Chapter 9: Meiosis and Sexual Reproduction Flashcards
Meiosis
nuclear division that is important in sexual reproduction
Meiosis has two main functions
Reduce chromosome number and shuffle chromosomes to create diversity/variation (evolution)
Gamates male
sperm. production does not begin until puberty, continues throughout lifetime
Gamates female
eggs. proccess of profucing an egg has started berfoe the female was born and ends around 50 years old.
Humans have
23 pairs of chromosomes or 46 chromosomes total
Diploid (2n)
46 chromosomes, the number of chromosomes. due to the fact we inherit one set of 23 chromosomes each
Haploid (n)
Half of the total chromosome number (23). identifies the number of chromosomes different crhomosomes in the cell
why does meiosis reduce the amount of chromosomes
gamates (sperm and egg) need to be haploid (n) so that the zygote can be diploid (2n) just like the adlult. the dipoloid zygote uses mitosis to grow/develope
Zygote
a cell formed from the union of two gamates (sperm and egg)
What happens when meiosis doesnt occur
evertime the cell and the egg would come together the chomosomes would double, eventually the cell would explode from the inside
Chromosomes
long strand of DNA tightly coilded up
Autosomes
22 pairs out of 23 that are the same in male and females
Sex chromsomes
the remianing pair of chromosomes containing the genes that determine gender. X the larger chromosome and Y the smaller chromosome
Female chormosome pair
XX
Male chromosome pair
XY
