Anatomy Unit 4: Cell Theory & Cellular Structures

Cell Theory Term “cell” was coined in 1665 by Robert Hooke when he looked at a slice of dried cork. He also observed that: 1.All living things are comprised of cells. 2.Cells are the smallest “living” unit in an organisms. 3.Cells come from previously existing cells.

Typical Cell

Cell Organization

The cell includes two basic parts: 1.Cell Membrane (outer covering of cell) 2.Cytoplasm Cytosol (fluid portion of the cytoplasm) Organelles (cell “organs” or functional parts)

Cell Membrane Outer boundary Physical Chemical Comprised of two layers of lipid (fat) –Outer and inner layers Proteins Proteins give the cell its unique “personality” or function

Cell Membrane

Function of Membrane Proteins 1.Transport (in and out of cell) 2.Receptors 3.Cell adhesion 4.Cell recognition

Cytoplasm Is comprised of: 1.Cytosol (fluid portion of the cytoplasm) 2.Organelles (cell “organs” or functional parts)

Organelles Components of a cell

Mitochondria Bean shaped Outer and inner membranes

Mitochondria Inner membrane folded into cristae Adenosine triphosphate (ATP) produced on cristae. ATP is high energy compound. ATP only produced in mitochondria.

Nucleus

Control center of cell Contains DNA/chromosomes Genetic repository for ~ 35,000 genes Genes control the synthesis of proteins in each cell. Red blood cells don’t have a nucleus. Skeletal muscle cells have multiple nuclei.

Vacuole Is in both plant and animal cells Is much larger in plant cells- controls water

Plant Cells Plant cells contain all of the organelles previously discussed. They do have two organelles that are different than an animal cell.

Chloroplast Contains the chlorophyll (green pigment in plants) Remember photosynthesis???

Cell Wall Gives plant cells structure