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

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

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.

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!!!!

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.

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.

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.

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.

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.

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.

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!!!!

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.

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

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.

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?