IF YOU WERE A SPY, HOW WOULD YOU WRITE A MESSAGE TO HEADQUARTERS IN A WAY THAT IF THE ENEMY INTERCEPTED IT, THEY WOULD NOT KNOW WHAT THE MESSAGE SAID? ???
Why are Codes Important? Nucleus (“Control Center”) What structures are found in the nucleus? Chromosomes What are chromosomes made of? DNA wrapped around proteins What are located on chromosomes? Genes GENES AND CHROMOSOMES WORK TOGETHER TO DECODE THE GENETIC CODE!!
How is genetic information passed on in such exact form? DNA (Deoxyribonucleic Acid)
The Structure of DNA DNA consists of 3 parts: 1. Sugar = Deoxyribose 2. Phosphate Group 3. Nitrogen Bases Deoxyribose Nitrogen Base
The Structure of DNA Deoxyribose (Sugar) + Phosphate Group + Nitrogen Base = NUCLEOTIDE
The Structure of DNA: 4 Kinds of Nitrogen Bases Adenine (A) Guanine (G) Thymine (T) Cytosine (C)
The Structure of DNA: Scientists Contributions Rosalind Franklin Used X-ray crystallography to study DNA structure
The Structure of DNA: Scientists Contributions James Watson and Francis Crick Discovered the structure of DNA by building 3D models.
The Watson and Crick DNA Model: Double Helix Double Stranded Resembles a LADDER Uprights = Sugar+Phophate Rungs = nitrogen bases joined together by chemical bonds
The Watson and Crick DNA Model: Nitrogen Base Pairs Adenine – Thymine (A-T) Cytosine – Guanine (C-G)
DNA Replication Replication- DNA copying process that allows new cells to have a complete set of DNA. Carried out by enzymes DNA polymerase- joins nucleotides to make a DNA molecule
DNA Replication Steps 1. DNA untwists from the double helix. 2. DNA unzips- the chemical bonds between the bases break and the 2 strands separate. 3. Exposed nitrogen bases are allowed to join with other bases using the rules of base pairing new identical DNA strands are produced.
DNA Replication
What are Proteins? Proteins- organic molecules made up of different combinations of amino acids. Order of amino acids varies greatly from protein to protein. Proteins have many functions in cells. (i.e. enzymes, carrier molecules, etc.
How are Genes and Proteins related? Genes control the synthesis of proteins.
Protein Synthesis: RNA RNA= Ribonucleic Acid RNA is single stranded. Made up of 3 parts: 1. Sugar = Ribose 2. Phosphate Group 3. Nitrogen Bases
RNA Base Pairs Adenine-Uracil (A-U) Note: In RNA, Thymine is replaced with Uracil Cytosine-Guanine (C-G)
3 Types of RNA 1. Messenger RNA (mRNA)- carries instructions for assembling amino acids into proteins. 2. Ribosomal RNA (rRNA)- found on ribosomes 3. Transfer RNA (tRNA)- transfers amino acids to the ribosomes
Protein Synthesis: Transcription Transcription- DNA code is transferred to RNA code 1. RNA polymerase unzips DNA molecule. 2. Exposed bases pair up with mRNA bases using the rules of base pairing. 3. mRNA leaves nucleus and goes to ribosomes.
How do we interpret the mRNA code? Codon- 3 bases that represent an amino acid CGA TTT ATA CAG (DNA) GCUAAAUAUGUC (mRNA) Alanine Lysine Tyrosine Valine
Protein Synthesis: Transcription 1. Match DNA base pairs with the corresponding mRNA base pairs. 2. Separate mRNA base pairs into codons. 3. Decode codons into amino acids with The Genetic Code. 4. Order of amino acids determines the type of protein.
Protein Synthesis: Translation Translation- decoding of mRNA message into protein (polypeptide chain). Takes place in the ribosomes Process is continuous. Different parts may happen at once.
Translation Steps 1. Ribosome moves along mRNA strand. 2. tRNA brings amino acid to mRNA. 3. Amino acid joins mRNA. 4. mRNA codons, UAG, UAA, UGA, stop the elongation process 5. Amino acids link together by peptide bonds.
Proteins are made of polypeptides. Polypeptide- amino acid chain