MMSC 491 Quiz 1-4 with Correct Answer

MMSC 491 Quiz 1-4 with Correct 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? - ANSWER-Guanine and Uracil Regarding the structure of bases in nucleic acids, which, if any, of the following statements is incorrect? - ANSWER-Purines carry an amino group, unlike pyrimidines True facts were: -Pyrimidines have a single heterocylic ring consisting of four carbon atoms plus two nitrogen atoms that are linked to the same carbonyl (-C=O) group -Purines have two heterocyclic rings, each with two nitrogen atoms -Thymine = 5-methyluracil. Copyright ©EMILLYCHARLOTE 2025 ACADEMIC YEAR, ALL RIGHTS RESERVED. Page 2/23 Regarding the sugar residues in nucleic acids, which, if any, of the following statements is incorrect? - ANSWER-The internal sugar residues in a DNA strand normally have free hydroxyl groups, unlike those in an RNA strand. Things that were correct: -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 atom. -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. Regarding DNA replication, which, if any, of the following statements is incorrect? - ANSWER-DNA replication is said to be semi-conservative because for each DNA helix only one strand serves as a template for new DNA synthesis. Copyright ©EMILLYCHARLOTE 2025 ACADEMIC YEAR, ALL RIGHTS RESERVED. Page 3/23 Correct facts: -The two DNA strands of the parental DNA helix are unwound using a DNA helicase. -The replication fork marks the point at which DNA is actively being replicated from a single DNA duplex to form new DNA strands. -The synthesis of new DNA strands always proceeds in the 5? ? 3? direction. Regarding DNA replication and DNA synthesis, which, if any, of the following statements is incorrect? - ANSWER-A DNA polymerase always requires a DNA template to synthesize a complementary DNA. Correct Facts: -The leading strand is replicated continuously. -The lagging strand is replicated discontinuously: the new DNA is synthesized as short pieces of DNA that must be ligated together. Copyright ©EMILLYCHARLOTE 2025 ACADEMIC YEAR, ALL RIGHTS RESERVED. Page 4/23 -A DNA polymerase requires a short RNA primer when synthesizing new DNA strands using a DNA template. Which is the best definition of noncoding RNA? - ANSWER-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. - ANSWER- 2n chromosomes, DNA content of 2C in G1; 2n chromosomes, DNA content of 4C in G2.` Regarding the cell cycle, which, if any, of the following statements is correct? - ANSWER-The M phase is the only phase in the cell cycle when chromosomes stained with chemical dyes are visible under the light microscope. Which of the following statements is incorrect? - ANSWER-The only structural difference between DNA and RNA strands is that they have different sugars, respectively deoxyribose and ribo