Chapter 9 Connect
The purpose of RNA synthesis is to provide a new copy of DNA as the original strand deteriorates over time.
False
Translation occurs on ribosomes only in bacteria.
False
Which part(s) of an operon will eventually be translated to protein?
Structural genes
Transcription begins when RNA polymerase binds to the _______.
promoter on DNA
If an organism lost the ability to make primase, what would it be unable to do?
Add a short sequence of complementary RNA to the existing DNA strand
Eukaryotic mRNA contains non-coding regions called ______.
introns
When a repressor binds to the operator site on DNA
it blocks RNA polymerase and mRNA synthesis.
Before an activator can bind to DNA,
it must react with the substrate it regulates.
If lactose is present, the operator of the lac operon is switched ____; therefore, this is an example of a(n) ______ operon.
on; inducible
The bond connecting amino acids is a _______ bond.
peptide
In the absence of lactose
a repressor binds to the operator site of the lac operon.
DNA polymerase can only
add nucleotides in a certain direction.
The two strands of the DNA molecule are ______.
antiparallel
Repressible operons (such as the arg operon)
are usually in the "on" mode.
Translation of mRNA into protein begins before transcription is complete in ______.
bacteria only
Introns are removed and exons are spliced together _____.
before translation
If the codon GGU is positioned in the A site of the ribosome, which of the following will occur?
A tRNA with the anticodon CCA will deliver its amino acid to the site.
_____ are groups of three bases in mRNA that specify one amino acid in the amino acid chain.
Codons
An operon is composed of _____.
DNA
Which of the following depicts the direction genetic information flows?
DNA → RNA → protein
Both DNA and RNA are usually double-stranded molecules.
False
Eukaryotic mRNA usually specifies multiple proteins.
False
Translation of eukaryotic mRNA can occur in the nucleus after exons are spliced together.
False
What component of RNA is different from one individual (or one bacterium) to the next?
Order of nitrogenous bases
The initial transfer RNA occupies the _______ site on the ribosome
P site
What three components make up RNA structure?
Phosphate, nitrogenous base, ribose sugar
What usually terminates the process of translation?
Presence of a stop codon on mRNA
DNA polymerase III
Responsible for adding bases to the new DNA chain and proofreading the newly laid down bases
DNA polymerase I
Responsible for removing the primer, closing gaps in the DNA and repairing mismatched bases
Topoisomerases I and II
Responsible for supercoiling and untangling of DNA
Primase
Responsible for synthesizing an RNA primer
Ligase
Responsible for the final binding of nicks in DNA during replication
What occurs in both bacteria as well as eukaryotes?
Translation DNA replication Transcription
All structural genes in an operon code for proteins related to the same function
True
Bacteria lack membrane-enclosed organelles.
True
If you know the sequence of nucleotides in mRNA, you can deduce the DNA sequence it was transcribed from.
True
In bacteria, the mRNA transcript encounters ribosomal parts immediately as it leaves the DNA.
True
Only eukaryotic mRNA is processed prior to translation.
True
Replication, transcription and translation take place in the bacterial cytoplasm.
True
Several codons can be translated into the same amino acid, but one particular codon cannot be translated into different amino acids.
True
The sequence of DNA bases ultimately determines the sequence of amino acids in a polypeptide.
True
The F pilus is
a protein appendage that attaches the donor to the recipient cell.
Plasmids are
able to replicate independently of the chromosome.
The plasmid is mobilized for transfer when
an endonuclease cleaves it at the origin of replication.
The first step in conjugation is
contact between the donor and recipient.
One bacterial chromosome replicates to become two chromosomes with
each made of one strand of DNA from the original chromosome and one newly synthesized strand.
One advantage of having genetic control mechanisms is
enzymes are only produced when they are needed.
A segment of DNA encoding a protein or an RNA molecule is a ________.
gene
F+ cells
have a plasmid and are donors in conjugation.
Early in the process of DNA replication, the enzyme ______ separates the two strands.
helicase
The two strands of DNA are joined to each other or held together by ______.
hydrogen bonding
Plasmid DNA is transferred
in single-stranded form.
Synthesis of mRNA is
in the 5' to 3' direction with new nucleotides being added to the 3' end of the mRNA molecule.
When a bacterium is grown on glucose only
it must synthesize all the amino acids it needs.
In an inducible operon, when a substrate or inducer is present
it reacts with the repressor and inactivates it.
The letters of an mRNA codon are based on the ______ in the nucleotides of the transcript.
nitrogenous bases
RNA is a chain of ______
nucleotides
Coordinated sets of genes that are regulated as a single unit are referred to as ______.
operons
The specific point on the DNA molecule where replication begins is the ______.
origin of replication
A _______ is the physical expression of the genes present and can change depending upon what genes are turned "on".
phenotype
The three basic parts of a nucleotide are ______.
phosphate, deoxyribose sugar, nitrogenous base
DNA polymerase
requires a template for the synthesis of DNA.
If you find that a particular plasmid has an R factor, the bacteria that has it will be
resistant to antibiotics.
The property of wobble means that ______ mutations result if changes occur in _____ position of some codons.
silent; the third
The F plasmid encodes for
the F pilus
After the transfer of the F plasmid is complete
the F- cell becomes F+
In some degradative pathways, in the absence of an inducer (e.g.: arabinose)
the activator protein can't bind to DNA, and RNA polymerase can't bind to the promoter site.
Two different mechanisms for copying the DNA strands are used because
the strands are oriented in opposite directions.
The process of transcription is similar to
the synthesis of the leading strand during DNA replication.
The main value of bacteria being able to carry out conjugation and other forms of recombination is
they create genetic diversity.
The process of synthesizing RNA from a DNA template is _______.
transcription
Unlike DNA, RNA is usually single-stranded.
True
When an amino acid such as arginine binds to a repressor
the repressor binds to the operator site on the DNA
The processes of transcription and translation differ between bacteria and eukaryotes in the following way.
Bacteria transcribe and translate simultaneously.
On one of the strands of bacterial DNA, the new complementary strand is synthesized discontinuously into small pieces of DNA called ______.
Okazaki fragments
Which of these are base-paired correctly? C - A G - T C - T T - A
T - A
What happens when a hairpin loop forms in mRNA?
The RNA polymerase and the mRNA dissociate from the DNA.
After mRNA is made, what generally occurs?
The mRNA is translated to protein.
Which nitrogenous base is NOT present in RNA?
Thymine
If RNA polymerase was reading a segment of DNA with the sequence AGGCGTA, what order of nucleotides would be added to the mRNA transcript?
UCCGCAU
If one strand of DNA contains the bases ACAGT, what would be the complementary bases on the mRNA strand?
UGUCA
Binding of an activator to the activator binding site on DNA
enhances the ability of RNA polymerase to bind to the promoter site.
A recombinant organism is
one that that contains genes from another organism.
A(n) ______ is a cluster of genes that perform related functions found in ______.
operon, bacteria
Protein synthesis occurs on ______.
ribosomes
The F pilus binds to
specific receptors on the cell wall of the recipient.
A mechanism that blocks transcription
will block the production of mRNA.
