MITOSIS AND MEIOSIS LAB QUIZ

what is the cell theory

all cells come from pre-existing cells

What are the three steps and their definitions for interphase?

G1 = replicate cellular contents

S = synthesis of DNA copies

G2 = double check for errors

what does mitosis do?

growth and repair; produces diploid cells that are genetically identical

what does meiosis do?

make haploid cells (egg/sperm); genetically distinct

what are diploid cells?

two copies of each chromosome

how many daughter cells does mitosis create

two identical daughter cells

what are the four stages of mitosis 

prophase, metaphase, anaphase, telophase

what is a centromere

provides mechanical force to move chromosomes and pull apart chromatids

what are kinetochore

proteins that microtubules/spindle fibers attach to; located at the centromere

what happens during telophase

• chromosomes condense

• nuclear membrane breaks down

• spindle fibers form and attach to the kinetochore on each centromere

• centriole pairs move towards opposite poles of cell

• microtubules extend from poles of cell to midline of cell

what happens during metaphase 

• spindle fibers are attached to kinetochore of sister chromatids 

  • chromosomes align along the midline of the cell 

what happens during anaphase

• sister chromatids are pulled apart and move towards opposite poles

what happens during telophase

• chromosomes are at opposite sides of cells and decondense

• spindle fibers disappear

• nuclear envelope re-forms

what happens during cytokinesis

• cleavage furrow forms in animal cells

• cell plate forms in plant cells 

• creation two genetically identical cells that enter interphase 

what happens during meiosis 

• it creates four genetically distinct daughter cells 

what are the four stages of meiosis 1

prophase 1, metaphase 1, anaphase 1, telophase 1

what happens in prophase 1

• crossing over occurs

what is crossing over

genetic material is exchanged between homologous chromosomes

what happens during metaphase 1 

• centromeres are attached to homologous pairs NOT sister chromatids like mitosis 

what happens during anaphase 1

the homologous chromosomes (each with two chromatids) move to opposite poles of the cell

what happens during telophase 1

• the chromosomes gather into nuclei, and the original cell divides

• does NOT enter back into interphase

what happens during prophase II 

• the chromosomes condense again, following a brief interphase (interkinesis) in which DNA does not replicate 

• 2N - diploid

what happens during metaphase II

the centromeres of the paired chromatids line up across the equatorial plates of each cell

what happens during anaphase II 

• The chromatids finally separate, becoming chromosomes in their own right, and are pulled to opposite poles. Because of crossing over and independent assortment, each new cell will have a different genetic makeup 

• sister chromatids divide NOT homologous pairs like Anaphase I 

what happens during telophase II

• the chromosomes gather into nuclei, and the cells divide

• 1N - haploid

what is the purpose of spindle fibers?

• to separate chromosomes during cell division to ensure the daughter cell receives the correct number of chromosomes