Nap attack 2

Question 1

regions of a protein more intimately associated with a proteins function show ________

Answer 1

a higher degree of sequence conservation

- though 25% of proteins have amino acid sequence variants

Question 2

polymorphic protein

Answer 2

a certain amount of variation,

Question 3

For polymorphic regions with a lot of diversity you can ________

Answer 3

more easily fuck with the amino acid sequence

Question 4

degeneracy of the genetic code

Answer 4

that most amino acids have multiple codons

Question 5

Open reading frame

Answer 5

A reading frame that codes for a protein

Question 6

With U in the middle of a codon

Answer 6

all amino acids are hydrophobic

Question 7

If you want to study human genes in bacteria

Answer 7

optimize codon because particular organisms have preferential codon usage

Question 8

trna molecules

Answer 8

serve as adaptors, read the codons of mRNA

• codon to anticodon base pairings bring in appropriate , activated amino acid
• reduced stringency for bonding of first position of anti-codon and third position of codon

Question 9

Wobble hypothesis

Answer 9

first two mRNA bases of the codon form strong W-C bonds with the corresponding bases of the anticodon(confers most of specificity)

• the first base of the anticodon determines the number of codons recognized by the tRNA
• when first base(anti-codon) is C or A base pairing is specific
• when first base is U or G bparing less specific, two different codons may be read
• inosine as first base means three different codons can be recognized
• codons that differ in either of the first two bases require different tRNA’s

Question 10

how many tRNA’s

Answer 10

minimum 32, 31 for codons and 1 for initiation

Question 11

conservative substitutions usually happen when

Answer 11

Theres a change in the sequence in the first position of the codon, (third of anti codon)

Question 12

frozen accident

Answer 12

accident in the sense that the natural genetic code was randomly selected w/ minor optimizations early in evolution
frozen in the sense that once adopted, no further changes to the code could be tolerated as they would introduce changes to every single protein

Question 13

the natural genetic code prioritizes

Answer 13

• error tolerance over information density
  
  • maintains polarity of amino acids
  • did not score that well in terms of maintaining electric charge

Question 14

What happens to introns

Answer 14

they are transcribed into RNA, and enzymatically excised from the resulting transcript, exons spliced together to make mature mRNA (splicing cleavage and polyadenylation goes on)

Question 15

alternative splicing can lead to

Answer 15

truncated proteins, proteins w/ different strectches of amino acids, frame shifts (large part of protein sequence different from in frame reading)