DNA and Protein Synthesis REVIEW 2012

1. DNA and Protein Synthesis REVIEW 2012 • DNA and RNA are polymers composed of repeating monomers calledNUCLEOTIDES

2. RNA and DNA structure Watson and Crick discovered DNA structure

4. DNA and RNA Continue Backbone of DNA and RNA are Sugar attached to Phosphate group. The rungs of the DNA ladder are the complementary bases bonded to each other through weak H- bonds A(dbl. ring purine) bonds T(single ring pyrimidine) G(dbl. ring purine) bonds C(single ring pyrimidine)

5. If one strand of the DNA molecule has the sequence AATCCG, what is the sequence of the other strand? What happens after replication ?

6. Transcription: From DNA to RNA • Transcription: initiation-elongation-termination • makes RNA from a DNA template, • uses a process that resembles the synthesis of a DNA strand during DNA replication, and • substitutes uracil (U) for thymine (T). • RNA nucleotides are linked by the transcription enzyme RNA polymerase. Responsible for RNA synthesis. • Sequence of 3 nitrogen bases in mRNA is called a CODON

7. RNA processing • RNA processing includes • adding a cap and tail consisting of extra nucleotides at the ends of the RNA transcript,-this protects RNA from cellular enzymes • removing introns (noncoding regions of the RNA), and • RNA splicing, joining exons (the parts of the gene that are expressed) together to form messenger RNA (mRNA).

8. Practice • If a strand of DNA has the sequence DNA AAACGCTTACGT mRNA Transcription will result in a single RNAstrand with what sequence?

9. Translation • Translation is the conversion from the nucleic acid language to the protein language. • Translation requires • mRNA, • ATP, • enzymes, • ribosomes, and • transfer RNA (tRNA).

10. How translation occurs 1. mRNA attaches to ribosome to be decoded - code is read in pieces called codons - codon – 3 nucleotides AUGCCUGGA - each codon codes for one amino acid

12. A new kind of RNA brings in the correct amino acid. - transfer RNA (tRNA) see diagram one end has the a.a. on it the other end has an anticodon • Anticodon 3 nucleotides on tRNA that base pair with nucleotides on mRNA - see diagram of tRNA This is how the correct a.a. is brought in

14. Anticodon 3 nucleotides on tRNA that base pair with nucleotides on mRNA - see diagram of tRNA This is how the correct a.a. is brought in

15. Steps of translation 1. Correct tRNA (carrying it’s specific a.a.)base pairs w/M-RNA (called initiation) 1st codon is always AUG (start codon) 2. Another tRNA base pairs w/the next codon (called elongation) 3. Peptide bond is formed b/w the a.a’s

16. 1sttRNA releases it’s a.a and leaves • mRNA moves over & process continues • Process continues until a stop codon is reached-the stop codon signals termination(3rd step) • Protein is released –ribosome splits into its 2 subunits

24. Single base substitution- sickle cell anemia

25. Deletions,insertions