MB (ASCP) Review & Exam Questions Part I Already Passed

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MB (ASCP) Review & Exam Questions Part I Already Passed Which bases are purines? Which bases are pyrimidines? Adenine (A) and Guanine (G) are purines Cytosine (C) and Thymine (T) / Uracil (U) are ... pyrimidines What kind of structure do purines have? What kind of structure do pyrimidines have? purines have a double ring structure pyrimidines have a single ring structure The phosphate group in a nucleotide is expected to be found on which position of the sugar? 5th carbon The nitrogen base in a nucleotide is expected to be found on which position of the sugar? 1st carbon What is the sugar in DNA? What is the sugar in RNA? deoxyribose in DNA ribose in RNA Which nucleotides pair with each other? Guanine (G) and Cytosine (c) pair together Adenine (A) and Thymine (T) / Uracil (U) pair together Where do you find hydrogen bonds? they form between nucleotides on different strands A forms two bonds with T / U C forms three bonds with G Where do you find phosphodiester bonds? they form the backbone of DNA. There is a linkage between the 3' carbon of one sugar molecule and the 5' carbon atom of another Where do you find ionic bonds? they form the bond between DNA and histones. DNA is negatively charged and histones are positively charged Where do you find glycosidic bonds? they form the bond between the nitrogenous base and ribose sugar group in RNA What happens in a missense mutation? the altered codon now corresponds to a different amino acid. As a result an incorrect amino acid is inserted into the protein being synthesized What happens in a nonsense mutation? instead of tagging an amino acid, the altered codon signals for transcription to stop. Thus a shorter mRNA strand is produced and the resulting protein is truncated or nonfunctional 00:1301:24 What happens in a silent mutation? Since a few different codons can correspond to the same amino acid, sometimes a base substitution does not affect which amino acid is picked. Everything remains the same in the resulting protein and the mutation would go undetected, or remain silent. What happens in a frameshift mutation? Sometimes a nucleotide is inserted or deleted from a DNA sequence during replication. Or, a small stretch of DNA is duplicated. Since a continuous group of three nucleotides forms a codon, an insertion, deletion or duplication changes which three nucleotides are grouped together and read as a codon. In essence it shifts the reading frame. Frameshift mutations ca [Show More]

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