Transcript Transcription

TRANSCRIPTION
Unit 4 Part I
Central Dogma
DNARNA Proteins Traits
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This is the central dogma (theme) of molecular
genetics.
These are the steps needed to get from a DNA
double helix to the traits you posses.
Central Dogma
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How do you get from DNA to RNA to Proteins to
Traits?
Amino Acids
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DNA  RNA  PROTEINS  TRAITS
TRANSCRIPTION TRANSLATION
control
Review
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DNA – only found in the nucleus
Ribosomes (protein factories) –
in the cytoplasm
Hoes does DNA get information
needed to make proteins from
the nucleus to the ribosome?
DNA makes mRNA which leaves
through the nucleuar pores in
the nucleus. Ribosomes then
read the mRNA to make
proteins.
DNA vs. RNA
DNA
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Deoxyribonucleic Acid
Deoxyribose sugar
Double stranded
N bases = A,T,C,G
Found in the nucleus
1 type
Contains a phosphate,
sugar, N base.
RNA
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Ribonucleic Acid
Ribose sugar
Single stranded
N bases = A,U,C,G
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Uracil replaces Thymine
Found in the nucleus and
cytoplasm
3 types
Contains a phosphate, sugar,
N base.
DNA vs. RNA
DNA
RNA
Types of RNA
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Messenger RNA
 mRNA
 Carries info from DNA and
delivers it to ribosome.
Ribosomal RNA
 rRNA
 Structural component of
ribosomes
Transfer RNA
 tRNA
 Translates mRNA sequences
into amino acid sequences
Transcription Steps:
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1. RNA Polymerase – binds to DNA and signals to start
making RNA, then unwinds/splits DNA into 2 separate
strands.
2. One strand – of DNA acts as a template for making
mRNA.
3. RNA Polymerase – moves along the DNA and pairs
each base with a complementary RNA nucleotide
4. Continues – until enzyme reaches a terminator (stop
signal).
5. RNA Polymerase – detaches from DNA and
releases mRNA from the nucleus.
DNA - RNA
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What would the mRNA strand be if the DNA
template is:
 (remember
that A now pairs with U and C
still pairs with G)
ATC CAG TCA GAT CTA CCG