Chapter 8: Cell Reproduction & Genetics 8.1: Chromosomes Do Now: Please answer the following questions on your handout: 1. What part of a eukaryotic cell are chromosomes found in? Hint – they’re made of DNA. 2. How are genes related to chromosomes?

Unit 6: Cell Reproduction & Classical Genetics

Unit 7: DNA & Molecular Genetics

Unit 8: Ecology

Unit 9: Evolution

Unit 10: Body Systems

Chromosomes

Chromosome Structure DNA strand Gets wrapped around many histone proteins (aka histones) forming a coil. Coils are coiled up even more to form a supercoil, which is then packaged even more to make a chromosome.

What’s the big idea? Most of the time, DNA is uncoiled, so that it can perform its function of providing instructions to the cell. Only during cell reproduction does DNA get tightly packed into chromosomes

Parts of a chromosome The 2 chromatids that make up a chromosome are called sister chromatids, which are extremely similar to each other.

Constructing Model Chromosomes Your group has been given enough materials to make 4 model chromosomes. There should be 3 parts to each model chromosome: 2 sister chromatids 1 centromere How many chromosome models could be built using the parts shown here?

Evaluating Your Model What do our models represent well? Some Questions What do our models represent well? What characteristics don’t they represent so well? Draw a sketch of your model into your notes, and Bring them to class tomorrow – we’ll be using them again!

Tonight’s Homework: Read pp. 145-146; Questions #2-3 p. 147