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Genetics Exam II
HU: Frankel
Question | Answer (1) | Answer (2) | Answer (3) |
---|---|---|---|
? -> mRNA -> ? | DNA -> mRNA -> polypeptide | central dogma | N/A |
What happens after mRNAs are modified? | they are incapable of pairing w/ anything | N/A | N/A |
capping enzyme | starts a nucleotide triphospate of guanine (GTP) | after methylization it is 7methyl guanosine (7mG) | N/A |
methyl transferases/"transcripts" | take methyl groups from molecules that donate them | takes up S-adenosyl methionine | N/A |
clipping sequence | appears in termination of all sequences recognized by the clipping enzyme ("tail) | N/A | N/A |
Where do caps get methylated? | the 7th point of guanine | N/A | N/A |
What happens when both the cap and the tail are on the mRNA? | degradation is prevented | N/A | N/A |
What base sequence make up the tail? | AAUAAA | N/A | N/A |
Before a capping enzyme is added, what is attached to the 5' side of the mRNA? | triphosphate (ppp) | N/A | N/A |
What is added after the mRNA is "clipped?" | Poly (A) polymerase | N/A | N/A |
primary transcript | precursor "unprocessed" mRNA | turn into mature mRNA once processed | N/A |
In what part of the cell does the primary transcript become processed? | in the nucleus | it travels to the cytoplasm once matured | N/A |
coupling | ribosomes attach and move down the mRNA (w/ amino acids) during translation | when mRNA peels off it is ready for translation | N/A |
post-transcription modification | where primary mRNA is convert to mature mRNA after synthesization | what a eukaryotes mRNA must complete after synthesization | N/A |
polyadenylation | when a Poly (A) tail is added to the 3' end of mRNA | a sequences containing multiple adenosine monophosphates | N/A |
What does Poly (A) polymerase do to the mRNA? | adds the Poly (A) tail | N/A | N/A |
intervening sequences | sequences that come between something | N/A | N/A |
exons | where the sequence makes genetic sense | will remain in the final product of the mRNA | N/A |
introns | important to be in the gene, but are not needed in the messenger | can buffer against random mutations | will be cut out of final product of the mRNA |
heterogeneous nuclear/(hmRNA) | primary transcript mRNA coming off of DNA | N/A | N/A |
? -> mRNA | hmRNA | N/A | N/A |
DNA-RNA hyridization | 1)when you add heat to DNA causing the helix to separate into two strands 2)one strand of the helix attaches to an RNA transcript and is cooled to form a duplex/hybrid | N/A | N/A |
What does a duplex/hybrid identify? | intron and gene location | N/A | N/A |
loops | regions of DNA that has nothing to pair w/, therefore forms a "loop" | contains intron region at its peak | regions that are not complimentary |
small nuclear smRNA | have the responsibility of cutting out introns | only found in eukaryotes (the nucleus) | N/A |
small nuclear ribonucleo proteins/(snRNPs)"snurps" | contain a large amount of uracil | N/A | N/A |
What are the three significant smRNAs containing snRNP? | 1)U1snRNA 2)U2snRNA 3)U5snRNA | N/A | N/A |
U1snRNA | has near perfect complimentation to the 5' splice site | facilitates a cut at the 5' | attaches to the U2 binding side so free ends are not lost |
spliceosome | formed from the excision of an intron | keeps exon ends "in hand" to join them together | N/A |
U2snRNA | allows U1smRNA to attach to it so excisioned ends are not free | N/A | N/A |
lariet model of intron excision | has lariet shape due to the bonding of the U1 excisioned 5' end and the U2 site | N/A | N/A |
U5smRNA | creates 3' splice site | facilitates a cut at the 3' end | has the responsibility of recognizing the 3' site |
What happens when the introns are removed? | the exons are joined | the mRNA is ready for translation | N/A |
B-thalessemia | a blood disorder due to splicing errors | "low hemoglobin levels" | N/A |
Where are the splice sites located? | at the 3' of every exon | at the 5' of every intron | N/A |
cryptic splice sites | when much mutation causes splice mechanism no to see the correct splice site which causes it to make an incorrect cut | N/A | N/A |
What does tRNA do? | brings amino acids to the site of protein synthesis | sequences amino acids in the polypeptide | N/A |
How many types of tRNAs are there and what are their lengths? | approximately 50 | 80-90 nucleotides long | N/A |
tRNA has what kind of sequence? | has inverted repeat sequences | N/A | N/A |
What is formed when strands pair? | "stems" | N/A | N/A |
methylation | are structural changes to the tRNA | establishes the "loop" | N/A |
Where do amino acids get attached to the tRNA and what is this called? | 3' end at ACC | amino acid attachment site | N/A |
How many naturally occuring amino acids exist? | 20 | N/A | N/A |
How many stems and loops does a tRNA form? | 4 "stems," 3 "loops" | N/A | N/A |
What happens when amino acids attach to the tRNA? | the tRNA becomes charged | N/A | N/A |
codons | linear sequence of three nucleotides that code for a given amino acid | will be recognized by an anticodon in the transcript | code for various amino acids |
anticodons | recognizes codons and attaches to them | N/A | N/A |
D-loop | first loop | is the enzyme recognition site | N/A |
anticodon loop | second loop | anticodon recognition site | where anticodons attach to the codons on mRNA |
T-loop | third loop | ribosomal attachment site | N/A |
eukaryotic translation | occurs in cytoplasm, NOT nucleus | has "special separation" after being transcribed | N/A |
steps of mRNA processing | 1)addition of a "cap" to the 5' end 2)addition of a "tail" to the 3' end 3)removal of nucleotides (excision) | N/A | N/A |
Where is GTP added to the mRNA? | backwards to the 5' (3' side) | N/A | N/A |