Cells Anatomy

Cells and Tissues Carry out all chemical activities Cells are the building blocks of all living things Tissues are groups of cells that are similar in structure and function

Anatomy of the Cell Cells are not all the same All cells share general structures All cells have three main regions Nucleus Cytoplasm Plasma membrane

The Nucleus Control center of the cell Contains genetic material (DNA)

The Nucleus Three regions Nuclear envelope (membrane) Nucleolus Chromatin

The Nucleus

The Nucleus Nuclear envelope (membrane) Double membrane nuclear pores - exchange of material

The Nucleus Nucleoli Sites of ribosome assembly Ribosomes move into the cytoplasm through nuclear pores

The Nucleus Chromatin DNA and protein Present when the cell is not dividing

Plasma Membrane Barrier for cell contents Double phospholipid layer Hydrophilic heads Hydrophobic tails

Plasma Membrane

Plasma Membrane Specializations Microvilli Finger-like projections that increase surface area for absorption Do all cells have microvilli?

Plasma Membrane Specializations Membrane junctions Tight junctions Desmosomes Gap junctions

Plasma Membrane Specializations

Cytoplasm Cytoplasm is the material outside the nucleus and inside the plasma membrane

Cytoplasm Cytosol Organelles Inclusions

Cytoplasmic Organelles

Cytoplasmic Organelles Mitochondria “Powerhouses” of the cell

Cytoplasmic Organelles Ribosomes Sites of protein synthesis Found at two locations:

Cytoplasmic Organelles Endoplasmic reticulum (ER) Fluid-filled tubules for carrying substances

Cytoplasmic Organelles Rough ER Smooth ER

Cytoplasmic Organelles Golgi apparatus Modifies and packages proteins:

Pathway 3 Pathway 2 Pathway 1 Rough ER Proteins in cisterna Cisterna Membrane Lysosome fuses with ingested substances Transport vesicle Golgi vesicle containing digestive enzymes becomes a lysosome Pathway 3 Pathway 2 Golgi apparatus Secretory vesicles Pathway 1 Golgi vesicle containing membrane components fuses with the plasma membrane Proteins Golgi vesicle containing proteins to be secreted becomes a secretory vesicle Secretion by exocytosis Plasma membrane Extracellular fluid

Cytoplasmic Organelles Lysosomes Contain enzymes that digest worn-out or non-usable materials within the cell

Cytoplasmic Organelles Peroxisomes Membranous sacs of oxidase enzymes Detoxify harmful substances Break down free radicals (highly reactive chemicals)

Cytoplasmic Organelles Cytoskeleton Internal framework/structure

Cytoplasmic Organelles Cytoskeleton Three different types:

Cytoplasmic Organelles Centrioles Rod-shaped structure made off microtubules Direct the formation of mitotic spindle during cell division

Cellular Projections Not found in all cells Used for movement

Cellular Projections Cilia: move materials across the cell surface Flagella: propel the cell