1. Warmup 11/6/15 Where have you heard the term "chromosome" before? Tell me what you think this is and how it relates to genes. Objective Tonight’s Homework To learn how DNA is grouped and clustered pp 117: 1, 4 Research a chromosome

2. Notes on Chromosomes Genes don’t just float around in the nucleus of a cell. They are attached end to end in very long strands of DNA.

3. Notes on Chromosomes Genes don’t just float around in the nucleus of a cell. They are attached end to end in very long strands of DNA. We call these super long strands chromosomes. Actually, what we’re seeing is two identical chromosomes that have been twisted together in the middle, like balloons in a balloon animal.

4. Notes on Chromosomes The DNA is held in this “X” shape by many different kinds of proteins. These proteins help hold, move, copy, and read the DNA

5. Notes on Chromosomes Chromosome Numbers So how many of these “X”s do we have? The average human adult has 22 pairs of chromosomes along with either an “XX” pair or an “XY” pair for gender.

6. Notes on Chromosomes Chromosome Numbers So how many of these “X”s do we have? The average human adult has 22 pairs of chromosomes along with either an “XX” pair or an “XY” pair for gender. 23 pairs, 46 chromosomes total.

7. Notes on Chromosomes Not all creatures have the same number of chromosomes. Some – like the fruit fly – have only 8. Others – like the crayfish – have 200.

8. Notes on Chromosomes Not all creatures have the same number of chromosomes. Some – like the fruit fly – have only 8. Others – like the crayfish – have 200. Many creatures have their chromosomes in pairs (called homologues). Any creature with its chromosomes in pairs is called “diploid”

9. Homework The average human has 23 different chromosomes. One of your tasks for homework is to pick one of the chromosomes (usually named and numbered like “1”, or “7”, etc) and research what genes this chromosome is known for. Find the following: - What major genes are on this chromosome - What diseases or disorders happen when something goes wrong on this chromosome - 1 other interesting fact about this chromosome

10. Mitosis Foldable We’re going to start talking about mitosis tomorrow as well: how cells split. You’re going to make a foldable of information. This will involve 3 pieces of paper. The middle piece will have all the information about each phase. The top piece will list the name of each phase along with a picture. You’ll put another top piece on the back, but you’ll leave this one blank. We’ll fill it out later when we do meiosis. Spend the rest of class setting your foldable up to be ready for info tomorrow.