Cell Reproduction

Chapter 8

Chromosomes

Vs.

Chromatin

Chromosomes

Chromatin

Think of it like

Cookies!

Chromatin

Chromosomes

MAKES

Our cells are constantly needing to replace themselves.

For example, when we get a paper cut or any kind of cut, those cells need to be replaced.

Also, cells in your stomach lining constantly need to be replaced, and even bone marrow cells.

Cell Division:

What is it?

The Cell Cycle is a sequence of separate periods of __________ & __________

The period where the cell grows in size, metabolizes, and spends a majority of its life is _______________

Also, during this period, the chromosomes are ___________ to prepare for cell division.

Growth Division

INTERPHASE

duplicated

The period where the cell undergoes nuclear division and creates 2 daughter cells is called ____________

Each daughter cell contains a ____________ set of the parent cell’s chromosomes.

MITOSIS

Complete

Which phase of the cell cycle takes the longest?

75% of a cell’s life is

spent in Interphase

Copies itschromosomes

G2

S

G1

“Checkpoints” = stop & go-ahead signals to regulate the cycle

Regulatory molecules, usually enzymes (protein kinases)To become active

kinases need a cyclin to trigger them

Often called “Cdks” (cyclin-dependent kinases)

The first phase = ____________

This is the ________ phase (OF MITOSIS) During this phase, chromatin coils to form visible _____________ Each chromosome is made up of ___ sister chromatids and are held together by a __________*Remember: The chromosomes are duplicated in ____________ to prepare for cell division

PROPHASE

longest

chromosomes2

centromere

Interphase

One Chromatid

Duplicated Chromatidsister chromatids

The TWO together are

In addition, the ________ envelope starts to disappear and the __________ disintegrates.

In animal cells, ___________ migrate to opposite ends of the cell and ________ ________ begin to form.

In plant cells _______ _______ form without centrioles.

nuclearnucleolus

centriolesspindle

fibers

Spindle fibers

The Second Phase = _____________

• The chromosomes begin to line up along the _________ of the cell

• The spindle fibers _______ to the centromeres.

• Each chromatid has its own spindle fiber attached

METAPHASE

Equator

attach

The Third Phase = ____________

This marks the ___________ of sister chromatids.

The centromeres ______ and the ______ ___________ are pulled apart to opposite poles of the cell by shortening spindle fibers

ANAPHASE

separation

splitsister chromatids

The Fourth Phase = ______________

Here two distinct _________ cells start to form.

In addition, the _____________ unwind, the spinder fibers ______ down, the _________ reappears, a new nuclear __________ forms, and a new double __________ begins to form between the two nuclei.

TELOPHASE

daughter

chromosomesbreak nucleolus

envelopemembrane

Cytokinesis

the division of ____________

Toward the end of telophase in animal cells, the plasma membrane _______ in along the equator

In plant cells, a ____ _________ forms around each cell and new cell ______ form on each side of the cell plate until separation is complete.

cytoplasm

pinches

cell membranewall

Can you identify any of the stages?

Now the cells are separated, they will continue in the cell cycle and enter __________interphase