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DNA, RNA, Protein Synthesis. DNA Review. Double helix- twisted ladder shape Nucleotide- deoxyribose (sugar), phosphate, base 4 bases- Adenine, Thymine, Guanine, Cytosine Purine bases: A, G- double ringed chemical structure Pyrimidine bases: C, T- single ringed structures
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DNA Review • Double helix- twisted ladder shape • Nucleotide- deoxyribose (sugar), phosphate, base • 4 bases- Adenine, Thymine, Guanine, Cytosine • Purine bases: A, G- double ringed chemical structure • Pyrimidine bases: C, T- single ringed structures • A & T held together with 2 hydrogen bonds • C & G held together with 3 hydrogen bonds
RNA Review • Single stranded • Sugar- ribose • Bases- Adenine, Uracil, Cytosine, Guanine • mRNA- carries genetic info from DNA to direct protein synthesis • rRNA- helps proteins form ribosomes • tRNA- transports amino acids to ribosome
Transcription • Synthesis of mRNA from DNA • mRNA then takes the code from DNA into the cytoplasm for protein synthesis • DNA is unzipped by RNA polymerase (if it ends in –ase its an enzyme)
Transcription • Breaks H bonds to open the DNA strand • New bases come in to make mRNA strand • mRNA moves out of nucleus and into cytoplasm • Proteins are made in the ribosome
The Genetic Code • DNA sequence varies from person to person • 4 bases code for 20 amino acids • Codon- the base code for amino acids • 1 start codon- AUG (methionine)- starts the transcription reading frame • 3 stop codons- UAA, UGA, UAG- stops transcription • Page 338 Genetic Code Chart- need to know
Translation • After mRNA is synthesized, moves to ribosome • In the ribosome, mRNA code is read and translated into proteins • tRNA interprets the codons and reads the code to produce the correct amino acids which form proteins