ASCP Molecular Biology Certification Exam | 321 Questions with 100% correct answers | Verified

Pyrimidine - One carbon ring Cytosine, Thymine, Uracil Purine - Two carbon rings Adenine, Guanine How are nucleotides joined together? - Condensation to form phosphodiester bond What is the function of mRNA? - Carries genetic info out of nucleus Transcript translated to protein What is the function of tRNA? - Carries aa to ribosome Anticodon pairs with codon on mRNA strand What is the function of rRNA? - part of ribosome structure most abundant RNA coordinated coupling of tRNA to mRNA codons Feedback inhibition - Product of pathway is noncompetitive inhibitor Binds to allosteric site to slow down rxn b/c too much product Exonucleases - Degrades nucleic acids by removing one terminal nt at a time Cleaves phosphodiester bond at end of chain 5' --> 3' and 3' --> 5'Endonucleases (Prok) - Restriction enzymes Cleaves phoshpodiester bonds w/i poly-nt chain Recognition site is palindromic sequence Types I-V ORI sites - nt sequence where replication is initiated Topoisomerase I - Induces ss breaks Remove DNA supercoils during TXN and DNA replication; for strand breakage during recombination; for chr condensation; and to disentangle intertwined DNA during mitosis topoisomerase II - cuts both strands of one DNA double helix, passes another unbroken DNA helix through it, and then reanneals the cut strands Gyrase (topoisomerase II) - Unwinds supercoiling caused by unwinding at the rep fork by introducing DSBs Helicase - Breaks H-bonds of double helix at the replication fork Primase - DNApol α (DNA dep RNA pol) adds short segments of complementary RNA to ssDNA template (primers), serves as starting points for replication single-strand DNA binding proteins (SSBPs) - Binds ssDNA and prevents it from re-annealing during TXN, replication, repair, and recombination