Transcript Cell Structure and Transport Unit Review

Cell Structure and Transport Unit Review
I Can… Explain how fundamental life processes
depend on the physical structure and chemical
activities of the cell. [CAPT Std. 10.1]
I Will…
• Describe the similarities and differences in the
basic structure of plant and animal cells [D 27]
• Explain the role of the cell membrane in supporting
cell function. [D 30]
Tenets of Cell Theory:
• All living things are made of cells
• All cells are produced/arise from
other preexisting living cells (all
cells come from cells)
• The cell is the basic unit of life
Cell theory is a unifying
biological concept
All cells
• Tend to be microscopic
• Must have
• A cell membrane
• Cytoplasm
There were two broad categories of cells:
Prokaryotic Cells
• Primitive
• e.g. Bacteria
• No nucleus
• No membranebound organelles
• Only single-cell
microscopic
organisms
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Eukaryotic Cells
Complex (you)
Nucleus
• Protects DNA and
regulates access to it
Membrane-bound
organelles
Can be single-cell or
form multicellular
organisms
Key Eukaryotic Cell Organelles
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Cell membrane
Cytoplasm
Cytoskeleton
Nucleus
Nucleolus
Ribosomes
Endoplasmic Reticulum
• Smooth E.R.
• Rough E.R
• Golgi apparatus
* Plant cells only
**Animal cells only
***Debate whether in plants
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Mitochondria
Vesicles
Vacuoles
Large central vacuole*
Lysosome***
Centrosome
Centriole**
Chloroplast*
Cell wall*
Cell Membrane
Two key functions:
Regulate what goes
in and out of the cell
Cell to cell communication
Form &
Function
Selectively Permeable Fluid Mosaic Model
• Phospholipid bilayer with embedded
cholesterol and protein molecules and
glycolipids and glycoproteins on the surface.
Phospholipid• Polar phosphate/glycerol head
• Hydrophilic
• Nonpolar fatty acid tails
• Hydrophobic
Cell to cell communication
Movement Across the Membrane
Passive – No cell energy (ATP) used
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Diffusion – Concentration gradient
• Crosses lipid bilayer
• Small, nonpolar/no charge
Facilitated diffusion – Protein channels
• Concentration gradient
• Small, charged ions and highly polar
molecules
Osmosis – Diffusion of H2O molecules
• Concentration gradient
• Lipid layer movement
• Aquaporin protein channels
Isotonic –
• Equal pull on the water
• Extracellular and intracellular
concentrations of water solvent
and solutes are equal
• Already in dynamic equilibrium
Osmosis
Hypotonic –
• Less pull on the water
• Extracellular solution has
• Less solute concentration
• Greater water solvent
concentration
• Water is pulled into the cell
Osmosis
Hypertonic –
• Greater/more pull on the water
• Extracellular solution has
• Greater solute concentration
• Less water solvent
concentration
• Water is pulled out of cell
Osmosis
Movement Across the Membrane
Active Transport – Requires cell energy - ATP used
• Protein Transport Pump
• Move particles against
concentration gradient
• Low to high
• Small, charged ions
Endocytosis
Exocytosis