Chapter 9, Section 2 & 3 Regular Biology DNA- Replication Chapter 9, Section 2 & 3 Regular Biology

Objectives Describe structure of DNA Explain importance of DNA Understand why living things need to make copies of DNA Describe how copies of DNA are made Explain what happens if a mutation occurs in replication

Deoxyribose Nucleic Acid Structure of DNA Deoxyribose Nucleic Acid Double helix Made of 2 strands of nucleotides Phosphate Sugar (deoxyribose) Nitrogen Base Adenine (“A”) Thymine (“T”) Cytosine (“C”) Guanine (“G”) Nucleotide

About DNA TATGGAGAGTC ATACCTCTCAG Sugar & Phosphate make up the sides In the middle of DNA Adenine pairs with Thymine (A-T) Cytosine pairs with Guanine (C-G) Practice: TATGGAGAGTC ATACCTCTCAG Complementary base pairs

More Practice CATAAGTCCT ATTGTCT CTAATGT 1. GTATTCAGGA 2. TAACAGA 3. GATTACA CTAATGT

Names to Know, pg 196 Chargaff- (1949) A pairs with T. G pairs with C Mrs. Franklin- (1952) X-ray pictures of DNA Watson & Crick- (1953) DNA is double helix

Prokaryote DNA is: Prokaryote DNA is circular Has 2 replication forks Replication occurs in opposite directions around the circle until they meet Can replicate in 1 hour or less

Eukaryote DNA is: Eukaryote DNA is double stranded Compacted in chromosomes Each chromosome can have about 100 replication forks Each “new” DNA strand is about 100,000 nucleotides long. The DNA in your body would wrap around the Earth about 1.5 times! Takes about 8 hours to replicate human chromosomes in Interphase

Prokaryote vs Eukaryote

Prokaryote vs Eukaryote DNA Make a Venn Diagram Prokaryote vs Eukaryote DNA

Replication- Making more DNA Happens in the nucleus What? Replication- Making more DNA Where? Happens in the nucleus When? Occurs during Interphase S (synthesis) phase Occurs whenever is needed

Replication- Making more DNA Why? Important for Mitosis and Meiosis Mitosis- new cells for growth & repair Meiosis- new cells for sperm & egg Important for making more copies of a protein, enzyme, etc

Replication- making more DNA Two strands separate, forming replication fork DNA polymerase (an enzyme) brings bases to make “new” strands 500/sec in bacteria, 50/sec in humans….WOW! Half of DNA strand is “old” and half is “new” Result: two strands of DNA form that are identical to the original molecule

But what if there’s a mistake? Types of Mutations Frameshift- (the new part of DNA shifts to be longer or shorter than it should be) Deletion Correct base is deleted Insertion Incorrect Base is added Point mutation (base pair substitution) Wrong base pair is stuck in the place of another

Build-in Mutation Reducers Replication has “proof-readers” to help reduce errors DNA polymerase Chaperone proteins These proteins and enzymes reduce errors to about 1 error for every 1 billion nucleotides.

But what if a mutation DOES happen? DNA RNA Protein (Genes) (Enzyme) Discussion!

Genetic Technology- Terms to Know Genetic engineering- Recombinant DNA- DNA made from 2 or more organisms Vector- What gets the gene into the cell Usually a virus, yeast, or plasmid Plasmid- circular bits of DNA Restriction enzymes- proteins which cut the DNA at specific points

New Technology Human Genome Project- mapping entire human genome sequence. Finished in 2003. Cloning- process used to creating identical copy of organism Polymerase Chain Reaction (PCR)- process that makes more DNA DNA Fingerprinting- use gel electrophoresis to separate DNA of different lengths

Genetic Engineering Information Gel Electrophoresis Uses electric charges within gel DNA is negative, thus travels to positive end Separates molecules by size http://learn.genetics.utah.edu/units/biotech/

More New Technology Genetically Modified Foods- genetically selecting certain traits for crop improvement Transgenic Animals- Animals that have other DNA in their cell. Used to make proteins, medicine, etc. Gene Therapy- insert genes into organism to help stop or prevent disease

“There is no gene for Human Spirit!” Remember… “There is no gene for Human Spirit!”