APPROPRIATE CELL DIVISION IS NECESSARY FOR: Living Environment Ospelt Unit 7: CELL DIVISION AND REPRODUCTION Nuclear membrane Every cell has a life of its own! Centrioles The nucleus of the cell contains the genetic material – DNA. It is usually found in an unorganized mass of CHROMATIN. In a reproducing cell, the DNA is “packaged” into chromosomes A computer to direct all cell activities chromatin nucleolus DNA is needed to function properly There is a limit to the size a cell can grow. It will have to divide into two new smaller cells. WHY?? DNA overload The DNA is not adequate to serve the increasing needs of the bigger cell Food, oxygen and water enter a cell by diffusion; wastes exit. The rate of exchange depends on______________________________ The rate at which food, oxygen and water are used up and wastes produced depends on the _________________________ Decreased surface area to volume ratio Surface area volume APPROPRIATE CELL DIVISION IS NECESSARY FOR: Cells lining the Villi of the Digestive Tract must constantly be replaced as they live only a day or 2 Skin cells are replaced every 6 – 12 day New cells must be produced to repair wounds Growth relies on new cell production GROWTH REPAIR MAINTENANCE Cells will divide forming 2 _________________________ cells TO PREPARE, A CELL MUST DUPLICATE (COPY) ALL THE ITS DNA SO THAT EACH DAUGHTER CELL GETS ON COMPLETE SET OF GENETIC INFORMATION daughter Controlled by chemicals (cyclins) & regulators (neighboring cells)

cell division (cytokinesis) CELL CYCLE: A cell grows, prepares for division, and divides to form two new IDENTICAL daughter cells. centromere Start with a full set of chromosomes 2n Diploid # Result: 2 cells Identical 2n Diploid # MITOSIS: Portion of the cell cycle in which chromosomes are distributed to two new cells Accompanied by cell division (cytokinesis) Previously, During Interphase, DNA has replicated STAGES OF MITOSIS: METAPHASE ANAPHASE PROPHASE TELOPHASE And CYTOKINESIS

Single celled organisms incorporate mitosis when they reproduce The normal number of chromosomes in an organism’s body cell is called the diploid number. There are two of each type of chromosome. This is represented as: 2n 2n = 4 2 Homologous pairs Replicated As a result of mitosis, _____ daughter cells are produced each with the ______________number. they are ________________ to the parent cell and each other. 2 diploid identical

Mitosis, Pretty Sweet! Mitosis is an awesome process in which two identical cells (daughter cells) are produced from one cell. Don’t you wish that it wasn’t just cells that went through mitosis. Think about how awesome it would be if some of our stuff could do that! Imagine a machine that could duplicate some of our stuff. Create an advertisement trying to sell this “Mitosis Machine”. Be sure to include; What does mitosis do for cells What does the mitosis machine do? What do you start with, and what do you end up with?

mitosis ASEXUAL REPRODUCTION Cell division Binary Fission Budding Key Idea 4: The continuity of life is sustained through reproduction and development Species transcend individual life spans through reproduction. ASEXUAL REPRODUCTION Involves one parent Utilizes ___________________ and subsequent _______________________________ mitosis Cell division 4.4b During mitosis, chromosomes are duplicated and then separated into two identical and complete sets to be passed to each of two resulting cells. All the genes come from a single parent, therefore all offspring are identical to each other and to the parents. Binary Fission Budding Unequal offspring 2 equal offspring Hydra Yeast Paramecium Ameoba Spore formation Regeneration Grow back Lost parts Specialized cells; contain DNA Bread mold Starfish Planaria Vegetative Propagation Artificial Vegetative Propagation Tuber runners Cuttings Bulb Grafting

B ABCD A D C

Metaphase Prophase Anaphase Telophase Interphase DNA overload. There is not enough DNA for the cell to function properly. It is like an entire class trying to do a lab with only one copy of instructions Decreased Surface area to volume ratio. The cell gets too big and cant diffuse waste out or nutrients in efficiently enough. Mitosis. Cell grows during interphase and replicated DNA. During prophase DNA coils into chromosomes, during metaphase they line up down the middle, move apart in anaphase and separate into two cells during telophase and cytokinesis It would die! The cell would have no instructions for living!

Homework OUT! Remember, it was that summarize the notes pages sheet thingy majiger

½ number of chromosomes SEXUAL REPRODUCTION: Involves two parents Produce gametes [female – egg / male – sperm] containing ½ the genetic content Offspring will receive ½ genetic material from each parent Mitosis will not work! Need a type of division to produce cells with ½ genetic content __ __ __ __ __ __ __ : process to produce nuclei with only ½ the genetic content Reduction Division MEIOSIS 2n diploid number = 4 Chromosomes replicate Crossing Over may occur Synapsis: Homologous pairs line up to form tetrads Division #1 Disjunction: Pull Apart Division #2 n Monoploid number = 2 End result: 4 cells, ½ number of chromosomes Gametogenesis: production of gametes Oogenesis: production of eggs Spermatogenesis: production of sperm Each gamete contains ½ genetic material, l homolog each 1 egg ; n  4 sperm ; n Sexual reproduction allows for variety as no two eggs and sperm are alike!

Undifferentiated cells Can form any type of cell FERTILIZATION AND EARLY DEVELOPMENT +  = The nucleus of the sperm joins the nucleus of the egg. Contains a unique combination of genetic material Contains all information necessary for growth, development and eventually reproduction Ready to begin to develop into a new individual Egg ZYGOTE 46 Sperm n 23 n 23 FERTILIZATION DEVELOPMENT: Highly regulated process involving mitosis and differentiation EARLY DEVELOPMENT Involves the process of CLEAVAGE: RAPID MITOTIC DIVISION All cells at this point have identical DNA Like stem cells Undifferentiated cells Can form any type of cell D I F F E R E N T I A T I O N At this point, cells will now undergo __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ as a result of Gene Expression Different gents are activated (or deactivated) in certain cells. This causes them to make only some of the proteins they are capable of synthesizing; thus producing _____________ cells Vs. cells of the _______________ As a result, these cells become different from others, and will develop into _________________________________ Which in turn will form ______________ and _________ of a multicellular organism Produces different types of cells as the zygote changes in to the embryo liver pancreas Specialized cells tissues organs Gene expression can be modified by interaction with the environment Skin exposure to sun Smoking Plants grown in the absence of light will NOT be green

Testosterone and Semen MALE REPRODUCTIVE ANATOMY Testosterone and Semen Purpose: To produce _________________________ To produce sperm, and deliver to the site of internal fertilization B C D E F A Male Gonads Spermatogenesis: production of sperm Secrete Testosterone: secondary sexual characteristics Located within these sacs. Lower temperature is necessary for sperm production B Passageway for sperm C Produce fluid D E Passageway for semen, and urine F Structural adaptation for internal fertilization Testes Scrotum Vas Deferens These fluids, together with sperm, produces semen Seminal Vesicles Prostate Urethra Penis Vasectomy _____________________: a procedure to cut the vas deferens; then sperm cannot pass

FEMALE REPRODUCTIVE ANATOMY: PURPOSE: To produce estrogen and progesterone To provide the site for internal fertilization and development A B C E D A FEMALE GONADS Produce eggs by oogenesis At birth, immature eggs are contained in special sacs called follicles. At puberty, one egg a month will mature and be released by ovulation. Secretes estrogen – responsible for secondary sexual characteristics B Tubes through which eggs travel when released from the ovaries to the uterus THIS IS WHERE FERTILIZATION WILL OCCUR C Thick walled structure; this is where the embryo will develop. D A muscular ring found at the neck (base) of the uterus. This opening is closed during gestation. E Birth canal OVARY OVIDUCTS Fallopian Tubes UTERUS CERVIX VAGINA

Sac of fluid; protects the fetus HUMAN FERTILIZATION, DEVELOPMENT AND BIRTH Fertilization Occurs in the 2. Occurs as the embryo travels through the oviduct Embryo will then implant in to the wall of the uterus OVIDUCT CLEAVAGE DIFFERENTIATION 4. Forms between the wall of the uterus and the embryo Organ of exchange - by diffusion: Nutrients and oxygen diffuse from mom to baby Wastes diffuse from the baby to the mom PLACENTA Note: blood does not mix AMNION _______________ Sac of fluid; protects the fetus Fetus harmed by: SMOKING: low birth weight ALCOHOL: FAS DRUGS: brain damage UMBILICAL CORD _______________ Connects the fetus to the placenta POOR NUTRITION

ULTRASOUND REPRODUCTIVE TECHNOLOGY __________________: a technique that uses sound waves to “see” the fetus Multiple births: Fraternal twins: ______________________________ Identical twins: _______________________________ 2 eggs, 2 sperm 1 egg/ 1 sperm: split Amniocentesis: extract amniotic fluid, test fluids, view embryonic cells with a microscope Karyotype

Follicle turns in to the corpus luteum MENSTRUAL CYCLE 1 2 FSH Causes egg to develop in follicles FSH LH Negative feedback Follicle turns in to the corpus luteum Which secretes: 3. Progesterone 4. estrogen Builds up uterine lining No fertilization; Corpus luteum breaks down, Lining is shed