Molecular Biology Flashcards
Esterification (ester bonds)
Carboxylic acid group of a fatty acid reacts with one of the glycerol hydroxyl groups to form a bond.
R-C=O + HO-R’ -> R-C=O +H2O
I I
OH OR’
Insulin
A peptide hormone, produced in the pancreas, and is central in regulating carbohydrate and fat metabolism in the body. It causes cells in liver, skeletal muscles, and fat tissue to absorb glucose from the blood. In the absence of insulin, only the brain and liver continues to absorb glucose.
Glucagon
Glucagon is a peptide hormone, produced in the pancreas, that raises blood glucose levels. Its effect is opposite that of insulin, which lowers blood glucose levels.
Fermentation
Fermentation is anaerobic respiration. It recycles NADH back to NAD+.
- Reduction of pyruvate to ethanol or lactic acid and the oxidation of NADH back to NAD+. NAD+ is restored for use in its role in glycolysis as a coenzymes and lactic acid or ethanol with CO2 is expelled from the cell as waste product.
Beta Oxidation
Process by which fatty acids are broken down in the mitochondria to generate Acetyl-CoA which enters the citric acid cycle and NADH and FADH2 which ae used by the electron transport chain.
Digestion Metabolism of Proteins and Fats
Substrate-level Phosphorylation
A metabloic reaction that results in the formation of ATP ot GTP by direct transfer and donation of a phosphate group to ADP or GDP from a phosphorylated reactive intermediate.
Glycolysis
Glycolsis occurs in the cytosol. It is a series of reations that breaks a 6-carbon glucose molecule into two 3-carbon molecules of pyruvate.
1 glucose → 2 pyruvate, 2ATP formed by subtrate-level phosphorylation, and 2 NADH.
C6H12O6 + 2 ADP + 2Pi + 2 NAD+ → 2Pyruvate + 2 ATP + 2 NADH + 2H + 2 H2O
6 Major Groups of Lipids
- Fatty acids (long carbon chain truncated at one end by a carboxylic acid)
- Triacylglycerols (3 carbon glycerol backbone w/3 fatty acids)
- Phosholipids (3 carbon glycerol backbone w/2 fatty acids and 1 phosphate group opposite side glycerol from the fatty acids)
- Glycolipids (3 carbon glycerol backbone w/2 fatty acids and one carbohydrate attached)
- Steroids (4 ringed structure)
- Terpenes (includes vitamin A)
Major function of Lipids
- Phospholipds - serve as a structual componet of membranes.
- Triacylglycerols - store metabolic energy, provides thermal insulation and padding.
- Steroids - regulate metabolic activites.
- Some fatty acids(eicosanoids) even serve as local hormones.
General Amino Acid Structure
Allosteric Interaction
The modification of the enzyme configuration resulting from the binding of an activator or inhibitor at a specific binding site on the enzyme.
Oxidative Phosphorylation
The metabolic pathway in which the mitochondria in cells use their structure, enzymes, and energy released by the oxidation of nutrients to reform ATP. The energy released by electrons flowing through this electron transport chain is used to transport protons across the inner mitochondrial membrane, in a process called electron transport.
Amino Acids by Category
Acidic (GA)
- Aspartic Acid
- Glutamic Acid
Basic (HAL)
- Histidine
- Arginine
- Lysine
Polar (Call Sally and George by AT&T)
- Cysteine
- Serine
- Glutamine
- Asparagine
- Tyrosine
- Threonine
Nonpolar (VIP MALT Ph Glycine)
- Valine
- Isoleucine
- Proline
- Methioine
- Alanine
- Leucine
- Tryptophan
- Phenylalanine
- Glycine
Amino Acid Facts
- Cysteine - forms disulfide bonds
- Tryptophan, tyrosine and phenylalanine strongly absorb UV.
- Methionine - first amino acid added to peptide chains
- Histidine - good buffer at physiological pH
- Proline and glycine are helix breakers
Glycogen
A multibranched polysaccharide of glucose that serves as a form of energy storage in animals and fungi. Glycogen represents the main storage form of glucose in the body.
Respiration
Respiration occurs in the matrix of the mitochondria. the products of glycoysis (pyruvate & NADH) are moved to the matrix.
- Pyruvate decarboxylation: Pyruvate converted to Acetyl CoA in the mitochondria. yeild→2AcetylCoA, 2CO2, 2NADH
- Citric acid cycle: Acetyl CoA enters, conenzymes exit. yeild→4CO2, 6NADH, 2FADH2, 2ATP, 4H+, 2 Coenzyme A
- Electron Transport Chain: Coenzymes are oxidized, and energy is relased as electrons are transferred form carrier to carrier. This creates a rich H+ gradient in the intermembrane space. Oxygen is the final electron acceptor. yeild→10NAD+, 2FAD, 34ATP, 10H2O
- Oxidative phosphorylation: Electrochemical grandiet caused by the oxidation of NADH and FADH2 provided the proton-motive force which propels protons through ATP synthase to phosphorylate ADP into ATP.
Net yeild = 36 ATP
Glucose + O2 → CO2 + H2O (no balanced)
Alkyl Groups
Five Forces that Contribute to Protein Tertiary Structure
- Covalent Disulfide Bonds - between two cysteines
- Electrostatic (ionic bonds) interactions - mostly between acidic and basic side chains
- Hydrogen Bonds
- Van der Waals forces
- Hydrophobic side chains pushed away from water (toward center of protein)
Cooperativity in Enzymes
Cooperativity has to do with the effect the binding of one substrate has on the binding of the second. If the first binds and increases the affinity of the second, this is called positive cooperativity. If the first inhibits the binding of the second, it is called negative cooperativity.
Osmotic pressure
Osmotic pressure is the pressure which needs to be applied to a solution to prevent the inward flow of water across a semipermeable membrane. It is also defined as the minimum pressure needed to nullify osmosis.
Peptide bond
A peptide bond (amide bond) is a covalent chemical bond formed between two molecules when the carboxyl group of one molecule reacts with the amino group of the other molecule, causing the release of a molecule of water (H2O), hence the process is a dehydration synthesis reaction (also known as a condensation reaction), and usually occurs between amino acids.
Second Messengers
Second messengers are molecules that relay signals from receptors on the cell surface to target molecules inside the cell, in the cytoplasm or nucleus. Secondary messengers are a component of signal transduction cascades.
Sodium-Potassium Pump
The process of moving 3 sodium and 2 potassium ions across the cell membrance is an active transport process involving the hydrolysis of ATP to provide the necessary energy. It involves an enzyme referred to as Na+/K+-ATPase.
It maintains proper osmotic gradient and prevents cell lysis.
