grade 12 bio exam

• Intermolecular attraction is the attraction between molecules, such as hydrogen bonds.
• Hydrogen bonds are a type of intermolecular attraction that involves dipole-dipole attraction between hydrogen and an electronegative atom.
• Intramolecular bonds are bonds between atoms.
• Water is a polar, universal solvent with properties of cohesion and adhesion.
• Cohesion is when water is attracted to water.
• Adhesion is when water is attracted to other substances.
• Hydrophilic refers to substances that are 'water-loving', such as salt.
• Hydrophobic refers to substances that are 'water-hating', such as fats.
• Main functional groups in biology include hydroxyl, carbonyl, carboxyl, amino, phosphate, and sulfhydryl.
• Condensation is when two molecules combine to form one molecule, for example, water and hydrogen form a molecule of hydrogen gas.
• Hydrolysis is when one molecule combines with water to form two molecules.
• Proteins are composed of peptide bonds, monomers are amino acids, and polymers are polypeptide chains.
• Carbohydrates are composed of glycosidic linkages, monomers are monosaccharides, and polymers are polysaccharides.
• Lipids are composed of ester bonds, monomers are glycerol and fatty acids, and polymers are triglycerides, phospholipids, waxes, and steroids.
• Nucleic acids are composed of phosphodiester bonds, monomers are nucleotides, and polymers are DNA and RNA.
• Enzymes are proteins that catalyze reactions.
• Enzyme-substrate complexes can lower activation energy by changing the substrate, its environment or both.
• Temperature, pH, concentration of enzymes/substrates and presence of inhibitors or activators all impact enzyme activity.
• Competitive inhibition is when an inhibitor interferes with the active site of the enzyme so the substrate cannot bind.
• Non-competitive inhibition is when an allosteric inhibitor changes the shape of the enzyme so it cannot bind to the substrate.
• Feedback inhibition is when the product of a metabolic pathway blocks an enzyme in the beginning of the pathway, occurring when there is a buildup/excess of product.
• The Fluid Mosaic model of the plasma membrane describes the structure of the cell membrane as a dynamic, flexible structure made up of different components such as phospholipids and proteins.
• The hydrophobic core of the membrane allows some materials to move through but blocks the movement of others.
• Hydrophobic molecules and small polar, uncharged molecules can pass through phospholipid bilayers.
• Larger polar molecules and ions cannot diffuse through the plasma membrane.
• Concentration gradient is the process of particles moving from high concentration to low concentration.
• Dynamic equilibrium is when the forward and reverse processes occur at the same rate, resulting in no observable change.
• Simple diffusion is when substances diffuse through the membrane down the concentration gradient without proteins.
• Facilitated diffusion is when a substance needs a protein to pass through the lipid bilayer.
• Catabolic reaction: large organic molecules are broken into smaller molecules, releasing energy in the process
• Anabolic reaction: using energy to join smaller molecules into a larger one.
• Endergonic reactions absorb energy from their surroundings
• Exergonic reactions release energy to their surroundings
• Cellular respiration includes glycolysis (cytoplasm), pyruvate oxidation (mitochondrial matrix), citric/Krebs cycle (mitochondrial matrix), and oxidative phosphorylation (mitochondria)
• Net production of ATP is 38: Glycolysis: 2 + 2 NADH = 6 (total 8 from glycolysis), Pyruvate oxidation: 2 NADH = 6 ATP, Citric Acid (Krebs) cycle: 2ATP 6 NADH, 2 FADH2 = 24 ATP, Oxidative phosphorylation: 34 ATP.
• At the end of glycolysis, glucose breaks down into pyruvate and energy.
• During glycolysis, 2 ATP molecules are used, and 4 ATP are produced and 2 NADH molecules are reduced.
• During pyruvate oxidation, one NADH is reduced (created).
• The final product of pyruvate oxidation is Acetyl coA, which is needed to start the Krebs cycle.
• 2 ATP are used for the Krebs cycle, and 2 ATP are created.