Mitosis

Question 1

What is the cell cycle?

Answer 1

an ordered series of events involving cell growth and division that produces two new daughter cells

Question 2

What are the two major parts of the cell cycle?

Answer 2

interphase, mitotic phase

Question 3

What is interphase in cell divison

Answer 3

phase of the cell cycle during which a eukaryotic cell grows, replicates its DNA, and prepares for cell division

Question 4

What does interphase consist of?

Answer 4

Consists of G1 , S (synthesis), and G2

Question 5

What is the longest part of the cell cycle?

Answer 5

interphase

Question 6

What parts of cell division does interphase encompass?

Answer 6

the period between cell divisions, where the cell grows, carries out its normal functions, and replicates its DNA

Question 7

What is the mitotic phase

Answer 7

also known as the M phase, is the phase of the cell cycle during which a eukaryotic cell divides into two identical daughter cells

Question 8

What does the mitotic phase include?

Answer 8

includes mitosis (nuclear division) and cytokinesis (cytoplasmic division)

Question 9

What is the name for nuclear divison and what step is it?

Answer 9

karyokinesis; the first step

Question 10

What is karyokinesis?

Answer 10

Process by which duplicated chromosomes are sorted and separated to form two identical nuclei for daughter cells

Question 11

What happens when G2 is complete?

Answer 11

the cell will enter mitosis

Question 12

How many phases are in mitosis? What are they in order?

Answer 12

5 phases; Prophase, Pro-metaphase, Meta phase, Anaphase, Telophase (Cytokinesis)

Question 13

What are the qualities of the phases in mitosis besides the metaphase and anaphase transition?

Answer 13

not discrete and happen as a continuous process

Question 14

What is cytokinesis?

Answer 14

the final stage of the cell cycle during which the cytoplasm and organelles of a parent cell are divided into two identical daughter cells. (second part of mitotic phase)

Question 15

Describe the G1 Phase (first gap)

Answer 15

• Change is not evident (“gap”) but the cell is biochemically active.
• S Phase is when DNA synthesis/replication occurs:
• Identical copies of the DNA molecules (sister chromatids) are joined at the centromere.

Question 16

Describe the G2 Phase (second gap)

Answer 16

• Energy is replenished, organelles reproduce, and cytoskeleton breaks down.

Question 18

What is the Mitotic Spindle?

Answer 18

• Microtubules and associated proteins
• Organizes chromosomes during mitosis
• Microtubules (spindle fibers) arise from centrosomes

Question 19

What happens is the Mitotic Spindle?

Answer 19

• Kinetochore microtubules attach to chromosomes
• Polar microtubules attach to each other

Question 20

Describe Prophase

Answer 20

• Nuclear envelope breaks down.
• Chromosomes condense and are now visible.
• Membranous organelles (e.g. Golgi complex, endoplasmic reticulum) disperse toward edges of the cell.
• The nucleolus disappears.
• Spindle fibers start to appear.
• Centrosomes begin migration to opposite poles

Question 21

What happens in pro-metaphase?

Answer 21

• Sister chromatids develop a protein kinetochore in the centromere region which attaches the chromatids to the spindle microtubules.
• Centrosomes continue to move towards opposite poles.
• mitotic spindle microtubules from opposite poles attach to each sister chromatid at the kinetochore

Question 22

What is the basic definition of Pro-metaphase?

Answer 22

Chromosome Attachment and Centrosome Movement

Question 23

How is anaphase related to pro-metaphase?

Answer 23

In anaphase, the connection between the sister chromatids breaks down, and the microtubules pull the chromosomes toward opposite poles

Question 24

What is the basic definition of metaphase?

Answer 24

Chromosome Alignment and Cohesion

Question 25

What happens in metaphase?

Answer 25

- The mitotic spindle is fully developed, and centrosomes are at opposite poles. - Chromosomes are aligned at the “equatorial plate” and each sister chromatid rests on one side of the plate, with spindle fibers attached to them. - Sister chromatids remain attached by cohesion proteins.

Question 26

What happens in chromosome alignment at the metaphase plate?

Answer 26

- The microtubule spindle has completed the alignment of chromosomes at the metaphase plate in preparation for the separation of sister chromatids during anaphase.

Question 27

What is the basic definition of anaphase?

Answer 27

Sister Chromatid Separation and Cell Elongation

Question 28

What happens in anaphase?

Answer 28

- Cohesion proteins degenerate allowing chromatids to separate. - Sister chromatids move in opposite directions toward the centrosomes to which their microtubules are attached. - Each chromatid is now a chromosome. - The cell elongates. - Shortest phase of mitosis

Question 29

What is the basic definition of telophase?

Answer 29

Chromosome De-condensation and Nuclear Envelope Formation

Question 30

What happens in telophase?

Answer 30

- Chromosomes reach opposite poles and begin to decondense (unravel). - Spindles depolymerize into tubulin monomers that will form cytoskeletal components for the daughter cells. - Nuclear envelopes form around the chromosomes, and nucleosomes appear within the nuclear area.

Question 31

What is the relationship between cytokinesis in plants and animals?

Answer 31

They differ

Question 32

How does cytokinesis happen in animal cells?

Answer 32

Animal cell cleavage: contraction of actin filaments by myosin pull the “equator” of the cell causing an invagination of the cell (a fissure called a cleavage furrow). The cleavage furrow gets continuously deeper until it eventually divides the cell into two new, independent daughter cells.

Question 33

How does cytokinesis happen in plant cells?

Answer 33

Plant cell wall formation: a mixture of enzymes, proteins, and glucose molecules are transported via vesicles to the center of the cell. These vesicles continuously build upon each other known as ‘Cell plate’ until a completely new cell wall has emerged, and two new cells are formed, independent of one another.