Does an animal get larger because each cell increases in size or because it produces more of them?

Does an animal get larger because each cell increases in size or because it produces more of them?

Cell Growth *As you might have guessed, living things grow by

producing more cells.

*Every living thing has cells, but depending on shape and size depends on how many cells they have!

Why Cells Must Divide In multi-celled organisms (like humans) cells

specialize for specific functions.

Cells can only become certain sizes. If cells are too big, they cannot get oxygen and nutrients.

As you Grow you simply need more cells. (You are bigger than when you were a baby.)

When cells die, fall off, and injured your body need

to replace and repair them with new cells.

Cell Cycle The series of events that cells go

through as they grow and divide.

interphase

G1 Phase- Cells increase in size. S Phase- DNA replicates (copies) and

Chromatin coils and become chromosomes. G2 Phase- Organelles are produced and the

cell gets ready for Mitosis.

interphase

Animal Cell Plant Cell

Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

Mitosiso Mitosis is the cell division of the

NUCLEUS creating new cells from an original cell.

o Contains 4 PHASES (PMAT)oProphase

oMetaphase

oAnaphase

oTelophase

Mitosis produces identical offspring (2N---2N)

Prophase1st stage of mitosis

• Longest stage • Nuclear membrane dissolves.• Centrioles (or poles) appear and move to opposite

end of the cell. • Spindle fibers form between the poles.• Sister Chromatids form.

Prophase

Animal Cell Plant Cell

Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

Spindle fibers

Centrioles

Metaphase2nd step in mitosis Chromosomes line up SINGLE file

along the equator (middle).

Metaphase

Animal Cell Plant Cell

Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

Anaphase3rd step in mitosis

Chromatids separate and are pulled towards the opposite poles

Anaphase

Animal Cell Plant Cell

Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

Telophase4th step in mitosis

Nuclear membrane reforms Spindle disappears Cytokinesis begins

Telophase

Animal Cell Plant Cell

Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

Cytokinesis

The division of the cytoplasm The result is two genetically

complete daughter cells!

I P on a MAT C*Interphase: preparation

between split

Prophase MetaphaseAnaphaseTelophase

*Cytokinesis: cells split

MITOSIS

Cell Division Rap

http://www.youtube.com/watch?v=I5uFuvkN97I

STARR Questions

If a cat has 38 chromosomes in each of its body cells, how many chromosomes will be in each daughter cell after mitosis?

F 11G 19H 38J 76

The diagram shows cell division in which an error has occurred. Which of these statements is most accurate?

A Cell A lacks the cytoplasm necessary to continue normal cell functions.

B Cell B contains enough genetic material for the cell to reproduce itself.

C Cell A is free of any mutation present in the genetic material of the parent cell.

D Cell B lacks instructions for making the proteins necessary for cell metabolism.

STARR questions

What stage is this?

What stage is this?

What stage is this?

What stage is this?