Deoxyribonucleic Acid

1. Deoxyribonucleic Acid DNA

2. DNA located in chromosomes in the nucleus • Genes are the basic unit of heredity found on chromosomes • Genes carry information from one generation to next • Genes (DNA) control protein (enzyme) synthesis • Monomer of Nucleic Acids are Nucleotides= phosphate group, 5 carbon sugar, nitrogen base P NB

3. Watson and Crick discovered shape of DNA • Double Helix (twisted Ladder) • Alternating phosphates and sugars form the uprights • Bases form the rungs of the ladder Nitrogen Bases -Purine always pairs with a Pyrimidine and are held together by weak hydrogen bonds (velcro) Purines (2rings) Pyrimidines(1ring) Adenine Thymine Guanine Cytosine

4. Chargaff’s Rule • Adenine=Thymine • Guanine=Cytosine • If DNA is 15% adenine, What are the percentages of thymine, guanine, and cytosine • A=15% • T=15% • G=35% • C=35%

5. DNA REPLICATION (synthesis, duplication)- DNA copies itself • Where-nucleus • When-Synthesis phase of interphase • Why- so each cell receives a full set of chromosomes

6. STEP 1- Enzymes cause DNA to unwind and unzip breaking hydrogen bonds STEP 2- Free nucleotides in cytoplasm enter nucleus and pair with corresponding base pair with help of DNA polymerase

7. Original DNA strands act as templates (patterns) for new strands • STEP 3-end up with 2 strands containing one old and one new strand, and they rewind

8. DNA Replication • Original New Strand 1 New Strand 2 • A-T A-T A-T • T-A T- -A • G-C G- -C • C-G C- -G • T-A T- -A • A-T A- -T

9. RNA-Ribonucleic Acid • Single stranded • Made of nucleotides – phosphate group, 5 carbon sugar ribose and a nitrogenous base

10. 4 bases in RNA: Adenine Bonds with Uracil; Guanine with Cytosine ( There Is No Thymine in RNA) 3 types of RNA: Messenger RNA (m-RNA); Transfer RNA (t-RNA); and Ribosomal RNA (r-RNA)

11. TRANSCRIPTION- DNA acts as a template to synthesize m-RNA • Where: NUCLEUS because DNA acts as the template for m-RNA and DNA NEVER leaves the nucleus • Why: m-RNA will code for the production of proteins • Step 1: DNA unwinds and unzips with the help of enzymes

12. Step 2: Free nucleotides from the cytoplasm match up to the DNA parent template with the help of RNA polymerase Step 3: DNA rezips and rewinds, and new m-RNA strand moves to the cytoplasm to the ribosome to be translated into a protein.

13. Transcription

14. Translation-m-RNA code is converted to a protein at the ribosome • M-RNA heads out of the nucleus to the ribosomes (r-RNA) in the cytoplasm • M-RNA contains codons (3 base pairs) that code for the amino acids that make-up the protein

15. Each codon has a complimentary anticodon found on the t-RNA in the cytoplasm • R-RNA reads the codons on the m-RNA which tells the t-RNA which amino acid to bring to the R-RNA • One by one amino acids are added in the sequence of the codons on the m-RNA at the ribosome. Amino acids are joined by peptide bonds.

16. Translation

17. Mutations • Mutations are changes in an organisms DNA • Examples are extra finger or toe, skin cancer, cystic fibrosis • Mutagens are substances that cause a mutation like UV rays, radiation, asbestos, chemicals, alcohol • Mutant is an organism in which a mutation has occurred

18. 2 types of Mutations: Gene and Chromosomal • 1. Gene Mutations involve a change in 1 nucleotide • Change in one base will cause a change in 1 amino acid

19. 2. Chromosomal or Frame-shift Mutations • ABC DEF • A. Insertion-Add a base throwing off the codon sequence the rest of the gene ABB CDE G • B. Deletion-Dropping a base throwing off the codon sequence the rest of the gene ACD EF

20. 3. Inversion- a reverse in the direction of part of the chromosome AED CBF • 4. Translocation- part of the chromosome breaks off and attaches to another ABC JKL and GHI DEF • Most mutations are neutral • Some mutations cause defective proteins • Some are beneficial and if are found in the sex cells will be passed to the next generation

21. Biotechnology- industrial process that uses DNA research for a practical means • 1. Recombinant DNA (rDNA)- a combination of DNA from 2 different species • Bacterial DNA is used because it is simple, reproduces quickly, and not controversial • Uses-Creates crops resistant to drought, disease, and insects • Creates insulin rapidly

22. Plasmid is a circular piece of DNA. Cut the plasmid using restriction enzymes Like scissors cutting the DNA at a specific location. DNA ligase is the tape that Connects the two pieces of DNA back together

23. DNA Fingerprinting-Gel Electrophoresis • The process in which a sample of DNA is exposed to an electrical current causing it to separate into bands. • Uses- to determine parents of a child and to help solve crimes (guilt or innocence) Banding pattern will be the same for the suspect and the crime scene

25. Determining Parents of a Child • Bands of child must be found in either the mother’s or father’s DNA