3. Introduction to Cell Biology
– Chemical in the cells
• Major Elements
– Carbon (C)
– Oxygen (O)
– Hydrogen (H)
– Nitrogen (N)
“Biology is the search for chemistry that works.”
4. Trace Elements
– Calcium (Ca)- blood
clotting
– Iron (Fe)- hemoglobin
– Iodine (I)- controls
metabolism
– Electrolytes- carry an
electrical charge
http://www.ehu.es/biomoleculas/PROT/hemoglobin.jpg
6. Water in the Cell
– Cells are 60% water
– Interstitial fluid
• Dilute, saltwater around cells
• Site of all exchanges between cells and blood
7. Variations in Cells- Length
http://www.acticare.com/conditions/images/sciatic_nerve2.jpg
http://www.iss.k12.nc.us/schools/shs/jmcCartney/redcell.jpg
2 micrometers
Over 1 meter
8. Variations in Cells- Shape
• Red Blood Cells- disk
shaped
• Nerve Cells- spindle
shaped
• Smooth Muscle Cells-
Threadlike
• Epithelial Cells-
Cubes
http://www.idahoptv.org/dialogue4kids/season3/brain/Images/neuronlabels.gif
10. The Generalized Cell
– Demonstrates the basic
parts that all cells
contain
– Has three parts
• Nucleus
• Plasma Membrane
• Cytoplasm
http://www.cse.ucsc.edu/~sugnet/documentation/biology_starter/images/animal_cell_580_915.jpg
11. The Nucleus
– Nuclear Envelope
• The membrane of the
Nucleus
– Nucleoli
• Where ribosomes are
assembled
• Round, dark staining
bodies
– Chromatin
• DNA combined with
protein
• When the cell divides the
DNA condenses into
chromosomes
12. Plasma Membrane
• Fragile, transparent barrier that contains the cell
contents and separates them from the surrounding
environment
– Lipid Bilayer
– Proteins
– Glycoproteins
14. Proteins
• scatter the surface of the plasma membrane
– Receptors for hormones
– Transport Proteins
http://www.nirgal.net/graphics/coli_protein.jpg
http://www.science.org.au/nobel/1996/images/picture-0.jpg
17. Specializations
• Tight Junctions
– impermeable junctions that
bind cells together into leak-
proof sheets
• Desmosomes
– Anchoring junctions that
prevent cells subjected to
mechanical stress from falling
apart
• Gap Junctions
– Allow communication
– Connexons- hollow cylinders
composed of proteins that span
the entire width of the abutting
membrane
18. Cytoplasm
– Cellular material outside the nucleus and inside
the plama membrane
– Site of most cellular activities (factory)
– Three Elements
• Cytosol- semitransparent fluid
• Organelles- parts that have specific functions
• Inclusions- non-functioning units
20. Cytoplasmic Organelles
• Mitochondria
– Enzymes break down
food and capture the
energy in ATP
molecules
– Liver and muscle
cells have hundreds
of mitochondria
http://www.cbs.dtu.dk/staff/dave/roanoke/mitochon.gif
21. Cytoplasmic Organelles
• Ribosomes
– Made of proteins and rRNA
– Site of protein synthesis
• Endoplasmic Reticulum
– System of fluid-filled
cisterns that coil and twist
through the cytoplasm
– Rough ER- studded with
ribosomes
– Smooth ER- cholesterol
synthesis and breakdown,
fat metabolism, and
detoxification http://dragon.seowon.ac.kr/~bioedu/bio/ohp/t-021.jpg
23. Cytoplasmic Organelles
– Lysosomes
– Sacs of powerful
digestive enzymes
– Digests wornout cell
structures and most
foreign substances
– Peroxisomes
– Sacs that contain
powerful oxidase
enzymes
– Detoxify poisonous
substances and
disarm free radicals
http://www.cs.utexas.edu/~s2s/latest/cell1/src/tutorial/lysosome.html
24. Cytoplasmic Organelles
• Cytoskeleton
– Provides cells framework
and cells shape
– Microfilaments- cell
motility and makes changes
in cell shape
– Intermediate Filaments-
form desmosomes and
resists pulling forces
– Microtubule- overall shape
of a cell and important in
cell shape
25. Cytoplasmic Organelles
– Centrioles
– Rod-shaped bodies that are at right angles
– Other Cell Structures
– Cilia- whiplike cellular extensions that move substances
along the cell surface
– Flagella- Longer projection that moves the cell
The dark-staining bodies where the ribosomes are assembled:
Chromatin
Chromosomes
Nucleolus
Nuclear membrane
Plasma membrane
The plasma membrane:
Is the gene-containing control center that directs all cellular activities
Regulates the entry and exit of cell materials
Is the site of most cellular activities
Is the site where ribosomes are assembled prior to their migration into the cytoplasm
Defines the limits of the nucleus
The primary lipids found in the cell membrane are:
Fat-soluble vitamins and neutral lipids
Fat-soluble vitamins and cholesterol
Neutral lipids and cholesterol
Neutral lipids and phospholipids
Phospholipids and cholesterol
The molecules in the cell membrane that serve as receptors or binding sites fro hormones other chemical messengers are the:
Glycoproteins
Proteins
Cholesterol molecules
Carbohydrates
Lipids