BIOCHEM ACS FINAL EXAM SCRIPT 2026
REAL 200 QUESTIONS AND FULL
SOLUTIONS 100% CORRECT
⩥ DNA. Answer: more stable nucleic acid, carrier of genetic
information, double stranded
⩥ RNA. Answer: less stable form of nucleic acid; intermediate in
expression of genetic information, usually single stranded
⩥ tRNA. Answer: transfer RNA, holds amino acids used in protein
synthesis, has wobble position(inosine)
⩥ rRNA. Answer: ribosomal RNA, part of the ribosome
⩥ siRNA. Answer: small interfering RNA, short term silencing of
pleiotrophin coding genes, targets mRNA for degradation
⩥ miRNA. Answer: micro RNA, silencing and post-transcriptional
regulation of gene expression
⩥ adenine and guanine. Answer: what are the two nitrogenous bases that
are purines
,⩥ purines. Answer: Bases with a double-ring structure.
(pyrimidine and imidazole ring)
⩥ pyrimidine. Answer: single-ring nitrogenous base
⩥ cytosine, thymine, uracil. Answer: what nitrogenous bases are
pyrimidines
⩥ -A-T has 2 H bonds
-G-C has 3 H bonds. Answer: how many H bonds are their between A-
T/U? what about G-C?
⩥ GC rich DNA because it had 3 H bonds. Answer: which has a higher
melting point GC rich DNA or AT rich DNA and why?
⩥ B DNA. Answer: type of DNA; 0.34 nm between bp, 3.4 nm per turn,
about 10 bp per turn; right handed helix, the bases are stacked parallel
and bases are facing each other at the same level making it have aa high
H-bonding
⩥ A DNA. Answer: type of DNA; Cylindrical CORE. 11bp per turn.
forms when DNA is dehydrated, more tightly wound than B DNA(right
handed helix). The bases are not parallel but at an angle (this angle gives
, it a less strong H-bonding making A conformation less stable than B
DNA)
⩥ Z DNA. Answer: type of DNA; 2 bp per turn. No grooves, left handed
helix, occurs in G/C rich regions
⩥ restriction endonucleases (REN). Answer: enzymes that recognize
specific sequences of nucleotides and cleave strands of DNA into
fragments wherever those sequences occur
⩥ dideoxy sequencing. Answer: a method of DNA sequencing that uses
dideoxyribonucleotides to terminate the growth of DNA strands; , DNA
polymerase will stop when ddNTPs are incorporated onto the DNA
strand. ddNTPs are color labeled for different bases. (ex: ddGTP is
yellow). Determines the nucleotide sequence (A,T,G,C) in one strand
⩥ PCR. Answer: -separates strands by denaturing at 95 C
-anneal primers 65 deg C
-extend primers w/ Taq polymerase
-generates millions of copies of DNA
⩥ helicase. Answer: protein that catalyzes the ATP-dependent unwinding
of DNA double helices
REAL 200 QUESTIONS AND FULL
SOLUTIONS 100% CORRECT
⩥ DNA. Answer: more stable nucleic acid, carrier of genetic
information, double stranded
⩥ RNA. Answer: less stable form of nucleic acid; intermediate in
expression of genetic information, usually single stranded
⩥ tRNA. Answer: transfer RNA, holds amino acids used in protein
synthesis, has wobble position(inosine)
⩥ rRNA. Answer: ribosomal RNA, part of the ribosome
⩥ siRNA. Answer: small interfering RNA, short term silencing of
pleiotrophin coding genes, targets mRNA for degradation
⩥ miRNA. Answer: micro RNA, silencing and post-transcriptional
regulation of gene expression
⩥ adenine and guanine. Answer: what are the two nitrogenous bases that
are purines
,⩥ purines. Answer: Bases with a double-ring structure.
(pyrimidine and imidazole ring)
⩥ pyrimidine. Answer: single-ring nitrogenous base
⩥ cytosine, thymine, uracil. Answer: what nitrogenous bases are
pyrimidines
⩥ -A-T has 2 H bonds
-G-C has 3 H bonds. Answer: how many H bonds are their between A-
T/U? what about G-C?
⩥ GC rich DNA because it had 3 H bonds. Answer: which has a higher
melting point GC rich DNA or AT rich DNA and why?
⩥ B DNA. Answer: type of DNA; 0.34 nm between bp, 3.4 nm per turn,
about 10 bp per turn; right handed helix, the bases are stacked parallel
and bases are facing each other at the same level making it have aa high
H-bonding
⩥ A DNA. Answer: type of DNA; Cylindrical CORE. 11bp per turn.
forms when DNA is dehydrated, more tightly wound than B DNA(right
handed helix). The bases are not parallel but at an angle (this angle gives
, it a less strong H-bonding making A conformation less stable than B
DNA)
⩥ Z DNA. Answer: type of DNA; 2 bp per turn. No grooves, left handed
helix, occurs in G/C rich regions
⩥ restriction endonucleases (REN). Answer: enzymes that recognize
specific sequences of nucleotides and cleave strands of DNA into
fragments wherever those sequences occur
⩥ dideoxy sequencing. Answer: a method of DNA sequencing that uses
dideoxyribonucleotides to terminate the growth of DNA strands; , DNA
polymerase will stop when ddNTPs are incorporated onto the DNA
strand. ddNTPs are color labeled for different bases. (ex: ddGTP is
yellow). Determines the nucleotide sequence (A,T,G,C) in one strand
⩥ PCR. Answer: -separates strands by denaturing at 95 C
-anneal primers 65 deg C
-extend primers w/ Taq polymerase
-generates millions of copies of DNA
⩥ helicase. Answer: protein that catalyzes the ATP-dependent unwinding
of DNA double helices
