Cell Structure & Function

http://koning.ecsu.ctstateu.edu/cell/cell.html

Cell Theory

• All living things are made up of cells.

• Cells are the smallest working units of all living things.

• All cells come from preexisting cells through cell division.

Definition of Cell

A cell is the smallest unit that is capable of performing life

functions.

Examples of Cells

Amoeba Proteus

Plant Stem

Red Blood Cell

Nerve Cell

Bacteria

Two Types of Cells

•Prokaryotic

•Eukaryotic

Prokaryotic

• Do not have structures surrounded by membranes

• Few internal structures

• One-celled organisms, Bacteria

http://library.thinkquest.org/C004535/prokaryotic_cells.html

Eukaryotic• Contain organelles surrounded by membranes• Most living organisms

Plant Animal

http://library.thinkquest.org/C004535/eukaryotic_cells.html

“Typical” Animal Cell

http://web.jjay.cuny.edu/~acarpi/NSC/images/cell.gif

http://waynesword.palomar.edu/images/plant3.gif

“Typical” Plant Cell

Cell Parts

Organelles

Cell Membrane

• Outer membrane of cell –Contains the cell contents–Controls what gets in and out of the cell–Is selectively permeable

http://library.thinkquest.org/12413/structures.html

Nucleus

• Directs cell activities- the “Control Center”• Contains genetic material – DNA• Usually the easiest organelle to see under a microscope

ADD

THE

LABELS

Cytoplasm

• Gel-like mixture

• Surrounded by cell membrane

Endoplasmic Reticulum• Moves materials around

in cell- the “Assembly line or Roads”

• Smooth type: lacks ribosomes

• Rough type (pictured): ribosomes attached to surface

http://library.thinkquest.org/12413/structures.html

Ribosomes• Each cell contains

thousands• Make proteins• Found on RER &

floating throughout the cell

http://library.thinkquest.org/12413/structures.html

Mitochondria

• Cellular respiration occurs here to release energy for the cell to use

• “Power plant” of the cell

http://library.thinkquest.org/12413/structures.html

Golgi Bodies

• Protein “packaging plant” or “shippers”

• Coats proteins and other materials so they can move different location inside/outside of cell

http://library.thinkquest.org/12413/structures.html

Golgi Apparatus

Lysosome• The “Clean-up Crew”• Filled with enzymes that

break apart molecules that are small enough for cell to use

• Get rid of wastes “garbage disposal”

• Destroy old cells/organelles; “suicide sacs”

http://library.thinkquest.org/12413/structures.html

Lysosomes

• Tay-Sachs disease occurs when the lysosome is missing the enzyme needed to digest a lipid found in nerve cells.– As a result the lipid accumulates and nerve

cells are damaged as the lysosome swells with undigested lipid.

Centriole• Aids in cell division• Only in animal cells

Vacuoles• Large central vacuole

in plant cells• Many smaller

vacuoles in animal cells

• “Storage container” for water, food, wastes, etc.

Plant Cell Features

• Unique Features of Plant Cells – Plant cells have three structures that animal

cells lack: • a cell wall• Chloroplasts• Large vacuole

Chloroplast

http://library.thinkquest.org/12413/structures.html

• Found in plant cells

• Capture energy from the sunlight and convert it into chemical energy…PHOTOSYNTHESIS!

• Green in color because of chlorophyll, a green pigment

Cell Wall• Found in plant and

bacterial cells• Rigid, protective

barrier that provides support

• Located outside of the cell membrane

• Made of cellulose (fiber)

Quick Review• Which organelle is the control center of the cell?

Nucleus

• Which organelle holds the cell together?Cell membrane

• Which organelles are not found in animal cells?Cell wall, chloroplasts

• Which organelle helps plant cells make food?Chloroplasts

• What does E.R. stand for?Endoplasmic reticulum

Elodea Cells

http://carnegieinstitution.org/first_light_case/horn/lessons/images/chlorop.jpg

Nucleus

Plasma Membrane

Cytoplasm

Cheek Cells Stained with Methyl Blue

http://faculty.kutztown.edu/friehauf/science_outreach/cheek_cells_005.jpg