AP Bio Chapter 13 Part 2 Flashcards
What happens in the second round of cell division
Sister chromatids finally separate, resulting in 4 haploid cells
What happens between rounds of cell division in meiosis
No DNA replication
What do the four produced haploid cells contain
Unduplicated chromosomes
What are the fundamental purposes of meiosis
Produces haploid cells
Creates cells with unique combinations of genetic information
When does DNA replication occur in mitosis and meiosis
Mi: during interphase before mitosis begins
Me: during interphase before meiosis 1 begins
What’s the number of divisions in mitosis and meiosis
Mi: 1 (pmat)
Me: 2 (pmat x2)
When does the synapsis of homologous chromosomes occur in mitosis and meiosis
Mi: does not occur
Me: prophase 1 along with crossing over between no sister chromatids. The resulting chiasmata hold pairs together due to sister chromatid cohesion
What’s the number of daughter cells and genetic composition of mitosis and meiosis
Mi: 2, each diploid (2n) and genetically identical to parent cell
Me: four, each haploid (n) containing half as many chromosomes as the parent cell; genetically different from the parent cell and each other
What is the role of mitosis and meiosis in the body of an animal
Mi: enables multicellular adult to arise from a zygote, produces cells for growth, repair, and asexual reproduction in some species
Me: produces gametes, reduces # of chromosomes by half, and introduces genetic variability among the genes
Sex increases variation ___________________
Exponentially
Sexual reproduction leads to a
Tremendous amount of variation in a population
What are the only ways asexually reproducing can create genetic variations
Mutations and horizontal genetic transfer
Sexually reproducing organisms generated variation through
Meiosis
The independent assortment of homologues during metaphase 1
?
How many possibilities are there from each of the 23 tetrads
23
How many pairs of autosomes and sex chromosomes in a karyotype
22 pairs of autosomes
1 pair of sex chromosomes
What does crossing over produce
Genetically unique chromatids. Random process
How often does crossing over occur
Unpredictable amount of times each mitotic process
Due to the the unpredictable nature of crossing over what conclusion can be drawn about offspring
Functionally infinite genetically unique offspring in a sexually reproductive species
Karyotype
A picture of an individual’s chromosomes
