Across
- 1. a test for the presence of reducing sugars
- 6. enzymes that have been fixed to a surface or trapped inside beads of agar gel
- 8. a relatively weak bond formed by the attraction between a group with a small positive charge on a hydrogen atom and another group carrying a small negative charge
- 9. the main structural protein of animals; known as ‘white fibres’, the fundamental unit of the fibre consists of three helical polypeptide chains wound around each other, forming a ‘triple helix’ with high tensile strength
- 11. test a test for the presence of amine groups and thus for the presence of protein
- 12. a chemical bond, represented as –COO– , formed when an acid reacts with an alcohol
- 15. a C–O–C link between two sugar molecules, formed by a condensation reaction; it is a covalent bond
- 17. bond the covalent bond joining neighbouring amino acids together in proteins
- 20. a hypothesis for enzyme action; the substrate is a complementary shape to the active site of the enzyme, but not an exact fit – the enzyme, or sometimes the substrate, can change shape slightly to ensure a perfect fit, but it is still described as showing specificity
- 21. a sugar molecule consisting of two monosaccharides joined together by a glycosidic bond
- 23. a protein produced by a living organism that acts as a biological catalyst in a chemical reaction by reducing activation energy
- 25. simple molecule which is used as a basic building block for the synthesis of a polymer
- 27. a polysaccharide made from beta- glucose subunits; used as a strengthening material in plant cell walls
Down
- 2. a chemical reaction involving the joining together of two molecules by removal of a water molecule
- 3. a protein whose molecules are folded into a relatively spherical shape, often has physiological roles and is often water-soluble and metabolically active
- 4. a large molecule such as a polysaccharide, protein or nucleic acid
- 5. a polysaccharide made of many glucose molecules linked together, that acts as a glucose store in liver and muscle cells
- 7. when a substance reduces the rate of activity of an enzyme by competing with the substrate molecules for the enzyme’s active site
- 8. a chemical reaction in which a chemical bond is broken by the addition of a water molecule
- 10. structure the structure of a protein molecule resulting from the regular coiling or folding of the chain of amino acids (an α-helix or β-pleated sheet)
- 13. a long chain of amino acids formed by condensation reactions between the individual amino acids
- 14. a molecule consisting of a single sugar unit
- 16. sheet a loose, sheet-like structure formed by hydrogen bonding between parallel polypeptide chains
- 18. a type of lipid formed when three fatty acid molecules combine with glycerol
- 19. the substrate concentration at which an enzyme works at half its maximum rate (1⁄2Vmax), used as a measure of the efficiency of an enzyme
- 22. an area on an enzyme molecule where the substrate can bind
- 24. the energy that must be provided to make a reaction take place
- 26. a giant molecule made from many similar repeating subunits joined together in a chain