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Cell Reproduction Notes Day 1

Cell Reproduction Notes Day 1. Warm Up Where are your genes located?. http://people.na.infn.it/~nicodem/research/cell_genes.jpg. FROM DNA TO CHROMOSOMES. DURING MOST OF THE CELL’S LIFE, DNA FORMS A TANGLED MASS CALLED CHROMATIN . CHROMATIN LOOKS LIKE A PLATE OF SPAGHETTI .

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Cell Reproduction Notes Day 1

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  1. Cell ReproductionNotes Day 1 Warm Up Where are your genes located?

  2. http://people.na.infn.it/~nicodem/research/cell_genes.jpg

  3. FROM DNA TO CHROMOSOMES • DURING MOST OF THE CELL’S LIFE, DNA FORMS A TANGLED MASS CALLED CHROMATIN. • CHROMATIN LOOKS LIKE A PLATE OF SPAGHETTI. • RIGHT BEFORE A CELL DIVIDES, THE CHROMATIN FORMS INTO CHROMOSOMES (X-SHAPED).

  4. CHROMATIN CHROMOSOMES MOST OF THE TIME ONCE IN A WHILE

  5. Cell Division • Chromosomes = Tightly coiled, rod-shaped DNA • Chromosomes are made of chromatin • Human body produces 2 trillion cells per day & 25 million per second • Cells are formed by cell division of older cells • When a cell divides, DNA is first copied & then distributed • Each cell ends up with a complete set of DNA

  6. Chromosome Number • Each human somatic cell has 2 copies of 23 different chromosomes • Total 46 • Somatic = any cell that is NOT a sex cell • (also called body cells or autosomes)

  7. Sets of Chromosomes • Each pair is made up of 2 homologous chromosomes • Homologous chromosomes = chromosomes that are similar in size, shape, & genetic content • Each homologue comes from one of the parents • One from mom • One from dad

  8. Cells Can Be Diploid or Haploid • Diploid = a cell that contains 2 sets of chromosomes (2n) • Haploid (monoploid) = a cell that contains only 1 set of chromosomes (1n or n)

  9. Chromosomes Determine Your Gender • Humans have 23 pairs of chromosomes • 22 pairs are autosomes (chromosomes NOT directly involved in determining sex) • 1 pair are sex chromosomes (contain genes that WILL determine the sex) • X & Y chromosomes

  10. X & Y Chromosomes • Male = XY • Female = XX • Male (dad) can donate an X or a Y to offspring • Female (mom) can ONLY donate an X So-Which parent determines the sex of the baby?

  11. MALEXY

  12. Gametes • Gametes are reproductive cells • Males = sperm (n = 23) • Female = egg (n = 23) • Combine in fertilization to make a: • Zygote(2n = 46)

  13. Karyotype • Karyotype = a photo of the chromosomes in a dividing cell that shows the chromosomes arranged by size.

  14. Karyotype cont’d • Each of an individual’s 46 chromosomes has thousands of genes so the presence of all chromosomes is essential for normal functioning • Humans who are missing a chromosome don’t survive • Humans with more than two copies of a chromosome, called trisomy, may survive but will not develop properly.

  15. What is wrong?

  16. The Cell Cycle • Repeating sequence of cell growth and division during an organism’s life • 90% of cell life is spent in INTERPHASE • Then it may go into MITOSIS & CYTOKINESIS

  17. INTERPHASE(divided into mini-phases) • G1(first growth) phase = Cell grows rapidly • S (synthesis) phase = DNA copied • G2 (2nd growth) phase = Nucleus prepares to divide

  18. http://publications.nigms.nih.gov/insidethecell/ch4_interphase_big.htmlhttp://publications.nigms.nih.gov/insidethecell/ch4_interphase_big.html

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