II. RNA

1. II. RNA Ribonucleic Acid Function – makes proteins

2. A. Differences between RNA and DNA -- DNARNA -- 2 strands 1 strand -- deoxyribose ribose sugar -- thymine uracil

3. B. 3 types of RNA 1. Messenger RNA (mRNA) - straight strand - transmit information from nucleus to ribosomes on how to make protein 2. Transfer RNA (tRNA) - folded strand - 20 types – each type is an amino acid - brings amino acid to ribosome to make protein 3. Ribosomal RNA (rRNA) - globular (round) - makes ribosomes

4. C. Transcription • The making of RNA from DNA • Done in the nucleus • Uses RNA polymerase instead of DNA helicase to break H-bonds between DNA strands. RNA polymerase attaches to a section of DNA called a promoter. Will stop transcribing when a termination signal is reached.

5. G A U A A C U C U A U U G A mRNA mRNA DNA strand C – G T – A A – T T – A T – A G – C A - T RNA polymerase

6. Introns – sections of DNA that will not be read (“junk DNA”) Exons – sections of DNA that will be read mRNA goes from nucleus to cytoplasm to ribosomes to make proteins.

7. D. Factors that damage DNA • Excessive body heat (fever) • Radiation (UV and X-rays) • Chemicals (carcinogens) **** errors do occur but rarely – about 1 per billion nucleotides **** DNA is constantly trying to repair itself, has proofreading enzymes

8. III. Protein Synthesisthe making of proteins using information coded from DNA and carried out by RNA. • A. Amino Acids - basic building blocks of proteins - 20 different ones - joined together by peptide bonds - carried by tRNA • B. Codon – 3 bases in a row within a mRNA strand that call for a specific anticodon that codes for a specific amino acid. *** AUG is the universal start codon for all organisms.

9. C. Translation – process of making proteins by using mRNA amino acids Start alanine stop alanine tRNA anticodon U A C C G C A U C C G A occurs in ribosomes A U G G C G U A G G C U mRNA codon

10. Human Genome Project • 15 year project with scientist all over the world. Mapped out the sequence and location of all traits (genes) on all chromosomes of a human. • Humans have 3,200,000,000 base pairs per sex cell. (It would take about 10yrs. to read each base.)

11. Transcription/translation Model

12. Review 1. What are the 3 types of RNA. 2. Give 3 differences between RNA and DNA. 3. The process of making more DNA is called ________ while the making of RNA is __________. 4. How does a cell know it is making RNA from DNA instead of making more DNA from DNA ? 5. Change the following DNA strand into mRNA T-T-A-A-G-C-G-A-T-C 6. RNA is used in the making of ___________. 7. There are 20 different kinds of this type of RNA.

13. Review • Change the following DNA strand into mRNA. A-T-C-G-C-G-T-T-A-G-C-T • Assemble the protein from the mRNA sequence from your answer to #1.

14. IV. Mutations - change in DNA - germ cell mutations – mutations in sex cells – affect offspring - somatic cell mutations – occur in body cells . Ex. Skin cancer, leukemia • A. Chromosome Mutations 1. Deletion – piece of chromosome breaks off. Ex. Fragile X syndrome 2. Inversion – piece breaks off and reattaches upside down. A A B C C B

15. 3. translocation – inversion with a non homologous chromosome. Piece breaks off and attaches to different # chromosome upside down. A B C D D C A B C D A B C D A B 21 19

16. 4. Nondisjunction- when chromosome pairs fail to separate so there are multiple copies. Ex. Down Syndome Ex. 21st chromosome B. Gene Mutations - occur within a specific gene or piece of a gene 1. Point mutation – substitution, addition, or deletion of a nitrogen base. Ex. Sickle cell anemia

17. -- frameshift mutation - type of point mutation that involves the addition or deletion of a nitrogen base. • Ex. ATTCGCGGT • ATTTCGCGGT • ATCGCGGT -- additions and deletions have a greater effect than substitutions.