2. Scientists
James Watson and
Francis Crick
discovered the double
helix shape of DNA in
1953
After visiting Maurice
Wilkins and Rosalind
Franklin at Kings
University
6. 6 DNA Structure Rules
1. Sides are composed of
alternating Deoxyribose
Sugars and Phosphates
2. Nitrogen bases attach to the
sides at the sugars only
3. Adenine only bonds with
thymine
7. 4. Cytosine only bonds with
guanine
5. Every 10-12 base pairs the
ladder/helix twists
6. Hydrogen bonds the base
pairs together
8. Two Main Functions of DNA
1. Code for
Genetics/Heredity
2. Provides blueprint for
making proteins
9. Shape of DNA
• DNA is made of nucleotides
• Nucleotides - 1 sugar, 1 phosphate, and 1 letter.
• Nucleotides can be in any order
• The “backbone” is the sugar/phosphate groups
11. Mutations
Any changes that are made to the genetic
material (DNA)
Mutagens – any substance that causes a
mutation
Examples: Ultraviolet Light, X-rays,
Medicines, etc.
12. Types of Mutations
• Point Mutation
– Substitution
• Framshift Mutation
– Addition/Duplication
– Deletion
14. Enzymes
• Helicase – unzips the original ladder
• Polymerase-brings the free floating
nucleotides to the original strands
• Ligase – rezips the ladder of the replicated
strands
– DRAWING
18. RNA’s 4 Nitrogen Bases
1. Adenine- A
2. Uracil – U ***New***
3. Cytosine- C
4. Guanine- G
19. 3 Main Differences
1. The sugar in RNA is ribose instead of
deoxyribose.
2. RNA is single-stranded.
3. RNA contains uracil in place of thymine.
20. 3 Types of RNA:
1. Messenger: takes message from DNA to
ribosome
2. Transfer: transfers amino acids to
ribosome
3. Ribosomal: makes protein
21. The Genetic Code = Making Proteins
1. DNA to RNA is called Transcription
DNA: A T C G A T C G G T A C
RNA:
1. RNA to Amino Acid (Protein) is called
Translation
U A G C U A G C C A U G
22. 3. A codon is a group of 3 RNA Nitrogen
Bases
4. There are 64 different codons
5. Codons represent the different amino
acids
6. Amino Acids are the building blocks of
proteins
23. 7. There are 20 different amino acids
8. From START (AUG) to a STOP (UGA,
UAA, UAG) codon is a protein
9. Genes are located on chromosomes &
contain instructions for making proteins
10.Protein is found in blood, muscle, and
body organs
26. Sample Set
***Have to Start with AUG***
DNA: T G T A C G A A C G C T A C T
RNA:
AA:
A C A U G C U U G C G A U G A
Methionine Leucine Alanine Methionine
HO CCHCH CH SCH HO CCHCH CH(CH ) CH CHCOOH₂ ₂ ₂ ₃ ₂ ₂ ₃ ₂ ₃
28. Protein Synthesis Key
A. Nucleus
B. mRNA
C. Ribosome
D. tRNA
E. Codon
F. Start Codon
(AUG)
G.mRNA
H. Amino Acid
Editor's Notes
DNA is a double helix in which two strands are wound around each other. Each strand is made up of a chain of nucleotides. The two strands are held together by hydrogen bonds between adenine and thymine and between guanine and cytosine.
A codon is a group of three nucleotides on messenger RNA that specify a particular amino acid.
The genetic code shows the amino acid to which each of the 64 possible codons corresponds. To decode a codon, start at the middle of the circle and move outward.
