Microbiology Chapter 9
Which template DNA sequence encodes the peptide sequence phenylalanine-leucine-aspartic acid-valine?
3'-AAAAACCTACAT-5'
All new DNA strands are synthesized from
5' to 3'
If a codon of mRNA reads 5'-UUG-3', the tRNA that delivers the amino acid to this location during translation will have an anticodon of 3'-____ -5'
AAC
In DNA, the two strands of the helix are arranged in ___ orientation
Antiparallel
what is true regarding adenine and guanine?
Both are purines
DNA polymerases are responsible for
Building the DNA chain Proofreading/repair
Which component of DNA determines the 3' and 5' ends of the strands?
Carbons in the deoxyribose sugar
During which method of gene transfer are bacterial cells in direct contact?
Conjugation
Which are parts of the lactose operon?
Control locus, Structural locus, Regulator
Transcription occurs in the ____ of bacteria and the ____ of yeast cells.
Cytoplasm, nucleus
Which is true regarding DNA replication?
Each new DNA helix contains one parent strand and one newly synthesized strand
What is the name of the specialized plasmid that directs conjugation in gram-negative cells?
F factor
Cytosine pairs with
Guanine
Which enzyme unzips the DNA helix prior to the start of replication?
Helicase
DNA polymerase ____ is the main enzyme involved in the building of the new DNA chain, whereas DNA polymerase ____ is involved mostly with removing the primers and repairing damaged DNA.
III/I
Which type of operon is typically in the "off" position until the appropriate substrate is present?
Inducible operon
Which enzyme completes the final sealing of nicks in a newly synthesized DNA strand?
Ligase
What amino acid sequence is encoded by the DNA template sequence 3'-TACCGCGCTCTACCG-5'?
Methionine-Alanine-Arginine-Aspartic Acid-Glycine
The genome of a prokaryotic or eukaryotic cell includes DNA found in which sites?
Mitochondria, chloroplasts, plasmids, chromosomes
Which of the following are parts of a nucleotide in DNA?
Nitrogenous base, Phosphate, Deoxyribose sugar
___ mutation results in early termination of the protein
Nonsense
In a protozoal or fungal cell, chromosomes are located in the
Nucleus
In replication of DNA, the lagging strand is replicated in a discontinuous manner forming
Okazaki fragments
The specific order of amino acids bound to each other by peptide bonds represents the ___ structure of a protein
Primary
How does RNA differ from DNA in bacteria and eukaryotes?
RNA is single-stranded, uracil replaces thymine
During transcription, RNA polymerase synthesizes ______ from a(n) ______ template.
RNA; DNA
____ operons often contain genes coding for anabolic enzymes and are usually turned off by the end product of the reactions catalyzed by these enzymes.
Repressible
Which of the following are functions of RNA polymerase?
Synthesizes an RNA molecule from DNA template Unwinds the DNA so that transcription can take place
The complementary sequence to 5'-AAGTC-3' is 3'-______-5
TTCAG
If one strand of DNA reads 5'-AAGCGTTA-3', the complementary sequence would be 3'- ___ -5'
TTCGCAAT
Which of the following describes the primary structure of a protein?
The chain of amino acids bound by peptide bonds
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.
In DNA, adenine pairs with what?
Thymine
During which process is mRNA converted into a protein?
Translation
During DNA replication, both the leading and lagging strands are synthesized in the 5' to 3' direction.
True
The tRNA ___ is complementary to the mRNA codon.
anticodon
Initiation of transcription involves ______.
binding of RNA polymerase to promoter region
tRNA (transfer RNA)
brings amino acids to the ribosome during the translation process
Transcription of the structural genes of the arg operon is inhibited when arginine
builds up and binds to and activates the repressor
Elongated genomes may fit inside the minuscule volumes of a cell because of the complex ___ of the DNA molecule
coiling
A bacterial cell described as ___ can accept soluble DNA from the surrounding environment.
competent
The lactose operon is composed of the regulator, the ______ locus, and the structural locus.
control
Protein synthesis takes place in (on) the _______ of eukaryotic cells.
cytoplasm
Chromosomes
discrete cellular structure composed of a neatly packaged DNA molecule.
DNA polymerase converts DNA into the various types of RNA during transcription.
false
Which type of mutation is generally most harmful to cells?
frameshift mutation
Random portions of host DNA are transferred by bacteriophage during ___ transduction.
generalized
Control mechanisms ensure that _____ are active only when their products are required.
genes
Where are the chromosomes of yeast cells located?
in the nucleus
After a eukaryotic mRNA has been transcribed, _______ are removed.
introns
Recombinant
is any organism that has acquired genes that originated in another organism.
Nucleotide
is the basic unit of DNA structure.
Transcription of the structural genes of the lac operon will be inhibited when
lactose concentration is low and glucose concentration is high.
Transcription of the structural genes of the lac operon will be greatest when
lactose is present in high concentrations but glucose is absent.
Which type of mutation results in a different amino acid being incorporated into a protein?
missense
An agent that induces changes in DNA is a(n)
mutagen
A permanent inheritable alteration in the DNA sequence of a cell is a(n)
mutation
What is the result of a point mutation that changes a template gene sequence from 3'-TACGCCATATAT-5' to 3'-TACGCCATCTAT-5'?
nonsense mutation
Gene expression in prokaryotes is regulated through _______.
operons
What is a small circular segment of DNA found in the cytoplasm of prokaryotes that is capable of independent replication and usually contains nonessential genes?
plasmid
Which enzyme synthesizes primer sequences during replication initiation?
primase
The initiation of transcription occurs when RNA polymerase recognizes and binds to a region of DNA called the ____ region.
promoter
During protein synthesis, many copies of a specific ____ can be synthesized from a single mRNA transcript.
protein
The prokaryotic ribosome is composed of ______ and protein.
rRNA
Two subunits of the ___comprise the site of protein synthesis
ribosome
Due to the separation of prophage DNA from the bacterial chromosome, a specific, adjacent part of the host genome is transferred during ___ transduction.
specialized
Codon
specific sequence of 3 mRNA nucleotides, based on a DNA triplet, that encodes a particular amino acid.
A special type of RNA called _______ remove introns from eukaryotic mRNA sequences.
splicesomes
____ mutations in DNA are caused by random mistakes in replication and not known to be influenced by any mutagenic agent.
spontaneous
the ___codon AUG of mRNA is associated with the tRNA anticodon UAC and the amino acid methionine.
start
Which are components of an operon in a sequence of DNA?
structural genes operator
The region of DNA that signals the end of an RNA transcript is the ___ sequence.
termination
___ involves the uptake of free DNA by competent bacterial cells.
transformation
The ribosome, composed of rRNA and protein, is involved in the process of
translation
"Jumping genes" are known as
transposons
The promoter of an operon is the location where RNA polymerase binds, whereas the operator acts as the on/off switch for transcription of the structural genes. True false question.
true
In protein synthesis, eukaryotic and prokaryotic cells show similarities in all of the following EXCEPT the
use of formyl-methionine as the first amino acid. number of proteins encoded on a single mRNA.
Which of the following is physical, as opposed to chemical, agents that can cause mutations?
x-rays and ultraviolet light