DNA

Deoxyribonucleic Acid

ScientistsJames Watson and

Francis Crick discovered the double helix shape of

DNA in 1953

After visiting Maurice Wilkins and Rosalind

Franklin at Kings University

DNA’s 3 Components

1. Sugar- Deoxyribose

2. Phosphate

3. Nitrogen Base (4)

4 Nitrogen Bases

1. Adenine- A

2. Thymine- T

3. Cytosine- C

4. Guanine- G

Sizes in Order

Smallest Largest

GenesDNAChromatin

SisterChromatidsChromosome

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

4. Cytosine only bonds with guanine

5. Every 10-12 base pairs the ladder/helix twists

6. Hydrogen bonds the base pairs together

Two Main Functions of DNA

1. Code for Genetics/Heredity

2. Provides blueprint for making proteins

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

DNA Double Helix

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.

Types of Mutations

• Point Mutation– Substitution

• Framshift Mutation– Addition/Duplication – Deletion

DNA Replication

What phase does this happen in?

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

Replicate the Following

• DNA

A T T C G A T T A A G C T A

RNA

Ribonucleic Acid

RNA’s 3 Components

1. Sugar- Ribose

2. Phosphate

3. Nitrogen Base (4)

RNA’s 4 Nitrogen Bases

1. Adenine- A

2. Uracil – U ***New***

3. Cytosine- C

4. Guanine- G

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.

3 Types of RNA:

1. Messenger: takes message from DNA to ribosome

2. Transfer: transfers amino acids to ribosome

3. Ribosomal: makes protein

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:

2. RNA to Amino Acid (Protein) is called Translation

U A G C U A G C C A U G

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

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

The Genetic Code

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

HO₂CCHCH₂CH₂SCH₃ HO₂CCHCH₂CH(CH₃)₂ CH₃CHCOOH

Protein Synthesis

H

Protein Synthesis Key

A. Nucleus

B. mRNA

C. Ribosome

D. tRNA

E. Codon

F. Start Codon (AUG)

G. mRNA

H. Amino Acid