Cell Structure & Function http://koning.ecsu.ctstateu.edu/cell/cell.html

Cell Theory All organisms are made of one or more cells. Cells are the basic unit of life in all living things. All cells come from existing cells.

Definition of Cell A membrane - covered structure that contains all of the materials necessary for life. A cell is the basic unit of life.

Examples of Cells Amoeba Proteus Plant Stem Bacteria Red Blood Cell Nerve Cell

Two Types of Cells Prokaryotic- primitive, disorganized without nucleus. Eukaryotic- organized, complicated with nucleus.

Prokaryotic Do not have structures surrounded by membranes Few internal structures One-celled organisms, like Bacteria Fossils of Prokaryotes have been found and estimated to be 3.5 billion years old http://library.thinkquest.org/C004535/prokaryotic_cells.html

Eukaryotic Animal Plant Contain organelles surrounded by membranes Most living organisms (plants, animals, fungi and protists) Fossil evidence suggests Eukaryotes to be 2 billion years old. More DNA and can be 10 times larger than Prokaryotic cells. Animal Plant http://library.thinkquest.org/C004535/eukaryotic_cells.html

“Typical” Animal Cell Cytoplasm Chromosomes http://web.jjay.cuny.edu/~acarpi/NSC/images/cell.gif

“Typical” Plant Cell http://waynesword.palomar.edu/images/plant3.gif

Cell Parts Organelles

Cell Wall Found only in plant cells, fungi cells & bacteria. Supports & protects plant, bacteria and some fungi cells Made of cellulose The strength of billions of cell walls in plants enable a tree to stand tall. It is made of cellulose fibers http://library.thinkquest.org/12413/structures.html

Cell Membrane A phospholipids double layer that controls what goes in and out of the cell. (see p. 45 for details green book). All cells have a cell membrane. Allows nutrients in and wastes out of the cell. The cell membrane keeps the cytoplasm inside, allow nutrients in and waste products out, and interact with things outside the cell. The cell membrane is made of phospholipids (fats) that allow movement of very small particles. http://library.thinkquest.org/12413/structures.html

Nucleus A membrane bound structure found only in Eukaryotic cells and is the control center or brain of the cell. The word nucleus means “kernal”. It is the control center of the cell, stores the DNA, and has information for making proteins. The Nucleolus stores materials that will be used later to make ribosomes in the cytoplasm.

Chromosomes A coiled structure found in the nucleus that contains instructions. DNA is packed into chromosomes. Humans have 46 chromosomes in each normal body cell. http://library.thinkquest.org/12413/structures.html

Vacuoles Membrane-bound sacs for storage of food and water. Some plants wilt when their cells vacuoles lose water. If you want crispy lettuce you need to let the vacuoles fill up by leaving the lettuce in water overnight. Plants have 1 large vacuole that helps give support. Animals have many smaller vacuoles. Liquids in vacuoles are what make oranges and other fruits juicy. http://library.thinkquest.org/12413/structures.html

Endoplasmic Reticulum A membrane bound structure that transports things around the cell. And, Smooth ER makes fats and breaks down drugs and chemicals that could damage the cell. http://library.thinkquest.org/12413/structures.html

Lysosome These are special vesicles in animal cells that breaks down proteins, fats, and carbohydrates and cleans and digest unwanted material in the cell. http://library.thinkquest.org/12413/structures.html

Golgi Bodies A membrane bound structure that modifies and packages protein for shipment out of the cell. It is usually close to the cell membrane. http://library.thinkquest.org/12413/structures.html

Mitochondria Make food molecules (ATP) by burning food for energy. You need to breath in O2 air so your mitochondria can work. More active cells like those in the liver and heart have more mitochondria. Energy in fats and carbohydrates ATP Energy http://library.thinkquest.org/12413/structures.html ATP Image taken from Google Images. Cell Energy

Cytoplasm Gel-like mixture that fills in all the empty space and surrounds organelles.

Ribosomes Each cell contains thousands Make proteins Found on ribosomes & floating throughout the cell Ribosomes are the smallest and most abundant organelle in the cell. http://library.thinkquest.org/12413/structures.html

Nuclear Membrane Surrounds nucleus Made of two layers Openings allow material to enter and leave nucleus (RNA) http://library.thinkquest.org/12413/structures.html

Nucleolus Inside nucleus Contains RNA to build proteins http://library.thinkquest.org/12413/structures.html

Chloroplast Usually found in plant cells Contains green chlorophyll Where photosynthesis takes place http://library.thinkquest.org/12413/structures.html