Biological Organization

Cell Structure & 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 Do not have structures surrounded by membranes Few internal structures One-celled organisms, Bacteria

Eukaryotic Contain organelles surrounded by membranes Most living organisms PlantAnimal

“Typical” Animal Cell /~ acarpi/NSC/images/cell.gif

“Typical” Plant Cell

Cell Parts Organelles

Surrounding the Cell

Cell Membrane Outer membrane of cell that controls movement in and out of the cell Double layer

Cell Wall Most commonly found in plant cells & bacteria Supports & protects cells

Inside the Cell

Nucleus Directs cell activities Separated from cytoplasm by nuclear membrane Contains genetic material - DNA

Nuclear Membrane Surrounds nucleus Made of two layers Openings allow material to enter and leave nucleus

Chromosomes In nucleus Made of DNA Contain instructions for traits & characteristics

Nucleolus Inside nucleus Contains RNA to build proteins

Cytoplasm Gel-like mixture Surrounded by cell membrane Contains hereditary material

Ribosomes Each cell contains thousands Make proteins Found on ER & floating throughout the cell

Endoplasmic Reticulum Moves proteins around in cell Smooth type: lacks ribosomes Rough type (pictured): ribosomes embedded in surface

Golgi Bodies “Protein Transporter” Move materials within the cell Move materials out of the cell

Mitochondria Produces energy through chemical reactions – breaking down fats & carbohydrates ***Cellular Respiration

Lysosome Cleans the cell of waste Cell breaks down if lysosome explodes

Vacuoles Used for storage of water and nutrients. Help plants maintain shape Especially large in plant cells

Chloroplast Only in plant cells Contains green chlorophyll Where photosynthesis takes place Most are found in leaves

Organelle Tutorial LP7xAr2FDFU

Interactive Cell natomy/cell/index.htmhttp:// natomy/cell/index.htm

How do particles move throughout a cell? DiffusionOsmosis

Diffusion The movement of molecules from a area in which they are highly concentrated to a area in which they are less concentrated. Ex. Ions, glucose, amino acids movie in and out of the cell

Diffusion Animation hill.com/sites/ /student_view0/ chapter2/animation__how_diffusion_works.html

Osmosis Movement of liquid (usually H20) through a membrane. The fluid will move from an area of low solute concentration to an area with a higher solute concentration until there is an equal concentration of fluid on both sides of the membrane.

Osmosis Animation hill.com/sites/ /student_view0/ chapter2/animation__how_osmosis_works.html

Tonicity Tonicity is a measure of the pressure of both solutions separated by a membrane. Often used to describe cells in different solutions

Hypertonic Solution IF the concentration of solute in the liquid is greater than the concentration of solute in the cells. The cell is in an hypertonic solution. (hyper = more than normal) What will happen to the cell?? Water will move out of The cell

Hypotonic If the concentration of solute in the liquid is less than the concentration of solute in the cells. The cell is in an hypotonic solution. (hypo = less than normal) What will happen to the cell? Water will move into of the cell

Isotonic If the concentration of solute in the liquid is equal to the concentration of solute in the cells. The cell is in an isotonic solution. (iso = same as normal) What will happen to the cell? Water moves in both directions

Tonicity animation 0animations.htm