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Nucleic Acids and Protein
DNA
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Deoxyribonucleic acid
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Deoxyribose
Phosphate
Base
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Adenine
Thymine
Cytosine
Guanine
Called a nucleotide
Function of DNA
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Stores Genetic info
Codes for production of
RNA
Makes up chromosomes
Prokaryotes
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One single circular strand
Eukaryotes
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Stored in nucleus
Multiple strands
Each own chromosome
Structure of DNA
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Double Helix
(Watson/Crick
1953)
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Two strands
(double)
Twisted around
central axis
(helix)
Think spiral stair
case
Rosalind Franklin
Structure (cont)
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Complementary base pairing
A with T
 C with G
 Based on number of H-bonds
 Allows DNA to replicate, and make RNA
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Purines/Pyrimidines
Purine: 2 rings, A and G
 Pyrimidine: 1 ring, T and C
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Base pairing
RNA
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Ribonucleic acid
Ribose
 Phosphate
 Base
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Adenine
 Guanine
 Cytosine
 Uracil (very similar to thymine from DNA)
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Function of RNA
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Connect DNA to ribosome
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Ribosome makes protein
Able to leave the nucleus
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Much smaller
Only one gene
 Single strand
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RNA base pairing (12/14)
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How RNA is made from
DNA
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DNA serves as the
template
DNA Base
RNA Base
Adenine
Uracil
Thymine
Adenine
Cytosine
Guanine
Guanine
Cytosine
Codons/Anticodon
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Codons are 3 nucleotide
sequence on mRNA
Anticodon is a 3
nucleotide segment on a
strand of tRNA
Pair using comp. base
pair rules
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3rd nucleotide can
sometimes flex
1 codon = 1 amino acid
Types of RNA
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mRNA
Carries information of DNA
 Linear
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tRNA
Brings amino acid to mRNA
 T-Shaped
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rRNA
Makes up the ribosome
 globular
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DNA Replication
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Self Replication
Possible for 2 main reasons
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Double Helix
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Comp. Base Pairing
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One strand serves as a template
Will get two identical strands
Why do you need to produce identical strands?
Steps to Replication (12/15)
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Formation of a
replication fork
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Enzyme = DNA helicase
Splits 2 strands
Add new bases
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Enzyme = DNA
polymerase
Adds bases to open
strands
Checks for errors
Transcription
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Process of making RNA from DNA
All forms of RNA are transcribed
RNA does not replicate in living things
Some viruses can
 Why does RNA not replicate?
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Takes place in nucleus of eukaryotes
Only one gene is transcribed
Process of Transcription
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Only one strand of DNA is transcribed
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Called the template strand (other is non-template)
Enzyme = RNA polymerase
Enzyme attaches (promoter) and separates
DNA strands
Adds RNA bases
Reaches a termination sequence
Stops, RNA breaks off, DNA recoils
Transcription
Translation
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Process used to produce a polypeptide (protein)
Uses all forms of RNA, ribosome, and amino
acids
mRNA = message
tRNA= transfer
rRNA = ribosomal
Takes place in the cytoplasm (where ribosomes
are)
Process of translation
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tRNA brings amino acids to the mRNA strand
rRNA helps link together amino acids
Protein is produced
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Function of protein
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Antibodies – fight infection
Contractile – responsible for movement
Enzymes – speed reactions
Hormones – coordinate body activities
Structure – build body, tendons/ligaments
Storage – store amino acids (egg whites)
Transport – move material into/out of cell
Codons and Amino Acids
DO NOT FORGET
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DNA  RNA  Protein  Structure 
Function
DNA  RNA =?
 RNA  Protein = ?
 DNA  DNA = ?
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