Cellular Reproduction

Cellular Division Chromosomes- structures that contain DNA and proteins, that replicate and divide during cellular reproduction During reproduction, chromosomes coil and twist to form an “X” shape

Cell Division Normally, DNA is uncoiled and CAN NOT be seen During reproduction, DNA coils to be read, this is when it CAN BE seen

Chromatid Half of a chromosome 2 chromatids are held together at the centromere Centromere is near the center of the chromosome

Autosomes (Non sex chromosomes) Chromosomes that carry all other genes 22 pairs of autosomes Homologous pairs- two sets of chromosomes that carry genes for the same trait

Cells Haploid cells Diploid cells Egg or sperm Contain one set of chromosomes Diploid cells Contain two sets of chromosomes All cells in humans are diploid EXCEPT sex chromosomes

Reproduction Asexual Reproduction: one parent produces an identical offspring Binary Fission: cell division of single cell organisms Example: bacteria Mitosis: nuclear division of a non sex cell Example: Sweet potatoes and strawberry plants Sexual Reproduction: two parent cells (sex cells) form one offspring Meiosis: nuclear division of sex cell Example: Humans and lions

Asexual Reproduction Regeneration: re-growth of a body part Example: sponges, planaria, sea stars Can be asexual reproduction ….too Budding: a new organism grows from the body of a parent organism Example hydra (mitosis and cell division)

Budding

Regeneration

Sex Chromosomes Chromosomes that carry the sex genes The X and Y chromosomes Females have two X Males have one X and one Y

Sex-linked Traits Females have 2 identical copies of all genes Males do not have 2 identical copies of all genes because the Y chromosome does not carry all the genes found on the X chromosome

Sex-linked Traits Therefore some sex-linked disorders occur more in males than females Example: Hemophilia Color-blindness Male pattern baldness