7CharacteristicsofLife

1. Interdependence2. Metabolism3. Homeostasis4. Cellular Structure and Function5. Reproduction6. Heredity7. Evolution

TheCellTheory�All living things are composed of one or

more cells.�Cells are the basic units of structure and

function in organisms.�All cells come from preexisting cells by

cell division.

OrganismOrganization

� CellæTissue – group of cells functioning together

æ Organ – group of tissues functioning togetheræOrgan System – group of

organs functioning togetheræOrganism – group of organ systems functioning together

CommonCellFeatures

Cells share common structural features, including:

� an outer boundary called the cell membrane,

� interior substance called cytoplasm,

� structural support called the cytoskeleton,

� genetic material in the form of DNA

� cellular structures that make proteins, called ribosomes

StructuresinALLCells

1.CELLMEMBRANE

� Encloses the cell, and regulates movement of materials in and out.

� Made of phospholipids and proteins

2.CYTOPLASMMaterial where

organelles are suspended, fills in the empty space of the cell

3.CYTOSKELETON�Provides support for

organelles and helps maintain cell shape

�Made of:�MICROTUBULUES

and MICROFILAMENTS

4.RIBOSOMES

� Sites where proteins are made

� Float free or are attached to the ER

5.DNA� Deoxyribonucleic Acid� Holds the hereditary information

TypesofCells

Prokaryoticv.Eukaryoticcells� PROKARYOTES

� No defined nucleus� No membrane bound organelles � Free floating DNA, RNA, and ribsomes� Ex: Bacteria

Prokaryoticv.Eukaryoticcells� EUKARYOTES – true cells

� True nucleus� Have membrane bound organelles� Protist & Fungus � Animal & Plant

Cytoskeleton�Provides support for

organelles and helps maintain cell shape

�Made of:�MICROTUBULUES and

MICROFILAMENTS

StructuresinEukaryoticCells

Nucleus1. Houses DNA�2. Nucleus controls most functions of cell �3. Double membrane called nuclear envelope

surrounds the nucleus.�4. Ribosomes and RNA are made in the nucleus.

ROUGHENDOPLASMICRETICULUM (ER)

� has ribosomes� Assembles and transports proteins

SMOOTHENDOPLASMICRETICULUM (ER)

� SMOOTH ER� Doesn’t have ribosomes � Makes fats and carbohydrates(in plant cells)

GOLGIAPPARATUS� Forms stacks of flat

tubes� Packages and secretes

proteins made by the cell at one location, and used at another

� Makes cellulose in plants

Vesicle� Transports substances

throughout the cell� Short lived and recycled� Formed from E.R. membrane

MITOCHONDRIA� Mitochondria are

organelles that harvest energy from organic compounds to make ATP.

� ATP is the main energy currency of cells. Most ATP is made inside the mitochondria.

Vacuole� Stores materials in cells� Water, food, ions, enzymes are

stored in vacuoles

LYSOSOMES� Produced by Golgi Body� Contain digestive

materials that break down materials:� Foreign material

(Bacteria and viruses): white blood cells

� Dead cells� Aging tissues� Food

� Malfunctions can lead to cancer and death of a cell

Centrioles� Cylinder shaped; made

of microtubules� Help cells divide

PlantCellsPlants have three unique structures that are not found in

animal cells:

� Cell Wall

� Chloroplasts

� Central Vacuole

CellWallThe cell membrane of plant cells is surrounded by a thick cell wall, composed of proteins and carbohydrates.

1. helps support and maintain the shape of the cell

2. protects the cell from damage

3. connects the cell with adjacent cells

CHLOROPLAST� Use light energy to make

carbohydrates.� Filled with a pigment, chlorophyll

to make them green

Chloroplasts are organelles that use light energy to make carbohydrates

� Most of a plant cell�s volume is taken up by a large, membrane-bound space called the central vacuole.

� The central vacuole stores water and may contain ions, nutrients, and wastes.

CENTRALVACUOLE

ComparisonofPlant&AnimalCells

STRUCTURESFORMOVEMENT� CILIA: short hair like structures all over cell� FLAGELLA: long, whip like structure� Mostly for Prokaryotes