BIOCHEM C785 Final Exam Latest update With Complete Solution.pdf

BIOCHEM C785 Kaleys Comprehensive Study Guide final Correctly Verified 2022
n n n n n n n n n




• DNA = phosphate + deoxyribose sugar + A/T/C/G
n n n n n n n


o Contains two strands. The strands are antiparallel (opposite each other).
n n n n n n n n n


o 5’ → 3’ n n n


3’ ← 5’ n n


• RNA = phosphate + ribose sugar + A/U/C/G
n n n n n n n


o Single strand, can fold back onto itself and form pairs between itself
n n n n n n n n n n n


(stem‐loop).
• Each nucleic acid is made up of polymers (many monomers) that are
n n n n n n n n n n n


called nucleotides. n


o Nucleotides contain one or more phosphates, a five‐ n n n n n n n


carbon sugar, and a nitrogen base. n n n n n


o Nucleotides are always made in the 5’ to 3’ direction. n n n n n n n n n


o 5 is always the beginning of the strand, 3 is the end where nucleotides are a
n n n n n n n n n n n n n n n


dded.
• DNA organization: DNA is wrapped around proteins called histones →
n n n n n n n n n n


nucleosome → chromatin fiber→chromosomes
n n n




• Steps to the central dogma:
n n n n


o Coding DNA → template DNA → mRNA → tRNA (amino acid)
n n n n n n n n n n


o DNA → transcribed to mRNA → translated to protein
n n n n n n n n


o Each step is complementary (opposite) to the previous step, but if you skip a s
n n n n n n n n n n n n n n


tep it will be identical to the previous step.
n n n n n n n n


o Example
▪ 1. Coding DNA strand 5’ AAA TTT GGG CCC 3’
n n n n n n n n




BIOCHEMnC785nKaleysnComprehensivenStudynGuidenfinal

,BIOCHEM C785 Kaleys Comprehensive Study Guide final Correctly Verified 2022
n n n n n n n n n


▪ 2. Template DNA strand 3’ TTT AAA CCC GGG 5’
n n n n n n n n n


▪ 3. mRNA n 5’ AAA UUU GGG CCC 3’ n n n n n


▪ 4. tRNA n Lys Phe Gly Pro n n n


• Pairing:
o DNA: A → T n n n


o RNA: A → U n n n


• DNA replication:
n


o Because DNA is a double helix, one strand can be separated and serve as a t
n n n n n n n n n n n n n n n


emplate for synthesis of anew strand.
n n n n n


o Semi‐
conservative: each copy of DNA contains a template strand and a new strand.
n n n n n n n n n n n n


o Steps of replication:
n n




BIOCHEMnC785nKaleysnComprehensivenStudynGuidenfinal

,BIOCHEM C785 Kaleys Comprehensive Study Guide final Correctly Verified 2022
n n n n n n n n n




1. The DNA must be separated, creating a replication fork. This is done by
o n n n n n n n n n n n n n


helicase.
o 2. Primase attaches an RNA primer, where the replication is to start.
n n n n n n n n n n n


o 3. DNA polymerase adds bases to the remaining of the strand until it reach
n n n n n n n n n n n n n


es a stop codon. Thisis done in fragments, called okazaki fragments.
n n n n n n n n n n


• If an error is detected, it removes the nucleotides and replaces them
n n n n n n n n n n n n


with correct ones,known as exonuclease. n n n n


o Exonuclease removes all of the RNA primers, and DNA polymerase fills in tn n n n n n n n n n n n


hose gaps. n


o DNA ligase seals the two strands forming a double helix.
n n n n n n n n n


• DNA → transcribed → mRNA → translated → protein
n n n n n n n n




• Transcription occurs in the nucleus:
n n n n


o Initiation: RNA polymerase binds to a sequence of DNA called the promoter, f
n n n n n n n n n n n n


ound near the beginningof a gene. Each gene has its own promoter. Once bo
n n n n n n n n n n n n n


und, RNA polymerase separates the DNA strands, providing the single‐
n n n n n n n n n


stranded template needed for transcription.
n n n n n




BIOCHEMnC785nKaleysnComprehensivenStudynGuidenfinal

, BIOCHEM C785 Kaleys Comprehensive Study Guide final Correctly Verified 2022
n n n n n n n n n




BIOCHEMnC785nKaleysnComprehensivenStudynGuidenfinal