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1

biological molecules

particular groups of chemicals that are found in living organisms

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organic molecules

carbon-containing molecules

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molecular biology

the study of particular groups of chemicals that are found in living organisms

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covalent bonding

type of chemical bond in which two atoms share a pair of electrons, one from each atom, forming a stable compund called a molecule

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ionic bonding

the electrostatic attraction between ions of opposite charges (weaker than covalent)

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hydrogen bonding

a weak electrostatic/chemical bond formed between the positive charge on a hydrogen atom and the negative charge of an adjacent molecule e.g. water - individually weak, collectively important forces that alter the physical properties of molecules

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reduction

chemical process involving the gain of electrons

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reducing sugar

a sugar that can donate e- to/reduce another chemical

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polar molecule

a molecule that has an uneven distribution of charge due to electrons tending to spend more time at one position rather than evenly distributing in a molecule

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polarised

a molecule that has an uneven distribution of charge due to electrons tending to spend more time at one position rather than evenly distributing in a molecule

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monomers

the smaller units/molecules from which larger molecules (polymers) are made

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polymers

molecules made from a large number of repeating monomers joined together

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polymerisation

the process of joining molecules made from a large number of repeating monomers together

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condensation

the chemical process of joining together of two molecules to form a more complex one with the formation of a chemical bond and involves the elimination of a molecule of water

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hydrolysis

breaking of a chemical bond between two molecules/monomers or polymer into its constituent parts and involves the use of a water molecule

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metabolism

all the chemical processes that take place in living organisms

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macromolecules

a molecule containing a very large number of atoms, such as a protein, nucleic acid, or synthetic polymer

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mole (mol)

the SI unit for measuring the amount of substance - one mole contains the same number of particles as there are in 12g of carbon-12 which is 6.022x10^23 carbon atoms - the molecular mass expressed as grams

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molar solution (M)

a solution that contains one mole of solute in each litre of solution

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neutrons

occur in the nucleus of an atom and has the same mass as protons but no electrical charge

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protons

occur in the nucleus of an atom and have the same mass as neutrons but do have a positive charge

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electrons

orbits in shells around the nucleus and has a small negligible mass and negatively charged and their number determines the chemical properties of an atom

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atomic number

number of protons in an atom

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mass number

the total number of protons and neutrons in an atom

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isotopes

variations ina chemical element that have the same number of protons and electrons, but different numbers of neutrons - differs in mass, but chemical properties are similar

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ion

an atom or group of atoms that has lost or gained one or more electrons, so they have a postitive or negative charge

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monosaccharide

the monomers from which larger carbohydrates are made

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disaccharide

two monosaccharides joined together by a glycosidic bond in a condensation reaction

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polysaccharide

many monosaccharides joined together by glycosidic bonds in condensation reactions

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glycosidic bond

the bond formed when a condensation reaction joins two monosaccharides together

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osmosis

the passage of water from a region of high water potential to a lower one, through a selectively permeable membrane

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triglycerides (saturated fats and unsaturated oils)

an individual lipid molecule made up of a glycerol molecule and three fatty acids

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phospholipids

a triglyceride in which one of the three fatty acid molecules is replaced by a phosphate molecule (diglyceride) - important in structure and function of plasma membranes

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cell membranes

a biological membrane that separates the interior of all cells/organelles from the outside environment (the extracellular space/cytoplasm) to protect it from its surroundings. it consists of a lipid bilayer with embedded proteins and it controls the movement of substances in and out of cells and organelles, so it is selectively permeable to ions and organic molecules

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saturated (fatty acid)

a fatty acid in which there are no double bonds between the carbon atoms

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unsaturated (fatty acid)

a fatty acid in which there are one or more double bonds between the carbon atoms

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mono-unsaturated (fatty acid)

a fatty acid that posses a carbon chain with a singl double bond

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polyunsaturated (fatty acid) - PUFA

a fatty acid that possess carbon chains wih many double bonds

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water potential

the pressure created by water molecules - the measure of the extent to which a solution gives out water - the greater the number of water molecules, the higher the water potential - pure water is 0

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hydrophillic

attract/interacts with water

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hydrophobic

repels/orients away from water

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peptide bond


a chemical bond formed when a condensation reaction joins two amino acids together (the C atoms of one aa and the N of another)

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dipeptide

formed by the condensation of two amino acids

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polypeptide

formed by the condensation of many amino acids

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collagen

fibrous protein that is the main constituent of connective tissues such as tendons, cartilage and bone

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enzyme

globular proteins that act as catalysts altering the rate of a chemical reaction by lowering the activation energy without getting used up or undergoing permanent changes themselves and can be reused repeatedly so are effective in small amounts

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products

a chemical substance formed as a result of a chemical reaction

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free energy

the energy of a system that is available to perform work

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activation energy

the minimum amount of energy required to bring about a reaction - lowered by the presence of enzymes

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substrates

a substance that is acted on or used by another substance or process e.g. microbiology, nutrient medium to grow microorganisms

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active site

a group of amino acids that make up the functional region of an enzyme into which the substrate fits, in order to catalyse a reaction

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enzyme-substrate complex

the intermediate formed when the substrate fits into the complementary active site of an enzyme and is held by bonds that temporarily form between certain amino acids of the active site and groups on the substrate molecule

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scientific model

a representation of how something works to explain scientific observations

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complementary

opposite shapes that fit exactly

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kinetic energy

energy that an object possess due to its motion

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denaturation

permanent changes due to the unravelling of the 3D structure of a protein as a result of disruptive factors such as changes in temp/pH - the protein may not function again

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thermophillic

heat-loving

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coagulate

clot

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Vmax

the maximum rate of reaction

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enzyme inhibitors

substances that directly or indirectly interfere with the functioning of the active site of an enzyme and so reduce its activity

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metabolic pathway

a series of reactions in which each step is catalysed by an enzyme

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end-product inhibition

a type of non-competitive enzyme inhibition where the product of an enzyme reaction, binds to the enzyme and inhibits its activity

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benedict's test

a simple biochemical reaction to detect the presence of reducing sugars

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biuret's test

a simple biochemical reaction to detect the presence of a protein (peptide bond)