07. Cell division.ppt

8/14/2019 07. Cell division.ppt

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Cell division: mitosis and meiosis

I. Dividing cellsII. Mitosis and the cell cycleIII. Stages of mitosis

A. ProphaseB. MetaphaseC. AnaphaseD. Telophase

IV. Stem cellsV. Telomeres and telomeraseVI. Cancer cellsVII. MeiosisVIII. Gametogenesis


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Binary Fission- prokaryotes


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Ploidy levels: diploid (2N) and haploid (1N)In mitosis, ploidy level is maintained

In meiosis, ploidy level is halved.

Human = 46

Chimpanzee = 48

Chicken = 78

Dog = 78

Record > 1000!

Meiosis, mitosis, and the chromosome number


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II. Mitosis and the cell cycle

10 hours 8 hours

5 hours

1 hour


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If a cell, like a red blood cell, were to stop dividing, what stage ofthe cell cycle would be terminal for that cell?

a. G1 b. G2 c. S d. mitotic

If a cell that was 4N at the start of meiosis, the end result wouldbe _______ cells .a. 1N b. 2N c. 3N d. 4N


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III. Stages of mitosis


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What is the ploidy of a cell in anaphase of mitosis?a. Haploid b. diploid c. triploid d. quatraploid

In what phase do chromosomes line up at the equator?a. metaphase b. anaphase c. prophase d. telophase

When attached together , what are the two replicated DNA strands ofa single chromosome called?a. centromeres b. chromosomes c. chromatids d. chromatin


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MitosisMitosis animation
http://highered.mcgraw-hill.com/olc/dl/120073/bio14.swfhttp://highered.mcgraw-hill.com/olc/dl/120073/bio14.swf


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DNA before and after mitosis


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Stem cell research

Adult stem cell research

Embryo stem cell research


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Stem cell potential

Adult cell cloning

Incompatibility, ethics, and the law


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IVF/ PGD and stem cell research


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How does the PGD technique circumvent the ethical issuessurrounding the use of embryos in stem cell research?

a. it doesntb. embryos are not used in any way for this technique

c. embryos are not destroyedd. only dead embryos are used

What is the advantage of using embryonic stem cells over othertypes of stems cells?

a.They divide more quicklyb.There is less controversy in using themc.They are easier to work withd.They are more versatile


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V. Telomeres and telomerase

TTAGGG

embryosstem cells

cancer cells


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What exactly are telomeres?a. Caps at the ends of chromosomesb. An enzyme that allows cells to keep dividingc. A repeated sequence of nucleotides at the ends of chromosomesd. Structures found only in embryos

Which of the following cells do not have telomerase?a. Mature skin cellsb. Liver stem cellsc. Early embryonic cellsd. Cancer cells


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VI. CancerA. Two types of tumors (neoplasms)B. Cancer cell anatomy and physiology

1. differentiation2. shape

3. embryonic proliferation4. non-programmed cell death

C. Genes and cancer1. oncogenes2. tumor suppressing genes

3. teleomerase


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A. Two types of tumors (neoplasms)An inappropriate proliferation of cells

Neoplasms: two types

benign

malignant

Metastasis


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B. Cancer cell anatomy and physiology

1. differentiation

2. shape

3. proliferation

4. Non-programmed cell death

5. Telomerase


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C. Genes and cancer

1. oncogenes

2. tumor suppressing genes

3. Telomerase genesProgression of cancer

Stem cells, cancer, and aging

Ink4
http://www.nytimes.com/2006/09/07/science/07stem.html?_r=1&ref=science&oref=sloginhttp://www.nytimes.com/2006/09/07/science/07stem.html?_r=1&ref=science&oref=slogin


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What is the problem with enhancing the activity of Ink4?a. Increased risk of cancerb. Speeding up of the aging processc. Both a and b

d. Neither a or b

What are oncogenes?a. Genes that regulate cell divisionb. Genes that suppress tumorsc. Genes that reestablish telomeres

d. Mutated proto-oncogenes


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VII. Meiosis

2. 2 goals: reducing the chromosome number by half andshuffling (recombining) the genes

1. Homologues/ homologous pairs

Why half?

A. Overview


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Human Life Cycle


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Meiosis I

Crossing over

IndependentAssortment

Meiosis II
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Crossing Over


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Independent Assortment2n= number of unique gametes
http://localhost/var/www/apps/conversion/tmp/scratch_4/07.%20Cell%20division.ppthttp://localhost/var/www/apps/conversion/tmp/scratch_4/07.%20Cell%20division.ppthttp://localhost/var/www/apps/conversion/tmp/scratch_4/07.%20Cell%20division.ppthttp://localhost/var/www/apps/conversion/tmp/scratch_4/07.%20Cell%20division.ppt


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Meiosis II Meiosis animation
http://highered.mcgraw-hill.com/olc/dl/120074/bio19.swfhttp://highered.mcgraw-hill.com/olc/dl/120074/bio19.swf


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In what phases of meiosis do genetic recombination take place?a. Prophase I and Prophase IIb. Metaphase I and Anaphase Ic. Prophase II and Metaphase IId. Prophase I and Metaphase I

If an organism has 3 pairs of chromosomes, based on independentassortment, how many genetically unique gametes would it have?a. 3 b. 6 c. 8 d. 9


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Problems in meiosis:aneuploidyNondisjunction and Trisomy: Anaphase II


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Nondisjunction and Trisomy

Women over 35, 2 to 6 times the number of mutations

Most common trisomy is trisomy 21 (Down Syndrome)

Problems in meiosis

Implantation of embryo more likely


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Trisomy 21: Down syndrome

Trisomy 21 karyotype


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Klinefelters Syndrome


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Turner Syndrome

Monosomy


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Which of the following is the most accurate statement concerninganeuploidy?a. Nondisjunction of chromosomes during meiosisb. A condition in which there are not the correct number ofchromosomesc. Three chromosomes at position number 21d. The result of early implantation of the embryo

What would be the result of a nondisjunction in Anaphase I?a. Two normal gametes, one with an extra chromosome, and onemissing a chromosomeb. Two normal gametes, two with an extra chromosomec. Three gametes with a missing chromosome, one with an extrachromosomed. Two gametes with an extra chromosome, two with a missingchromosome


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Meiosis compared to mitosis

Purpose

Number of cells produced

Genetics of cells produced

Ploidy of cells produced

Where they occur

Somatic cells Sex cells


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Meiosis compared to mitosis


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VIII. Gametogenesis


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Spermatogenesis

Puberty

Average sperm production =100 million per day


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Oogenesis

In embryo

At birth

Arrested atProphase I

Ovulation

Arrested at

Metaphase II

Meiosis completedat fertilization

Approximately 400, 000

400 released


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When does oogenesis start in female mammals?a. At birthb. Before birthc. At puberty

d. At fertilization

When does oogenesis end in female mammals?a. At birthb. Before birth

c. At pubertyd. At fertilization


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In oogenesis, what is the end result of interkinesis?a. Two secondary oocytesb. One secondary oocyte and one polar bodyc. One secondary oocyte and two polar bodiesd. Two secondary oocytes and two polar bodies


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egg sperm

1. Haploid set of chromosomes 1. Haploid set2. X to males and females 2. X to females;

Y to males3. Protection

4. Nourishment

5. Directions for early development6. Mitochondria

Mutations?

Contributions of egg and sperm to embryo


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Which of the following is a contribution of the sperm to the embryo?a. Mitochondriab. Directions for early developmentc. Protectiond. Nourishmente. Most mutations

The contribution of the sperm above is __________ .a. Beneficialb. Detrimental

c. Neutrald. Could be any or all of the above


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07. Cell division.ppt

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