MMSC491 Exam 1 QUESTIONS WITH ANSWERS

MMSC491 Exam 1 QUESTIONS WITH |\ |\ |\ |\ |\




ANSWERS


In a DNA double helix each type of base forms a stable base pair
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\


with only one type of base. When bases on an RNA strand are
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\


involved in base pairing, which bases can form stable base pairs
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\


with more than one type of base?
|\ |\ |\ |\ |\ |\




Adenine and uracil |\ |\




cytosine and uracil |\ |\




guanine and uracil |\ |\




uracil - CORRECT ANSWERS ✔✔guanine and uracil
|\ |\ |\ |\ |\ |\




Regarding the structure of bases in nucleic acids, which, if any, of
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\


the following statements is incorrect?
|\ |\ |\ |\ |\




Pyrimidines have a single heterocyclic ring consisting of four
|\ |\ |\ |\ |\ |\ |\ |\ |\


carbon atoms plus two nitrogen atoms that are linked to the
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\


same carbonyl group |\ |\




Purines have two heterocyclic rings, each with two nitrogen
|\ |\ |\ |\ |\ |\ |\ |\ |\


atoms

,thymine = 5-methyluracil |\ |\




pruines carry an amino group, unlike pyrimidines - CORRECT
|\ |\ |\ |\ |\ |\ |\ |\ |\


ANSWERS ✔✔purines carry an amino group, unlike pyrimidines
|\ |\ |\ |\ |\ |\ |\




Regarding the sugar residues in nucleic acids, which, if any, of
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\


the following statements is incorrect?
|\ |\ |\ |\




The sugar is always based on a heterocyclic ring that consists of
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\


one oxygen atom and four carbon atoms, one of which is
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\


connected to a fifth carbon atom, the 5 carbon 5' carbon atom
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\




The internal sugar residues in a DNA strand normally have free
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\


hydroxyl groups, unlike those in an RNA strand.
|\ |\ |\ |\ |\ |\ |\ |\




Bases are covalently linked to the carbon 1' atoms of the sugars.
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\




Neighboring sugar residues are linked to each other by a
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\


phosphodiester bond that connects the 3' carbon atom on one |\ |\ |\ |\ |\ |\ |\ |\ |\ |\


sugar to the 5' carbon atom of its neighbor. - CORRECT ANSWERS
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\


✔✔The internal sugar residues in a DNA strand normally have
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\


free hydroxyl groups, unlike those in an RNA strand.
|\ |\ |\ |\ |\ |\ |\ |\




Regarding the DNA replication, which, if any, of the following
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\


statements is incorrect? |\ |\

,a) DNA replication is said to be semi-conservative because for
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\


each DNA helix only one strand serves as a template for new
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\


DNA synthesis. |\ |\




b) The two DNA strands of the parental DNA helix are unwound
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\


using a DNA helicase. |\ |\ |\ |\




c) The replication fork marks the point at which DNA is actively
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\


being replicated from a single DNA duplex to form new DNA
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\


strands. |\




d) The synthesis of new DNA strands always proceeds in the 5' →
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\


3' direction. - CORRECT ANSWERS ✔✔a) DNA replication is said
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\


to be semi-conservative because for each DNA helix only one
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\


strand serves as a template for new DNA synthesis.
|\ |\ |\ |\ |\ |\ |\ |\




Regarding DNA replication and DNA synthesis, which, if any, of
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\


the following statements is incorrect?
|\ |\ |\ |\ |\




a) The leading strand is replicated continuously.
|\ |\ |\ |\ |\ |\ |\




b) The lagging strand is replicated discontinuously: the new DNA
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\


is synthesized as short pieces of DNA that must be ligated
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\


together. |\




c) A DNA polymerase always requires a DNA template to
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\


synthesize a complementary DNA. |\ |\ |\ |\

, d) A DNA polymerase requires a short RNA primer when
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\


synthesizing new DNA strands using a DNA template. - CORRECT |\ |\ |\ |\ |\ |\ |\ |\ |\ |\


ANSWERS ✔✔c) A DNA polymerase always requires a DNA |\ |\ |\ |\ |\ |\ |\ |\ |\


template to synthesize a complementary DNA. |\ |\ |\ |\ |\




Which is the best definition of noncoding RNA?
|\ |\ |\ |\ |\ |\ |\ |\




a) A mutant mRNA that is not capable of making a protein.
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\




b) Any RNA sequence that is not translated to make a protein
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\




c) Any RNA sequence in an mRNA, or in the primary transcript
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\


used to make the mRNA, that is not translated to make a protein.
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
|\




d) A functional RNA that is not translated to make a protein. -
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\


CORRECT ANSWERS ✔✔d) A functional RNA that is not translated
|\ |\ |\ |\ |\ |\ |\ |\ |\


to make a protein.
|\ |\ |\ |\




If we take the number of chromosomes in a haploid sperm cell or
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\


egg cell to be n and the total content of genomic DNA to be C,
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\


what is the number of chromosomes and the total genomic DNA
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\


content of a diploid G1 phase cell and in a diploid G2 phase cell
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\


from the same organism. |\ |\ |\ |\




a) n chromosomes, DNA content of 2C in G1; 2n chromosomes,
|\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\


DNA content of 4C in G2.
|\ |\ |\ |\ |\ |\