Biology Cell Division

Front 1

Chromosomes, duplicated during S phase, cannot be seen individually because they have not yet condensed

Back 1

Interphase

Front 2

The chromatin fibers become more tightly coiled, condensing into discrete chromosomes observable with a light microscope

Back 2

Prophase

Front 3

The nuclear envelope fragments

Back 3

Prometaphase

Front 4

The nucleus contains one or more nucleoli

Back 4

interphase

Front 5

By the end of this phase, the two ends of the cell have equivalent and complete collections of chromosomes.

Back 5

Anaphase

Front 6

The nucleoli disappear

Back 6

Prophase

Front 7

the centrosomes are now at opposite ends of the cell

Back 7

Metaphase

Front 8

Each duplicated chromosome appears as two identical sister chromatids joined together

Back 8

Prophase

Front 9

The chromosomes become less condensed

Back 9

Telophase

Front 10

In animal cells, each centrosome features two centrioles

Back 10

Interphase

Front 11

The mitotic spindle begins to form. It is composed of the centrosomes and the microtubules that extend from them. The radial arrays of shorter microtubules that extend from the centrosomes are called asters

Back 11

Prophase

Front 12

Each of the 2 chromatids of a chromosome now has a kinetochore, a specialized prtein structure located at the centromere.

Back 12

Prometaphase

Front 13

The centrosomes move away from each other, apparently propelled by the lengthening microtubules between them.

Back 13

Prophase

Front 14

A nuclear envelope bounds the nucleus

Back 14

Interphase

Front 15

The microtubules of the spindle can now invade the nuclear area and interact with the chromosomes, which have become even more condensed.

Back 15

Prometaphase

Front 16

Microtubules extend from each centrosome toward the middle of the cell

Back 16

Prometaphase

Front 17

two centrosomes have formed by replication of a single centrosome

Back 17

Interphase

Front 18

Some of the microtubules attach to the kinetochores, becoming "kinetochore microtubules"; thesse jerk the chromosomes back and forth.

Back 18

Prometaphase

Front 19

The chromosomes convene on the metaphase plate, an imaginary plane that is equidistant between the spindle's two poles. The chromosomes' centromeres lie on the metaphase plate.

Back 19

Metaphase

Front 20

Begins when the 2 sister chromatids of each pair suddenly part. Each chromatid thus becomes a full fledged chromosome.

Back 20

Anaphase

Front 21

For each chromosome, the kinetochores of the sister chromatids are attached to kinetochore microtubules coming from opposite poles

Back 21

Metaphase

Front 22

Nonkinetochore microtubules interact with those from the opposite pole of the spindle.

Back 22

Prometaphase

Front 23

longest stage of mitosis, lasting about 20 minutes

Back 23

metaphase

Front 24

The entire apparatus of microtubules is called the spindle because of its shape

Back 24

Metaphase

Front 25

the shortest stage of mitosis, lasting only a few minutes

Back 25

Anaphase

Front 26

The cell elongates as the nonkinetochore microtubules lengthen

Back 26

Anaphase

Front 27

Two daughter nuclei begin to form in the cell

Back 27

Telophase

Front 28

The division of the cytoplasm is usually well underway by late telophase, so the 2 daughter cells appear shortly after the end of mitosis

Back 28

Cytokinesis

Front 29

Nuclear envelopes arise from the fragments of the parent cell's nuclear envelope and other portions of the endomembrane system

Back 29

Telophase

Front 30

In animal cells, cytokinesis involves the formation of a cleavage furrow, which pinches the cell in two.

Back 30

Cytokinesis

Front 31

The two liberated chromosomes begin moving toward opposite ends of hte cell, as their kinetochore microtubules shorten. Because these microtubules are attached at the centromere region, the chromosomes move centromere first

Back 31

Anaphase

Front 32

Mitosis, the division of one nucleus into two genetically identical nuclei, is now complete

Back 32

Telophase