1. Protein synthesis continued

2.  Transcription is step 1  DNA  mRNA  Nucleus  RNA polymerase

3.  Contains 4 nucleotides, but the order the bases are placed vary between organisms  The strand of mRNA is read by “Words” = -  These codons will code for -

4.  The order of codons in mRNA determines the order of amino acids  -

6. Determine the amino acids:  AUG (start codon) --  GAC --  CAC --  UUU --

8.  -  Mostly at the ribosome  Three stages:  -  Elongation  -

9.  Begins when a small ribosome unit binds to the mRNA.  -  -  A large ribosome unit not binds the small to create an initiation complex

10.  The initiator tRNA carries methionine to start the polypeptide chain  -

11.  Triggers enzyme activity to detach the mRNA and polypeptide chain from the ribosome

12. mRNA, tRNA, and rRNA come together during translation  mRNA – -  tRNA – -  - – help hold ribosomal proteins in place and help locate the beginning of the mRNA message  Gene expression – the way in which DNA, RNA, and proteins are involved in putting genetic information into action in living cells

14. --

15.  We know that the sequence of bases in DNA are coded messages, but what would happen if those letters accidently changed??  MUTATIONS = -

16. Gene Mutations - Chromosomal Mutations -

17. Point Mutation – - - – one base is “substituted” or changed for another. Insertion or Deletion – one base is inserted or removed -because its shifts the “reading frame” of letters and can change every amino acid that follows the point mutation. Can drastically alter protein structure and function

20. Many mutations are produced by errors in genetic processes, such as DNA replication. - Stressful environmental conditions Mutagens - Ex: pesticides, tobacco smoke, X-rays and ultraviolet radiation

21. - Some mutations are harmful… Change protein structure or gene activity Ex: cancer, sickle cell anemia, cystic fibrosis

22. - Source of genetic variation! Ex: Polyploidy – condition in which organisms have extra sets of chromosomes (3N and 4N) Polyploidy plants are often larger and stronger.