Transcript The Cellular Basis of Life

The Cellular Basis of Life
Chapter 3
Part 1
The Magic School Bus:
Goes Cellular
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.”
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
Iodine Deficiency
http://www.mja.com.au/public/issues/178_01_060103/li10764_fm-4.jpg
http://carondelet.net/PeriodicTable/I/iodized%20salt.jpg
Water in the Cell
– Cells are 60% water
– Interstitial fluid
• Dilute, saltwater around cells
• Site of all exchanges between cells and blood
Variations in Cells- Length
Over 1 meter
2 micrometers
http://www.iss.k12.nc.us/schools/shs/jmcCartney/redcell.jpg
http://www.acticare.com/conditions/images/sciatic_nerve2.jpg
Variations in Cells- Shape
• Red Blood Cells- disk
shaped
• Nerve Cells- spindle
shaped
• Smooth Muscle CellsThreadlike
• Epithelial CellsCubes
http://www.idahoptv.org/dialogue4kids/season3/brain/Images/neuronlabels.gif
Variations in Cells- Function
• Over 200 cell types found in the body
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
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
Plasma Membrane
• Fragile, transparent barrier that contains the cell
contents and separates them from the surrounding
environment
– Lipid Bilayer
– Proteins
– Glycoproteins
Lipid Bilayer
• Phospholipid
• Cholesterol
http://www.biology.arizona.edu/chh/problem_sets/kidneysmetals/graphics/bilayer.gif
Proteins
• scatter the surface of the plasma membrane
– Receptors for hormones
– Transport Proteins
http://www.science.org.au/nobel/1996/images/picture-0.jpg
http://www.nirgal.net/graphics/coli_protein.jpg
Glycoproteins
• Blood type
• Cell-cell
communication
http://www.funhousefilms.com/glycolip.jpg
Specializations
• Microvilli
– finger-like projections to
increase cell’s surface area
Specializations
• Tight Junctions
– impermeable junctions that
bind cells together into leakproof 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
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
Cytoplasmic Organelles
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
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
Cytoplasmic Organelles
– Golgi Apparatus
– stack of flattened sacs
– Modifies and packages proteins
Cytoplasmic Organelles
– Lysosomes
– Sacs of powerful
digestive enzymes
– Digests wornout cell
structures and most
foreign substances
– Peroxisomes
http://www.cs.utexas.edu/~s2s/latest/cell1/src/tutorial/lysosome.html
– Sacs that contain
powerful oxidase
enzymes
– Detoxify poisonous
substances and
disarm free radicals
Cytoplasmic Organelles
• Cytoskeleton
– Provides cells framework
and cells shape
– Microfilaments- cell
motility and makes changes
in cell shape
– Intermediate Filamentsform desmosomes and
resists pulling forces
– Microtubule- overall shape
of a cell and important in
cell shape
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
Cell Diversity
• Trillions of cells in the body, 200 different cell types
Cells that connect body parts
• Fibroblast- secretes cable-like fibers
• Erythrocyte (red blood cell)- carries oxygen in the
blood stream
Cells that cover and line body
organs
– Epithelial cell- pack together into sheets
Cells that move organs and body
parts
• Skeletal and Smooth Muscle cells- contract in order
to move bones or internal organs
Cell that stores nutrients
• Fat cell- stores a lipid droplet
Cell that fights disease
• Macrophage- digest infectious microorganisms
Cell that gathers information and
controls body functions
• Nerve cell (neuron)- send electrical signals
Cells of reproduction
• Oocyte- female egg cell
• Sperm- male cell with flagellum