TOPIC: Genetics AIM: What is DNA & RNA?

TOPIC: Genetics AIM: How does DNA store genetic information? DO NOW: 1. Parents: Hybrid blood type A x pure blood type A What are the chances of having a child with blood type O?

AO x AA A O 0% CHANCE OF HAVING A CHILD WITH BLOOD TYPE O AA AO A

2. Cross a female with pure blood type A and a male with heterozygous B blood type. AA x BO

AA x BO B O A A B A O 50% blood type AB A A B A O 50% blood type A

Chromosomes & Genes… Humans are 99.9% genetically identical – only 0.1% of our genetic make-up differs. All of your genetic information that’s contained inside the microscopic nucleus of a cell is so tiny that it could easily fit on the head of a pin!  If all 46 chromosomes from one cell were combined and arranged lengthwise, the total length would be 1.8 meters. Humans have approximately 30,000 different genes spread out over the 46. Our genes are remarkably similar to those of other life forms. For example, we share 98% of our genes with chimpanzees, 90% with mice, 85% with zebra fish, 21% with worms, and 7% with a simple bacterium such as E. coli.

DNA Deoxyribonucleic acid Makes up genes

Function of DNA Stores & passes on genetic info : DNA Codes for specific proteins to be made in the cells.

2 strands, spiral staircase Shape of DNA Double Helix 2 strands, spiral staircase

Who discovered DNA? Rosalind Franklin (double helix)

James Watson & Francis Crick (1950’s - Nobel Prize for creating model)

Structure of DNA

Nucleotide Building block of DNA

3 parts: 1. sugar 2. Phosphate group sugar phosphate

3. Nitrogen base: adenine, thymine, guanine, or cytosine - A, T, C, G sugar phosphate Nitrogen base

DNA = 2 strands of nucleotides twisted around each other G G C

Each strand is complimentary (match up) Nitrogen Bases Pair up = A-T, G-C Each strand is complimentary (match up)

Base pairing: A T T A C G G C

If you stretched out the strands of DNA from a single human cell end to end, it would measure about 6 feet long but it would be so incredibly thin, 50 trillionths of an inch wide, that you wouldn’t be able to see it. The DNA in a newborn baby would reach from the sun to the planet Pluto and back 15 times if it was completely stretched out.

Order of nitrogen bases determines which genes you have

How a copy of the DNA is made Replication How a copy of the DNA is made

Interphase of cell division

Steps: 1. DNA unzips (strands separate) between the nitrogen bases at the hydrogen bonds.

2. Free nitrogen bases match up on each strand

RESULT = 2 new identical DNA molecules

Review: 1. Write the complimentary DNA strand that would be attached to the one below: A T C G G A T G T 2. What is the first step of DNA replication? 3. What is DNA made of? 4. Where is DNA found? 5. Explain the shape of DNA.