bio 2 - cell cycle, mitosis, meiosis

what is the first phase of mitosis and what happens in it?

• prophase

• DNA condenses down into chromosomes and the duplicated centrosomes separate

what is the second phase of mitosis and what happens in it?

• metaphase

• sister chromatids line up on metaphase plate and connect to fibers from centrosomes

what is the third phase of mitosis and what happens in it?

• anaphase

• sister chromatids are pulled apart

what is the fourth phase of mitosis and what happens in it?

• telophase

• nuclear envelope starts to reform and DNA de-condenses

what is binary fission?

type of asexual reproduction where one cell divides into two identical cells

what happens in prophase I?

homologous chromosomes are held together by chiasmata

what happens in anaphase I and anaphase II?

• anaphase I: homologous chromosomes separate

• anaphase II: sister chromatids separate

what is the end result of meiosis?

4 unique cells

what are sister chromatids and when do they separate?

• identical copies of a chromosome

• separate in meiosis II

what are homologous chromosomes and when do they separate?

• carry the same genes but may have different alleles

• separate in meiosis I

what is an allele?

• one of many versions of a gene that can make trait variations

what phase of the cell cycle would stop if you disrupted the protein DNA polymerase?

S phase

what phase of the cell cycle would stop if you disrupted the depolymerization of the microtubules?

metaphase

what phase of the cell cycle would stop if you disrupted the polymerization of actin?

cytokinesis

what phase of the cell cycle would stop if you disrupted the protein ligase?

S phase

what phase of the cell cycle would stop if you disrupted the chiasmata formation?

prophase I

why is the event of homologous chromosomes pairing up and separating into different cells critical for genetic diversity, and how does it differ from what happens in mitosis?

allows crossing over and independent assortment of homologous chromosomes