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Genetics Exam #2
Terms in this set (36)
What does it mean when we say that the genetic code is 'degenerate'?
More than one codon encodes for the same amino acid.
The igf2 locus is a classic example of an imprinted gene. This imprint means the gene
is expressed from which parent?
Father or Paternal
What DNA modification is responsible for maintaining this imprint?
_____ seals the nick in the phosphodiester backbone after primers are removed in DNA replication.
_____ and ______ bind to the TATA box found in the _____ to initiate _____
TFIID and TBP bind to the TATA box found in the Core Promoter to initiate Transcription
_____ creates small (~11nt) RNAs that provide a 3'-OH so _____ is able to initiate the synthesis of a new strand of DNA during DNA replication.
Primase creates small RNAs that provide a 3'-OH so DNA Polymerase is able to initiate the synthesis of a new strand of DNA during DNA replication.
_____ relieves torsional strain caused by _____ unwinding DNA's helical structure.
Topoisomerase relieves torsional strain caused by helicase unwinding DNAs helical structure.
_____ uses its 5' -> 3' exonuclease activity to terminate RNA polymerase II transcription.
In a typical eukaryotic cell, approximately how much of the cellular RNAs are ribosomal RNAs?
What characteristic of double-stranded DNA ensures the 'sides' of the 'ladder' remain the same distance apart for the length of the DNA?
Pairing of purines with pyrimidines.
A nucleosome is DNA wrapped around what type of proteins?
The tails of these proteins undergo various modifications that change the way they interact with the DNA that dramatically affects the DNA's
_____ structure. This interaction is mediated by the _____ charge of DNA interacting with the _____ charge of the tails.
tertiary, negative, positive
Which of these modifications is typically associated with an open
chromatin state or active transcription?
Many RNAs, such as tRNAs and rRNAs, fold into complex secondary structures that
often give them their function, Many of the structures take on a 'stem' or 'loop'
formation. Why do these RNAs take on these complex structures (specifically, what
about the RNA makes this happen)?
Complementary binding with itself due to single-strandedness
What two things explain how several different length polypeptides can be encoded
by the same gene?
Alternate splicing and Alternate Cleavage
What part of the tRNA 'reads' the triplet code of an mRNA?
An E. coli strain has a mutation in the regulator protein sequence for its Lac operon that
renders the inducer binding site nonfunctional. How would these cell's Lac operon
expression differ from wild-type cells in the presence of lactose?
They would be incapable of responding to Lactose and would not have expression
from their Lac operon.
What process uses a Kozak sequence?
When a ribosome reads a nonsense codon, what molecule causes the complex to disassociate with the mRNA?
How would you expect the lac operon to behave if the operator sequence in the promoter were mutated where the regulator protein binds?
The operon would be continually expressed.
In the Gal4 system in yeast, the protein GAL4 binds to the UAS stimulating transcription. In this system, the UAS is an
GAL4 is an
DNA methylation is generally associated with what type of DNA?
The antiparallel nature of DNA refers to
the opposite direction of the two strands of nucleotides
The phenomena of early onset and worse prognosis is referred to as
What molecular mechanism is responsible for CAG expansions?
Which process makes production of two functionally and structurally different proteins from the same gene possible?
Alternative RNA processing
Which statement concerning the concept of collinearity is incorrect?
The vast majority of eukaryotic genes follow the concept of collinearity although the size of genes might be larger.
The regulation of the igf2 locus involves methylation of what?
What type of bonds does DNA ligase create between adjacent nucleotides?
Heat can disrupt hydrogen bonding between DNA strands. Which of the following DNA strands would denature at the highest temperature?
10% AT and 90% GC
Small interfering RNA (siRNA) evolved in eukaryotes as a defense mechanism against what?
Double stranded RNA viruses
When siRNA are present, the rate of mRNA degradation _____ and the rate of protein production _____.
Insulators can block the effects of enhancers only when they lie
between an enhancer and a promoter
Telomerase activity is most likely found in which cells in humans?
Germ line cells
Highly condensed DNA bound with histone proteins _____ DNA expression
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