bio 1-4

• Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus, Sulfur are the CHONPS elements.
• Carbohydrates are made up of monosaccharides, mainly sugars and starches, and function as an energy source and storage.
• Lipids are insoluble in water, made up of glycerol with three fatty acids attached, and function as a long term energy reserve and structural components.
• Proteins are made up of amino acid monomers, that from polypeptide chains, with α-amino acids being the most common, and function as altered by the conversion of certain amino acid residues.
• Nucleic Acids consist of 5-carbon sugar (deoxyribose & ribose), nitrogen bases (purines; AG — pyrimidines; CTU), and millions of nucleotides are linked by phosphodiester linkage, functioning as a store of genetic information and decoding genetic info for protein synthesis.
• DNA consists of both coding (genes) and noncoding sequences, is a double-stranded molecule, and forms a right-handed double helix with A-T, G-C hydrogen bonding.
• ATP is referred to as “energy currency” because cells can transfer P molecules by coupling reactions to ATP hydrolysis.
• ATP is exergonic, meaning its entropy is greater than ADP.
• Reduction stabilizes ATP by resonance, reducing electrostatic repulsion.
• NADH is involved in the complete oxidation of glucose and fatty acids, a process that yields large amounts of ATP.
• ATP is the most important source of immediate energy in a living cell, produced by the reaction of adenosine diphosphate and Pi in redox reactions.
• NADPH donates a high-energy electron in the biosynthesis of molecules such as fatty acids and cholesterol.
• FADH2, the reduced form of FAD, functions in a large variety of redox reactions, with the most prominent roles in the citric acid cycle and as a product of fatty acid degradation.
• Electrons, along with the energy they contain, are transferred from reduced molecules to oxidized molecules in redox reactions.
• ATP is the most important source of energy in cells, with hydrolysis driving many reactions through the release of free energy, including biosynthesis of biomolecules, active transport, and mechanical work.
• RNA is a single-stranded molecule, folds into a complex 3-d structure, and converts genetic info contained in DNA to build proteins.
• Gene expression controls when info encoded in a gene will be accessed, starting with transcription, where a DNA segment is used to synthesize a gene product, and translation, the second step in getting from a gene to a protein, takes place in the cytoplasm.
• Metabolic pathways include homeostasis, energy production, interconversion of intermediates, synthesis and transport, information storage, retrieval, maintenance and replication.
• Metabolic pathways can be anabolic (biosynthetic, requires energy input) and catabolic (degrading, releases energy).
• Energy transfer pathways capture energy and transform it into forms usable by cells.
• Signal transduction allows cells to receive and respond to signals.
• Biochemical reactions include nucleophilic substitution, elimination, addition, isomerization, oxidation-reduction, and biological order.
• Both endo- and exocytosis are important for cellular information processing.
• Chaperones begin folding, stress is caused by improper folding, smooth endoplasmic reticulum (SER) has no ribosomes and synthesizes lipid molecules, golgi apparatus functions, processes, packages, and distributes cell products after synthesis, glycosylation of proteins and lipids is constantly recycled, trans-golgi network sorts processed molecules and packages them into vesicles coated with proteins that guide to right location.
• Endocytic pathway is composed of vesicular organelles and lysosomes, endocytosis is a cellular process in which plasma membrane protein receptors bound to specific substances, pinch off regions of the plasma membrane and become endosome.
• Peroxisomes are small, spherical organelles in all human cell except erythrocytes, generation and breakdown of peroxides occurs when oxygen is used to remove hydrogen from organic molecules.
• Cytoskeleton is responsible for cell shape responses to external signals, large and small scale movement, rapidly assemble and disassemble based on needs.
• Early endosomes determine if the molecules are sent back to the plasma membrane, delivered to the TGN to move through the cell, or degraded by lysosomes.
• Late endosomes receive acid hydrolases from TGN and transform into lysosomes if pH drops below 5.
• Bent at 104.5 degree, hydrogen bond occurs when hydrogen atoms share unequally by two electronegative centers.
• Synthesis and degradation of biomolecules, transport of ions and molecules across cell membranes, production of force and movement, and waste removal are processes that require ATP and can be used as structure, information, or catalyzers (enzymes).
• Receptors are binding sites for signal molecules to trigger a cellular response.
• The rough endoplasmic reticulum (RER) contains ribosomes, makes proteins, and polypeptides enter during protein synthesis, folding hydrophobic regions to stop movement through RER and molecules.
• Prokaryotic cells have no nucleus, are small and simple, and have no membrane-bound organelles.
• Plasmids are circular DNA outside of nucleoid that can replicate independently and carry codes for antibiotic resistance.
• Signal transduction phases include Reception, Transduction, Response, and Termination.
• Some prokaryotic cells produce biofilm, grow thicker and secrete material, accumulate.
• Integral proteins are embedded in the membrane and diffuse laterally.
• Misfolded proteins or aggregates can be devastating to cells and the overall organism.
• Large number of electronegative oxygen or nitrogen atoms (NaCl) interact easily with water, forming clusters and limiting surface area, hence do not interact well with water.