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i.
The flow of genetic information from DNA to protein in eukaryotic cells
is called the central dogma of biology
a. Explain the role of each of the following in protein synthesis in eukaryotic cells
i. RNA polymerase matches with the DNA and carries it
ii. Spliceosomes remove the introns and then splice the exons together
iii. Codons are a triplet genetic code that codes for an amino acid/
messenger RNAs
iv. Ribosomes operate as sites of amino acid synthesis
v. tRNA transfers the amino acids
b. Information flow can be altered by mutation. Describe two different types of
mutations and their effect on protein synthesis
i. A missense mutation changes one nucleotide and results in the creation
of a different amino acid
ii. A silent mutation is a change in one nucleotide, however, it has no effect
on the resulting amino acid
iii. A nonsense mutation is the changing of one nucleotide that changes that
specific codon to mean STOP
iv. Frameshift mutations are caused by the insertion or deletion of a
nucleotide, causing all nucleotides downstream to be grouped
incorrectly, thus changing most, if not all, of the resulting amino acids.
c. Identify two environmental factors that increase the mutation rate in an
organism, and discuss their effect on the genome of the organism
i. Exposure to radiation creates errors in the genetic code
ii. Carcinogens cause the cancer mutation by creating errors in the genetic
code.
ii.
Suppose a gene has the DNA nucleotide sequence
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
C T G G C A T G C T
T C G G A A A
Explain which one of the following mutations would probably
produce the greatest change in the activity of the protein for which this
gene codes and justify your answer.
a)
b)
c)
d)
Substitution of A for G in 3
Deletion of C at 5
Deletion of A at 15
Addition of G between 14 and 15
The deletion of C at position 5 is the most damaging because it causes a change in each amino
acid that follows position 5. This frameshift mutation would cause a significant change in the
resulting protein.
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