POB EXAM 2 - SHADWICK UARK STUDY GUIDE
Nucleotide - Answers :monomer of DNA or RNA
4 DNA nucleotides - Answers :adenine
cytosine
thymine
guanine
Discovered DNA - Answers :James Watson and Francis Crick
DNA structure - Answers :backbone of alternating phosphate and sugar
double helix held together by hydrogen bonding
complimentary base pairing
semiconservative replication - Answers :uses each original strand as a template to
produce a new complimentary strand
daughter DNA molecules identical to the parent molecule
DNA polymerase - Answers :key enzyme to replicate DNA
Steps of DNA replication - Answers :1. strands start hydrogen bonds
2. DNA helicase unwinds DNA
3. new strands built complimentary base pairing of nucleotides by DNA polymerase
4. DNA ligase seals breaks in backbone
4. 2 double helix models created and to the original molecule
Gene Expression - Answers :the process of using a gene sequence to synthesize a
protein.
two processes: transcription, translation
DNA --> transcription --> mRNA --> translation --> polypeptide
transcription - Answers :in the nucleus
part of DNA serves as a template for mRNA formation
translation - Answers :in the cytoplasm
sequence of mRNA determines the sequence of amino acids in a polypeptide
tRNA assists by bringing amino acids to the ribosome
mRNA - Answers :carries genetic info from DNA to ribosomes
formed from transcription
contains introns and exons
introns - Answers :segments that get removed from mRNA
, exon - Answers :portion of the gene that is expressed from mRNA
The Genetic Code - Answers :triplet code: for each 3 nucleotide unit of an mRNA
molecule is a called a codon
codon (mRNA) --> anticodon (tRNA) --> protein
tRNA - Answers :transports amino acids to the ribosomes
amino acid binds to one end, the opposite end has an anticodon
Ribosomes - Answers :composed of proteins and rRNA
has binding site for mRNA and three tRNA's
steps of translation - Answers :initiation
elongation
termination
initiation - Answers :brings all components together
tRNA attaches to start codon
ribosome has 3 binding sites (P, A, and E)
elongation - Answers :polypeptide increases in length
steps
1. tRNA w/ peptide at P site, tRNA w/ amino acids at A site
2. tRNA at A site, peptide chain is transferred to it
3. shifts over one codon and the "spent" tRNA exit
termination - Answers :new protein, rRNA, tRNA, and mRNA separate
occurs at stop codon
the ribosome dissociate into 2 subunits
gene mutations - Answers :a permanent change in the sequence of bases in DNA
errors in replication - Answers :rare source
proofreading by DNA polymerase usually catches errors
mutagens - Answers :environmental influences that can cause mutations
DNA repair enzymes constantly monitor and repair any irregularities
transposons - Answers :jumping genes
specific DNA sequences that move within and between chromosomes
Nucleotide - Answers :monomer of DNA or RNA
4 DNA nucleotides - Answers :adenine
cytosine
thymine
guanine
Discovered DNA - Answers :James Watson and Francis Crick
DNA structure - Answers :backbone of alternating phosphate and sugar
double helix held together by hydrogen bonding
complimentary base pairing
semiconservative replication - Answers :uses each original strand as a template to
produce a new complimentary strand
daughter DNA molecules identical to the parent molecule
DNA polymerase - Answers :key enzyme to replicate DNA
Steps of DNA replication - Answers :1. strands start hydrogen bonds
2. DNA helicase unwinds DNA
3. new strands built complimentary base pairing of nucleotides by DNA polymerase
4. DNA ligase seals breaks in backbone
4. 2 double helix models created and to the original molecule
Gene Expression - Answers :the process of using a gene sequence to synthesize a
protein.
two processes: transcription, translation
DNA --> transcription --> mRNA --> translation --> polypeptide
transcription - Answers :in the nucleus
part of DNA serves as a template for mRNA formation
translation - Answers :in the cytoplasm
sequence of mRNA determines the sequence of amino acids in a polypeptide
tRNA assists by bringing amino acids to the ribosome
mRNA - Answers :carries genetic info from DNA to ribosomes
formed from transcription
contains introns and exons
introns - Answers :segments that get removed from mRNA
, exon - Answers :portion of the gene that is expressed from mRNA
The Genetic Code - Answers :triplet code: for each 3 nucleotide unit of an mRNA
molecule is a called a codon
codon (mRNA) --> anticodon (tRNA) --> protein
tRNA - Answers :transports amino acids to the ribosomes
amino acid binds to one end, the opposite end has an anticodon
Ribosomes - Answers :composed of proteins and rRNA
has binding site for mRNA and three tRNA's
steps of translation - Answers :initiation
elongation
termination
initiation - Answers :brings all components together
tRNA attaches to start codon
ribosome has 3 binding sites (P, A, and E)
elongation - Answers :polypeptide increases in length
steps
1. tRNA w/ peptide at P site, tRNA w/ amino acids at A site
2. tRNA at A site, peptide chain is transferred to it
3. shifts over one codon and the "spent" tRNA exit
termination - Answers :new protein, rRNA, tRNA, and mRNA separate
occurs at stop codon
the ribosome dissociate into 2 subunits
gene mutations - Answers :a permanent change in the sequence of bases in DNA
errors in replication - Answers :rare source
proofreading by DNA polymerase usually catches errors
mutagens - Answers :environmental influences that can cause mutations
DNA repair enzymes constantly monitor and repair any irregularities
transposons - Answers :jumping genes
specific DNA sequences that move within and between chromosomes
