08 the Cellular Basis of Inheritance-H

8/8/2019 08 the Cellular Basis of Inheritance-H

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The Cell Cycle

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A. Growth, Repair, & Reproduce

B. Chromosomes

C. The Cell Cycle


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A. Grow, Repair, & Reproduce

1. All cells come from other cells

2. The division of cells allowsliving things to:

a. repair damage

b. growc. reproduce offspring

1) asexual

2) sexual_

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B. Chromosomes

1. DNA usually exists in thenucleus as chromatin string

a. before cells divide DNAduplicates & condenses_


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b. chromosomes are DNAwound around proteins(histones)

c. sister chromatids joinedat the centromere_


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1. Interphase (90%): cell doesnormal cell activities and:

a. G1- increases proteins,organelles, and size

b. S- duplicates DNA *

c. G2- increases supplies forcell division

(G0 cells that no longerdivide)

(Cyclins - proteinsresponsible for controllingvarious stages of cell cycle)_

C.The Cell Cycle

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2. Mitotic phase: division of cell *

a. mitosis (M)- nucleusdivides (PMAT)

b. cytokinesis- cytoplasmdivides_

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1. Benign tumor is a mass ofnormal cells

2. Malignant tumor is a mass ofcancer cells

a. cancer is a disease caused

when cells divide andgrow out of control

b. when cancer spreads it iscalled metastasis

c. cancer is treated by:

1) radiation

2) chemotherapy_

D. Cancer

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THEEND


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The Mitotic Phase

A. The Stages of Mitosis

B. Cytokinesis

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1. Prophase- DNA condenses

Nucleus disappears

Spindle Fibers appearand attach tokinetochores

2. Metaphase- DNA lines up inthe middle

3. Anaphase- DNA separates

4. Telophase- Opposite ofProphase_

A.The Stages of Mitosis

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4. Telophase- DNA relaxes_



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4. Telophase-

DNA relaxes_



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4. Telophase-

DNA relaxes_



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4. Telophase-

DNA relaxes_



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4. Telophase-

DNA relaxes_



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4.Telophase

-DNA relaxes_



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4.Telophase

-DNA relaxes_



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1. Animal cells pinch in themiddle (cleavage furrow)

2. Plant cells form a cell plate inthe middle

New cells called daughter cells_

B. Cytokinesis

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C. Reproduction inProkaryotes

1. Binary fission- 1 cell dividesinto 2 daughter cells

a. asexual reproduction

b. divide every 20 minutes_


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THEEND


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Sexual Reproduction

A. Homologous Chromosomes

B. Diploid and Haploid Cells

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1. Chromosomes can be examinedby amniocentesis

a. the display of thechromosomes is called akaryotype_

A.Homologous Chromosomes


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2. Each chromosome has a twinreferred to as a homologouschromosome

a. homologous pairs containthe same types of genes

b. the genes may havedifferent versions ofthe same trait(eyes: blue/brown)_


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1. Diploid cells (2n) have two setsof homologous chromosomes

a. humans body cells (46)

b. 23 homologous pairs(numbered 1-23)

c. one set from each parent_

B.Diploid and Haploid Cells


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d. pair #23 are the sexchromosomes

1) female- XX

2) male- XY

e. all other pairs calledautosomes_


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2. Haploid cells (n) have one setof chromosomes

a. human sex cells (23)

3. When two sex cells (gametes)are joined (fertilization) a

zygote is formed_


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4. Spermatogenesis

a. Meiosis results in 4spermatids_

5. Oogenesis

a. Meiosis results in oneovum and 2 or 3 polarbodies

b. Ova receive most of thecytoplasm_


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THEEND


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Meiosis & Variations

A. The Stages of Meiosis

B. Causes of Genetic Variations

C. Mitosis vs. Meiosis

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A.The Stages of Meiosis

1. Meiosis I: separation ofhomologous pairs

a. prophase I: crossing overb/w homologous pairs

b. metaphase I: homologous

pairs line upc. anaphase I: homologous

pairs separate

d. telophase I: homologouspairs sometimes relax

(interkinesis)_

n=2

2(n)

2(n)x2

(n)x2

(n)


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2. Meiosis II (same as mitosis) :separation of sisterchromatids_

n=2

2(n)

2(n)x2

(n)x2

(n)


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1. Crossing overa. Synapsis occurs forming

tetrads

b. exchange of DNAbetween homologous

pairsc. different chromosomes

are produced throughgenetic recombination_

B. Causes of Genetic Variations


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2. Independent Assortmenta. homologous pairs of

chromosomes areseparated randomly

b. 2n possible combinations

223 = 8 million_


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1. Mitosis produces:a. 2 cells

b. diploid (2n)

c. genetically identical

2. Meiosis produces:a. 4 cells

b. haploid (n)

c. genetically different_

C. Mitosis vs. Meiosis


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THEEND


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1. Prophase- DNA condenses2. Metaphase- DNA lines up in

the middle


4. Telophase- DNA relaxes_


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Sexual Reproduction



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Sexual Reproduction




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a b 1. Diploid cells (2n) have two setsof homologous chromosomes

a. humans body cells (46)

b. 23 homologous pairs(numbered 1-23)

c. one set from each parent_

B.Diploid and Haploid Cells

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08 the Cellular Basis of Inheritance-H