Macromolecules and Biological Processes

Macromolecules and Biological Processes

• Lipids: Diverse biomolecules, hydrophobic, soluble in non-polar solvents, mostly hydrocarbon chains (C&H). Some have polar regions (amphipathic).
• Saturated Fats: Solid at room temperature, single bonds between carbons.
• Unsaturated Fats: Liquid at room temperature, double bonds between carbons. Polyunsaturated fats have more than one double bond.
• Polysaccharides: Long chains of glucose molecules, examples include starch, glycogen, and cellulose.
• Dehydration Synthesis: Joins molecules by removing water. Formation of a dipeptide is an example, with Amino Acid + Amino Acid --> dipeptide + water.
• Proteins: Complex molecules formed from amino acids. Each amino acid has a central carbon, hydrogen, amine group, carboxyl group, and an R group. The R group varies between different amino acids.
• Nucleic Acids: DNA and RNA. DNA's sugar is deoxyribose; RNA's sugar is ribose. DNA's nitrogenous bases are Adenine, Thymine, Guanine, and Cytosine (A-T, G-C pairing). RNA's nitrogenous bases are Adenine, Uracil, Guanine, and Cytosine (A-U, G-C). DNA is the genetic material.
• Water: Polar molecule with opposite charges at opposite ends. Important for cohesion and adhesion. It also has high specific heat, high heat of vaporization, and is less dense as a solid.
• Cell Transport:
  • Simple Diffusion: Movement of molecules from high to low concentration.
  • Facilitated Diffusion: Movement of molecules across a membrane with the help of protein channels.
  • Active Transport: Movement of molecules against the concentration gradient, requiring energy (ATP).
  • Osmosis: Diffusion of water across a selectively permeable membrane. Requires a partially permeable membrane. Hypertonic means a higher solute concentration outside the cell; hypotonic means a lower concentration; isotonic means equal concentration.
• Cell Respiration: Aerobic process that produces ATP (energy), carbon dioxide, and water. It occurs in the mitochondrial matrix.
  • Glycolysis: The first stage of cell respiration.
  • Krebs Cycle: Middle stage of cell respiration that takes place in the Mitochondrial Matrix. It produces ATP, carbon dioxide, and reduced coenzymes.
  • Anaerobic Respiration (in yeast): Produces ethanol and carbon dioxide.
• Photosynthesis: The process of converting light energy into chemical energy (sugar) using water and carbon dioxide. It happens in chloroplasts.
  • Light-Dependent Reactions: Generate ATP, electrons, and oxygen from water using sunlight. Oxygen is a product of the light-dependent reactions but not needed for the light-independent reactions. Photolysis (splitting of water) happens here.
  • Light-Independent Reactions (Calvin Cycle): Carbon fixation happens here, using carbon dioxide and ATP to make sugars in the stroma of the chloroplast.
• Microscopy: Electron microscopes provide higher resolution than light microscopes. Magnification = image size/real size. Real size = image size / magnification. Image size = actual size x magnification.
• Cell Structure and Classification: Prokaryotes lack membrane-bound organelles, while eukaryotes have them, including a nucleus. Eukaryotes also have 80s ribosomes. Living things are made up of cells.
• Genetics: Mutations (changes in DNA) can be caused by mutagens. Enzymes catalyze reactions and have an active site for this. Silent mutations have no effect on protein function.
• Important Concepts:
  • Categorizing living things: Autotrophs make their own food (photosynthesis); heterotrophs cannot. Biotic means living, abiotic means non-living.
  • Control Variables: The independent variable is changed; the dependent variable is measured. Experiments should have control variables, and the difference in effects can be measured.
  • Enzyme denaturation: Denatured enzymes lose their biological function. Activation energy is the minimum energy required for a reaction to occur which the enzyme may reduce.