BMSC 200 MOD 10 (Nucleic acids)
Exam Questions and Answers
RNA structure - ANSWER-contains ribose
contains uracil instead of thymine
RNA is single stranded but can adopt three dimensional structures
vulnerable to fall apart from hydrolysis
RNA functions (4 types) - ANSWER-rRNA-ribosomal RNA, an integral part of
ribosomes
tRNA-transfer RNA, carry activated amino acids to ribosomes for protein synthesis
(small)
mRNA-messenger RNA, code for proteins, contain triplet codons that specify the
amino acid sequence of a protein
miRNA-microRNA, short oligonucleotides that function in transcriptional and post-
translational regulation of gene expression
double helix - ANSWER-right handed double helix
strands run in opposite directions
complimentary to eachother
sugar-phosphate backbones on outside
nitrogenous bases on inside
base pairs perpendicular to helix axis
match purine with pyrimidine though h-bonds
base pairing - ANSWER-A and T (DNA)
A and U (RNA)
G and C (DNA &RNA)
Chargraff's Rule - ANSWER-amount of adenines = amount of thymines; amount of
guanines = amount of cytosines
guanine and cytosine - ANSWER-3 hydrogen bonds
stronger due to h-bonds and stacking forces
adenine and thymine - ANSWER-2 hydrogen bonds
major and minor grooves - ANSWER-base pairs are exposed and accessible for
interaction with other molecules
restriction endonucleases - ANSWER-an enzyme that cuts DNA at specific sites
bacterial defence mechanism against viral invasion
host cell protects their own DNA through methylation of bases
Exam Questions and Answers
RNA structure - ANSWER-contains ribose
contains uracil instead of thymine
RNA is single stranded but can adopt three dimensional structures
vulnerable to fall apart from hydrolysis
RNA functions (4 types) - ANSWER-rRNA-ribosomal RNA, an integral part of
ribosomes
tRNA-transfer RNA, carry activated amino acids to ribosomes for protein synthesis
(small)
mRNA-messenger RNA, code for proteins, contain triplet codons that specify the
amino acid sequence of a protein
miRNA-microRNA, short oligonucleotides that function in transcriptional and post-
translational regulation of gene expression
double helix - ANSWER-right handed double helix
strands run in opposite directions
complimentary to eachother
sugar-phosphate backbones on outside
nitrogenous bases on inside
base pairs perpendicular to helix axis
match purine with pyrimidine though h-bonds
base pairing - ANSWER-A and T (DNA)
A and U (RNA)
G and C (DNA &RNA)
Chargraff's Rule - ANSWER-amount of adenines = amount of thymines; amount of
guanines = amount of cytosines
guanine and cytosine - ANSWER-3 hydrogen bonds
stronger due to h-bonds and stacking forces
adenine and thymine - ANSWER-2 hydrogen bonds
major and minor grooves - ANSWER-base pairs are exposed and accessible for
interaction with other molecules
restriction endonucleases - ANSWER-an enzyme that cuts DNA at specific sites
bacterial defence mechanism against viral invasion
host cell protects their own DNA through methylation of bases
