3.01 Mitosis

Question 1

What is mitosis?

Answer 1

A process in which new identical cells are formed from one parent cell.

Question 2

Parts of the Cell Cycle

Interphase and cell division sections:

Answer 2

Interphase and cell division cycle: The life cycle of a cell can be divided into two main sections: interphase and cell division.

Interphase section divided into three separate phases: Most of a cell’s life is spent in interphase. The amount of time a cell spends in this phase varies depending on the type of cell. For example, a human skin cell will spend about 20 hours in interphase. Interphase can be divided into three phases.

Question 3

G1 Phase:

Answer 3

G1 phase: The G1 phase is the longest stage of interphase. During this time the cell grows in size and performs its particular jobs and functions within the organism. For example, liver cells in your body work to store sugar from your food and the leaf cells in a tree perform photosynthesis to harness energy from the sun. Cells in this phase will work and grow until they get too large to continue normal daily activity. When they reach that point, a chemical signal is activated to send them into the S phase.

Question 4

S Phase:

Answer 4

S phase: In the S stage, or the synthesis phase, the cell will make a copy of the chromatin in its nucleus. The chromatin contains the cell’s DNA. Once this genetic material has been copied, the cell moves on to the G2 phase.

Question 5

G2 Phase:

Answer 5

G2 Phase: Now in the G2 phase, the cell grows a bit and makes final preparations for cell division. At the end of this phase, the cell is ready to divide.

Question 6

Cell Division:

Answer 6

Cell Division: Cell division is divided into two phases: mitosis and cytokinesis.

Question 7

Mitosis:

Answer 7

Mitosis: Following interphase, cell division begins with mitosis. In this phase, the cell distributes the copied genetic material made in the S phase into two separate nuclei.

Question 8

Cytokinesis:

Answer 8

Cytokinesis: During cytokinesis, the cell divides into two separate cells, called “daughter cells.” These new cells each contain an identical copy of the original cell’s genetic material, and they are now ready to begin the cell cycle over again.

Question 9

DNA:

Answer 9

DNA: Genetic blueprint of the cells genetic information

Question 10

Chromosomes:

Answer 10

Chromosomes: “x” shaped molecules that are made up of DNA and proteins tightly bonded together

Question 11

Stages of Mitosis:

Prophase:

Answer 11

Prophase: The duplicated chromatin inside the nucleus condenses into chromosomes, becoming more visible under a microscope. These identical copies of chromosomes, called sister chromatids, are held together at the center by a centromere. This is why each pair of sister chromatids resembles the letter “x.”

Question 12

Metaphase:

Answer 12

Metaphase : The nuclear membrane and the nucleolus begin to break down and disappear.
Spindle fibers, fanlike structures of very thin fibers, begin to form from one end of the cell to another. Centrioles, tiny structures within the cell’s cytoplasm, organize the spindle fibers.

Question 13

Anaphase:

Answer 13

Anaphase: The centromeres that are holding the sister chromatids together divide, and the individual chromosomes are pulled apart.
The individual chromosomes move along the spindle fibers to opposite ends of the cell. Each resulting set of chromosomes contains an exact copy of the original genetic information.

Question 14

Telophase:

Answer 14

Telophase: The condensed chromosomes stretch out to form thin, tangled chromatin again. Nuclear membranes form around each set of chromosomes. The spindle breaks apart.
A nucleolus forms in each nucleus.

Question 15

Cytokinesis:

Answer 15

Cytokinesis is the division of the cytoplasm, organelles, and other material contained within the cell. Cytokinesis differs in plant and animal cells