Post on 04-Jan-2016
transcript
Anatomy and Physiology
Cell Structure
Structure• Cell (plasma) membrane - The
selectively permeableselectively permeable outer boundary of a cell consisting of a phospholipids bilayer embedded with proteins.
• Nucleus - Cellular organelle that is enclosed by a double layer, porous membrane, and contains DNA.
• Cytoplasm - The entire contents inside of a cell excluding the cell membrane and nucleus. Cytosol - liquid portion
Cell Structure
• Shape differs according to cell function.
Cell Membrane• Encloses the cell.• Internal cell
membrane forms membrane of nucleus and organelles.
• Composed mainly of phospholipids and protein.
• Described as being a fluid mosaicfluid mosaic model.
• Lipid layer
Lipid Layer
• Heads are made of phosphate groups and are considered hydrophilic = water loving.
• Tails are made of lipid molecules and are considered hydrophobic = water fearing.
Lipid Layer
• Proteins are embedded on and in the lipid layer.
• Some are attached to the surface, inner layer, and all the way through.
Function of the Cell Membrane
• Receives information from other cells.
• Transportation of molecules into and out of cells.
• Recognizes cells as belonging to a particular person.– Tissue typing for transplants.
Organelles
• Endoplasmic Reticulum– Network of tunnels
throughout the cytoplasm of the cell.
– Miniature circulatory system for the cell.
• 2 Types– Smooth (SER)
• Synthesizes lipids
– Rough (RER) - has ribosomes
• Synthesizes proteins
Organelles
• Ribosomes– Function to make
proteins for the cell.
• 2 Locations– Free floating in
the cytoplasm.– Attached to
endoplasmic reticulum.
Organelles• Golgi Apparatus
– AKA Golgi Body or Golgi Complex
– Consists of tiny sacs stacked on top of one another.
– Synthesizes large carbohydrates and combines with proteins=glycoprotein
– Transport vesicles form, carrying substances to different parts of the cell.
Organelles• Mitochondria
– “Powerhouse of the cell”
– Consists of a double membrane wall.
– Inner membrane folds into extentions-cristae
– This is the site of cellular respiration for production of ATP - cellular energy molecule.
Organelles
• Mitochondria continued…
• The more work a cell completes, the more mitochondria.– Ex. Muscle cells
Organelles
• Lysosomes– “Suicide bags or
garbage disposals”
– Contain enzymes that break down cell parts.
– Destroy bacteria when it enters the body.
• White blood cells engulf bacteria and lysosomes destroy them.
Organelles
• Peroxisomes– Located in all
human cells but most abundant in liver cells.
– Among many functions, it helps in the detoxification of alcohol.
Organelles
• Centrioles– Appear as two
dots located near the nucleus.
– Forms spindle fibers during cell division (mitosis/meiosis).
Organelles• Cell Fibers
– Made of proteins
• Form a 3-D lattice which helps support the cell. (cytoskeleton)– Serves as the
muscle of the cell.
• Ex.- microfilaments and microtubules.
Organelles
• Nucleus– Largest cell
structure.– Contains DNA.– The center of
the nucleus contains the nucleolus.•Nucleolus
manufactures ribosomes.
Inclusions
•Lifeless chemicals •In a cell temporarily•Store
– Nutrients - glycogen and lipids– Pigments - ex. Melanin
• http://www.wiley.com/legacy/college/boyer/0470003790/animations/cell_structure/cell_structure.htm