Chromosomes Karyotypes copyright cmassengale 1 Chromosomes copyright cmassengale

Chromosomes & Karyotypes copyright cmassengale 1

Chromosomes copyright cmassengale 2

Chromosome Number All cells in the human body 1. have 46 chromosomes called the 1. DIPLOID number, 2 n or 2. 23 pairs of chromosomes which is called 2. the HAPLOID or 1 n. copyright cmassengale 3

3. Sex Chromosomes The 23 rd pair of chromosomes determine the sex of a child. A female has 2 X-chromosomes (XX) A male has an X and a Y chromosome (XY) copyright cmassengale 4

SOMATIC CELLS All cells in the human body contain 46 chromosomes. Body cells are called 5. SOMATIC CELLS. Since they contain the total number of chormosomes, they contain the DIPLOID or 5. 2 n number of chromosomes. copyright cmassengale 5

Sex CELLS 6. GAMETES (eggs & sperm) 7. have only 23 chromosomes called the 1 n number. copyright cmassengale 6

We ALL started off as 1 cell! copyright cmassengale 7

8. Nondisjunction Chromosomes may fail to separate during meiosis Resulting gametes may have too few or too many chromosomes Disorders: 9. Down Syndrome – three 21 st chromosomes 10. Turner Syndrome – single X chromosome 11. Klinefelter’s Syndrome – XXY chromosomes copyright cmassengale 8

Normal Male copyright cmassengale 2 n = 46 9

Normal Female copyright cmassengale 2 n = 46 10

Male, Trisomy 21 (Down’s) copyright cmassengale 2 n = 47 11

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Female Down’s Syndrome copyright cmassengale 2 n = 47 13

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Klinefelter’s Syndrome copyright cmassengale 2 n = 47 15

JAMIE LEE CURTIS copyright cmassengale 16

Turner’s Syndrome 2 n = 45 copyright cmassengale 17

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