protozoal or fungal cell, chromosomes are located in the...
nucleus
A(n) ... is a sequence of DNA nucleotides that codes for one functional protein or RNA.
gene
When a cell is actively growing, the arg operon is ...., and the arginine is ....
on; actively synthesized
When E. coli is grown in a medium containing both glucose and lactose, it will first consume the
glucose
The purine nitrogenous bases found in RNA are adenine and
guanine
In bacterial conjugation, a donor cell with a F (fertility) .... located in the cytoplasm is considered F+
plasmid
The protein bridge between two bacteria during conjugation is called the
pilus
The ... of the lac operon is a gene that encodes a repressor protein
regulator
Ensuring that the DNA code will be maintained during cell growth and cell ... is one of the two essential effects of the structure of DNA
replication
DNA ... are enzymes responsible for the replication of DNA.
polymerases
The ... is a particle composed of two subunits of rRNA that is the site of protein synthesis
ribosome
Mutations that occur because of errors in DNA replication are termed...
spontaneous
The mRNA sequence AUG, specifying the first amino acid in protein sequences, is called the .... codon
start
The ... of lac operon is comprised of three genes, each encoding a different enzyme needed to catabolize lactose
structural locus
Which RNA carries amino acids to the ribosome during protein synthesis?
tRNA
The process of transcription ... results in the release of a completed RNA transcript
termination
True or false: Several codons code for the same amino acid, which is called redundancy of the code.
true
True or false: The expression of the genotype creates traits referred to as the phenotype
true
The pyramidine nitrogenous bases found in RNA are cytosine and...
uracil
The native or ... type strain exhibits nonmutated characteristics
wild type
The two versions of transduction are...
specialized and generalized
Which is true regarding bacterial chromosomes?
Located in the nucleoid region of the cytoplasm.
The pyrimidine nitrogenous bases found in DNA are thymine and ...
Cytosine
An insertion sequence consists of only two genetic elements:
DNA encoding enzymes for transposition and tandem repeats
Which is the main event of translation?
mRNA binds to the ribosome
During semiconservative ... the DNA is duplicated prior to binary fission.
replication
When E. coli is grown in a medium containing both glucose and lactose, the lac operon will be
repressed until the glucose is consumed
Which is the main event of translation termination?
A nonsense codon is reached and the peptide is released from the ribosome
Which is the main event of translation elongation?
Amino acids are joined by peptide bonds.
What is the main event of transcription termination
RNA polymerase reaches a terminator region
Transposable elements are capable of moving from
The chromosome to a plasmid, one site in the chromosome to another site in the chromosome, and a plasmid to the chromosome.
Transposable elements are capable of moving from ...
The chromosome to a plasmid, one site in the chromosome to another site in the chromosome, and a plasmid to the chromosome.
... involves the uptake of free DNA by competent bacterial cells
Transformation
True or false: Topoisomerases relieve the superhelical tension as DNA is replicated.
True
.... , .... , and .... are the three stop codons within the genetic code.
UAG, UAA, UGA
The structure of DNA was discovered in 1953 by
Watson and Crick
True or false: The phenotype is the sum of all the genes constituting an organism's distinct genetic makeup.
false
The binding of lactose to the lactose repressor protein causes the repressor to leave the operator region. This happens because lactose...
induces a conformation change in the protein.
The ... DNA strand is the strand that is not directly used for transcription into mRNA during protein synthesis.
nontemplate
The DNA genome of DNA animal viruses is replicated in the ... ; the genome of RNA viruses is replicated in the ....
nucleus; cytoplasm
During ... DNA replication, the newly made double helices are composed of one parent template and one newly synthesized strand.
semiconservative
The 3' end of a eukaryotic chromosome that cannot be copied is called the ...
telomere
The parent strands in a DNA molecule are used as a ... to synthesize a complementary strand of DNA
template
Conjugation is a conservative process, meaning that...
the donor retains a copy of the genetic material being transferred
The antibiotic rifamycin can be used to treat tuberculosis because
the drug is more active against bacterial RNA polymerase than the human enzyme.
How do an Hfr cell and an F+ cell differ?
the plasmid is integrated into the chromosome of an Hfr cell but not in an F+ cell
The term ... is a sequence of 3 consecutive nucleotide bases in DNA that encodes an amino acid.
triplet
True or false: Within a nucleotide, the phosphate group is linked to the 5' carbon of the pentose sugar.
true
Which template DNA sequence encodes the peptide sequence Phenylalanine-Leucine-Aspartic Acide-Valine?
3'-AAAAACCTACAT-5'
A DNA triplet encodes ... mRNA codon(s) and ... amino acid(s).
1;1
Which type of RNA is transcribed from a DNA template?
All types of RNA
The ... test is a method of detecting mutagenic and potentially carcinogenic agents based upon the genetic alteration of nutritionally defective bacteria.
Ames
The genes of which microorganisms are arranged as operons?
Bacteria
What is the function of tRNA?
Brings amnio acids to ribososmes to make proteins
Which two of the following statements regarding DNA packaging are correct?
DNA is thousands of times longer than the cell, and the intricate coiling of DNA is required to package it inside the cell.
Which is the main enzyme in elongation of a DNA strand during replication?
DNA polymerase
... is the pentose sugar in DNA
Deoxyribose
In bacterial conjugation, a recipient cell having no ... plasmid is considered F-
F
Which term represents all of the genetic information within a cell?
Genome
In bacterial conjugation, which type of donor has the fertility factor integrated into the chromosome?
Hfr
What is the result of a point mutation that changes a template gene sequence from 3'-TACGCCATATAT-5' to 3'-TACGCCATCTAT-5'?
Nonsense mutation
the central dogma, DNA encodes ... which encodes protein.
RNA
Which enzyme transcribes DNA into RNA?
RNA polymerase
Which two of the following statements regarding tRNA charging with amino acids are correct?
The anticodon in tRNA specifies which amino acid it carries, and "Charging" refers to the process of adding an amino acid to a tRNA.
The pyrimidine nitrogenous bases found in DNA are cytosine and ...
Thymine
Which term, synonymous with codon, describes a trinucleotide sequence coding an amino acid in DNA?
Triplet
The biosynthesis of the amino acid histidine requires enzymes whose genes are organized in the his operon. The his operon would be expected to be active when the cell is growing in a medium containing
a low concentration of amino acids
The regulator of the lac operon is a gene that encodes
a repressor protein
The purine nitrogenous bases found in RNA are guanine and ...
adenine
Which two of the following operons in E. Coli would be repressible?
an operon encoding amino acid biosynthetic enzymes, an operon encoding vitamin biosynthetic enzymes.
The enzyme beta-galactosidase, encoded in the lac operon has an enzymatic activity to
hydrolyze lactose
Mutations that occur because of exposure to know mutagens are termed
induced
Because lactose is ultimately responsible for stimulating protein synthesis from the lac operon it is called the
inducer
Many catabolic operons are ... , while those that encode anabolic enzymes are ...
inducible; repressible
A mutation that leads to the insertion of a different amino acid in the encoded protein is termed a ... mutation
missense
A mutation that leads to the insertion of a different amino acid in the encoded protein is termed a ... mutation.
missense
In bacteria, a regulatory gene, a control region, and structural genes collectively are referred to as a(n)...
operon
During replication initiation, the enzyme ... synthesizes primer sequences.
primase
RNA ... are structures that provide DNA polymerase with the 3' end needed for synthesis during DNA
primers
RNA polymerase binds to the ...region of the DNA to initiate transcription.
promoter
The ... of the lac operon is a region of DNA that is recognized by RNA polymerase.
promoter
During protein synthesis, many copies of a specific...can be synthesized from a single mRNA transcript.
protein
... and proteins compose ribosome subunits.
rRNA
In general, a strand of RNA made from DNA is called an RNA...
transcript
One reason protein synthesis is more efficient in bacteria than in eukaryotes is because bacterial ... and ... are simultaneous
transcription, translation
The process of introducing foreign genes to a plant cell by adding the DNA directly to the cell medium us termed
transfection
The process of shifting the ribosome down the nRNA to read new codons is termed...
translocation
What did Griffith's experiment using Streptococcus pneumoniae demonstrate?
That DNA released from a dead cell can be transferred to live cell
The genes of the lac operon in E.coli encode enzymes that
catabolize lactose
