Chromosomes and cell reproduction Chapter 6
Why does a cell reproduce? • Growth • Repair • Gamete production
Prokaryotes Reproduce by binary fission asexual produces an exact copy (clone) have one chromosome that is circular (a ring)
Eukaryotes Multiple, paired chromosomes Rod shaped (kinda) Sexual
Things to remember • Each chromosome contains thousands of genes • Humans must have all 46 chromosomes in order to survive • Having extra chromosomes usually results in death. At the very least, development is impaired
Examples of trisomy Down’s Syndrome (#21) Patau’sSyndrome (#13) Edwards Syndrome (#18) Most include physical deformities (cleft palate, small eyes, enlarged tongue, clenched fingers, heart problems, etc.
Mutations These involve missing portions of chromosomes, or chromosomes that have broken fragments rearranged in a new order
Mutation Types Deletion – a chromosome is missing a segment Duplication – a chromosome has a duplicated segment (like a stutter, or repeated portion) Inversion – a chromosome fragment breaks off, and reattaches in reverse order Translocation – a chromosome fragment breaks off, and reattaches to a non-homologous chromosome