{Science 9} 5 The Cell Cycle And Mitosis : The Basis For Asexual Reproduction

Front 1

Why do an organism's cells divide?

Back 1

For growth and repair.

Front 2

How does a cell know when to divide?

Back 2

The DNA decides this.

Front 3

What cells need to be replaced more frequently:
and less frequently:

Back 3

Skin cells
Brain cells

Front 4

During cell division a cell goes through a set series of __________, which is referred to as the cell cycle.

Back 4

stages

Front 5

The cell cycle consists of 3 stages:
_________________ : __________________ and ________________
_________________ : _____________________________________
_________________ : __________________________________

Back 5

interphase: cells carry out normal functions and prepare to divide
mitosis: after duplication of contents, the cell's nucleus divides into 2 equal and identical parts
cytokinesis: the two nuclei and two cell content(s) seperate into 2 daughter cells

Front 6

Interphase.

Back 6

Longest stage in the cell cycle.

Front 7

Interphase.

Back 7

During this phase, DNA is in the form of chromatin.

Front 8

Interphase is divided into 3 stages.

Back 8

Growth & Preparation: Cell grows in size and doubles its organelles (while performing its usual functions).

Front 9

Interphase is divided into 3 stages:

Back 9

DNA Replication: DNA duplicates, making an exact copy of itself. Because DNA replication occurs before mitosis, the chromatin condenses in the form of duplicated chromosomes, which are composed of two sister chromatids.

Front 10

DNA Replication (Stage 2 of 3 in Interphase)

Back 10

(Enzyme unzips DNA by separating base pairs. New bases pair with bases on original DNA strand. Two new identical DNA molecules are produced.)

Front 11

Interphase is divided into 3 stages:

Back 11

Continued Growth & Preparation: After DNA replicates, the cell continues to grow and prepare for division while performing its usual functions. In particular, it synthesizes a lot of proteins needed for cell division.

Front 12

Mitosis.

Back 12

Shortest stage in cell cycle. Contents of nucleus divide, resulting in 2 daughter nuclei that are identical to the original parent cell.

Front 13

Spindle fibers.

Back 13

Protein structures that move the chromosomes during cell division.

Front 14

Centrioles.

Back 14

Organelles that control the spindle fibers during cell division, not found in plant cells.

Front 15

Mitosis is divided into 4 stages.

Back 15

Prophase
Metaphase
Anaphase
Telophase

Front 16

Prophase.

Back 16

Early prophase: duplicated chromosomes condense into x-shape. Nucleolus disappears. Nuclear membrane breaks down. Spindle fibers form and spread across the cell. Centrioles move to opposite ends of the cell.

Front 17

Prophase.

Back 17

Late prophase: Spindle fibers complete forming. They attach to chromosomes at their centromeres. By the end of prophase, the nuclear membrane and nucleolus have disappeared.

Front 18

Metaphase.

Back 18

Spindle fibers pull chromosomes into a line across the metaphase plate along the center of the cell.

Front 19

Anaphase.

Back 19

Spindle fibers contract and shorten to pull the sister chromatids apart toward opposite poles of the cell. The sister chromatids are now considered to be daughter chromosomes.

Front 20

Telophase. (4 of 4 mitosis pmat)

Back 20

Final stage of mitosis. A complete set of chromosomes is at each end of the cell. Nuclear membrane reforms around each set of chromosomes. Nucleolus reappears. Spindle fibers disappear. Now there are two nuclei in one cell.

Front 21

Cytokinesis

Back 21

Final stage of the cell cycle. The cell with 2 nuclei splits into 2 daughter cells. The new cells are identical to each other and the original parent cell. Cytokinesis is different in animal and plant cells due to the presence of the cell wall in plants.

Front 22

Cytokinesis in animal cells:
and plant cells:

Back 22

cell membrane pinches together to separate nuclei and organelles.
cell plate forms along center of cell.