BCH441 CH. 10 EXAM QUESTIONS AND ANSWERS WITH
COMPLETE SOLUTIONS
information transfer in cells
-dna to rna to protein
-dna gets replicated - dna replication yields two dna molecules identical to the original
one, ensuring transmission of genetic information to daughter cells with exceptional
fidelity
-transcription: the sequence of bases in dna is encoded as a sequence of
complementary bases in a single stranded mRNA molecule
-translation - three-base codons on the mRNA corresponding to specific amino acids
direct the sequence of building a protein. these codons are recognized by tRNAs
carrying the appropriate amino acids. ribosomes are the "machinery" for protein
synthesis
-"central dogma" - francis crick
purines
-larger bases, 2 rings
-adenine, guanine
pyrimidines
-smaller bases
-double bond is conserved, with an N at bottom and 2 bonds over
-cytosine, uracil, thymine
other naturally occuring purine derivatives
, -hypoxanthine, xanthine, uric acid
nucleosides
-compounds formed when a base is linked to a sugar. the sugars are pentoses
-d-ribose in RNA
-2 deoxy d ribose in RNA
-the difference is 2'-OH vs 2'-H
-this difference changes everything
the common ribonucleosides
-cytidine, uridine, adenosine, guanosine
nucleoside facts
-base is linked via a glycosidic bond (beta-up)
-uses c1 for the glycosidic bond
-named by adding -idine to the root name of a pyrimidine or -osine to the root name of a
purine
-condormation can be syn or anti
-sugars make nucleosides more water-soluble than free bases
-rotation around the glycosidic bond is sterically hindered
nucleotides
=nucleoside+phosphate
-AMP, GMP, CMP, UMP
-help solubility of nitrogenous bases
-robose and phosphate are hydrophilic, bases are mostly hydrophobic
functions of nucleotides
COMPLETE SOLUTIONS
information transfer in cells
-dna to rna to protein
-dna gets replicated - dna replication yields two dna molecules identical to the original
one, ensuring transmission of genetic information to daughter cells with exceptional
fidelity
-transcription: the sequence of bases in dna is encoded as a sequence of
complementary bases in a single stranded mRNA molecule
-translation - three-base codons on the mRNA corresponding to specific amino acids
direct the sequence of building a protein. these codons are recognized by tRNAs
carrying the appropriate amino acids. ribosomes are the "machinery" for protein
synthesis
-"central dogma" - francis crick
purines
-larger bases, 2 rings
-adenine, guanine
pyrimidines
-smaller bases
-double bond is conserved, with an N at bottom and 2 bonds over
-cytosine, uracil, thymine
other naturally occuring purine derivatives
, -hypoxanthine, xanthine, uric acid
nucleosides
-compounds formed when a base is linked to a sugar. the sugars are pentoses
-d-ribose in RNA
-2 deoxy d ribose in RNA
-the difference is 2'-OH vs 2'-H
-this difference changes everything
the common ribonucleosides
-cytidine, uridine, adenosine, guanosine
nucleoside facts
-base is linked via a glycosidic bond (beta-up)
-uses c1 for the glycosidic bond
-named by adding -idine to the root name of a pyrimidine or -osine to the root name of a
purine
-condormation can be syn or anti
-sugars make nucleosides more water-soluble than free bases
-rotation around the glycosidic bond is sterically hindered
nucleotides
=nucleoside+phosphate
-AMP, GMP, CMP, UMP
-help solubility of nitrogenous bases
-robose and phosphate are hydrophilic, bases are mostly hydrophobic
functions of nucleotides
