1. Protein Synthesis and Central Dogma

All the following statements regarding the nucleic acid DNA are true EXCEPT

• It codes for RNA in mitochondria

• It can be present as a single strand in some viruses

• It is the genetic material of all viruses

• It is found outside of chromosomes in bacteria

• It shows homology in closely related species

Thymine is present in which of the following?

• tRNA

• none of these

• ribosomal RNA

• prokaryotic mRNA

• mammalian mRNA

All the following statements apply to the enzyme DNA polymerase III EXCEPT that

• Four different deoxyribonucleoside 5’-triphosphates are required

• Pyrophosphate is a product of the reaction

• Deoxyribonucleotides are added to a primer chain

• Deoxyribonucleotides are added to the 5’-hydroxyl terminus of preexisting DNA

• Double-stranded DNA may be used as a template

Template-directed DNA synthesis occurs in all the following EXCEPT

• expression of oncogenes

• growth of RNA tumor viruses

• repair of thymine dimers

• the replication fork

So-called caps of RNA molecules

• allow correct translation of prokaryotic mRNA

• are unique to eukaryotic mRNA

• allow tRNA to be processed

• occur at the 3’ end of tRNA

• are composed of poly A tail

The function of factor rho is to

• increase rate of RNA synthesis

• participate in the proper termination of transcription

• eliminate the binding of RNA polymerase to the promoter

• allow proper initiation of transcription

• bind catabolite repressor to the promoter region

Using written convention, which of the following sequences is complementary to TGGCAGCCT?

• AGGCTGCCA

• ACCGUCGGA

• TCCGACGGT

• ACCGTCGGA

• TGGCTCGGA

In contrast to DNA polymerase, RNA polymerase

• synthesizes RNA primer to initiate DNA synthesis

• fills in the gap between Okazaki fragments

• adds nucleoside monophosphates to the growing polynucleotides.

• edits as it synthesizes

• works only in a 5’ to 3’ direction

Sickle cell anemia is the clinical manifestation of homozygous genes for an abnormal hemoglobin molecule. The mutational event responsible for the mutation in the beta-chain is

• nondisjunction

• deletion

• crossing over

• point mutation

• insertion

Owing to “wobble”, which of the following occurs?

• Certain anticodons pair with codons differing at the 3’ end.

• Strict Watson-Crick base-pairing of codons and anticodons occurs.

• Lysogenic virus can become virulent.

• Certain codons pair with anticodons differing at the 5’ end.

• Errors in transcription occur.