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39 Cards in this Set

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what is the name for the portion of a gene that is copied into RNA?
transcription unit
what is the name for the strand of DNA that is identical to the RNA? Complementary to the RNA?
coding strand; non-coding strand
By convention, when the sequence of a gene is recorded, which strand is indicated?
coding strand
the region of RNA that encodes a protein is called what?
coding region
what is the sequence of the start codon? Of the 3 stop codons?
AUG; UAA, UAG, UGA
which protein catalyzes RNA synthesis?
RNA polymerase
what is the composition of the RNA pol core enzyme?
a2bb’
what is the composition of the RNA pol holoenzyme?
a­2bb’σ
is the promoter region located upstream or downstream of coding region?
upstream
what is the name for the first nucleotide in the transcription unit?
transcription start site
what is the position number for the transcription start site?
1
which subunit of the RNA holoenzyme is responsible for recognizing specific sequences in the promoter?
σ
which part of the RNA polymerase protein is responsible for the synthesis of the mRNA chain?
core enzyme (σ falls off following binding of holoenzyme)
None
what catalyzes mRNA elongation?
release of pyrophosphate from the nucleoside triphosphate and hydrolysis of pyrophosphate into inorganic phosphate.
Does RNA polymerase require a primer for mRNA production?
no
what is the term for cluster of adjacent gene coding regions which endode proteins required for a common metabolic process?
operons
do operons produce one or multiple strands of mRNA? What is a term to describe this mRNA?
one; polycistronic
how many genes are encoded in the lac operon?
3
what is the name of the area on the DNA that the repressor binds in situations of no lactose?
operator
how is the operator located in the lac operon in relationship to the promoter?
downstream
what is the name for the gene encoding the lac operon repressor? Is this gene facultatively or constitutively expressed?
I gene; constitutively
what is the term used to refer to the promoter and operator of the lac operon? To the repressor of the operon?
cis-acting sequences; transacting sequence
what is meant by cis-acting in relation to promoter and operator in lac operon?
they must be physically connected to the genes they regulate
what happens to the lac operon repressor in the presence of lactose?
lactose binds the repressor and causes a conformational change which causes repressor-lactose complex to fall off operator sequence.
does glucose trigger or repress production of lactose enzymes?
repress
what is the relationship between cAMP, CAP, and glucose for the lac operon?
in the absense of glucose, levels of cAMP rise. cAMP binds to CAP, and this complex binds, in turn, to the lac promoter just upstream of the RNA polymerase.
what effect does CAP-cAMP binding to promoter have on RNA polymerase activity?
it causes RNA pol to bind more tightly to DNA and allows transcription to initiate more efficiently
what does CAP stand for?
catabolite activator protein
in the presence of glucose and absense of lactose, will the repressor be bound to the operator? Will levels of cAMP be high or low? Will CAP be bound to promoter? Will any transcription of the operon occur?
yes; low; no; no
in the presence of glucose and lactose, will the repressor be bound to the operator? Will levels of cAMP be high or low? Will CAP be bound to promoter? Will any transcription of the operon occur?
no; low; no; yes but at low levels
in the absence of glucose and lactose, will the repressor be bound to the operator? Will levels of cAMP be high or low? Will CAP be bound to promoter? Will any transcription of the operon occur?
yes; high; yes; no because the repressor wins
in the absence of glucose and presence of lactose, will the repressor be bound to the operator? Will levels of cAMP be high or low? Will CAP be bound to promoter? Will any transcription of the operon occur?
no; high; yes; yes, at high levels
what are the three ways in which the RNA transcript is modified post-transcriptionally?
capping, splicing, polyadenylation
following transcription, a poly-A tail is added to which end of the RNA transcript? A cap is added to which end?
3'; 5'
are eukaryotic mRNAs poly- or monocistronic?
monocistronic
which two sites are essential for splicing of the introns?
splice donor site and splice acceptor site
None
what are gene families? Are they always located on the same chromosome?
duplicated genes that are closely related but not identical, and that encode proteins with similar functions; no
are repeats in 'junk' DNA identical in each individual?
no
what is an SNP? How many SNPs are present between pairs of human sequence?
single nucleotide polymorphisms; 1 per 1000 base pairs