DNA is the chemical compound that contains the genetic instructions used in the development and functioning of all living organisms. It is found within the nuclei of cells. DNA is composed of nucleotides, which contain phosphate, sugar, and a nitrogenous base. The four nucleotides are attached via covalent bonds to form two strands that twist into a double helix structure. DNA is organized into structures called chromosomes within the cell nucleus. It replicates via semi-conservative replication and uses transcription and translation to synthesize proteins. RNA assists in protein production by carrying protein building instructions from DNA to the ribosomes.

1. DNA: deoxyribonucleic acid
• Chemical compound that
passes hereditary
information from
generation to generation
• Where is DNA found in
Eukaryotic cells? (plant,
animal, fungi, protist)?

2. Nucleotide
• Building block of DNA
• 3 parts
Nitrogen Base
Phosphate
5 carbon sugar
Deoxyribose
Attached with
covalent bonds

3. 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)

4. 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

5. 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

6. 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.

7. Replication
• DNA polymerase adds nucleotides
• Complementary base pairing

8. Semi-Conservative Replication
• Each new molecule consists of one old
strand and one new strand

9. RNA
• Directs protein
synthesis
• Not helical
• Single stranded
• 5 carbon sugar is
Ribose
• 4 nucleotides
– Adenine
– Guanine
– Cytosine
– Uracil

10. 3 classes of RNA
1. Messenger RNA (mRNA)
2. Transfer RNA (tRNA)
3. Ribosomal RNA (rRNA)
Makes up ribosome
Carries protein building instructions
Transports amino acid

11. Transcription
• One strand of DNA is
the template
• Begins at promoter
• Enzyme: RNA
polymerase
• Complementary base
pairing
• Ends at terminator

12. 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

13. Codons
• Start codon: AUG
– Codes for methionine
– First amino acid
• UAA, UAG and UGA are stop codons
– Prevent further amino acid addition

14. Codon chart
1st
base
2nd base
3rd
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
AUU
Ile/I
(Isoleucine)
ACU
Thr/T
(Threonine)
AAU Asn/N
(Asparagine)
AGU
Ser/S (Serine)
U
AUC ACC AAC AGC C
AUA ACA AAA
Lys/K
(Lysine)
AGA
Arg/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

15. Translation
1. Initiation
2. Elongation
3. Termination

16. Today’s lab
• Extract DNA from strawberry
• Add extraction buffer
– Made of shampoo and salt
– Breaks open cells
– Helps to separate DNA from protein
• Add ethanol
– Precipitates out DNA
• Collect spool of DNA
• Take home if you want to