Download Introduction to Cells

Introduction to Cells
SJCHS
November 2010
Cell Theory
• All life is made of 1 or more cells
• Cells are the basic units of structure and organization of life
• Cells only arise from previously existing cells and pass on copies of
their DNA
Cells
•Cell Size: between 1- 100
micrometers
Eukaryotic Cells
• DNA in nucleus
• Can be unicellular or
multicellular
• Have Organelles
Prokaryotic Cells
• DNA not in nucleus
• Lacks most organelles
• Mainly unicellular
• Examples: Bacteria or
Archaea
Prokaryotic Cells
• DNA in nucleoid region
• Bacteria: No protein, no introns; Archaea: Protein and DNA, some introns
• Have ribosomes, RNA, Cell Wall, Plasma Membrane, Flagella
Review
• In a Venn Diagram, compare and contrast prokaryotic
and eukaryotic cells and viruses. Make sure to include
specifics about their internal structure.
Eukaryotic Cells
• Endomembrane system:
Make, modify, and/or transport
cellular products
Eukaryotic Cells
• Endoplasmic Reticulum: Two types
• Rough ER: Has ribosomes on it
that produce proteins
• Smooth: Produces lipids,
detoxify cells
Eukaryotic Cells
• Vesicles: Membranous spheres transport substances in the cell
Eukaryotic Cells
• Golgi Apparatus: Receives, modifies, stores, and distributes chemical
products inside and outside the cell
Eukaryotic Cells
• Vacuoles: Store chemicals or liquid
Eukaryotic Cells
• Lysosomes (animal only): Enzyme filled structure that breaks down
macromolecules, bacteria, damaged organelles
• Digestive enzymes packaged so cell not destroyed
Signaling
• Cells communicate with chemical signals
• Neighboring cells: Direct contact, sending chemical signals
• Hormones: Chemicals that affect cells throughout body
Signaling
• Signal transduction pathway
• Signaling cell releases specific
chemical
• Chemical binds with receptor
protein
• Proteins direct response
• Change shape, activate
enzyme, secrete chemical,
cause transcription
Lost Signal
Target Ignores Signal
Signal Doesn’t Reach Target
Multiple Sclerosis (MS)
Too Much Signal
Video
Review
• Cells in saliva glands excrete an enzyme that breaks
down food.
• Starting with the DNA in the nucleus, explain how the
enzyme in the cell would be made, processed, excreted
from the cell, and how excess amounts of the enzyme
could be broken down or stored inside of the cell.
• Make sure to include which organelles are involved and
what their function is.
Eukaryotic Cells
• Cilia: Back and forth motion; moves substances across cell surface
• Flagella: Whip-like motion
Flagella Video
Eukaryotic Cells
• Energy Conversion
• Chloroplasts: Site of photosynthesis (light to glucose)
• Mitochondria: Site of cellular respiration (glucose to ATP)
ATP
•ATP (Adenosine triphosphate): A chemical which the cell uses to supply
energy
• Breakdown of chemical energy in food is used to generate ATP
ATP
• Final phosphate in ATP is unstable and there is a tendency for it to break
away, releasing energy
• Left with ADP and phosphate (can be used with other molecules)
ATP
• Phosphate Transfer: Released phosphate transferred to other molecules, helps
the cell perform work (mechanical, transportation, chemical)
Eukaryotic Cells
• Plasma Membrane: Boundary of Cell
• Phospholipid: Protein/Lipid structure that has a hydrophillic
“head” and hydrophobic “tail”
• Phospholipid Bilayer: Two layered, phospholipid membrane
arranged tail to tail; selectively permeable
Eukaryotic Cells
• Membrane Proteins: Maintain shape, signaling, transportation, joining
cells, enzyme activity
• Carbohydrates: Cell identification
Eukaryotic Cells
• Fluid Mosaic Model: Plasma membrane and the proteins in it are not
rigidly locked in place; molecules can move past each other
Review
• How can a cell move itself?
• What is the plasma membrane? Describe the structure.
• Concept Map: Energy, Chloroplasts, Mitochondria,
ATP, ADP, phosphate, phosphate transfer
Transportation- Small
• Diffusion (passive): Molecules move from areas of high concentration to
areas of low concentration until there is equilibrium
• Small molecules go through membrane (O2, CO2)
Transportation-Small
• Osmosis (passive): Water movement
to equal out solute concentration
• Solute: Chemical that dissolves in
water
Transportation-Small
• Concentration of solution is relative
• Hypotonic solution: Low concentration
• Hypertonic solution: High concentration
• Isotonic solutions: Equal concentrations
Transportation-Small
• Osmoregulation: Organisms balancing water uptake and loss
Transportation-Large
• Facilitated Diffusion (passive): Molecules move through transport proteins
Transportation- Large
• Exocytosis: Moving large molecules out of cell using vacuole
Transportation- Large
• Endocytosis: Moving large molecules into cell using vacuole
•
Transportation-Large
• Receptor mediated endocytosis: Moving specific large molecules into
cell using receptor proteins
Transportation-Large or Small
• Active transport: Transporting molecules from low concentrations to
high concentrations
• Specific protein pumps in membrane transports specific molecules
Review
• Concept Map: Active Transport, Plasma Membrane,
Passive Transport, Diffusion, Osmosis, Hypertonic,
Hypotonic, Isotonic, Protein Pumps, Endocytosis,
Exocytosis