The Cell And all its parts!

The cell The basic unit of structure and function in all living things.

Without Jansenn's microscope invention we would not have discovered cells 3

The average cell is between 2 and 200µm  (micrometers). To give you an idea of how big a micrometer is, the thickness of a strand of human hair ranges from 50 to 200 micrometers.  Dark hair is usually thicker than blonde hair. The smallest particle that can be seen by the human eye is about 10 micrometers.  The eyepiece of your microscope has a special tool to measure micrometers. Cells Alive

Entering (and exiting) the cell CELL WALL A stiff wall that surrounds the cell membrane, giving the cell a rigid boxlike shape Function: protection & support This structure is found in plant & bacteria cells CELL MEMBRANE Forms the outside boundary that separates the cell from its environment Function: controls what comes in and out of the cell

Cell Wall/ Cell Membrane

Cell Wall/Cell Membrane _________________ _____________

Nucleus Acts as the “brain” of the cell or the control center Directs all of the cell’s activities Where DNA is found

Nucleus Cells without a nucleus: prokaryotes Cells with a nucleus: eukaryotes ___________________________ ___________________________

Nucleus The nucleus of the cell contains the genetic information (DNA)

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

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

Chromosomes In nucleus Made of DNA Contain instructions for traits & characteristics http://library.thinkquest.org/12413/structures.html

Cytoplasm A gel-like fluid found throughout the entire cell wherein the organelles are found. It is constantly moving so the cell does not need to propel itself.

Mitochondria The “powerhouse” of the cell Produces energy for the cell

Ribosomes “Factories” that produce protein

Endoplasmic Reticulum Carry proteins and other materials from one part of the cell to another

Endoplasmic Reticulum Moves materials around in cell Smooth type: lacks ribosomes Rough type (pictured): ribosomes embedded in surface http://library.thinkquest.org/12413/structures.html

Endoplasmic Reticulum & Ribosomes

Golgi Bodies The cell’s “mailroom” Receives proteins and other materials from the ER, packages them and distributes them to other parts of the cell.

VACUOLES Storage area of the cell Stores food and water Plants have one large vacuole for water Some animal cells have them & others do not

Lysosomes Cell’s cleanup crew Breaks down old cell parts and releases the substances so they can be used again.

Chloroplasts Capture energy from the sunlight and use it to produce food for the cell Found only in the plant cell

Eukaryotes Nucleus has a permeable membrane surrounding it Nucleus contains the organism’s genetic material (DNA) Most organelles also have a membrane around them Mostly eukaryotic kingdoms are multicellular

Plant Cells Animal Cells Smaller vacuoles, some have no vacuoles No cell wall and no chloroplast More lysosomes More mitochondria Larger vacuoles Chloroplast Cell wall Cells have definite shape

Prokaryotes Bacteria Kingdoms ONLY Have no nucleus (lack a nucleus) Have only ribosomes, cytoplasm, and genetic material (DNA or RNA) Genetic material floats freely in the cytoplasm (No nucleus) Cell Wall and cell membrane ALL unicellular