Pre-Lecture Lesson 2.4 - Meiosis & Sexual Reproduction

What issue would you run into if we simply keep merging cells through syngamy over and over again without preceding syngamy with meiotic divisions?

The number of homologs of each chromosome type would double every generation

Which of the following is true about the life cycle of animals?

Gametes are produced by meiosis; somatic (body) cells are produced by mitosis

Are gametes (sex cells that will fuse during fertilization) produced by mitosis or through meiosis in fungi & plants?

mitosis in a haploid multicellular stage (fungi) or gametophyte (plants)

By the end of Meiosis I, we have 2 daughter cells that are:

haploid, but each chromosome is a replicated chromosome with 2 sister chromatids

What changed as a result of Meiosis II?

replicated to unreplicated chromosomes in daughter cells

How many copies of each gene does a diploid cell carry?

2

How many distinct combinations of alleles of the 2 genes could occur as gametes at the end of Meiosis?

4

Which of the chromosome combinations in the 4 possible gametes that this individual can produce are identical to the maternal and paternal gametes that gave rise to this individual in the first place?

Only the first 2 (brown eyes black hair; green eyes red hair)

How many genetically distinct gametes can be produced by an individual with 1 chromosome that contains 2 linked genes, where maternal and paternal chromosomes carry a different allele for each of these 2 genes, assuming that crossing-over takes place?

4

How many genetically distinct gametes can be produced by an individual with 1 chromosome that contains 2 linked genes, where maternal and paternal chromosomes carry a different allele for each of these 2 genes, assuming that crossing-over DOES NOT take place?

2