Chapter 12 DNA & RNA

Question of the day What does DNA stand for? Deoxyribonucleic Acid What does it do?

Ch. 12 Essential Questions What is DNA made of? How is DNA stored? How do DNA & RNA replicate? What are gene mutations?

12-1 DNA Evolution of DNA research First “discovered” by Watson & Crick who beat out teams of others - first to see double helix

Structure of DNA Made of long units called what? NUCLEOTIDES Each strand has 3 parts: 5 Carbon sugar - deoxyribose 1 Phosphate Group 1 Nitrogen Base

Parts of DNA Purine Group Pyrimidine Group 4 kinds of Nitrogen Bases in 2 groups Purine Group Adenine Guanine Pyrimidine Group Cytosine Thymine

Nitrogenous Pairs These Groups pair up 1 Purine + 1 Pyrimidine Always with the same combo Adenine + Thymine Cytosine + Guanine Or AT, CG Connected by a Hydrogen bond Called Base Pairing

Shape of DNA What does it look like? A spiral staircase Called a double helix 2 sides of a spiral form or structure.

12-2 Chromosomes & DNA Made up of CHROMATIN - DNA & Protein packed together Double Helices wrapped around HISTONES - proteins DNA coiled around All packed into NUCLEOSOMES Wrapped in COILS Then SUPERCOILS Makeup a Chromosome

DNA Replication How does DNA reproduce itself? Double Helix “Unzips” into 2 single helices By using an enzyme Helicase Put back together Called DNA POLYMERASE Then it “Copies” or REPLICATES Put back together by a fork

12-3 RNA & Protein Synthesis What is RNA? A Genetic Message for something to be produced RNA is a little different than DNA: Sugar is Ribose RNA is single stranded RNA has Uracil, not Thymine

Different Types of RNA Many functions of RNA but mostly makes proteins Messenger RNA (mRNA) - Instruction Carrier for proteins Ribosomal RNA (rRNA) - where proteins are assembled Transfer RNA (tRNA) - moves amino acids to ribosomes (Taxi)

How to Make RNA Where DNA gets converted into RNA TRANSCRIPTION Uses RNA Polymerase (RP) Where does RP know where to start & stop? PROMOTERS - enzyme that binds to specific DNA sequence

RNA Is Made - The Genetic Code RNA makes amino groups Groups called CODONS Group of 3 specific nucleotides 64 possible codon combinations

Roles of DNA & RNA DNA is the master plan RNA is the blueprint of master plan DNA remains safely in nucleus RNA goes to protein building sites in cytoplasm & ribosomes

12-4 Mutations Mutation - to change Not all mutations are bad Can have two kinds: Gene - on a single gene Chromosome - whole chromosome change Point Mutation - one nucleotide is affected Frameshift - Deletes 1 nucleotide and causes every one to shift up

12-5 Gene Regulation Some Genes are turned on & off at times Turn on/off at promoter Use Operons & Hox genes to help develop and turn on/off parts of genes

Final Thoughts on Mutations Are all mutations bad? Do they need to cause immediate change? Can there be real life X-Men?