1) DNA is a chemical that stores information as a code. This code is instructions for how to make life. 2) DNA carries hereditary information from one generation to the next.

3D model – What are the parts?

All nucleotides have the same structure. The only thing that changes is the base. There are 4 bases, Adenine, Thymine, Cytosine, and Guanine Phosphate Sugar Base

The rungs of the DNA ladder are made from pairs of bases. There are four types of bases. They have complicated names so it is easier to use their initials instead. These bases always pair together in the same way. How do you think the four bases pair up? denine ytosine uanine hymine

Base pairs hold the two strands of the DNA helix together. The rules for base pairing are… There are millions of base pairs in a DNA molecule that always follow these rules. A always pairs with T C always pairs with G Amazingly, it is the sequence of bases along a DNA molecule that forms the genetic code – it’s that simple!

 Before cells divide the chromosomes must make perfect copies of themselves.  The special shape of the DNA molecule means that each half of the molecule acts like a template or model for the construction of a perfect new copy.

 In this way making a new chromosome is like making a new zipper by using the old zipper as a model.

Semi- Conservative

... begins when the two complementary DNA strands are separated. This is usually accomplished by special proteins that unwind the molecule and expose the nucleotide bases.  New complimentary DNA strands are then synthesized by joining together deoxyribonucleotide triphosphates, one at a time, and with the removal of a di-phosphate  At the end of the process the cell has made to identical copies of all the biological information contained on the original, parental, DNA molecule, but the two new daughter DNA molecules are "Half old" and "Half new". Half the original DNA molecule is saved, or conserved in the daughter molecules. This is why the process is called semi- conservative.

 2 types Mitosis Occurs in body cells Exact copy Growth/repair of organism Meiosis Occurs in testes and ovaries Results in cells with half the number of chromosom chromosomes (n) Produces variation

This single cell is copied repeatedly to form an adult with approximately 10,000,000,000,000 cells – all with exactly the same information. How does this copying take place? 1.Each chromosome copies its information (DNA replication) and is now called a chromatid. 2. The chromatids line up in the middle of the cell. 3. Half of each chromatid goes to each end of the cell. 4. Two new cells are formed. MITOSIS See an animation of Mitosisanimation

 SNE9pNE

MEIOSIS Meiosis is the special type of cell division that creates gametes. Why is it necessary to halve the amount of information passed on? Two gametes (one from each parent) fuse to form a zygote. A child is born How does meiosis happen? 1. Chromosomes double, just like in Mitosis to form chromatids. 2. Half of the chromatids go one way and half the other. 3. Two new cells are made. 4. The chromatids divide again to form four cells. Each with one set of information. Haploid = 1 set of chromosomes Diploid = 2 sets of chromosomes Mitosis /meiosi s test Square dance

 Is a special type of cell division which occurs in the ovaries and testes in the production of gametes  Gametes have half the number of chromosomes (1n) present in other body cells  An important feature of meiosis is the mixing of genetic material  The four gametes formed are all different  (Watch the animation)

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 This project (passed down to me from a fellow teacher) is based on the old cartoon flip book idea. Students use template cards (printed on cover stock or glued to index cards) to create a booklet that illustrates the steps involved in cell division. After reviewing the stages in cell division (see the Mitosis Note page below), I provide a set of templates (see Mitosis Book below) for them to use to make a flip book. From phase to phase, they must draw diagrams to show the changes that occur throughout the process. I encourage "color coding" to make the end effect easy to follow. Once all the Pages are completed and in the correct order, students use a heavy duty stapler to bind them together. They can flip through the pages and "see" mitosis in action.

 See an animation of Mitosisanimation  Square dance Square dance  12Bio 2010

1. Crossing Over 2. Independent assortment: Homologues line up or "shuffle" randomly on the metaphase plate in Meiosis I. With 23 chromosomes assorting independently, there are 2^23, or 8 million, possible assortments of chromosomes inherited for every cell!! 3. Random fertilization: The ovum has 8 million possible chromosome combinations, so does the sperm cell. 8 million x 8 million = 64 trillion possible diploid combinations in EACH AND EVERY zygote! WOW!!

 Create a paragraph that compares mitosis and meiosis  You will have ten minutes then I will choose some people to read out their paragraph

CloningThoughts on use BrewingThoughts on use Bread MakingThoughts on use Dairy ProductsThoughts on use AntibioticsThoughts on use

 What exactly is cloning? Cloning is the creation of an organism that is an exact genetic copy of another. This means that every single bit of DNA is the same between the two!

 Extract from pigs  Gene cloning