121R Unit V Cell Division Chp 12 & 13

122L Cell Cycle: life of a cell from its formation until it divides to make ______ cells. Functions of Cell Division: ___________- make a new organism. Growth - increase in___________ Tissue Repair –___________new cells The Cell Cycle: Making an ___________copy Occurs in ___________cells (Body cells) Happens in plant & animal cells Results in ___ identical daughter cells Centrioles Chromatin

Homologous Chromosomes Genome = all of a cell’s ___________info (DNA) Prokaryote: single, ___________chromosome Eukaryote: more than one ___________chromosomes Ex. Human: ____ chromosomes 123R Discovery of chromosomes  All Eukaryotic organisms have a ___________ number of chromosomes in their cells Human somatic cells (Body cells) have 46 chromosomes. A ___________chromosome number. After cell division, the ___________cells will contain the ___________number of chromosomes during mitosis. Human ___________cells (sperm & egg) have ____ chromosomes. A ___________ (half) chromosomes number during meiosis. Parts to a chromosome  Chromosomes are always in___________ They are called ___________chromosomes Each chromosome contain the following” * 2 ___________chromatids *1___________ * 2___________ Centromere Sister chromatids (Mom) (Dad) Homologous Chromosomes

Phases of the Cell Cycle Interphase (90% of cell cycle) G1S G2 M Phases (___________) Mitosis: nucleus divides Cytokinesis: ___________divides 124L Paste “cell cycle” here A) Interphase The majority of a cells life (____) is spent in this growth period. Divided into three parts: G1, S, G2 G1 = Gap 1 S = Synthesis G2 = Gap 2 First growth phase ________& development Metabolic activity Approx ___ hours ________ synthesis Chromosome_________ Approx ___ hours Second growth phase Synthesis of ___________and replication of centrioles Approx ___ hours

Paste “ Mitosis” picture here B) Mitotic Phase Division of the___________ Divided into stages Prophase ___________ Metaphase Anaphase Telophase 125R Paste “ Mitosis” picture here

MITOSIS Prophase Prometaphase 126L Metaphase Nuclear Division Spindle fibers Doubled chromosome Chromosome___________ Mitotic spindle begins to form Nuclear membrane___________ Disappearing nuclear envelope Prometaphase ___________membrane begins to disappear Centromeres contain protein called___________ Mitotic spindle attaches to___________ ___________move to opposite sides of cell Spindle fibers Metaphase Centromere Chromosomes are pulled toward the _______ (Metaphase plate) and line up at the ___________of the spindle. Spindle fibers

Paste “ Cytokinesis” here Anaphase 127R Chromosomes move toward ___________ poles Spindle fibers pull chromosomes to opposite sides of cell Cell___________ Spindle fibers Telophase Nuclear membrane ___________ (reappear) Chromosomes ___________to form chromatin (threadlike bundles of DNA) Nuclear envelope reappears Two daughter cells are formed C) Cytokinesis Division of the___________ Animal Cells: cleavage_ __________ Plant Cells: cell _____ forms Paste “ Cytokinesis” here

128L Paste “ Drawing of mitosis” here

Paste “ Circle of mitosis” here

Paste “ concept covered: Name that stage” here 130L Paste “ concept covered: Name that stage” here

Cell Cycle Control System ____________= control point where stop/go signals regulate the cell cycle G1 checkpoint (Most important!) Controlled by cell____ , growth factors, ____________ “Go”  completes whole cell cycle “Stop”  cell enters non-dividing state (G0 Phase) Nerve, muscle cells, liver cells stay at G0 for an extended period of time. Regrow at a very slow rate Paste “checkpoints” picture here Density dependent inhibition Density dependent inhibition – when normal crowded cells ______dividing ____________dependency – when normal cells are attached to a tissue to divide Paste “inhibition” picture here

Tumors = mass of abnormal cells Transformation: process that converts a normal cell to a ____________ cell 132L Cancer cells: in which cells _______ the ability to control growth by ______ responding to checkpoints. They ______ the density dependent inhibition and _______ to divide non-stop Tumors = mass of abnormal cells ______ tumor: lump of cells remain at original site ______ tumor: invasive - impairs functions (called cancer) _________ : cells separate from tumor and ______ to other parts of body Bacterial cells -divide by ________ Fission -____________ simply divide into two cells -occurs very____________ Paste “ binary fission” picture here

Types of reproduction: MEIOSIS Formation of Gametes (Egg and sperm) 133R ________ are segments of DNA that code for the basic unit of heredity and transmitted from one generation to the next _________ are sex cells (sperm & Egg) A ______ (loci) is the location of a gene on a chromosome. Types of reproduction: Asexual reproduction – a _______ parent is the sole parent of passes copies of all its genes to the offspring. Occurs by mitosis. This process gives rises to clones, a group of genetically identical individuals Sexual reproduction – two individuals (parents) contribute ________ to the offspring. Has a greater genetic________. Gametes (Meiosis) Sex cells (sperm/egg) ________ (n): 1 of each type of chromosome Divide by________ Humans: n = 23

Meiosis stages: 134L Facts About Meiosis Interphase Two meiotic divisions Meiosis I – separates _________ chromosomes Meiosis II – separates sister_________ Facts About Meiosis Produces ___________ (eggs & sperm) Occurs in the testes in males (____________) Occurs in the ovaries in females (____________) Original cell is ____________ (2n) (Specialized cells – germ cells) Interphase only takes place at the ____________of meiosis I ____________daughters cells are produced that are haploid (n)

Meiosis: Two Part Cell Division Meiosis I Meiosis II Interphase divided into three parts: G1 – Growth & development S – DNA____________ G2 –____________replicate S G2 G1

Meiosis I: Reduction Division 136L 1st stage = Prophase I Early prophase ____________pair Crossing _________ occurs. Late prophase Chromosomes____________. ____________forms. Nuclear envelope____________ Tetrads Form in Prophase I Homologous chromosomes (each with sister chromatids)   Join to form a____________ Called Synapsis

Crossing- Over Crossing-Over only occurs in prophase I 137R Homologous chromosomes in a tetrad ________ over each other Pieces of chromosomes or genes are____________ Produces Genetic ____________in the offspring Crossing- Over Each chromatid is now ____________from the other for independent assortment

4th stage = Telophase I/Cytokinesis 2nd stage = Metaphase I 138L Homologous pairs of chromosomes _______along the equator of the cell 3rd stage = Anaphase I _________ separate and move to opposite poles. Sister ____________remain attached at their centromeres. 4th stage = Telophase I/Cytokinesis Nuclear envelopes____________. Spindle disappears. Cytokinesis divides cell into__________ .

Meiosis II: Reducing Chromosome Number 5th stage = Prophase II Nuclear envelope____________. ____________forms. 6th stage = Metaphase II Chromosomes align along ____________of cell. 7th stage = Anaphase II Sister __________ separate and move to opposite poles.

8th stage = Telophase II/Cytokinesis Nuclear ____________assembles. Chromosomes____________. Spindle disappears. ____________divides cell into two. Results of Meiosis ____________ (egg & sperm) form ____________haploid cells with one copy of each chromosome One allele of each____________ Different ____________of alleles for different genes along the chromosome

Paste “Drawing of Meiosis” here

142L Paste “ concepts: comparing mitosis & meiosis” picture here

Paste “ Venn diagram” here

Chromosomes & Karyotype 144L Chromosome Number ____________Cells Body cells ____________ (2n) Divide by____________ Humans: 2n = 46 chromosomes

Karyotype 145R Paste “Human Karyotype” picture here A ____________of an individual's somatic cells. Are arranged in a sequence (#1-23) Always in____________ ____________ Total of 46 chromosomes. Autosomes – non sex chromosomes # 1 - 22 Sex chromosomes – determines the individual’s sex # 23 XX – ____________ XY – ____________ Determine disorders of an individual Paste “Human Karyotype” picture here

Nondisjunction Disorders 146L _______ to separate during meiosis too few or too many____________ Disorders: (____________) See handout Paste “ chromosomal nondisjunction disorders” picture here

Controlling cell division: Cell needs essential ____________in order to divide “growth factors” Skin cells divide most____________ _________ & muscle cells DO NOT divide in a mature adult (Go phase) Growth factors protein _________ released by body cells that stimulate other cells to divide density-dependent inhibition ____________cells stop dividing each cell binds a bit of ____________factor not enough activator left to trigger division in any one cell Cancer cells divide excessively and invade other tissues, they ignore the density – dependent inhibitor ____________– the spread of cancer cells beyond the original site. Tumor – mass of cancer cells Benign – noncancerous Remain at the cancer site Malignant -____________ Move toward other sites

The End