Made up of DNA and proteins Chromosome Made up of DNA and proteins

Chromatid ½ of a chromosome 2 chromatids = 1 chromosome TWO appear during the process of mitosis = SISTERS!

What does homologous mean? Homo = the same Hetero = different

Homologous The same!! We get ½ our chromosomes from … and ½ our chromosomes from

Mom Dad Homologous Pair Dad Mom

Who you callin' a diploid?? Haploid vs. Diploid Who you callin' a diploid??

*Has only ONE set of unpaired chromosomes* Haploid cells *Has only ONE set of unpaired chromosomes* What is the haploid number of human cells? 23

Cell that contains TWO haploid sets of chromosomes Diploid cells Cell that contains TWO haploid sets of chromosomes What is the diploid number of human cells? 46

Haploid vs. Diploid The reference to haploid cells is 1N The reference to diploid cells is 2N If N = 23 for humans (haploid) Then 2N ( 2 x 23 ) = 46 (diploid) Get it??

Human gemetes = Haploid = 23 chromosomes each Gametes Hey baby… You complete me! are SEX CELLS! Sperm Ovum (egg) Human gemetes = Haploid = 23 chromosomes each

With a partner, determine the haploid number for gametes of the following organisms

Sex chromosomes vs. Autosomes Sex chromosomes = this is what determines our sex (duh!) Autosomes = all the other chromosomes

Humans have 1 pair of sex chromosomes and 22 pairs of autosomes X and Y (male) X and X (female)

Sexual Reproduction TWO parents Each contribute ½ the genetic information by fusion of haploid gametes (sperm and egg) Offspring contains traits from both parents, but not identical to either Involves FERTILIZATION = the moment sperm enters the egg

Asexual Reproduction ONE parent NO fusion of gametes Offspring are clones (identical) to parent

Pick a corner Sexual Asexual Both are equally advantageous I don’t have an opinion yet, I need more time

Which type of reproduction do you think is more of an advantage for organisms? WHY?

Response:

What is Meiosis?? Process of cell division in which the chromosomal number is cut in ½, resulting in creation of gametes In other words – the genetic mix-up to make sure that all sperm and egg have a different genetic code

Spermatogenesis The process in which sperm is produced = 4 sperm per 1 cell!

Oogenesis The process in which an ovum (egg) is produced = 1 egg and 3 polar bodies per 1 cell!

Crossing-Over The exchange of genetic material between homologous chromosomes during meiosis

Law of Independent Assortment States that genes separate independently from one another in meiosis

Any questions??