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92 Cards in this Set

  • Front
  • Back
Gene
discrete, functional DNA;
when expressed, yields a functional products
Open reading frame
long stretch of nucleotides that can encode polypeptide due to absence of stop codons
Chromosome
discrete, linear molecule of double-stranded DNA
Centromere
site that connects sister chromatids
Kinetochore
attachment site of spindle to chromosome
Teleomere
nucleotide repeat at end of linear chromosome
Telomer
resists nuclease digestion;
synthesized by Telomerase
Karyotype
photograph of chromosomes from a single organism
What is the function of histone proteins?
Histone proteins package eukaryotic nuclear DNA.
Chromatin
Nuclear DNA+Associated proteins
Heterochromatin
condensed, transcriptionally inactive chromatin
Constituitive heterochromatin
DNA is never transcribed
Facultative heterochromatin
DNA is not transcribed in that cell type, but is transcribed in other cell types.
Euchromatin
decondensed, transcriptionally active interphase chromatin
Nucleosome core particle
146 b.p. DNA wraps 1.75 times around histone octomer
Chromatosome
166 b.p. DNA locked in place around histone octomer by histone H1
What do chromatosomes pack to form?
Chromatin fibers
Central Dogma of Molecular Biology
DNA → RNA → Protein via replication, transcription, and translation, respectively
Mutation
change in DNA sequence
What does it mean to say that DNA replication is Semiconservative?
Each parental strand serves as template for synthesis of a new complementary strand.
In what direction does DNA polymerase synthesis DNA?
5' to 3'
DNA Polymerase
template directed synthesis of complementary DNA strand by addition of nucleotides
Name the five DNA polymerases and tell the function of each.
α-replicative
β-repair
γ-organelle
δ-replicative
Δ-unclear
Helicase
unwinds DNA
Primase
synthesizes RNA primers
Topoisomerase
relives torsenal strain in DNA double helix
Topoiomerase type I
breaks phosphodiester bond on one DNA strand
Topoiomerase type II
breaks phosphodiester bond on both DNA strands
Ligase
seals nicks (breaks) in phosphodiester backbone
RNase H
digests RNA molecule n DNA:RNA hybrid
Single Stranded DNA Binding Protein
binds and protects single stranded DNA
Exonuclease
digests DNA
Exonuclease 5' to 3'
digests DNA in fron of synthesis
Exonuclease 3' to 5'
removes newly synthesized nucleotide (especially if incorrectly incorporated)
(proofreading)
Reverse transcriptase
RNA molecule serves as template for DNA synthesis
Leading strand
continous synthesis
Lagging strand
discontiuous synthesis (Okazaki fragments)
What happens if the incorrefct base is incorporated?
creates mutation which is the fuel for evolution
Origin
discrete site on chromsome where replication begins
Trasciption
occurs in nucleus;
catalzed by RNA polymerase
In what direction is RNA synthesized?
5' to 3'
RNA Polymerase I
functions in the nucleolus;
synthesizes 45S pre rRNA (18S, 5.8S, 28S rRNA)
RNA Polymerase II
functions in the nucleus;
pre-mRNA
Monocistronic
endcode one polypeptide per transcript
Polycistronic
encode several polypeptides per transcript
Chromatosome
166 b.p. DNA locked in place around histone octomer by histone H1
What do chromatosomes pack to form?
Chromatin fibers
Central Dogma of Molecular Biology
DNA → RNA → Protein via replication, transcription, and translation, respectively
Mutation
change in DNA sequence
What does it mean to say that DNA replication is Semiconservative?
Each parental strand serves as template for synthesis of a new complementary strand.
In what direction does DNA polymerase synthesis DNA?
5' to 3'
DNA Polymerase
template directed synthesis of complementary DNA strand by addition of nucleotides
Name the five DNA polymerases and tell the function of each.
α-replicative
β-repair
γ-organelle
δ-replicative
Δ-unclear
Helicase
unwinds DNA
Primase
synthesizes RNA primers
Topoisomerase
relives torsenal strain in DNA double helix
Topoiomerase type I
breaks phosphodiester bond on one DNA strand
Topoiomerase type II
breaks phosphodiester bond on both DNA strands
Ligase
seals nicks (breaks) in phosphodiester backbone
RNase H
digests RNA molecule n DNA:RNA hybrid
Single Stranded DNA Binding Protein
binds and protects single stranded DNA
Telomerase
synthesizes telomeres
Exon Nuclease
digests DNA
Exon Nuclease 5' to 3'
digests DNA in front of synthesis
Exon Nuclease 3' to 5'
removes newly synthesized nucleotide (especially if incorrectly incorporated)
Reverse transcriptase
RNA molecule serves as template for DNA synthesis
Leading strand
continous sythesis
Lagging strand
discontinous sythesis (Okazaki fragments)
Origin
discrete site on chromosome where replication begins
Transcription
occurs in nucleus;
catalzyed by RNA polymerase
In what direction is RNA sythesized?
5' to 3'
RNA Polymerase I
functions in nucleolus;
synthesizes 45S preRNA (18S, 5.8S,and 28S rRNA)
RNA Polymerase II
function in nucleus
synthesizes pre-mRNA
Monocistronic
encodes one polypeptide per transcript
Polycistronic
encodes several polypeptides per transcript
Capping
addition of methylguanosine to 5' end of transcript;
reverse 5' to 5' linkage of methylguanosine
Polyadenylation
addition of chain of AMP to 3' end of transcript
Splicing
removal of introns
Intron
noncoding region
Exon
coding region
RNA Polymerase III
function in nucleus;
5.0 rRNA;
sythesizes pre tRNA
Pre tRNA
single strand of 70-80 ribonucleotides;
folds into a cloverleaf structure
Describe how tRNA is synthesized from pre tRNA.
5' end cleaved by RNAse P ribozyme;
3' end cleaved by RNAse;
CCA added to 3' end;
base modified;
anticodon used
CCA
attachment site for amino acid
Translation
protein sythesis in cytosol
Ribosome
rRNA + r proteins
mRNA
homologous to DNA sequence;
contains codon (3 nucleotides)
tRNA
adapter between amino aicd and mRNA;
amino attachment site CCA 3';
anticodon interacts with codon of mRNA
Where are ribosomal subunits assembled?
in the nucleus
Where are ribosomal subunits transported to?
They are transported through nuclear pore into the cytoplasm.
Where are free ribosomes found?
in the cytoplasm
Where are bound ribosomes found?
attached to the ER