1. Somatic cells make up the body and undergo mitosis, while gamete cells (sperm and egg) undergo meiosis and are haploid. 2. Chromosomes contain DNA and come in pairs, with one chromosome from each parent. Autosomes are non-sex chromosomes 1-22, while sex chromosomes are X and Y and determine gender. 3. Asexual reproduction involves one parent and produces genetically identical offspring through mitosis, while sexual reproduction combines gametes through fertilization producing offspring with a mix of parental genes.

1. Genetics

2. Somatic vs. Gamete Cells
•Somatic Cell
• Cell that makes up all of the
body tissues and organs
• Mitosis
•Gamete Cell
• Haploid reproductive cell
• Sperm cell or egg cell
•Meiosis

3. Chromosomes
•Homologous “homo” = same
• Two (2) chromosomes
• One from mother
• One from father

4. Chromosomes (continued)
•Autosomes
• Pairs 1 through 22
• Genes for characteristics
•Sex Chromosomes
• 23rd chromosome pair
• Controls development of sex characteristics

5. X andY Chromosomes
• How gender is determined
• XX is female
• XY is male
• X chromosome is larger
• Contains numerous genes unrelated to sexual characteristics
• Y chromosome is smallest chromosome
• Carries fewest genes
• Contains genes that direct development of testes and other male
traits

6. Types of Reproduction
1.Asexual Reproduction
•Single individual is the only parent
•Passes copies of all its genes to it’s offspring
•Mitosis
•Genetically identical to its parent or a clone.

7. Types of Reproduction
2. Sexual Reproduction
•Fusion of 2 gametes
•Results in offspring that are a genetic mixture of both
parents
• Fertilization is the fusion of the nuclei of the egg and
sperm cells
•Forms one nucleus with correct number of
chromosomes
•46 in humans

8. Meiosis
•Form of nuclear division that divides a diploid into
haploid cells

9. Mitosis
vs.
Meiosis

10. Meiosis I
•DNA has already been replicated
1.Prophase I
2.Metaphase I
3.Anaphase I
4.Telophase I

11. Prophase I
• Nuclear membrane breaks
down
• Centrioles start to form
spindle fibers
• Duplicated chromosomes
organize and pair up forming
a tetrad
• Chromosomes complete the
process of crossing-over by
exchanging portions of their
chromatids

12. Metaphase I
•Chromosome pairs line up along
middle of the cell by spindle fibers
• 23 chromosomes are lined up along side
each side of the equator
•Some from mother and some from father
•This mixes up the chromosome
combination creating genetic
diversity
•Approximately 8,388,608
possible combinations of
chromosomes

13. Anaphase I
•Paired homologous
chromosomes separate
from each other and
move to opposite sides

14. Telophase I
•Nuclear membrane re-forms
•Spindle disappears

15. Cytokinesis
•Cytoplasm splits to create
2 daughter cells

16. Meiosis II
•DNA is not copied again between Meiosis I and Meiosis II
1.Prophase II
2.Metaphase II
3.Anaphase II
4.Telophase II

17. Prophase II
•Nuclear membrane
breaks down
•Centrioles create
spindle fibers
•Chromosomes
organize

18. Metaphase II
•Spindle fibers align 23
chromosomes at equator
•Each chromosome has
two sister chromatids

19. Anaphase II
•Sister chromatids are
pulled apart
•Chromatids move to
opposite sides of the cell

20. Telophase II
•Nuclear membrane
re-forms around
chromosomes
•Spindle fibers break
apart

21. Cytokinesis
•Cell cytoplasm splits to form
FOUR (4) haploid cells
• Each haploid cell has a
combination of chromosomes
from both the mother and
father