Biochemistry

• Protein folding involves hydrogen bonds between amino acids, disulfide bridges (covalent), ionic interactions, van der Waals forces, and hydrophobic interactions.
• A membrane is collage of different proteins embedded in the fluid matrix of the lipid bilayer
• Integral proteins penetrate the hydrophobic core of the lipid bilayer


  Are often transmembrane proteins, completely spanning in the membrane
• Six major functions of proteins: transport, structural support, enzymatic activity, signal transduction, intercellular joining, and cell-cell recognition.
• Integral protein: A protein that is embedded in the membrane of the cell.
• Integral proteins are proteins that are embedded in the membrane and are not easily removed
• The type of hydrocarbon tails in phospholipid determines the type of membrane
• Saturated fatty acids have a single carbon-carbon double bond.
• Unsaturated fatty acids have double bonded carbon atoms
• Trans oleic acid is a monounsaturated fatty acid that is found in olive oil.
• The steroid cholesterol has different effects on membrane fluidity at different temperatures.

  • Reduces phospholipid movement
  • Hinders solidification at low temperatures
• According to spatial relationship of protein domains to the lipid bilayer, plasma membrane proteins fall into six categories: Type 1 and 2, which have only one transmembrane helix, the amino terminal domain is outside the cell in type 1 proteins and inside in type 2; Type 3, which have multiple transmembrane helices in a single polypeptide; Type 4, which have several transmembrane domains from different polypeptide chains to form a channel through the membrane; Type 5, which are held to the bilayer primarily by covalently linked lipid; and Type 6, which have both transmembrane helices and lip
• The role of membrane carbohydrates in cell-cell recognition

  • Is the ability to distinguish one type of neighboring cell from another
• The role of membrane carbohydrates in cell-cell recognition:

  Membrane carbohydrates- interact with the surface molecules of other cells, facilitating cell-cell recognition
• Solute transport across membrane are passive, active transport and bulk transport.
• 3 types of passive transport: facilitated diffusion, osmosis, and simple diffusion.
• Factors affecting diffusion: Temperature, pressure, solvent density, concentration gradient, and solute solubility.
• Hypotonic solution: little solute, lots of water
• Hypertonic solution: lots of solute, little water
• 3 types of solutions: hypertonic, hypotonic, and isotonic.
• Hypotonic solution has higher concentration of water outside than inside the cell, causing the cell to shrink.
• Hypertonic solution has a higher concentration of water inside the cell than outside the cell causing the cell to shrink.
• Isotonic solution is a solution that has the same solute concentration as the extracellular fluid.
• : Cell structure: The basic structure of a cell, including the nucleus, cytoplasm, and organelles.
• Levels of structural organization: Molecular, cellular, tissue, organ, organ system, organism.
• 4 biomolecules are: carbohydrates, lipids, proteins and nucleic acids.
• Phospholipid bilayer is a phospholipid bilayer that is permeable to water and polar molecule.
• Hydrophilic: having a tendency to mix with, dissolve in, or be wetted by water.
• Hydrophobic: tending to repel or fail to mix with water.
• Selectively permeable membrane: A membrane that allows some substances to pass through it but not others.
• Flow of biological information: DNA -> RNA -> Protein -> Cellular function.
• Polymers are giant molecules made up of many monomers joined together.
• Examples of polymers are DNA, proteins, and starch.
• Cell link monomers by a process called condensation or dehydration synthesis
• Cells break down macromolecules by a process called hydrolysis.
• Monosaccharides are called simple sugars
• Isomer: each of two or more compounds with the same formula but a different arrangement of atoms in the molecule and different properties.
• Disaccharides is a double sugar. It includes sucrose, lactose, and maltose.
• Polysaccharides are composed of many monosaccharides joined together by glycosidic bonds.
• Eukaryotic cells have a nucleus, mitochondria, chloroplasts, and a cell membrane.