Biological Molecules Definitions


Undergraduate Biology (Biological Molecules) Flashcards on Biological Molecules Definitions, created by siobhan.quirk on 11/05/2013.
Flashcards by siobhan.quirk, updated more than 1 year ago
Created by siobhan.quirk almost 11 years ago

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Question Answer
Define covalent bonds are formed when electrons are shared between atoms. These bonds are very strong. Covalently bonded atoms form new molecules.
Define carbohydrates make up a group of molecules containing carbon, hydrogen and oxygen in the ratio Cn(H2O)n
Define polysaccharide polymers of monosaccharides. Consist of hundreds of monosaccharide monomers bonded together to form a large molecule
Define cellulose a carbohydrate polymer made by bonding beta-glucose molecules together in a long chain
Define amino acids monomers of all proteins. All amino acids have the same basic structure. The 20 different amino acids involved in protein synthesis differ only in the R-group bonded to the central carbon
Define primary structure the specific sequence of amino acids that make up a protein
Define secondary sequence coiling and pleating of parts of the polypeptide molecule
Define tertiary structure the overall 3D structure of the final polypeptide or protein molecule
Define haemoglobin globular transport protein
Define collagen a fibrous structural protein
Define lipids a group of chemicals that dissolve in organic solvents, such as alcohol but NOT water. Include fatty acids, triglycerides and cholesterol
Define triglyceride one glycerol molecule and three fatty acids
Define hydrogen bond a weak interaction that can occur whenever molecules contain a slightly negative atom bonded to a slightly positive hydrogen.
Define food tests simple tests that show the presence of various biological molecules in samples or structures. Iodine can stain plant tissue sections to show where starch is
Define quantitative test a measure of substance in units
Define assay techniques are often use to compare measurements with known samples so that quantitative measurements can be made
Define nucleotides monomers of nucleic acids. Each nucleotide is formed by bonding toher a phosphate group, a sugar molecule and a nitrogenous base
Define DNA stable polynucleotide molecule. Acts as information store because the bases projecting from the backbone act as a coded sequence. Organisms differ in their DNA only because they contain different sequences of bases in the DNA
Define gene a length of DNA that codes for one polypeptide. Each gene occupies a specific place on a chromosome.
Define allele different versions of the same gene
Define catalyst a molecule that speeds up a chemical reaction but does not get used up. At the end of the reaction the catalyst remains unchanged.
Define extracellular enzymes catalyse reactions outside the cell
Define intracellular enzymes catalyse reactions inside the cell
Define activation energy the amount of energy that must be applied for a reaction to proceed. Different reactions have different activation energies. Enzymes lower the activation energy
Define denaturation changes to the tertiary structure of an enzyme such that it cannot function and its function cannot be restored. The primary structure is not affected
Define optimum pH the pH value at which the rate of an enzyme controlled reaction is at its maximum. Each enzyme has a different optimum pH
Define limiting factor if all other conditions are kept constant, increasing concentration of that factor alone will inrease the reaction rate
Define enzyme inhibitor any substance or molecule that slows down the rate of an enzyme-controlled reaction by affecting the enzyme molecule in some way
Define cofactor any substance that must be present to ensure enzyme-controlled reactions take place at the appropriate rate. Some cofactors are a part of the enzyme (prosthetic groups), others are temporary (coenzymes and inorganic ion cofactors)
Define biosensor uses enyme-controlled reactions to deect the presence of substances in a highly sensitive and specific way. If the substance is present, the enzyme-controlled reaction takes place. The biosensor has a mechanism for revealing whether a product is made
Define variable any factor that may change and therefore affect the reaction rate
Define anomalous a result that looks out of place compared with other results
Define turnover number the number of reactions an enzyme molecule can catalyse in one second. In catalase the turnover number is up to 200 000
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