2. A. Chromosomes are made of DNA B.Segments of DNA code for a protein C.A protein in turn, relates to a trait or a gene (examples: eye color, hair color, enzymes, hormones…) I. How do chromosomes lead to specific traits?

3. How do we get proteins from genes (coding DNA)? Let’s find out: http://www.wisc- online.com/objects/index_tj.asp?objID=AP1302

4. I.Structure and Function of RNA A) Why is RNA needed? 1) proteins are made by ribosomes outside the nucleus (on the rough Endoplasmic Reticulum)

5. 2) DNA cannot leave the nucleus (it’s stuck) 3) RNA is needed so that it can carry the genetic code (DNA) needed for making proteins to the ribosomes

6. B)What is RNA? 1) RNA - Ribonucleic Acid a) the sugar in RNA is ribose b) in RNA the base thymine is replaced with URACIL.

7. 2) There are 3 kinds of RNA a) r RNA - Ribosomal RNA - makes up ribosomes b) mRNA- messenger RNA -carries the genetic code out of the nucleus to the ribosomes

8. c) tRNA- Transfer RNA - transfers amino acids to the ribosome in order to make proteins

9. II. RNA Code a) mRNA carries the code for an amino acid in a series of 3 nucleotides (like DNA triplet) b) A group of 3 mRNA nucleotides is called a codon.

10. c) A group of 3 tRNA nucleotides is called an anti-codon (opposite of the codon) ex. mRNA codon = UAG tRNA anti-codon = AUC d) The genetic code is universal - codons code for the same amino acids in all known life forms

11. Protein Synthesis is a two part process 1) Transcription (in the nucleus) 2) Translation (in the cytoplasm)

12. III. Transcription - mRNA is copied from DNA Steps: 1) DNA unzips 2) RNA nucleotides bond to the exposed bases on the DNA strand (note: transcription is similar to DNA replication except in RNA adenine pairs with uracil) 3) Transcription continues until a stop” codon is reached

14. IV. Translation - mRNA is used to make protein Steps: 1) mRNA leaves the DNA in the nucleus and travels to a ribosome 2) the ribosome begin “translating” the mRNA into protein when it reaches a “start” codon

15. 3) the ribosome”translates” the mRNA into a sequence of amino acids that make up a specific protein 4) Translation continues until a “stop” codon is reached.

17. V. How do the Ribosome do their job? 1)tRNA is the key 2) What is tRNA? tRNA carries an amino acid on one end. The other end contains the anti- codon (three nitrogen bases) that will match up with the mRNA codon.

18. 3) tRNA molecules match their anti-codon to the mRNA codon 4)A protein is formed as tRNA’s release their amino acids which bond together to make a protein (peptide bond)

19. mRNA Ribosome Protein (amino acid chain)

20. All of the proteins in your body are made up of combinations of only 20 different amino acids linked together in different ways. (see codon chart)

21. Third Letter

22. TRANSCRIPTION (in the nucleus) –1. DNA helix opens –2. mRNA chain is copied from DNA TRANSLATION (in the cytoplasm) 1. mRNA attaches to a ribosome in the cytoplasm 2. tRNA molecules carrying amino acids match anti-codon to mRNA codon 3. Amino acids are released and bonded together to make a protein.