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DNA. "The Blueprint of Life". Breaking Down the Definitions. Nucleotide Deoxyribose Nitrogenous base Purine Pyrimidine Base-pairing rules Complementary base pairs Base sequence DNA replication Helicase Replication fork DNA polymerase. Semi-conservative replication Mutation RNA
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DNA "The Blueprint of Life"
Breaking Down the Definitions • Nucleotide • Deoxyribose • Nitrogenous base • Purine • Pyrimidine • Base-pairing rules • Complementary base pairs • Base sequence • DNA replication • Helicase • Replication fork • DNA polymerase • Semi-conservative replication • Mutation • RNA • Transcription • Translation • Protein synthesis • Ribose • mRNA • rRNA • tRNA • RNA polymerase • Promoter • Termination signal • Genetic code • Codon • Anticodon • genome
DNA stands for... DeoxyriboNucleicAcid Time for a Song!
DNA FACTS • established by James Watson and Francis Crick • Shape of a double helix
codes for your genes (traits/allleles) • made of repeating subunits called nucleotides
What is a nucleotide? Has three parts: PHOSPHATE DEOXYRIBOSE (5 Carbon sugar) BASE (A,T,G,C)
Base-Pair Rule Adenine <==> Thymine Guanine <==> Cytosine The sides of the DNA ladder are phosphate & sugar held together by hydrogen bonds
Mnemonic Come up with a memory device/slogan/phrase to remember the 4 nitrogen bases and how they pair up.
Base Pair Rule One side: A T A T C A T G C G G G Other side:
Let's Review What We Know About DNA 1. DNA stands for: De _____ ribo ______ acid 2. What is the shape of DNA? _______________ 3. Who established the structure of DNA? ____________ 4. Adenine always pairs with _______________ 5. The sides of the DNA ladder are deoxyribose and _____ 6. Guanine always pairs with _____________ 7. What is the complimentary sequence: A A T G C A 8. The two sides of DNA are held together by _______ bonds. 9. DNA is composed of repeating subunits called ______________________ 10. What are the 4 bases that make up the rungs of the DNA ladder? _______________________________________
DNA REPLICATION the process by which DNA makes a copy of itself (cell division) SEMI-CONSERVATIVE - half of the old strand is saved
Errors in Replication • DNA replication usually occurs with great accuracy. • Only about 1 error for every BILLION pairs of nucleotides (for example: retyping your Biology text book 1000 times and only making 1 typo) • When a mistake occurs, the base sequence is changed; this is called a MUTATION
Protein Synthesis A gene (a segment on a DNA strand) codes for a specific hereditary item (ie hair color). The gene is the instruction for the making of the protein that creates that item (ie blond hair). To get the instructions to the ribosome (where proteins are made) DNA uses RNA to deliver the genetic information to the ribosome where the protein is created. This entire process= PROTEIN SYNTHESIS
RNA - the messenger *single strand *ribose sugar *contains no thymine, uracil instead *follows base pair rule DNA: A T A G C G RNA:
RNA carries the "message" to the ribosomes, where proteins are made
DNA --> RNA --> Protein Proteins are the building blocks of the organism (traits)
Transcription - process where RNA is made from DNA Translation - process where proteins are made from RNA
How the Code Works The combination of A,T,G,C determines what traits you might have..... C A T C A T = purple hair T A C T A C = yellow hair
Think of the bases of DNA like letters. Letters form words.... Words form sentences.... *endless combinations
The Genetic Code 3 adjacent nucleotides (‘letters’) in mRNA specify a particular amino acid (‘word’). 3 nucleotides also = a codon. There are 64 codons that encode most organisms. GCU, GCC, GCA, and GCG are all codons that code for the amino acid, Alanine.
