ACS BIOCHEMISTRY EXAM QUESTIONS AND ANSWERS 2024

ACS BIOCHEMISTRY EXAM QUESTIONS AND ANSWERS 2024 what are nucleotides? nucleotides are the monomer unit for nucleic acids and are composed of nitrogenous bases, 5 carbon sugars and a phosphate group. nucleic acids are bipolymers of _____ nucleotide monomers what is DNA and what is its stability? DNA is more stable than RNA and carries genetic information, and is double stranded. what is RNA and what is its stability? RNA is less stable and is an intermediate in expression of genetic information. RNA can form secondary structure (as in tRNA) by hydrogen bonds with itself. Not all forms of RNA are intermediates for genetic information. RNA is usually single stranded. What are the four different types of RNA? tRNA, rRNA, siRNA, and miRNA tRNA transfer RNA, holds amino acids and used in protein synthesis. rRNA ribosomal RNA, part of the ribosome siRNA small interfering RNA, short term silencing of pleiotrophin coding genes, targets mRNA for degradation. miRNA micro RNA, silencing and post-transcriptional regulation of gene expression. what are the four DNA nitrogenous bases? adenine, cytosine, guanine, and thymine what are purines? Adenine and Guanine what are pyrimidines (one ring)? cytosine, thymine, and uracil (in RNA only) are pyrimidine derivatives in nucleic acids. how many H bonds does A-T-U base pair have? 2 H bonds How many H bonds does a G-C base pair have? 3 H bonds what is Tm? temperature at with 50% of DNA is annealed (recombine DNA in the double-stranded form) does GC rich DNA or AT rich DNA have a higher melting point and why? melting point of GC rich DNA is higher than AT rich DNA because it has more hydrogen bonds. what are the characteristics of B DNA? -0.34 nm between bp -10 bp per turn -right handed helix -bases are stacked parallel and facing each other which makes a high H-bonding. what are the characteristics of A DNA -clyindrical CORE 11 bp per turn. -forms when DNA is dehydrated, more tightly wound than B DNA. -right handed helix. -bases are at an angle, not parallel. -angle gives less strong H-bonding making A conformation less stable than B DNA. What are the characteristics of Z DNA -12 bp per turn -no grooves -left handed helix -occurs in G/C rich regions What is REN manipulation? Restriction Endonuclease Recombination.