Cell Membrane

• Cell Membrane Lesson 10 MARVIN M FELICIANO, LPT, Manila Central University, January 2024- Cell Membrane - Cell Transport - ATP - ADP Cycle - Biomolecules - Enzymes - Aerobic Respiration - Anaerobic Respiration.
• The cell membrane acts as the skin of the cell, has a crucial role because it allows the passage of substances to go in and out of the cell, and demarcates the internal and external environment of the cell.
• The cell membrane is dynamic in nature, constantly showing changes in structure, size and function.
• The model of the cell membrane is known as the Fluid Mosaic Model proposed by Singer and Nicolson in 1972.
• Both glycoprotein and glycolipid are molecules and are found on the extracellular part of the cell.
• Glycoprotein is a short chain carbohydrate attached to a protein.
• The cell membrane acts as a framework that gives the cell’s shape.
• Glycolipid is a short chain carbohydrate attached to a lipid.
• There are two types of proteins in the cell membrane, known as specific proteins or extrinsic proteins, which are located in the inner or outer surface of the phospholipid bilayer and play a structural role by helping to stabilize and shape the plasma membrane.
• Transports two different substances in the same direction.
• The cell membrane is designed to be selectively permeable.
• Three important characteristics of molecules that may affect their ability to cross the cell membrane are size (macromolecules or micromolecules), charge (noncharged or charged molecules), and solubility (lipid-soluble molecules or not).
• Passive transport is the transport of molecules across the cell membrane without the need for energy.
• Active transport is the transport of molecules across the cell membrane with the need for energy.
• There are two types of transporter proteins in general: transport molecules (ex Glucose, amino acids, nucleic acids) and transport ions (Charged particles, e.g H˖, Na˖, Cl-).
• Uniporter transports one substance in one direction.
• Transport molecules allow solute to move from one side to another, change shape, and require ATP.
• Types of integral proteins include Channel, carrier, cell recognition, receptor and enzymatic proteins.
• NaCl and Mg(OH)2 cannot cross or enter the phospholipid bilayer, hence they are gatekeepers.
• Transport ions are also hydrophilic channels (Aquaporins), gates which can open or close, and provide a tunnel/corridor that allow specific molecule or ion to cross the plasma membrane, and require no ATP.
• There are two types of proteins in general: AKA Intrinsic protein and Transmembrane.
• The AKA Intrinsic protein passes into the bilipid layer which serves as a tunnel or channel for the passage of water and other substances.
• Small and large molecules are entering to the gate of the cell.
• Symporter transports two different substances in opposite directions.
• The phospholipid bilayer is selectively permeable, allowing certain molecules to cross while blocking others.
• The phospholipid bilayer is designed to be selectively permeable, allowing certain molecules to cross while blocking others.