MEIOSIS: Reduction Division

http://www.youtube.com/watch?v=rB_8dTuh73c

Concept: 13.1 Offspring acquire genes from parents by inheriting chromosomes

Gene: hereditary unit that codes for a proteinLocus: a gene’s specific location on a

chromosomeGamete: sex cell Male gamete: spermFemale gamete: egg (ovum)Asexual reproduction: a single individual is the

sole parent and passes copies of all its genes to its offspring (which is a clone of its parent)

Sexual reproduction: two parents give rise to offspring that have unique combinations of genes inherited from both parents

2. 46

3.DNA wrapped around histones (packing proteins), that becomes coiled upon itself in preparation for cell division

4. A normal body cell. Skin cell, muscle cell, adipose cell

5. Somatic cells are diploid; gamete cells are haploid

6. Sex chromosomes: X and Y in humans. Determine sex of the individual. 2 per cell (either XX= female or XY = male); set # 23

Autosomes: Homologous chromosomes sets # 1-22

7. Karyotype: Photographic display of homologous chromosome pairs from longest to shortest based on length, centromere location, and staining patterns

8. Homologous chromosomes: pair of chromosomes carrying genes controlling the same inheritance characters.

9………regular body cells are diploid!

………sex cells are haploid!

10. Bone cell = 78

Sperm = 39

Haploid = 39

Somatic = 78

Zygote (is a fertilized cell, the beginnings of an embryo) = 78

• sister chromatids

• Homologous chromosomes

• centromere

• Replicated chromosome

• Maternal chromosome (color it red or pink)

• Paternal chromosme (color it blue..look on page 251)

12.

12

3

12

diploid

13.Eggs are produced in the ovaries

• Sperm are produced in the tesicles

14. Meiosis: oogenesis (female meiosis)

spermatogenesis (male meiosis)

15. Zygote; 2n diploid

16. Reduce the diploid chromosome number in half to haploid

17. diploid; haploid

18. Life cycle that includes both diploid and haploid stages that are multicellular

18. Life cycle that includes both diploid and haploid stages that are multicellular

• Sporophyte (diploid)

• Gametophyte (haploid)

• Page 252 Moss life cycleM

19. alleles: contrasting forms of a gene

Synapsis: when homologous chromosomes are held tightly together by proteins along their length

Crossing over: the exchange of corresponding segments of DNA molecules by non sister chromatids (this give rise to new gene combinations )

Chiasmata: points where crossing over has occurred

21. One chromosome of each homologous pair is facing each pole, I mitosis the pairs are on top of each other and the copies go to opposite poles

22. The homologous pairs23. 6 chromosomes; haploid….but like a

double haploid

25. The replicated sister chromatids26. a. it is reduced by half

b. Meiosis Ic. Reduction division= to produce haploid gametesd. twicee. oncef. 4 (note: in oogenesis, 3 polar bodies will disintegrate, leaving only one egg; in spermatogenesis 4 sperm are produced)g. n (half the original 2n number)

h. chromosome of a pair that have matching genes

i. homologs are held tightly together

j. the exchange of genes between non sister chromatids

• 27.

28.

Mitosis Meiosis

Role in the animal body Development of zygote; growth, repair and asexual reproduction

Produces haploid gametes; introduces genetic variability

Number of DNA

replications1 1

Number of divisions 1 2

Number of daughter

cells

Two, each genetically identical to the parent cell

Four, each genetically different from the parent cell and from each other

Chromosome number

of daughter cells

Diploid Haploid

29. Prophase I30. Replicated homologs pair up and

become physically connected along their lengths by a zipper-like protein structure called the synaptonemal complex in a process called synapsis. Chiasmata are X-shaped regions where crossing over has occurred as the homologs are trying to separate, yet the sister chromatid cohesion is still operating

31. Independent assortment of chromosomes: random orientation of homologs in Metaphase I resulting in each pair sorting its maternal and paternal homologs into daughter cells independently of the other pairs

Crossing over: yields recombinant chromosomes (individual chromosomes that carry genes from two different parents)

Random fertilization: The fusion of a human sperm and egg during fertilization will produce a zygote with any of about 70 trillion (223 x 223) diploid combinations

32. a. 223 (about 8.4 million)

b. 70 trillion (223 x 223)

COMPLETE PAGE 9 ON YOUR OWN! STUDY FOR OUR QUIZ ON FRIES-DAY!

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