MITOSIS and MEIOSIS Two Jobs of DNA Proteins Synthesis Self Replication Mitosis: body cell division: somatic cell division Meiosis: sex cell division: gamete formation

MITOSIS and MEIOSIS A. Prefixes telo end chromo color some body locus place homo same hetero different haplo half mono one di two pro first

Why Mitosis?  Cell Growth

A.  Why must cells divide? larger 1. The ____________a cell becomes, the more demands the cell places on its ________ In addition, the cell has more trouble moving enough ________and __________ across the cell membrane. DNA wastes nutrients The rate at which food, oxygen and water are used and waste is produced depends on the cell’s ________________. volume The rate at which food, oxygen, water, and wastes are moved in and out of the cell is dependent on the ___________________ of the cell. surface area

Ratio of Surface Area to Volume As the length of a cell increases, its volume increases __________ than the surface area. The decrease in the cell’s ratio of surface area to volume makes it more __________ for the cell to move needed materials in and waste products out quickly enough for the cell to survive. faster difficult

Division of the Cell Before it becomes too large, a growing cell divides forming two _______________ cells. The process by which a cell divides into two new daughter cells is called cell division or __________________. daughter MITOSIS In some eukaryotic one celled organisms this mode of division is called ___________________ reproduction because the genetic information remains constant from one cell cycle to another asexual Prefix “a” means: not or no

CANCER What happens when cell growth becomes unregulated? What are some forms of cancer? SKIN CANCER VIDEO

MITOSIS A. General information 1. Definition: Somatic cell division 2. Nickname: “Normal” cell division B. Background Information 1. Pairs of shoes? a. chromosomes are like shoes they come in pairs b. this is called the diploid condition c. this is designated 2n d. What would the n condition be called?

MEIOSIS A. General information 1. Definition: formation of sex cells 2. Nickname: “reduction” cell division 3. Starting cell: germ cell 4. Start with one cell : end with 4 “cells”

Homologous chromosomes MITOSIS Same: eyes Different: hair, nose and ears B. Background Information 1. Homologous Chromosomes b. the chromosomes to the right are homologues, they control like traits (hair/eye color, nose shape, ear lobes), but the control can be the same or different Homologous chromosomes a. def: chromosomes that control the same traits but not necessarily in the same way Question: which traits are controlled the same? Which differently? Punch here for answer

Sister chromatids attached by a centromere MITOSIS C. Jobs of DNA: Replication and Protein Synthesis 1. Prior to cell division DNA replicates itself. Each chromosome forms a mirror image of itself called a sister chromatid Sister chromatids attached by a centromere Question: If the chromosome on the right replicates itself what will it look like. Draw a picture in your notes Click here for answer

Lets go to the video tape THE MITOSIS ZONE Lets go to the video tape

MITOSIS INTERPHASE EVENTS: CELL IS AT REST

EARLY PROPHASE EVENTS IN EARLY PROPHASE 1. Nuclear membrane begins to disappear Nuclear membrane nucleolus centrioles Question: Don’t go until you can identify homologues and chromatids 2. Nucleolus disappears 3.Chromatin duplicates 4. Chromatin shortens and thickens 5. Centrioles duplicate and migrate

Late Prophase Events during late prophase 1. Aster rays appear 2. Spindle fibers appear

Metaphase Events of metaphase 1. Chromosomes line up on cell equator 2.. Homologous chromosomes are present but they do not pair (match) up. Metaphase

Anaphase Events of anaphase 1. Chromosomes begin to migrate to poles 2/4/2019 Events of anaphase 1. Chromosomes begin to migrate to poles

Telophase Events of telophase 7. Partition forms two new cells a. plants: plate/cell wall Events of telophase b. animals: membrane pinches off 1. Chromosomes lengthen and thin become chromatin 2. Aster rays disappear 3. Spindle fibers disappear 4. Nuclear membrane reforms 5. Nucleolus reforms 6. Centrioles reform

Interphase Cell is at rest Two identical cells

Onion Cell Mitosis

Specialized diploid cell found in the ovaries and testes Meiosis Interphase Germ Cell Specialized diploid cell found in the ovaries and testes

Meiosis Early Prophase Events 1. Chromosomes condense 2. Chromosomes duplicate 3. Nuclear membrane disappearing 4. Nucleolus disappearing 5. Centrioles migrate

Meiosis Late Prophase I Events 1. Aster rays appear 2. Spindle fibers appear

Meiosis Metaphase I Events