Asexual Reproduction

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Asexual ReproductionMitosis

DSQ: Mitosis is the process in which the nucleus divides to form two new nuclei. How does mitosis differ in plants and animals?

Mrs. Camp

7th Grade Life Science

•Contains the genetic information Contains the genetic information in form of genes which control in form of genes which control how an animal or plant grows and how an animal or plant grows and what it becomes.what it becomes.

Importance of maintaining species Importance of maintaining species chromosome numberchromosome number

• Each species has a specific number of Each species has a specific number of chromosomes in its body cells: which is called chromosomes in its body cells: which is called chromosome numbers for that species.chromosome numbers for that species.

****Research why a potato has more Research why a potato has more chromosomes than humanschromosomes than humans

Species # of chromosome

Onion 16

Tomato 24

Corn 40

Human 46

Potato 48

55 5

Asexual ReproductionMitosis

DSQ: Mitosis is the process in which the nucleus divides to form two new nuclei. How does mitosis differ in plants and animals? ANALYZE (break apart, study the pieces)

There is a question within a question in this DSQ. Can you identify the

question within the DSQ?

How do little elephants grow up to be BIG How do little elephants grow up to be BIG elephants?elephants?

Why do animals shed their skin?

The process of asexual reproduction begins

after a sperm fertilizes an egg.

Three reasons why cells reproduce by asexual

reproduction:

1. Growth 2. Repair

3. Replacement

Skin cancer - the abnormal growth of skin cells - most often develops on skin exposed to the sun.

Cell that reproduce by asexual reproduction reproduce constantly.

Animated Mitosis Cyclehttp://www.cellsalive.com/mitosis.htm

• Interphase

• Prophase

• Metaphase

• Anaphase

• Telophase & Cytokinesis

Interphase occurs before mitosis begins

• Cell is prepared for divisionCell is prepared for division

• Chromosomes become shorter and fatter (easily seen)Chromosomes become shorter and fatter (easily seen)

• Chromosomes are Chromosomes are copiedcopied (# doubles) (# doubles)

• Forms two chromatids joined at a centromere.Forms two chromatids joined at a centromere.

• Chromosomes appear as threadlike coils (Chromosomes appear as threadlike coils (chromatinchromatin) at the start, but each chromosome ) at the start, but each chromosome and its copy(and its copy(sistersister chromosome) change to sister chromatids at end of this phase chromosome) change to sister chromatids at end of this phase

CELL MEMBRANENucleus

Cytoplasm

InterphaseInterphase

Animal Cell Plant Cell

Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

Prophase 1st step in Mitosis

• MitosisMitosis begins (cell begins to divide)begins (cell begins to divide)

• Chromosomes( made of two chromatids) are visibleChromosomes( made of two chromatids) are visible

• Nucleolus shrinks and disappearsNucleolus shrinks and disappears

• CentriolesCentrioles (or poles) appear and begin to move to opposite end of (or poles) appear and begin to move to opposite end of the cell. the cell.

• Spindle fibersSpindle fibers form between the poles.form between the poles.

• Nuclear envelope breaks downNuclear envelope breaks down

CentriolesSister chromatids

Spindle fibers

ProphaseProphase

Animal Cell Plant Cell

Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

Spindle fibers

Centrioles

Metaphase 2nd step in Mitosis

• ChromatidsChromatids (or pairs of chromosomes) attach to the (or pairs of chromosomes) attach to the spindle fibers.spindle fibers.

• Chromosomes line up along the equator of the cellChromosomes line up along the equator of the cell

• Chromatids are joined by a centromereChromatids are joined by a centromere

Centrioles

Spindle fibers

MetaphaseMetaphase

Animal Cell Plant Cell

Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

Anaphase 3rd step in Mitosis

• ChromatidsChromatids (or pairs of chromosomes) separate and (or pairs of chromosomes) separate and begin to move to opposite ends of the cell.begin to move to opposite ends of the cell.

• Chromatids reach opposite sides of the cellChromatids reach opposite sides of the cell

• Exact copies of chromosomes are at both sides of the Exact copies of chromosomes are at both sides of the cell. cell.

Centrioles

Spindle fibers

AnaphaseAnaphase

Animal Cell Plant Cell

Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

Telophase 4th step in Mitosis

• Chromosomes lengthen as they unravelChromosomes lengthen as they unravel

• Nuclear envelope forms around each group of chromosomes to make Nuclear envelope forms around each group of chromosomes to make two nucleitwo nuclei

• Two new Two new nucleinuclei form.form.

• Chromosomes appear as chromatin Chromosomes appear as chromatin ((threadsthreads rather than rather than rodsrods).).

• MitosisMitosis ends.ends.

NucleiNuclei

Chromatin

TelophaseTelophase

Animal Cell Plant Cell

Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

Cytokinesisoccurs after mitosis

• Cell membrane moves inward to create two Cell membrane moves inward to create two daughterdaughter

cells – each with its own cells – each with its own nucleusnucleus with identical with identical chromosomes.chromosomes.

Animal Mitosis -- Review

Interphase

Prophase

Metaphase

Anaphase

Telophase

Interphase

Plant Mitosis -- ReviewInterphase

Prophase

Metaphase

Anaphase

Telophase

Interphase

Cell CycleCell Cycle

2525

The Cell CycleThe Cell Cycle

2626

- Cell Division

26

MitosisMitosis AnimationAnimation

Quiz#1 vocabQuiz#1 vocab

• Define the following:Define the following:

• 1. Chromosomes1. Chromosomes

• 2.Chromatin2.Chromatin

• 3.Chromatid3.Chromatid

• 4. Holds the sister chromatids together4. Holds the sister chromatids together

• 5. Meaning of DNA?5. Meaning of DNA?

MitosisMitosis• Cell division that occurs in all Cell division that occurs in all BODY CELL BODY CELL except in except in Gamete Gamete

formationformation..

• Results in identical cells, each containing the same number of Results in identical cells, each containing the same number of chromosomes and the same combination of genes.chromosomes and the same combination of genes.

• Cell= Cell= DiploidDiploid or or 2n( meaning the whole full chromosome 2n( meaning the whole full chromosome number)number)

• Essential for Repair and Growth.Essential for Repair and Growth.

• Reproduce asexually= identical offspringsReproduce asexually= identical offsprings

• * Mitosis ensures that chromosome # is maintained* Mitosis ensures that chromosome # is maintained

• * Mitosis ensure that daughter cell recieves an identical * Mitosis ensure that daughter cell recieves an identical combination of genes. combination of genes.

Do you remember?Do you remember?

• What happens when the male gamete fuses What happens when the male gamete fuses with the female gamete? (fertilization)with the female gamete? (fertilization)

• What forms ?What forms ?

THENTHEN What happens? What happens?

Well!Well!

•The zygote forms which is Two The zygote forms which is Two Cells and starts to Divide into a Cells and starts to Divide into a bunch of identical cells (mitosis) bunch of identical cells (mitosis) which turns into a blastocyst then which turns into a blastocyst then an embryo an embryo

QuestionQuestion

• If a rabbit has 48 chromosomes , If a rabbit has 48 chromosomes , body cells divide by Mitosis and body cells divide by Mitosis and produces two sister cells. How produces two sister cells. How many Chromosomes will the sister many Chromosomes will the sister cell have?cell have?

QuestionQuestion

• If a rabbit has 48 chromosomes , body cells If a rabbit has 48 chromosomes , body cells divide by Mitosis and produces two sister divide by Mitosis and produces two sister cells. How many Chromosomes will the sister cells. How many Chromosomes will the sister cell have?cell have?

• 2n or 48 chromosomes2n or 48 chromosomes

Replication of Replication of chromosomeschromosomes

• Replication is the process during interphase Replication is the process during interphase by which chromosomes is able to copy itself by which chromosomes is able to copy itself exactly. exactly.

• Chromosome carries an exact copy of itself in Chromosome carries an exact copy of itself in the form of deoxyribonucleid acid (DNA).the form of deoxyribonucleid acid (DNA).

• Double Helix processDouble Helix process

Double helixDouble helix

Booklet: mitosis and asexual Booklet: mitosis and asexual reproductionreproduction

• Introduction : Asexual reproductionIntroduction : Asexual reproduction

• Body: Binary fission, Vegetative propagation, cuttings, Body: Binary fission, Vegetative propagation, cuttings, grafting, tissue culture, cloninggrafting, tissue culture, cloning

• On tissue culture: How it works? list the advantages and On tissue culture: How it works? list the advantages and disadvantages disadvantages

• On cloning of animals: How it works? List advantages and On cloning of animals: How it works? List advantages and disadvantagesdisadvantages

• Provide Visuals, Researchers who are working on these.Provide Visuals, Researchers who are working on these.(evidence) (evidence)

• Reference page: where did you get your info,Reference page: where did you get your info,

• 35pts: 5 intro, 15 body, 5 visuals, 5 Evidence, 5refernece 35pts: 5 intro, 15 body, 5 visuals, 5 Evidence, 5refernece page.page.

Materials need 4 ThursdayMaterials need 4 Thursday

• 3 strawberries. Frozen strawberries should be 3 strawberries. Frozen strawberries should be thawed at room temperature.thawed at room temperature.

• 50ml Dishwasher deterent50ml Dishwasher deterent• 15 grams NaCl (salt)15 grams NaCl (salt)

• 1 small ice pack1 small ice pack

• 1 Ziploc 1 Ziploc TM TM bagbag

• 1 clear conical tube1 clear conical tube

• 1 funnel lined with a moistened paper 1 funnel lined with a moistened paper toweltowel

• 1 cotton swab1 cotton swab

• 1 liter water1 liter water