Ch 14: Gene Expression Flashcards
Which of the following is a stop codon?
UGA
Which of the following is not a post-translational modification that might be required of a protein before it becomes functional in a cell?
All of the listed responses are post-translational modifications required of some proteins.
Which binding site on a ribosome holds a tRNA attached to a growing polypeptide chain?
P site
Which of the following is true of RNA processing?
Assemblies of protein and small RNAs, called spliceosomes, may catalyze splicing.
The type of mutation responsible for sickle-cell anemia is __________.
both a point mutation and a nucleotide-pair substitution
Which of the following is not transcribed from DNA?
Promoter
Which of the following is true of transcription factors?
All of the listed responses are correct.
A nucleotide deletion early in the coding sequence of a gene would most likely result in __________.
All of the listed choices are correct.
Transcription involves the transfer of information from __________.
DNA to RNA
Transfer RNA binds to what?
its specific amino acid in the active site of an aminoacyl-tRNA synthetase
A stretch of bacterial DNA 600 nucleotides long can code at most for a polypeptide of how many amino acids?
200
RNA polymerase moves along which strand of DNA and elongates RNA in which direction?
moves along the template strand of DNA, elongating an RNA molecule in a 5′ → 3′ direction
A ribozyme is __________.
an RNA molecule that functions as an enzyme
A series of studies on mutants of Neurospora identified three classes of mutants that needed arginine added to minimal media in order to grow. The production of arginine includes the following steps: precursor → ornithine → citrulline → arginine. What nutrient(s) have to be supplied to the mutants that had a defective enzyme for the ornithine → citrulline step in order to grow?
Citrulline
Which of the following is not part of the translation initiation complex?
TATA box
A signal peptide is __________.
the first 20 or so amino acids of a protein destined for a membrane location or for secretion from the cell
How is the template strand for a particular gene determined?
It is established by the presence of the promoter.
If the 5′ → 3′ nucleotide sequence on the nontemplate DNA strand is CAT, what is the corresponding codon on mRNA?
CAU
Which enzyme synthesizes tRNA?
RNA polymerase
The energy required for assembly of a polypeptide by a ribosome comes directly from __________.
GTP
There are how many types of bacterial RNA polymerase?
One
Which of the following is transcribed and then translated to form a protein product?
A gene for a transcription factor
Which of the following is not involved in the formation of a eukaryotic transcription initiation complex?
Small RNA molecules
Which of the following would not be found in a bacterial cell?
Small RNAs in spliceosome
Which of the following individuals was the first to suggest that genes dictate phenotypes through enzymes?
Archibald Garrod
Holds the tRNA that carries the growing
polypeptide chain
P site
The three stages of translation
- Initiation
- Elongation
- Termination
elongation factors occurs in what three steps:
codon recognition, peptide
bond formation, and translocation
Polypeptides destined for the ER or for secretion are
marked by a _______, which targets the protein to
the ER
signal peptide
Binds to the signal
peptide
signal-recognition particle (SRP)
Holds the tRNA that carries the next amino
acid to be added to the chain
A site
The exit site, where discharged tRNA’s
leave the ribosome
E site
Can eukaryotes use coupled transcription and translation at the same time? Why or Why not?
No. Because eukaryotes have transcription happen in the nucleus and translation happens in the cytoplasm
Changes in the genetic material of a cell
Mutations
Are frame shift or point mutations worse?
Frame shift mutations
Chemical changes in just one
nucleotide pair of a gene
Point mutations
have no effect on the amino acid
produced by a codon because of redundancy in the
genetic code
Silent mutations
change one amino acid to another
Missense mutations
change an amino acid codon into
a stop codon, nearly always leading to a nonfunctional
protein
Nonsense mutations
an Insertion or deletion of nucleotides that may alter the reading frame of the genetic message (changes the whole thing)
frameshift
mutation
physical or chemical agents that can
cause mutations
Mutagens
– A discrete unit of inheritance
– A region of specific nucleotide sequence in a
chromosome
– A DNA sequence that codes for a specific polypeptide
chain
Gene
an infectious particle consisting of little more
than genes packaged into a protein coat
virus
may consist of either
– Double- or single-stranded DNA, or
– Double- or single-stranded RNA
Viral genomes
a phage replicative cycle that
culminates in the death of the host cell
and produces new phages and lyses (breaks
open) the host’s cell wall, releasing the progeny viruses
lytic cycle
replicates the phage genome
without destroying the host
lysogenic cycle
Phage DNA is often identified as foreign and cut up by ____?
restriction enzymes
system consists of clustered regularly
interspaced short palindromic repeats and nuclease
enzymes called Cas, CRISPR-associated proteins
CRISPR-Cas
the major medical tool for preventing viral
infections, a harmless derivative of a pathogen that
stimulates the immune system to mount defenses against
the harmful pathogen
Vaccines
general outbreak
epidemic
global epidemic
pandemic
Proteins that are known to be
infectious and appear to cause a number of degenerative brain
diseases in various animal species. They can be transmitted in food and act very slowly, with an incubation period of at
least 10 years. They are also virtually indestructable
prions
the study of fossils
Paleontology
a process in which individuals with
favorable inherited traits are more likely to survive and
reproduce
Natural selection
Descent with modification by natural selection explains
three broad observations about nature
- The unity of life
- The diversity of life
- The ways that organisms are suited for life in their
environments
