Cell Membrane

Cell Membrane Functions

• The primary function of the cell membrane is to regulate the movement of materials in and out of the cell.
• Flexibility is the property that allows the cell membrane to change shape.
• The fluidity of the cell membrane is the ability of membrane lipids and proteins to move within the bilayer.
• Eukaryotic cells use compartmentalization to separate opposing processes.
• Phospholipids are the most abundant lipids in the cell membrane.
• Cholesterol is a major component of animal cell membranes.
• Integral proteins span the entire lipid bilayer.
• Nucleic acids aren't a component of the cell membrane.
• The lipid bilayer primarily consists of phospholipids.
• The hydrophilic heads of phospholipids face the extracellular and intracellular environments in a lipid bilayer.
• Fatty acid tails form the hydrophobic portion of a phospholipid molecule.
• Lipid bilayers spontaneously form sealed compartments in aqueous environments to maximize the interaction of polar heads with water

Membrane Transport

• Passive transport is the movement of molecules from an area of high concentration to an area of low concentration.
• Facilitated diffusion does not requireenergy.
• A transport protein helps a solute move across the membrane during facilitated diffusion.
• The concentration gradient is directly proportional to the rate of transport in simple diffusion.
• The number of available transport proteins limits the rate of transport in facilitated diffusion.
• Uniport is the transport of a single molecule across a membrane.
• Symport is the transport of two different molecules in the same direction.
• Antiport is the transport of two different molecules in opposite directions.
• The Na+/K+ ATPase pump is an example of antiport.
• The Na+/K+ ATPase pump transports 3 Na+ ions out of the cell and 2 K+ ions into the cell.
• ATP hydrolysis provides the energy for primary active transport.
• An electrochemical gradient of another solute provides the energy for secondary active transport.
• An electrochemical gradient of another solute drives tertiary active transport.

Cytoskeleton

• The cytoskeleton is a network of protein filaments located in the cytoplasm.
• DNA replication isn't a function of the cytoskeleton.
• Myosin filaments aren't a type of cytoskeletal filament.
• Actin isn't what actin filaments are composed of.
• Tubulin is what microtubules are composed of.
• Intermediate filaments are rope-like fibers.
• Muscle contraction is an activity actin filaments are involved in.
• Muscle contraction is an activity microtubules are involved in.
• Intermediate filaments primarily provide mechanical strength.
• Actin monomers bind to ATP.
• Polymerization is the process of actin monomers adding to the ends of filaments.
• Motor proteins bind to actin filaments and alter their assembly and organization.
• Actin filaments are what myosin is a motor protein associated with.
• Myosin walking along actin filaments drives muscle contraction.
• Calcium ions bind to troponin during muscle contraction.
• The sarcomere is the basic contractile unit of a muscle cell.
• Kinesin and dynein are the motor proteins associated with microtubules.
• Kinesin moves cargo towards the plus (+) end of microtubules.
• Dynein moves cargo towards the minus (-) end of microtubules.
• Microtubules originate from a specific cellular location known as the microtubule-organizing center (MTOC).
• The centrosome is the main MTOC in animal cells.
• Two centrioles make up the centrosome.
• During cell division, microtubules form the mitotic spindle.