Welcome! Monday, 1/14 Gametes – sperm and egg are gametes Gene – A section of DNA that codes for a protein Chromosome – Visable DNA Chromatids – two exact copies of a chromosome Centromere – Where chromatids join

TOC 1. Reviewing terms from book 1/8 2. Probability 1/8 3 Mitosis/Meiosis 1/11 4 Meiosis Notes

Somatic Cell – any cell in the body other than gametes Human somatic cells have a total of 46 chromosomes or 23pairs.

Homologous Chromosomes – similar size, shape, and genetic content Diploid – two sets of chromsomes diploid number in a human somatic cell can be written as: 2n=46 Haploid – one set of chromsomes haploid number in a human gamete can be written as: n=23

Zygote – fertilized egg Fertilization – uniting of sperm and egg autosomes – any of the chromosomes not used in determining sex Of the 23 pairs of chromosomes, how many pairs are autosomes? 22

Male: XY Female: XX Ultimately, the sex of the child is determined by the male.

Meiosis – form of division that results in half of the chromosomes Crossing over – breaking/joining and remixing of homologous chromosomes Independent assortment -is the random assortment of chromosomes during the production of gametes

Random fertilization: The ovum has 8 million possible chromosome combinations, so does the sperm cell. 8 million x 8 million = 64 trillion possible diploid combinations in EACH AND EVERY zygote! WOW!! In other words, you're unique...(...just like everyone else.....).

Spermatogenesis – process that makes sperms sperm – a male gamete used in reproduction Oogenesis - The formation, development, and maturation of an ovum – a mature egg Polar body - minute cell produced and ultimately discarded in the development of an oocyte

Life cycle Parthenogenesis - is type of asexual reproduction in which a female gamete or egg cell develops into an individual without fertilization