DNA: deoxyribonucleic acid
• Chemical compound that passes hereditary information from generation to generation
• Where is DNA found in Eukaryotic cells? (plant, animal, fungi, protist)?
Nucleotide• Building block of DNA
• 3 parts Nitrogen Base
Phosphate
5 carbon sugarDeoxyribose
Attached with covalent bonds
Four different nucleotides make up DNA
• Each has a different nitrogen base
Purines
2 ring nitrogen base structure
Pyrimidines
1 ring nitrogen base structure(uracil is only in RNA—not DNA)
Double Helix Structure• Ladder
– Sugar-phosphate are the sides
– Nitrogen bases attach across as the rungs
• A binds with T• G binds with C
– Attach with hydrogen bonds
• Two strands run antiparallel
DNA is organized into chromosomes
• Genome: All of the genetic material for a specific organism
• Gene: portion of DNA that carries information for a single protein
Central Theory of Molecular Biology
The process of replication creates new copies of DNA.
The process of transcription
creates an RNA using
DNA information.
The process of translation
creates a protein using
RNA information.
RNA
• Directs protein synthesis
• Not helical• Single stranded• 5 carbon sugar is
Ribose• 4 nucleotides
– Adenine– Guanine– Cytosine– Uracil
3 classes of RNA1. Messenger RNA (mRNA)
2. Transfer RNA (tRNA)
3. Ribosomal RNA (rRNA) Makes up ribosome
Carries protein building instructions
Transports amino acid
Transcription• One strand of DNA is
the template• Begins at promoter
• Enzyme: RNA polymerase
• Complementary base pairing
• Ends at terminator
RNA to protein• Occurs in cytoplasm on ribosomes• Ribosomes read mRNA bases in triplets called codons• 64 different codons• Code for 20 amino acids
– Most correspond to more than one codon
• Example: glutamate: GAA and GAG
Codons
• Start codon: AUG – Codes for methionine– First amino acid
• UAA, UAG and UGA are stop codons– Prevent further amino acid addition
Codon chart1st
base
2nd base3rd
baseU C A G
U
UUU Phe/F(Phenylalanine)
UCU
Ser/S(Serine)
UAU Tyr/T(Tyrosine)
UGU Cys/C(Cysteine)
U
UUC UCC UAC UGC C
UUA
Leu/L(Leucine)
UCA UAA Stop (Ochre) UGA Stop (Opal) A
UUG UCG UAG Stop (Amber) UGG Trp/W (Tryptophan) G
C
CUU CCU
Pro/P(Proline)
CAU His/H(Histidine)
CGU
Arg/R (Arginine)
U
CUC CCC CAC CGC C
CUA CCU CAA Gln/Q(Glutamine)
CGA A
CUG CCG CAG CGG G
A
AUUIle/I
(Isoleucine)
ACU
Thr/T(Threonine)
AAU Asn/N(Asparagine)
AGUSer/S (Serine)
U
AUC ACC AAC AGC C
AUA ACA AAALys/K
(Lysine)
AGAArg/R (Arginine)
A
AUG Met/M (Methionine) ACG AAG AGG G
G
GUU
Val/V(Valine)
GCU
Ala/A(Alanine)
GAU Asp/D(Aspartic acid)
GGU
Gly/G (Glycine)
U
GUC GCC GAC GGC C
GUA GCA GAA Glu/E(Glutamic acid)
GGA A
GUG GCG GAG GGG G
Key Nonpolar Polar Basic Acidic Stop codon