Cell Structure and Function AP Biology Ch. 7 Ms. Haut

Cytology Light microscope –Focuses light through specimen Electron microscope –Transmission (TEM) Transmits electrons through specimen –Scanning (SEM) Electron beam scans cell surface

Cell Size Cell size is limited by metabolic requirements –Lower limits: Enough DNA to program metabolism Enough ribosomes, enzymes, & cellular components –Upper limits: Surface area and plasma membrane large enough for cell volume to allow exchange of nutrients and wastes

Nucleus Double membrane perforated with pores Contains most of cell’s DNA Houses nucleolus –Makes ribosomal subunits

Ribosomes

Endomembrane System Nuclear envelope Endoplasmic reticulum Golgi apparatus Lysosomes Vacuoles

Endoplasmic Reticulum Makes membranes and other biosynthetic functions Smooth ER –Synthesizes lipids, phospholipids, and steroids –Carbohydrate metabolism –Detoxifies drugs & poisons Rough ER –Protein synthesis –Membrane production

Golgi Apparatus Finishes, sorts, and ships cell products

Lysosomes Intracellular digestion Recycle cell’s own organic material Programmed cell destruction (apoptosis)

Peroxisome Contain enzymes for specific metabolic pathways; all contain peroxide-producing oxidases (i.e. H 2 O 2 ) Contain catalase –2H 2 O 2 catalase 2H 2 O + O 2

Food Vacuoles

Plant Cell Vacuole Stores organic compounds Stores inorganic ions May contain soluble pigments May contain poisons Plays role in plant growth & elongation

Mitochondrion Enclosed by double membrane Contains ribosomes and own DNA (maternal) Semiautonomous –Grow and reproduce within cells Responsible for Cellular Respiration and ATP production

Chloroplast Enclosed by double membrane Contains ribosomes and own DNA Site of photosynthesis in plants

Cytoskeleton

Extracellular Matrix

Centrosomes

Flagellum

Plasma Membrane

Plant Cell Wall

Cellular Junctions

Animal Cell

Plant Cell

Prokaryotic Cell