Nucleic Acids and Protein Synthesis How we make the proteins that our body is made of

I.DNA: Deoxyribonucleic Acid A. Nucleotides are subunits of DNA; Consist of sugar, phosphate, and nitrogenous base

B. Structure of DNA has 2 parts 1. Backbone of DNA is made of Sugar (Deoxyribose) and Phosphate groups

2. Rungs of DNA are made up of Nitrogen Containing Bases a. Purines: Two rings i. Adenine (A) ii. Guanine (G)

b. Pyrimidines: One Ring i. Thymine (T) ii. Cytosine (C)

C. The Double Helix 1. First proposed by James Watson and Francis Crick in 1953

D. Complimentary Base Pairing 1. Base Pairs connect to each other with Hydrogen Bonds 2. Cytosine bonds with Guanine and vice versaG-C (Base Pair) C-G (Base Pair) 3. Adenine bonds with Thymine and vice versaT-A (Base Pair) A-T (Base Pair)

E. DNA replication: making copies of DNA 1. DNA double helix is unzipped using the enzyme Helicase

2. DNA polymerase moves along the exposed chains and adds nucleotides by using base pairing rules

II.RNA: Ribonucleic Acid A. Differences from DNA 1. Sugar is ribose not Deoxyribose

2. RNA is single stranded (DNA is double stranded)

3. Nitrogenous Base: RNA uses the pyrimidine Uracil (U) instead of Thymine (T) 4. So in RNA Uracil pairs with Adenine U-A A-U

B. Types of RNA: 1. Messenger RNA (mRNA): a copy of DNA; carries genetic info from the nucleus to the cytoplasm so it can be “read”

2. Transfer RNA (tRNA): Brings amino acids to mRNA strand so they can be used to make a protein

3. Ribosomal RNA (rRNA): makes up the ribosomes (where proteins are made)

III. Transcription: Process in which the genetic information for an organism is copied from DNA to RNA.

A. RNA is made from DNA by the enzyme RNA polymerase

B. As RNA polymerase moves along DNA strand, it uses base pairing to add the correct nucleotides C. Promoter: Region of DNA where transcription will begin D. Termination Signal: Region of DNA where transcription stops

Transcription

IV.Genetic Code: The exact same code that is used by most organisms to translate mRNA into proteins A. Codons: A 3 letter sequence that codes for a specific amino acid (22 different AA). 1. Codons are read from the mRNA

V.Translation: the making of polypeptides (proteins) by using the information from the mRNA strand

A.Steps of translation: 1. mRNA leaves nucleus through pore and goes to cytoplasm

2. tRNA molecules float in cytoplasm. tRNA contains an anticodon i. Anticodon: corresponding sequence of letters to codon ex. Codon = UCA Anticodon= AGU

3.Ribosome reads the codons on the mRNA strand and signals for the corresponding tRNA which is carrying an Amino Acid a. Start Codon: Codon that tells the ribosome to begin translation b. Stop Codon: Codon that tells the ribosome to stop translating