PS275 Chapter Notes - Chapter 3 & 4: Miscarriage, Intellectual Disability, Spina Bifida
Document Summary
After the sperm and egg meet, body cells begin to form by duplicating its chromosomes. Step 1: original parent cell (only 4 of the 23 chromosomes are shown here) Step 2: each chromosome splits lengthwise, producing a duplicate. Step 3: the duplicate chromosomes move to opposite ends of the parent which begins to divide. Step 4: the cell completes its division, producing two daughter cells that have identical sets of chromosomes. Germ cells produce gametes (sperm for males, ova in females) Tep 1: ea(cid:272)h ger(cid:373) (cid:272)ell"s origi(cid:374)al (cid:272)hro(cid:373)oso(cid:373)es dupli(cid:272)ates itself. Step 2: crossing-over takes place among adjacent chromosomes to create a new hereditary combination. Step 3: the original cell divides to form 2 parent cells, each of which have 23 duplicated chromosomes. Tep 4: ea(cid:272)h (cid:272)hro(cid:373)oso(cid:373)e a(cid:374)d it"s dupli(cid:272)ate split a(cid:374)d segregate into separate gametes. Each gamete has o(cid:374)l(cid:455) half the (cid:272)hro(cid:373)oso(cid:373)es of it"s pare(cid:374)t (cid:272)ell. Monozygotic (identical): a zygote that divides to form two genetically identical individuals.
