A Model Med Exam for CLS 232
1) Which of the following is an amino acid that is found in proteins?
(d) linoleic acid
2) Prosthetic groups are:
(a) required by all enzymes in the cell
(b) loosely bound to enzymes via hydrogen bonds
(c) sites on the enzyme molecule that permit allosteric modification of enzyme activity
(d) linked to phosphate groups
(e) tightly bound to enzymes and are required for their activity
3) In a double stranded molecule of DNA, the ratio of purines : pyrimidines is:
(b) determined by the base sequence in RNA
(c) genetically determined
(d) always 1:1
(e) determined by the number of purines in the sense strand of the DNA
4) Which of the following nucleotide bases is not found in RNA?
5) Which of the following molecules does not form part of DNA?
(d) amino acid
6) The transcription of DNA to a molecule of messenger RNA occurs:
(a) on the ribosomes
(b) in the cytosol
(c) in the nucleus
(d) only during cell division
(e) when amino acids are made available by transfer RNA
7) The process of translation requires the presence of:
(a) mRNA, tRNA and ribosomes
(b) mRNA, ribosomes and RNA polymerase
(c) DNA, mRNA and RNA polymerase
(d) chromatin, DNA and amino acids
(e) free nucleotide bases, amino acids and ribosomes
8) Codons are composed of:
(a) triplet sequences of nucleotide bases in mRNA
(b) triplet sequences of nucleotide bases in DNA
(c) triplet sequences of amino acids in polypeptide chains
(d) triplet sequences of deoxyribose sugars in DNA
(e) none of the above
9)What type of compounds would be expected to dissolve in water?
10) An example of a disaccharide is …………..
11) Amino acids are classified according to ---------
(a) Their solubility.
(b) Their side chain (R group).
(c) Their sizes.
(d) Their polarity.
12) Which of the following correctly describes the expected products obtained when the polypeptide arg-phe-leu-met-lys is treated as indicated below?
- Treatment with cyanogen bromide yields two products.
- Treatment with Trypsin gives three products.
- Treatment with Phenylisothiocyanate followed by mild acidification yields three products.
- Treatment with Urea gives three products.
13) Which one of the following statements about protein structure is correct?
- Proteins consisting of one polypeptide can have quaternary structure.
- The formation of disulfide bond in a protein requires that the tow participating cysteine residues be adjacent to each other in the primary sequence of the protein.
- The denaturation of proteins always leads to irreversible loss of secondary and tertiary structure.
- The information required for the correct folding of a protein is contained in the specific sequence of amino acids along the polypeptide chain.