Question

Use the mRNA codon chart to translate this DNA message:

DNA	TAC	TGC	CAC	ATT
mRNA
amino acid

1. List the sequence of amino acids in this chain
2. Suppose the sixth base in the DNA chain was an A instead of a C. How would this affect the protein

            produced?

3. What is the name given to this type of mutation in a protein chain? Explain

Which of the following bird species are most closely related?

       A. Picoides borealis and Phylloscopus borealis

       B. Numenius borealis and Picoides borealis sapiens

      C. Numenius americanus and Grus Americana

      D. Picoides villosus and Picoides borealis

The similarity of the embryos of chickens and humans is evidence of ________.

       A. biochemical similarities

       B. developmental similarities

       C. morphological similarities

       D. biogeography

If the coat of a virus about to attack a bacterium is labeled with radioactive sulfur and the DNA is labeled with

                 radioactive phosphorous, over time

1. both the sulfur and the phosphorous will be found within the bacterium
2. only the sulfur will be found inside the bacterium
3. only the phosphorous will be found inside the bacterium
4. both the sulfur and the phosphorous will be found outside the bacterium

The joining of amino acid 2 to amino acid 3 (letter "D") will be by

a.	an ionic bond.
b.	protein linkage.
c.	a peptide bond.
d.	hydrogen linkage.
e.	a hook.

Answer 1

DNA: TAC TGC CAC ATT mRNA: AUG ACG GUG UAA Amino acid: Met-Thr-Val-STOP

A). The sequence of amino acids in this chain: Methionine – Threonine – Valine.

B). Mutated DNA sequence: TAC TGA CAC ATT. The second triplet will be TGA instead of TGC after mutation. Corresponding codon to TGA is ACU, which also codes for Threonine. So, there will not be any changes in the amino acid sequence due to this mutation.

C). These types of mutations are called Silent mutations. A silent mutation is a change in the sequence of DNA, without a subsequent change in the amino acid sequence or the function of the overall protein. These do not have an observable effect on the organism's phenotype.

D). The similarity of the embryos of chickens and humans is evidence of ________.

Answer: B. developmental similarities

Vertebrate embryos are found to begin developing similar features due to related ancestors. As the embryo grows, it may drop some of their ancestral traits. As it develops, its genetic code becomes more specific for that species and specific characters develop in it.

E) If the coat of a virus about to attack a bacterium is labeled with radioactive sulfur and the DNA is labeled with radioactive phosphorous, over time

Answer: C. only the phosphorous will be found inside the bacterium

When phages infect a host bacterium, the phage coats attach themselves to the membrane of the bacterium and only the DNA of the phage enters the bacterium to subsequently replicate inside the cell.

F) The joining of amino acid 2 to amino acid 3 (letter "D") will be by

Answer: C). A peptide bond.

Amino acids are linked together by formation of peptide bonds to form polypeptides.