1. Chapter 6-Chromosomes and Cell Reproduction Section 1-Chromosomes-Formation of new cells by cell division – How chromosome numbers and structure affect Development Section 2-The Cell Cycle – The life of a eukaryotic cell – Control of the cell cycle Section 3-Mitosis and Cytokinesis

2. Homework for Chapter 6 Key terms-Section 1-14 points Supplemental puzzle and reading-33 points Key terms-Section 2-5 points Mitosis-Drawing-50 points (more later) Key terms-Section 3-1 point Possible paper on genetic mutations with citations-50 points Test Chapter 6-90 or so points Total this chapter-Approximately 243 points

3. Chromosomes Formation of new cells by cell division – About 2 trillion cells are produced by an adult human body every day! About 25 million/minute. – The type of cell division differs depending on the organism and why the cell is dividing. – The babies are growing and the skin is in need of a repair.

4. Prokaryotes, eukaryotes, and gametes undergo different types of cell division Gametes-An organism’s reproductive cells, such as a sperm or egg cell. When a cell divides, the DNA is first copied and then distributed. Each cell ends up with a complete set (copy) of the DNA. What is DNA? Deoxyribonucleic acid, oh no it came back to haunt us!!!!

5. Prokaryotic Cell Reproduction Binary fission-A form of asexual reproduction that produces identical offspring. In asexual reproduction, a single parent passes exact copies of all its DNA to its offspring.

6. Eukaryotic Cell Reproduction Gene-No not my dad, but a segment of DNA that codes for a protein or RNA molecule. A single molecule of DNA has thousand of genes lined up like train cars. – Play an important role in determining how a person’s body develops and functions. Chromosomes-The DNA and the proteins associated with the DNA become visible.

7. Before the DNA coils up the DNA is copied. Chromatid-The two exact copies of DNA that make up each chromosome. Centromere-Two chromatids of a chromosome are attached at this point.

8. How chromosome number and structure affect development Each human somatic cell (other than sperm and egg)has two copies of 23 different chromosomes. Homologous chromosomes-Chromosomes that are similar in size, shape, and genetic content.

9. Diploid-Somatic cells that contain two sets of chromosomes. Haploid-Contains one set of chromosomes. – n-haploid number in a human gamete(sex cells) – 2n-diploid number in somatic cells(other cells) Zygote-Fertilized egg cell, the first cell of a new individual. Let’s look at page 121.

10. Sex Chromosomes Autosomes-Chromosomes that are not directly involved in determining the sex (gender) of an individual. Sex chromosomes-One of the 23 pairs of chromosomes in humans, which contain genes that will determine the sex of the individual.

11. Change in chromosome number Trisomy-Humans with more than two copies of chromosomes. – Trisomy 13, 18, and 21 Karyotype-Abnormalities in chromosome number can be detected using this. Ms. Todd will go over CVS, eggs, and sperm cells. Let’s go over karyotyping and do the worksheet. Mutations-Library, November 21-22, citations needed. We will all be doing different mutations. End of Section 1!!!!

12. The Cell Cycle Cell cycle-A repeating sequence of cellular growth and division during the life of an organism. Interphase-90% of a cell spends its time in the first three phases. – First growth (G₁) phase-Cell grows – Synthesis (S) phase-A cell DNA’s is copied – Second growth (G₂) phase-Preparations for nuclear division – Mitosis-Process of cell division – Cytokinesis-Cytoplasm divides. – Work on worksheet, finish up after mitosis lecture.

13. Cancer-The uncontrolled growth of cells, a disorder of cell division. End of section 2-Know the stages of cell cycle

14. Mitosis and Cytokinesis During mitosis the nucleus divides to form two nuclei, each containing a complete set of the cell’s chromosomes. During cytokinesis the cytoplasm is divided between the two resulting cells.

15. Spindle-Cell structures made up of both centrioles and individual microtubule fibers that are involved in moving chromosomes during cell division. Centrioles and spindle fibers-Are made up of microtubules!!! Remember that?