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GENETICS I CHROMOSOMES

GENETICS I CHROMOSOMES. A. CHROMOSOMES. Chromosomes are found in the nucleus of the cell. CHROMOSOMES. CHROMOSOMES within a cell are arranged in pairs from the largest to the smallest, followed by sex-chromosomes.

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GENETICS I CHROMOSOMES

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  1. GENETICS ICHROMOSOMES

  2. A. CHROMOSOMES • Chromosomes are found in the nucleus of the cell

  3. CHROMOSOMES • CHROMOSOMES within a cell are arranged in pairs from the largest to the smallest, followed by sex-chromosomes

  4. As you can see, we have: two #1 chromosomes,two # 2 chromosomes,two # 3 chromosomes,and so on for all the pairs.  

  5. B.AUTOSOMES • The first 22 pairs are called AUTOSOMES, and are shared by both the male and the female.

  6. C. SEX CHROMOSOMES • Chromosomes in pair #23 are called sex-chromosomes.

  7. FEMALES • A woman has two X sex-chromosomes XX

  8. MALES • A man has oneX sex-chromosome and one Y sex-chromosome. XY

  9. D. KARYOTYPES WHAT’S A KARYOTYPE?

  10. Karyotype • A karyotype is a photograph of chromosomes grouped in order in pairs. • Karyotyping is a test to examine chromosomes in a cell, which can help identify genetic problems as the cause of a disorder or disease. This test can • Count the number of Chromosomes • Look for structural changes in the chromosomes

  11. SINGLE CHROMOSOMEKARYOTYPE

  12. PAIRED CHROMOSOMESKARYOTYPE

  13. Karyotypes of a male and female

  14. F. Determining sex

  15. A. FERTILIZATION • Life begins when a spermatozoa and an ovumunite to form one single cell called a zygote, which as of that moment, will undergo a series of divisions (mitosis) that will result in the birth of an infant. • This process is known as fertilization, and it takes place in the female's uterine tubes.

  16. Humans have 23 pairs of chromosomes • 1-22 are homologous and are called autosomes • Pair 23 are the sex chromosomes and determine your sex

  17. Fertilization happens when an egg cell and sperm unite Note: Egg and sperm not shown to scale Most of our cells contain 46

  18. What determines if you are a male or female? • XY = male • XX = female Human Female Karyotype

  19. As a result of chromosome separation during meiosis, each gamete contains one sex chromosome and one of each pair 1-22

  20. F. GAMETES(SEX CELLS) • All egg cells contain 1 X chromosome • 50% of sperm cells contain an X chromosome • The other 50% contain a Y chromosome • So, what determines the sex of the zygote?

  21. What about twins? • Identical twins come from one fertilized egg that splits early in the pregnancy and develops into more than one fetus. This is different because not only do the fetuses share the same placenta, but they also share the same genetic material. That is why they are identical (they have the same hair color, eye color, sex, and blood type).

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