Amino acids, mutations, and western blots Flashcards
How do peptide bonds form between amino acids?
Through hydrolysis, the bond occurs between COO and NH3
Peptide bonds between amino acids form what?
Proteins
Do proteins have directionality? If so, how?
Yes, they have a N terminal (amino NH3) end and C terminal (COO ) end
What changes among amino acids structures? What consistent? Draw it
The carbon end COO and the amine end H3N are consistent, the R group changes among amino acids
The genetic code is degenerate, what does that mean?
Means that multiple codons, code for the same thing
How is the genetic codes degeneracy helping to buffer against mutations?
They buffer against transition SNPS, as CAU and CAC differ by one amino acid, but code for the same thing so if the T went to G in the original code it would still be fine
What is the start codon?
AUG
What defines the reading frame?
start codon
Which terminal end is made first of proteins? Which is made last?
N terminal end made first, C terminal end made last
How do amino acids get put together from mrna?
Trna
What is the anticodon loop?
Is a loop in tRNA molecule which is complimentary to the mRNA, it recognizes a specific amino acid
Where is the amino acid attached on the tRNA mlcl?
The 3’ end
What is a charged tRNA?
A tRNA molecule that has the correct amino acid, (corresponding to the mRNA) attached
What enzyme attached the amino acid to the tRNA?
the enzyme aminoacyl-tRNA synthetase
What brings together the charged tRNA and mRNA?
ribosomes
What are ribosomes made of? What do they look like structurally?
Made of 1/3 protein, and 2/d rRNA, contain a large and small subunit
Ribosomes move across mRNA in what direction?
5’ to 3’
What combines the amino acids brought in by the charged tRNA into peptides?
Peptidyl-transferase center
What is the Shine-Dalgarno Sequence?
is a sequence in mRNA and that is recognized by rRNA in the small subunit of the ribosome, it helps position ribosomes upstream of the start codon
What is the Kozak sequence?
does same function as shine dalgarno, but in eukaryotes
SNPS in exons result in which 4 different outcomes?
NO mutation
silent mutations
missense mutation
nonsense mutations
What is a silent mutation?
get same amino acid after change in nucleotide
What is a missense mutation?
get chemically similar or different (nonconservative) amino acid
whats a nonense mutation?
get a stop codon
When can a silent mutation is have phenotypic effects?
Say the nucleotide changes which effects stability of mRNA and then causes less expressivity
or it can be near the end of an exon which might interfere with splicing
What is Western blotting used for?
Used to detect a particular protein from a mixture of protein
* Can also determine the size of the protein and level of protein expression
What gel are western blots done?
polyacrylamide gel
How does western blotting work?
we boil samples and then add detergent to separate the proteins by size
then we use probes which bind to our proteins of interest to visualize them in gel
what are the probes in western blotting? describe the structure of them and how they help to visualize proteins
these are antibodies that recognize specific proteins and bind to them (the primary antibody binds) and the antibody with the fluorescent label (called the secondary antibody) makes it so you can see it in the gel
Say we have a STR in one gene will travel farther or shorter distance than the WT gene?
shorter
Say we have a higher expression in one gene, what will it look like in the western blot?
it’ll be bigger as more of the proteins are being made
