Question of the Day GOAL SETTING: Unit 4 Test grade = ____% I feel I was successful or unsuccessful 3. I prepared by… 4. Next time I will prepare by… 5. Goal for next time = ____ If you met your goal + got an A: You may maintain or improve. If you met your goal but did not get an A: You must improve at least 1 percentage points. If you did not meet your goal it stays the same. 2-22

Question of the Day 2-23 2 things you know about DNA = ??? (can be anything you’ve learned before – write something down!!!)

Objectives Describe shape / function of a chromosome Describe differences between autosome & sex chromosomes.

Chromosome Structure Chromosomes Histones - rod-shaped structures made of DNA and protein – formed during cell division Histones - Proteins that DNA wrap around aids in the compact structure of the chromosome

Chromosome Structure

Parts of a chromosome Eukaryotic cells: Chapter 8 Eukaryotic cells: Chromatids – ½ of the chromosome – identical to other half – replicated in the “S phase” for replication Centromere – where sister chromatids are joined. Genes – bands found on the chromosome

Chromatin – uncoiled DNA found in nucleus – Seen when cell isn’t dividing

Contain only 1 circular chromosome Chapter 8 Prokaryotic cells: Contain only 1 circular chromosome

Comparing Cell Division in Prokaryotes and Eukaryotes Chapter 8 Comparing Cell Division in Prokaryotes and Eukaryotes Prokaryotic cells reproduce faster than eukaryotic cells – Less sophisticated, takes less time

Chromosome Numbers Different species have a characteristic number of chromosomes in each cell. More chromosomes do not always equal more sophisticated

Previewing Assignment 2-22 In owl book – get questions from me and read pages 145-147 (Cell Reproduction – section # 1)

Question of the Day 2-24 What is the relationship between DNA and chromosomes?

Review 2-24 What am I? What am I? What am I? What am I?

Objectives Describe shape / function of a chromosome Describe differences between autosome & sex chromosomes.

Chromosome Type Autosomes Non-sex chromosomes 22 pairs Sex Chromosomes determine the sex of an organism In humans: X and Y XX = female XY = male

Homologous chromosomes Chromosomes that carry the same genes (not necessarily the same code) One from dad other from mom Karyotype Picture of chromosomes in a normal dividing cell

Karyotype Used primarily to study chromosome problems Stop cell in metaphase and stain the chromosomes Match use length and bands (bands can represent 100’s of genes)

Karyotype Identifying a Chromosome: Length Placement of centromere Banding patter http://learn.genetics.utah.edu/content/begin/traits/karyotype/

Diploid and Haploid Cells Diploid - Cells having two sets of chromosomes – 2n - which means 2 x number of chromosomes All human cells except sex cells Haploid Cells – Cells which have only one set of chromosomes (1n) Sperm and egg cells ASSIGNMENT

Review Describe the structure of a chromosome. Identify the differences in structure between prokaryotic chromosomes and eukaryotic chromosomes. Compare the numbers of chromosomes in different species. Explain the differences between sex chromosomes and autosomes. Distinguish between diploid and haploid cells.