Cell Processes: Cell Division

Studying a Cell’s Size: Finding surface area to volume ratio 2.3 cm 4.5 cm

Cell Size Surface Area (length x width x 6) Volume (length x width x height) Ratio of Surface Area to Volume Ratio of Surface Area to Volume in Cells Section 10-1 Go to Section:

Cell’s Are Limited in Size! DNA Overload- not enough information to support large cells Exchanging Materials across the cell’s membrane is affected Water Oxygen Glucose Waste

Structure of a Chromosome Chromosome Supercoils Coils Nucleosome Histones DNA double helix Go to Section: Chromosome Structure in Eukaryotes

OrganismNumber (2n) of Chromosomes Yeast16 Mosquito6 Housefly12 Garden Pea14 Corn20 Fern480-1,020 Frog26 Human46 Orangutan48 Dog78

M phase G 2 phase S phase G 1 phase The Cell Cycle Section 10-2 Go to Section: Gap 1 Cells grow, photosynthesize/respire, make proteins and organelles ~12 hours

M phase G 2 phase S phase G 1 phase The Cell Cycle Section 10-2 Go to Section: S phase Chromosomes are replicated Each chromatid gets a “sister” ~ 6 hours

M phase G 2 phase S phase G 1 phase The Cell Cycle Section 10-2 Go to Section: Gap 2 Any organelles or molecules needed for cell division are produced- “getting prepared” ~ 6 hours

Centrioles Chromatin Interphase Nuclear envelope Cytokinesis Nuclear envelope reforming Telophase Anaphase Individual chromosomes Metaphase Centriole Spindle Centriole Chromosomes (paired chromatids) Prophase Centromere Spindle forming Section 10-2 Figure 10–5 Mitosis and Cytokinesis Go to Section:

Centrioles Chromatin Interphase Nuclear envelope Cytokinesis Nuclear envelope reforming Telophase Anaphase Individual chromosomes Metaphase Centriole Spindle Centriole Chromosomes (paired chromatids) Prophase Centromere Spindle forming Section 10-2 Figure 10–5 Mitosis and Cytokinesis Go to Section:

Centrioles Chromatin Interphase Nuclear envelope Cytokinesis Nuclear envelope reforming Telophase Anaphase Individual chromosomes Metaphase Centriole Spindle Centriole Chromosomes (paired chromatids) Prophase Centromere Spindle forming Section 10-2 Figure 10–5 Mitosis and Cytokinesis Go to Section:

Centrioles Chromatin Interphase Nuclear envelope Cytokinesis Nuclear envelope reforming Telophase Anaphase Individual chromosomes Metaphase Centriole Spindle Centriole Chromosomes (paired chromatids) Prophase Centromere Spindle forming Section 10-2 Figure 10–5 Mitosis and Cytokinesis Go to Section:

Centrioles Chromatin Interphase Nuclear envelope Cytokinesis Nuclear envelope reforming Telophase Anaphase Individual chromosomes Metaphase Centriole Spindle Centriole Chromosomes (paired chromatids) Prophase Centromere Spindle forming Section 10-2 Figure 10–5 Mitosis and Cytokinesis Go to Section:

Centrioles Chromatin Interphase Nuclear envelope Cytokinesis Nuclear envelope reforming Telophase Anaphase Individual chromosomes Metaphase Centriole Spindle Centriole Chromosomes (paired chromatids) Prophase Centromere Spindle forming Section 10-2 Figure 10–5 Mitosis and Cytokinesis Go to Section:

Drawing Mitosis

Pneumonic devices! Cell Cycle: G1, S, G2, Mitosis, Cytokinesis Go Sally Go! Make Children! Mitosis: (Prophase, Metaphase, Anaphase and Telophase) People Meet And Talk!

Cell Division Times Cell TypeProcessTime fly embryomitosis8 minutes bacteriamitosis20 minutes yeastmitosis2 hours human skinmitosis hours human spermmeiosisabout 64 days human livermitosis1 year or more human eggmeiosisup to 40 years or more human nervemitosisnever, once mature

Triffle?

What is a homologous pair of chromosomes? Chromosomes that “match” because they carry information for the same traits. Organism created by sexual reproduction receive one from their mother and one from their father.

Diploid Definition: A diploid cell is a cell that contains two sets of chromosomes. One set of chromosomes is donated from each parent.cellchromosomes Cells made through Mitosis are “Diploid”

#6 uses the word Allele Alelle- fancy word for “different forms of a gene” Example- Gene for ear lobe placement: ear lobes attached or ear lobes free

Diploid Number The diploid number of a cell is the number of chromosomes in the cell. This number is commonly abbreviated as 2n, where ‘n’ stands for the number of chromosomes. Humans Diploid Number:2N= 46 Fruit Fly Diploid Number:2N=8

includes is divided into Concept Map Section 10-2 Cell Cycle M phase (Mitosis) Interphase G 1 phaseS phaseProphaseG 2 phaseMetaphaseTelophaseAnaphase Go to Section:

How many chromosomes would a human sperm or an egg contain if either one resulted from the process of mitosis? Section 11-4 Interest Grabber continued Go to Section:

If a sperm containing 46 chromosomes fused with an egg containing 46 chromosomes, how many chromosomes would the resulting fertilized egg contain? Do you think this would create any problems in the developing embryo?

In order to produce a fertilized egg with the appropriate number of chromosomes (46), how many chromosomes should each sperm and egg have?

Instead of “Diploid” Sex Cells, we need “Haploid” Sex cells

What’s the difference? Diploid Cells “two sets” of chromosomes Cells made in Mitosis Humans 2N= 46 Fruit Fly2N=8 Haploid Cells “one set” of chromosomes Cells made in Meiosis Humans N= 23 Fruit Fly N=4

Meiosis I Interphase I Prophase I Metaphase I Anaphase I Cells undergo a round of DNA replication, forming duplicate Chromosomes. Each chromosome pairs with its corresponding homologous chromosome to form a tetrad. Spindle fibers attach to the chromosomes. The fibers pull the homologous chromosomes toward the opposite ends of the cell. Section 11-4 Figure Meiosis Go to Section:

Meiosis I Interphase I Prophase I Metaphase I Anaphase I Cells undergo a round of DNA replication, forming duplicate Chromosomes. Each chromosome pairs with its corresponding homologous chromosome to form a tetrad. Spindle fibers attach to the chromosomes. The fibers pull the homologous chromosomes toward the opposite ends of the cell. Section 11-4 Figure Meiosis Go to Section:

Meiosis I Interphase I Prophase I Metaphase I Anaphase I Cells undergo a round of DNA replication, forming duplicate Chromosomes. Each chromosome pairs with its corresponding homologous chromosome to form a tetrad. Spindle fibers attach to the chromosomes. The fibers pull the homologous chromosomes toward the opposite ends of the cell. Section 11-4 Figure Meiosis Go to Section:

Meiosis I Interphase I Prophase I Metaphase I Anaphase I Cells undergo a round of DNA replication, forming duplicate Chromosomes. Each chromosome pairs with its corresponding homologous chromosome to form a tetrad. Spindle fibers attach to the chromosomes. The fibers pull the homologous chromosomes toward the opposite ends of the cell. Section 11-4 Figure Meiosis Go to Section:

Meiosis II Meiosis I results in two haploid (N) daughter cells, each with half the number of chromosomes as the original. Prophase IIMetaphase IIAnaphase IITelophase II The chromosomes line up in a similar way to the metaphase stage of mitosis. The sister chromatids separate and move toward opposite ends of the cell. Meiosis II results in four haploid (N) daughter cells. Section 11-4 Figure Meiosis II Go to Section:

Meiosis II Meiosis I results in two haploid (N) daughter cells, each with half the number of chromosomes as the original. Prophase IIMetaphase IIAnaphase IITelophase II The chromosomes line up in a similar way to the metaphase stage of mitosis. The sister chromatids separate and move toward opposite ends of the cell. Meiosis II results in four haploid (N) daughter cells. Section 11-4 Figure Meiosis II Go to Section:

Meiosis II Meiosis I results in two haploid (N) daughter cells, each with half the number of chromosomes as the original. Prophase IIMetaphase IIAnaphase IITelophase II The chromosomes line up in a similar way to the metaphase stage of mitosis. The sister chromatids separate and move toward opposite ends of the cell. Meiosis II results in four haploid (N) daughter cells. Section 11-4 Figure Meiosis II Go to Section:

Meiosis II Meiosis I results in two haploid (N) daughter cells, each with half the number of chromosomes as the original. Prophase IIMetaphase IIAnaphase IITelophase II The chromosomes line up in a similar way to the metaphase stage of mitosis. The sister chromatids separate and move toward opposite ends of the cell. Meiosis II results in four haploid (N) daughter cells. Section 11-4 Figure Meiosis II Go to Section:

Meiosis II Meiosis I results in two haploid (N) daughter cells, each with half the number of chromosomes as the original. Prophase IIMetaphase IIAnaphase IITelophase II The chromosomes line up in a similar way to the metaphase stage of mitosis. The sister chromatids separate and move toward opposite ends of the cell. Meiosis II results in four haploid (N) daughter cells. Section 11-4 Figure Meiosis II Go to Section:

Special Events Of Meiosis: Crossing Over during Prophase I Interaction between non-sister chromatids of a homologous pair of chromosomes Chromatids break at same places along the length and exchange corresponding segments

Section 11-4 Crossing-Over Go to Section:

Section 11-4 Crossing-Over Go to Section:

Section 11-4 Crossing-Over Go to Section:

Another Special Event of Meiosis Alignment of Homologous Pairs in Metaphase I The alignment of homologous chromosomes is a random event which places maternal and paternal chromosomes in a random location Possible combinations: Crossing over + Random alignment = ?

Another Special Event of Meiosis Alignment of Homologous Pairs in Metaphase I The alignment of homologous chromosomes is a random event which places maternal and paternal chromosomes in a random location Possible combinations: 2 n = 2 23 Crossing over + Random alignment = ?

Results of Meiosis In Males 4 genetically different, but equal in size sperm result each time Meiosis occurs This happens at sexual maturity and as needed in the testes In Females One viable egg is produced the other three cells are called polar bodies This process occurs in the ovaries of the female in utero. The eggs will become ready at sexual maturity.

Earth Country State City People Cell Chromosome Chromosome fragment Gene Nucleotide base pairs Section 11-5 Comparative Scale of a Gene Map Go to Section: Mapping of Earth’s Features Mapping of Cells, Chromosomes, and Genes