Cell Structure and Function

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 cell• Do not have

internal structures surrounded by membranes

• Few internal structures

• One-celled organisms, Bacteria

Prokaryotic cell

Eukaryotic cells

Plant cellAnimal cell

• Contain organelles surrounded by membranes• Most living organisms

Eukaryotic cellsPlant cells (onion cells)

Animal cell (Amoeba)

Organelles

Cell Membrane

• Outer membrane of cell that controls movement in and out of the cell

• Double layer

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

Cell Wall

• Most commonly found in plant cells & bacteria

• Supports & protects cells

Nucleus

• Directs cell activities

• Separated from cytoplasm by nuclear membrane

• Contains genetic material - DNA

Nucleus

Cytoplasm

• Gel-like mixture

• Surrounded by cell membrane

• Contains all the organelles

• In it, all the chemical reactions occur.

Ribosomes• Each cell contains thousands• Make proteins• Found on rough endoplasmic reticulum & floating

throughout the cell

Endoplasmic reticulum• Moves

materials around in cell:

• Lipids and carbohydrates in smooth type

• Proteins in rough type

Golgi apparatus

• Protein 'packaging plant'• Move materials within the cell and out

of the cell by using vesicles

RE and Golgi apparatus

Vacuole

• Membrane-bound sacs for storage, digestion, and waste removal

• Help plants maintain shape

Lysosome

• Contains digestive enzymes for proteins, fats, and carbohydrates

• Transports undigested material to cell membrane for removal

• Cell breaks down if lysosome explodes

Mitochondrion

• Produces energy through chemical reactions – breaking down fats & carbohydrate

Chloroplast

• Contains green chlorophyll

• Where photosynthesis takes place

Centrioles

•Lead cromosomes movement during cell division

•Control flagella and cilia vibration

Cytoskeleton

•Support organelles and cell shape and place a role in cell motion

Flagellum and cillia

Help cell move