1. Chromosomes You have 2 major types of cells: Somatic cells- body cells
Asexual
Gametes-
Germ cells/sex cells such as sperm and egg
sexual

2. *Every species has a specific number of chromosomes.
Only duplicated in “Synthesis” phase of cell cycle (for mitosis)
*Every species has a specific number of chromosomes.
Humans= 46 chromosomes (these come in 23 pairs)

3. Diploid Chromosome Number
Common Name
Genus and Species
Diploid Chromosome Number
Buffalo
Bison bison 60
Cat
Felis catus 38
Cattle
Bos taurus, B. indicus
Dog
Canis familiaris 78
Donkey
E. asinus 62
Goat
Capra hircus
Horse
Equus caballus 64
Human
Homo sapiens 46
Pig
Sus scrofa
Sheep
Ovis aries 54

4. Body cells and gametes have different numbers of chromosomes!
Diploid(2n)= 2 copies of each chromosome (46)
Haploid(n)= 1 copy of each chromosome (23)
Meiosis divides diploid cells into haploid cells!

5. 1) Autosomes= Chromosome pairs #1-22
(related to body appearance; not body sex)
2) Chromosomes come in homologous pairs-
(2 chromosomes each: 1 from mom, 1 from dad)
*homo= same (same length/size/genes)
3) Sex Chromosomes= Chromosome pair #23
(sex chromosomes, X and Y, determine gender in mammals)

6. Karyotype- Image of all cell chromosomes
#1-22= autosomes
#23= Sex chromosomes

7. XX = Female
XY = Male
*Male determines sex of child!
Abnormalities in Chromosomes
Autosome abnormalties:
Down syndrome (trisomy 21): The result of an extra copy of chromosome 21.
Down syndrome affects 1:800 children

8. Down syndrome

9. Sex Chromosome abnormalties:
Klinefelter syndrome: 47, XXY males. Male sex organs; unusually small testes, sterile. Breast enlargement and other feminine body characteristics. Normal intelligence.

10. 47, XYY males: Individuals are somewhat taller than average and often have below normal intelligence. At one time (~1970s), it was thought that these men were likely to be criminally aggressive, but this hypothesis has been disproven over time.

11. Trisomy X: 47, XXX females. 1:1000 live births - healthy and fertile - usually cannot be distinguished from normal female except by karyotype.

12. Monosomy X (Turner's syndrome): 1:5000 live births; the only viable monosomy in humans - women with Turner's have only 45 chromosomes!!! XO individuals are genetically female, however, they do not mature sexually during puberty and are sterile. Short stature and normal intelligence.
(98% of these fetuses die before birth)

13. Sexual Reproduction- Fission of 2 gametes
(= genetic mixture of parents)
Actual fission of egg and sperm = Fertilization
Meiosis- Process of making new sex cells.