Cell Structure and FunctionDonald Winslow, St. Gregory’s University

25 January 2011

Readings:Mader, Sylvia 2011

Inquiry into Life, 13th ed.McGraw-Hill, NY

Ch. 3; pp 47-52, 54-61, 63Ch. 4; pp 68-69, 71-78 (on membranes)

Objectives

List organelles found in most cells. Describe structure & function of these organelles. Give examples of cells where particular types of

organelles are abundant. Describe structure & function of cell membranes. Contrast cell membranes & cell walls. Explain membrane transport processes.

Organelles in an endothelial cell

Nucleus

Envelope (2 membranes) Functions in DNA replication & RNA synthesis Most eukaryotic cells have one nucleus. Syncytial eukaryotic cells have multiple nuclei. Prokaryotic cells do not have nuclei.

Mitochondria & chloroplasts

Mitochondria Inner membrane & outer membrane Function in cellular respiration Especially abundant in muscle cells

Chloroplasts Inner membrane & outer membrane Function in photosynthesis Especially abundant in leaf cells

Endoplasmic reticulum

One membrane surrounding lumen Lipid bilayer synthesis, transport to membranes Rough endoplasmic reticulum (with ribosomes)

Proteins imported into ER as they are made

Smooth endoplasmic reticulum

Ribosomes

No membranes 2 subunits composed of protein & RNA Protein synthesis from info in messenger RNA Especially abundant in cells that secrete proteins

Lysosomes & peroxisomes

Lysosomes One membrane Intracellular digestion

Peroxisomes One membrane Oxidation of toxins by peroxide Especially abundant in protective tissues

Golgi apparatus

Stack of membrane-bound “pancakes” Staging area for ER products

Vesicular transportTransport vesicle

Cell membrane