Chapter 15 Flashcards
You are studying a biochemical pathway in the mold Neurospora where enzyme 1 converts the initial substrate into intermediate substrate A; enzyme 2 converts intermediate substrate A into intermediate substrate B; enzyme 3 converts intermediate substrate B into intermediate substrate C; and enzyme 4 converts intermediate substrate C into the end product, an amino acid that is essential for growth. You isolate a mutant that is unable to grow on minimal media. Which data would provide the strongest support for the hypothesis that this mutation occurred in the gene that codes for enzyme 2?
A. The mold can grow on rich medium plus intermediate substrate C, but not on rich medium plus intermediate substrate B.
B. The mold can grow on minimal medium plus intermediate substrate B, but not on minimal medium plus the initial substrate.
C. The mold can grow on minimal medium plus intermediate substrate A, but not on minimal medium plus intermediate substrate C.
D. The mold can grow on rich medium plus intermediate substrate D, but not on rich medium plus intermediate substrate C.
E. The mold can grow on minimal medium plus intermediate substrate B, but not on minimal medium plus intermediate substrate A.
E. The mold can grow on minimal medium plus intermediate substrate B, but not on minimal medium plus intermediate substrate A.
If part of a DNA template strand is the sequence GTTAGTCTGTGGGCT, then the DNA coding strand has the sequence
CAATCAGACACCCGA.
what best describes translation?
RNA -> Protein
The amino acid sequence corresponding to the DNA template sequence of GTTAGTCTGTGGGCT is
gln-ser-asp-thr-arg.
Why is RNA synthesis called ‘transcription’ and protein synthesis called ‘translation?’
RNA synthesis makes a complementary copy of the DNA using nucleic acid and protein synthesis uses the information in the RNA to make a different type of molecule.
Translation is the synthesis of
proteins from mRNA
The Rho protein is involved in the _________ stage of transcription.
termination
The complementary messenger RNA strand that would be synthesized from the DNA template sequence of 5’ CTGAC 3’ would be…
3’ GACUG 5’
You are studying a eukaryotic gene that codes for the alpha-subunit in hemoglobin. What is the most likely result if base substitutions occur in the first nucleotide at the 5’ end of an intron and also in the last nucleotide of that intron at the 3’ end?
This intron will not be removed during pre-mRNA splicing because the spliceosome will not recognize the intron-exon junctions.
A mutation has occurred such that a snRNP cannot recognize the 5’ splice site of an intron. What is the most likely effect that this mutation will have on the resulting protein?
The final protein will be longer than normal and non-functional.
What do snRNPs bind to?
5’ and 3’ ends of the intron
what are statements that are true for RNA splicing?
It removes the introns, It is performed by the spliceosome, It shortens the RNA molecule, It always occurs in the nucleus
The segment of the DNA molecule where messenger RNA synthesis begins is called the
The assembly of transcription factors begins
upstream from the transcription start site.
Accurate inhabitation of transcription requires two sites in DNA what are they?
promoter and a start site
