AP Bio - Unit 6
what is gene transcription?
copying the DNA code into RNA format
what is gene translation?
copying the RNA code into the language of proteins (polypeptide chain)
in prokaryotes, RNA Polymerase can bind __?
directly to promoter
RNA Polymerase moves __stream?
downstream
what is the E site?
exit site; where discharged tRNAs leave the ribosome
where does gene translation occur?
in the cytoplasm, at ribosome
what are the steps of transcription?
initiation, elongation, termination
what is the difference between introns vs. exons?
introns: intervening sequence; don't code for amino acids exons: expressed sections; DO code for amino acids
how does a cat like its steak?
medium-RAWR
what is redundancy within genetic code?
multiple codons can code for the same amino acid
What must eukaryotes do before translation?
must undergo 3 modifications
what does no ambiguity mean?
no codon can code for multiple amino acids
where does gene transcription occur in eukaryotes?
nucleus
amino acids are linked by
peptide bonds
in eukaryotes, RNA Polymerase transcribes a sequence of DNA called the ___
polyadenylation sequence
what is the P site?
polypeptide site; holds the tRNA that carries the growing polypeptide chain
what is 5' cap?
receives a modified guanine nucleotide "cap"
where does translation occur?
ribosome
what does transfer RNA (tRNA) do?
tRNA brings amino acids to the ribosome during the synthesis of a polypeptide.
in prokaryotes, transcription proceeds through a ___
termination sequence
what is translation?
the decoding of an mRNA message into a protein to synthesize a polypeptide
what is gene expression?
the process by which DNA directs the synthesis of proteins
translation begins when?
the small ribosomal subunit binds to the mRNA and a charged tRNA binds to the start codon, AUG, on the mRNA
what is an anticodon?
the tRNA complement to the mRNA codon
what are the two stages of gene expression?
transcription and translation
what is transfer RNA (tRNA)?
type of RNA molecule that transfers amino acids to ribosomes during protein synthesis
promoter is always __stream
upstream of the gene of interest to be transcribed
how does tRNa attach to mRNA?
via their anticodon
what does gene transcription allow for?
"message" of DNA to be transcribed
what are the base paring rules (RNA)?
A=U C=G
what is the polyadenylation sequence?
AAUAAA
if a DNA template strand read TAC AAT CAG GGC TAA TCA AAC, what would the mRNA read?
AUG UUA GUC CCG AUU AGU UUG
if a DNA template strand read CCA TAA ATA GAA CAT TTC GTA, what would the tRNA anticodon read?
CCA UAA AUA GAA CAU UUC GUA
what is messenger RNA (mRNA)?
Carries information coding for protein synthesis from DNA to the ribosomes of the cell
what are the three key RNA molecules?
Messenger RNA (mRNA) Ribosomal RNA (rRNA) Transfer RNA (tRNA)
the tRNA carries what?
Methionine
why did the chicken cross the road?
To get to the other side
what is poly-A tail?
a sequence of 50-250 adenine nucleotides added onto the 3' end of a pre-mRNA molecule
what is a codon?
a sequence of three nucleotides that together form a unit of genetic code in a DNA or RNA molecule.
a nucleotide sequence in translation becomes a ___ sequence
amino acid
proteins are made up of
amino acids
what is the A site?
aminoacyl site; holds next tRNA carrying an amino acid
what enzyme is responsible for attaching amino acids to tRNA?
aminoacyl-tRNA synthetase
tRNA has an ______ region which is complementary and ______ to mRNA
anticodon; antiparallel
what to the 5' cap and poly-A tail function to?
- protect mRNA from degredation - help ribosomes attach to 5' end - mature mRNA to leave nucleus
how many stop codons are there?
3 (UAA, UAG, UGA)
what are the three modifications that must occur to eukaryotic pre-mRNA before translation?
5' cap poly-A tail RNA splicing
how many codon combos code for amino acids?
61
how many different codon combinations are there?
64
what 3 sites do large ribosomal subunits have?
A site, P site, E site
What is the promoter region?
A specific sequence of DNA bases at the start of a gene on the sense strand where RNA polymerase binds.
if a DNA coding strand read CCG GAC CGA AAA ATC TTA GAT, what would the DNA template strand read?
GGC CTG GCT TTT TAG AAT CTA
Does transcription require a primer?
No, RNA polymerase starts it
what happens in elongation?
RNA Polymerase opens the DNA and reads the triplet code of the template strand
What is elongation in transcription?
RNA nucleotides are added to the 3' end of the new RNA (moves 3' to 5')
what is initiation in transcription?
RNA polymerase attaches to the DNA on the promoter region
what is termination in transcription?
RNA polymerase stops transcription when it encounters terminators in the DNA sequence
what is RNA splicing?
RNA splicing: sequences called introns are cut out, sequences called exons are kept and and spliced (joined) together.
what is ribosomal RNA (rRNA)?
RNA that becomes part of ribosomes (the main component of ribosomes) and catalyzes the bonding of amino acids
what is the promoter region in DNA called?
TATA box
