MCAT Biology Lecture 1 2
Terms
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- WATER
- most abundant molecule in cells at 70% of the cell mass
- CYTOSOL
- aqueous component of the cytoplasm that does not contain organelles
- HYDROLYSIS
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1. chemical decomposition of macromolecules, disassembly of polymers into monomers by reacting with water
2. opposite of dyhydration reactions - DEHYDRATION/CONDENSATION
-
1.covalent bonding of monomers through the loss of a water molecule that requires energy and enzymes
2. opposite of hydrolysis reactions - MACROMOLECULES
- nutrients in their unbroken down state; polymers consisting of repeating subunits (40-50 monomers)
- INTERMOLECULAR BONDS
- forces of attraction BETWEEN the molecules of a substance or substances; weaker than covalent or ionic bonding
- HYDROGEN BONDS
- intermolecular force between two partial electric charges of opposite polarity, like two water molecules or between the NH and CO groups of the peptide backbone, create tertiary and secondary structures
- HYDROPHILIC
- water loving or polar molecules
- HYDROPHOBIC
- water fearing or non-polar molecules
- POLAR MOLECLUES
- molecules that have a slightly positive part and a slightly negative part
- AMPHIPATHIC
- molecule contains both hydrophobic/non-polar and hydrophilic/polar groups
- LOW SOLUBILITY
- incapable of being dissolved; insoluble
- TERPENES
- major group of lipids made up of hydrocarbons
- TRIGLYCERIDES
- major group of lipids; three carbon chains dangling from a three carbon backbone and each carbon chain attached by an ester group
- FATTY ACIDS
- major group of lipids; amphiapathic consisting of a carboxylic acid and carbon chain; either saturated or unsaturated
- SATURATED FATTY ACIDS
- all carbons in the chain are connected by single bonds, thus fully saturated with hydrogen atoms
- UNSATURATED FATTY ACIDS
- the carbon chain has at least one double bond; lower melting point
- PHOSPHOLIPIDS
- major group of lipids; consists of three carbon backbone, two carbon chains attached to the backbone by an ester group, third backbone carbon has a phosphate group attached; amphipathic molecule
- LIPID BI-LAYER
- composed of phospholipid molecules found in cell membranes; polar regions face aqueous solution inside and outside the cell; non-polar carbon chains face the interior of the membrane
- GLYCOLIPIDS
- are like phospholipids but phosphate group is replaced with a carbohydrate
- STERIODS
- major group of lipids, four ring structures slightly amphiapathic
- LIPOPROTEINS
- particles (not molecules) comprised of proteins and lipids shell that surrounds lipids for transport
- PROTEINS
- organic compounds made up of long chains of amino acids
- AMINO ACIDS
- molecule that contains both amine and carboxylic acid functional groups, plus a side chain attached to the α–carbon; 20 types of amino acids
- ALPHA CARBON
- the first carbon attached to the carbonyl carbon and an amine; stereocenter for every amino acid except glycine
- SIDE CHAIN
- one of 20 possible structures that distinguish the 20 common amino acids; placed in four categories polar, non-polar, basic and acidic
- ESSENTIAL AMINO ACID
- between 8-11 amino acids that the body cannot produce in sufficient quantities and are to be provided via diet
- PRIMARY STRUCTURE OF PROTEIN
- number and sequence of amino acids including the locations of the disulfide bonds between cysteines
- SECONDARY STRUCTURE OF PROTEIN
- generated by the twisting of the α-helix or the folding of the β-pleated sheets, held together by hydrogen bonds between the amine of one amino acid residue and the carbonyl oxygen of another residue
- TERTIARY STRUCTURE OF PROTEIN
- the bending of the amino acid string into a pretzel shape or a glob via five forces hydrogen bonds, covalent disulfide bonds, ionic bonds, hydrophobic and hydrophilic effects and electrostatic forces/Van der Waals
- QUATERNARY STRUCTURE OF PROTEIN
- consists of two or more of these pretzel-like polypeptides held together by the same five forces that hold together the tertiary structure
- PEPTIDE
- small number of amino acids are joined together to form a protein by peptide bonds
- PEPTIDE BOND
- formed between amino acids when the carboxyl group of one molecule reacts with the amino group of the other releasing a molecule of water (H2O)dehydration synthesis reaction, resulting in a CO-NH bond and amide molecule
- POLYPEPTIDE
- long chain of amino acids joined together to form a protein by a series of peptide bonds
- AMINO ACID RESIDUE
- an amino acid incorporated into the peptide chain
- GLOBULAR PROTEINS
- protein with tertiary and quaternary structure
- BETA-PLEATED SHEETS
- polypeptide chain can be extended into a sheet-like structure by hydrogen bonding with another chain that runs in the same or opposite direction, hydrogen bonding involves the C=O group of one peptide bond and the NH group of another
- ALPHA HELIX
- righthanded coiled conformation stabilized by hydrogen bonds formed between the C=O group and NH group of the peptide bond four residues farther along the polypeptide chain, one turn for every 4 amino acids
- DISULFIDE BOND/DISULFIDE BRIDGE
- S-S BOND is a single covalent bond between two cysteines that are themselves not bonded to sulfur
- IONIC BONDING
- occur between amino acids with oppositely charged groups like acidic and basic amino acids
- HYDROPHILIC AND HYDROPHOBIC EFFECTS
- occur between amino acids with the same polar and nonpolar side chains
- ELECTROSTATIC FORCES
- the forces between particles that are caused by their electric charges
- VAN DER WAALS FORCES
- where portions of the molecule have dipoles or instantaneous dipoles
- PROTEIN SUBUNIT
- single protein molecule that assembles with other protein molecules to form a quaternary structure
- DENATURIZATION
- addding heat or chemicals to disrupt the five forces, primary structure exempt, resulting in the unfolding of polypeptide chain
- GLYCOPROTEINS
- proteins with carbohydrate portions attached
- PROTEOGLYCANS
- carbohydrates with protein portions attached
- CYTOCHROMES
- proteins that require non-proteinaceous portions to function; embedded in the inner membrane of the mitochondrion and pass down high energy electrons from one protein to the next
- CONJUGATED PROTEINS
- proteins with non-proteinaceous groups
- CARBOHYDRATES
- consists of carbon and water Cn(H2O)n, water is added to break of individual glucose molecules
- GLUCOSE
- most important carbohydrate monosaccharide used as a source of metabolic energy, made up of an aldehyde with four chiral carbons C6H12O6
- BETA ANOMER
- stereoisomer of the cyclic form of a carbohydrate in which the hydroxyl group at C-1 is UP
- ALPHA ANOMER
- stereoisomer of the cyclic form of a carbohydrate in which the hydroxyl group at C-1 is DOWN
- GLYCOGEN
- carbohydrate chains of glucose molecules attached via alpha-linkages stored in animals
- STARCH
- chief form of fuel storage in most plants that contain alpha-linkages and resembles glycogen
- CELLULOSE
- plant cell walls are made from this carbohydrate chain, glucose molecules attached via beta-linkages
- NUCLEOTIDES
- made up of ribose sugar, nitrogenous base, and phosphate group; they are the structural units of DNA and RNA
- NUCLEIC ACID
- complex, high-molecular-weight biochemical macromolecule composed of nucleotide chains that convey genetic information like DNA and RNA
- DNA
- deoxyribonucleic acid; double stranded helix containing the genetic instructions monitoring the biological development of all cellular forms of life
- RNA
- ribonucleic acid; single-stranded molecules transcribed from DNA containing along the strand a linear sequence of nucleotide bases that is complementary to the DNA strand from which it is transcribed
- NADH
- important nucleotide in the reduced form of nicotinamide adenine dinucleotide (NAD) in electron transport reactions
- FADH
- important nucleotide in the reduced form of flavin adenine dinucleotide (FAD)functions in certain oxidation-reduction reactions in the body
- ATP
- adenosine triphosphate; supplies large amounts of energy to cells for various biochemical processes, including muscle contraction and sugar metabolism, through its hydrolysis to ADP
- cyclic AMP
- cyclic nucleotide of adenosine that acts at the cellular level to regulate various metabolic processes and mediate the effects of many hormones
- MINERALS
- inorganic elements that exist in the form of ions inside and outside the cell; establish electrochemical gradients, act as co-factors to enable protein function, and form matrix compounds in bone and else where
- ENZYMES
- catalyst and protein that increases the reaction rate by lowering activation energy, one enzyme for nearly every reaction in a living cell
- ACTIVATION ENERGY
- energy needed to break the bonds of the reactants creating the transition state or the species between the reactants and the products
- CATALYST
- substance that initiates or accelerates a chemical reaction without itself being affected, example being the function of enzymes to break down organic matter
- TRANSITION STATE
- the activated state of a molecule that has partly undergone a chemical reaction
- SUBSTRATE
- molecule or molecules an enzyme works on, they attach to the enzymes at an active site which may fit like a key in a lock or induce the enzyme to change shape to make it fit
- LOCK AND KEY MODEL
- when only a certain substrate (key) can fit into a certain active site (key hole) in the enzyme (lock)
- INDUCE FIT MODEL
- moulds enzyme to change shape to make substrate fit it
- ENZYME SPECIFICITY
- each enzyme must be tailored made for one reaction, which gives the cell more control in regulating chemical reactions
- SATURATION KINETICS
- occurs after the substrate has bound to the enzyme no further rate increase is possible even after adding more substrate
- OPTIMAL TEMPERATURE
- enzymes are dependent upon a temperature until it denatures (enzymes are proteins)
- OPTIMAL pH
- enzymes are dependent upon a narrow pH range (near neutrality) and will denature when pH is too far
- FEEDBACK INHIBITION
- works at the protein level and occurs when a product of a reaction near the end of a chain of reactions inhibits the function of an enzyme of an earlier reaction in that chain
- COMPETITIVE INHIBITION
- where binding of the inhibitor to the enzyme prevents binding of the substrate and vice versa, can be overcome by high substrate concentrations
- NON-COMPETITIVE INHIBITION
- does not attach to the active site instead it changes the shape of the enzyme so the substrate doesn’t fit as well, cannot be overcome with substrate concentration
- IRREVERSIBLE INHIBITION
- combine with the enzyme by forming a strong, covalent bond
- ZYMOGEN/PROENZYME
- an inactive enzyme precursor that requires a biochemical change (such as a hydrolysis reaction revealing the active site, or changing the configuration to reveal the active site) for it to become an active enzyme
- PHOSPHORYLATION
- the addition of a phosphate (PO4) group to a protein or a small molecule or the introduction of a phosphate group into an organic molecule
- DEPHOSPHORYLATION
- subtraction of a phosphate (PO4) group to a protein or a small molecule or the introduction of a phosphate group into an organic molecule
- CONTROL PROTEINS
- activate or inactivate enzymes
- CELLULAR RESPIRATION
- metabolic processes where certain organisms obtain energy from organic moelcules; processes that take place in the cells and tissues during which energy is released and carbon dioxide is produced and absorbed by the blood to be transported to the lungs
- METABOLISM
- the sum of the physical and chemical processes in an organism by which its material substance is produced, maintained, and destroyed, and by which energy is made available
- GLYCOLYSIS
- conversion of a monosaccharide (generally glucose) to 2 pyruvates that produces 2 ATPs, and 2 NADHs via the glycolytic pathway in the cytosol
- AEROBIC RESPIRATION
- the release of energy from glucose or another organic substrate in the presence of Oxygen; oxidation or combustion of glucose
- ANAEROBIC RESPIRATION
- the release of energy from glucose or another organic substrate in the absence of Oxygen
- FERMENTATION
- energy-yielding anaerobic metabolic breakdown of a nutrient molecule, like glucose, that yields lactic acid, carbon dioxide, ethanol, or some other simple product
- MITOCHONDRION
- rod-like structures inside cells of the body whose primary functions include the production and regulation of energy for all cellular functions
- ELECTRON TRANSPORT CHAIN
- group of electron carriers in mitochondria that transport electrons to and from each other in a sequence, in order to generate ATP
- KREBS CYCLE/CITRIC ACID CYCLE
- series of reactions by which fragments from any of the energy nutrients (proteins, carbohydrates, and fats) are completely broken down to carbon dioxide and water, releasing energy for the formation of adenosine triphosphate (ATP), the final common pathway for all nutrient metabolites involved in energy production, and provides more than 90% of the body's energy
- ATP SYNTHASE
- enzyme in mitochondria's nucleus that produces ATP by adding a phosphate group to the molecule ADP by utilizing some form of energy