AQA Biol1 Glossary

  • Created by: lucie
  • Created on: 16-05-13 18:53
The passing of digested food molecules through the gut wall and into the blood
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Activation Energy
The minimum amount of kinetic energy needed for a reaction to occur
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Active Site
The place on an enzyme where a substrate molecule is temporarily bound during a chemical reaction. It is complementary in shape to the substrate.
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Active Transport
The movement of molecules across a membrane from an area where they are in lower concentration to an area where they are in higher concentration, using specialised transport molecules, and using ATP energy.
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Aerobic Respiration
Respiration using oxygen.
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Alpha Helix Structure
A form of secondary structure in a protein. It consists of a long polypeptie chain held in a helix by hydrogen bonds.
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A tiny air sac in the lungs where gas exchange occurs
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Amino Acid
The monomer used as the building block of polypeptides and proteins. Each has an amino -NH2 and a carboxylic acid group - COOH
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An enzyme that digests starch into maltose
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Anaerobic Respiration
Respiration without using oxygen
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A protein produced by plasma cells that binds specifically to an antigen
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A large molecule, usually on the surface of a cell, that triggers an immune response
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A major artery that takes oxygenated blood from the left ventricle of the heart round the body
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A blood vessel that carries blood away from the heart
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An allergic response in which the airways become narrowed, causing difficulty in breathing
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Fatty deposits that build up in the wall of an artery. This is the underlying cause of coronary heart disease.
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The immediate source of energy in biological reactions. ATP loses a phosphate group to become ADP, releasing energy.
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Atrioventricular node
A mass of specialised heart tissue that delays the wave of electrical excitation from the sinoatrial node for a fraction of a second. This allows the atria to empty completely before the ventricles contract.
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Atrioventricular Valve
A valve in the heart between the atrium and ventricle, which closes to stop blood flowing backwards into the atrium from the ventricle.
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An upper chamber of the human heart. It has relatively thin walls.
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These cells form part of the immune system and produce plasma cells that make antibodies, as well as memory cells.
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Benedict's Solution
A blue solution used to test for the presence of reducing sugars, such as glucose and maltose.
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Beta - Pleated Sheet
A form of secondary structure in a protein in which part of the polypeptide chain forms flattened, pleated areas held together by hydrogen bonds.
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A double layer of phospholipid molecules that make up the main part of the cell surface membrane.
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Forming a temporary bond between a substrate and the active site of an enzyme, or between a membrane protein and the substance it recognises.
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Biuret Solution
A solution used to test for the presence of proteins. The blue solution is added to a sample, and if a protein is present, it turns lilac.
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There are two branches from the trachea that carry air towards (or away from) the lungs.
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Small tubes branching from the bronchi in the lungs
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A solution that maintains a pH. It is often used in enzyme investigations to ensure that pH remains constant.
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A microscopic blood vessel that carries oxygen to the tissues
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A slimy layer found on the outside of some bacterial cells.
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A class of compounds made of carbon, hydrogen and oxygen. This group includes sugar such as glucose and sucrose, as well as polysaccarides such as starch and cellulose
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Cardiac Cycle
The sequence of events that make up the heartbeat
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Carrier Protein
A protein that carries molecules of a specific type across a cell membrane.
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The building block of which all living organisms are composed
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A device that spins at high speed, separating the denser components out of a suspension to form a solid pellet, while the less dense components remain suspended in the liquid supernatant.
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Channel Protein
A protein or pore that spans the cell surface membrane and allows molecules of a specific type to pass through by facilitated diffusion
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Disease caused by a bacterium that releases a toxin called CT. This toxin activates a protein in the gut that transports chloride ions into the gut. This lowers the water potential in the gut and causes diarrhoea
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Competitive Inhibitor
A molecule that is similar in shape to a substrate molecule that can bind to an enzyme's active site, preventing the substrate molecule from binding.
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Two substances that have shapes that allow them to fit together.
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Concentration Gradient
A difference in the concentration of a substance between two areas
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Condensation Reaction
A reaction that forms a bond and removes a molecule of water.
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Coronary Artery
These are arteries that supply oxygenated blood to the heart muscle
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This is when a change in one variable is reflected by a change in a second variable
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This is when one molecule is taken into a cell using a protein in the cell membrane, alongside another molecule or ion. For example, glucose enters the epithelium of the gut alongside a sodium ion.
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The folds in the inner membrane of the mitochondrion that increase the surface area for ATP production
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The watery solution in a cell that is outside the membrane-bound organelles
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This happens to an enzyme when its tertiary structure is changed, so its active site is no longer the right shape for the substrate to fit in.
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A sheet of muscle that separates the thorax from the abdomen. It contracts when a person breathes in.
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The period in the cardiac cycle when the atria and ventricles are relaxing.
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The movement of molecules or ions from a region where they are in higher concentration to a region where they are in lower concentration down a concentration gradient.
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Breaking down large molecules into smaller, soluble molecules that can be absorbed.
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A sugar made when two monosaccarides join together, e.g. sucrose and maltose.
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Disulfide Bridge
This is a strong covalent bond formed between the R-groups of some amino acids. These bonds hold protein in their tertiary structure.
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The first part of the digestive system.
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Electron Microscope
A microscope that uses electron beams and magnetic lenses to produce a magnified image of an object.
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A disease in which the walls of the alveoli break down, reducing the surface area for gas exchange. The patient becomes breathless.
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Emulsion Test
This a test for lipids. You shake the substance up with ethanol, then add an equal volume of water. If a lipid is present, it goes milky.
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Endoplasmic Reticulum
System of phospholipid membranes extending through most of the cell, divides the cell up into compartments. There are two types: Smooth ER and Rough ER.
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Layer of cells lining an internal tissue, eg the lining of an artery or the wall of a capillary
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A protein with a complex tertiary structure that lowers the activation energy for a reaction to occur. It has an active site that is specific for a particular substrate.
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The tissue that covers the surfaces of the body and its organ, e.g. the alveoli.
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Eukaryotic Cell
A cell containing membrane-bound nucleus and membrane-bound organelles such as mitochondria and endoplasmic reticulum.
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Breathing out
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Facilitated Diffusion
Diffusion across a membrane involving protein channels or carrier molecules.
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Fatty Acid
An organic molecule consisting of a hydrocarbon tail and a carboxylic acid group. R-COOH
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A lung disease caused by breathing in dust and dirt. It causes the walls of the alveoli to become thicker, making gas exchange less efficient.
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A long 'whip-like' structure used for movement in some organisms, e.g. bacteria.
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Fluid Mosaic Model
A model of the cell surface membrane, which has mobile proteins scattered among phospholipids which move around gently.
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A monosaccaride that is found in the disaccaride sucrose.
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A monosaccaride that joins with glucose to make lactose
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A monosaccaride with the formula C6H12O6
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An organic compound which combines with fatty acids to form a lipid.
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A protein with a carbohydrate attached.
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Golgi Body/Apparatus
Stack of flattened membrane-bound sacs in which proteins are processed and packaged for export out of the cell in secretory vesicles.
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Equipment used to break open and homogenise cells during cell fractionation
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Hydrogen Bonds
A weak bond that forms between R-groups of different amino acids in the polypeptide chain. These bonds hold proteins in their secondary and tertiary structures.
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The breaking down of large molecules into smaller soluble ones by breaking bonds with the addition of water.
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This term is used to describe the 'head' of a phospholipid which arranged itself towards water.
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This term is used to describe the 'tail' of a phospholipid which arranges itself away from water.
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Part of the small intestine where dissolved nutrients are absorbed.
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Immune System
The way that the body that the body responds to infection by a pathogen, using B-cells and T-cells.
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Induced Fit
This theory explains how enzymes work. The active site changes shape as the substrate binds to make a close fit. The reaction occurs and the products are released.
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Breathing in
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Intercostal Muscles
The muscles between the ribs that contract and relax to raise and lower the rib cage during breathing.
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Iodine Test
This is a test for starch - you add this solution, and if starch is present it goes blue-black
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A solution that has the same water potential as the cell, so does not allow net movement of water into or out of the cell.
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A disaccaride made when glucose and galactose join together, found in milk.
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Lactose Intolerance
A person who does not have enough lactase enzyme to digest the lactose normally present in the diet.
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An enzyme that hydrolyses lipids
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A molecule made up of fatty acids attached to a glycerol molecule.
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Lock and Key
This theory explains how enzymes work. The substrate fits exactly into the enzyme's active site, reducing activation energy causing a reaction to occur.
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The hollow cavity inside a tubular structure such as the gut or a blood vessel.
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A disaccaride made when two glucose molecules join together.
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Tiny finger-like projections from the cell surface membrane of some animal cells, e.g. those lining the small intestine. They increase the surface area for absorption.
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The organelle that carries out aerobic respiration and produces most of a cell's ATP.
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Monoclonal Antibodies
Name given to antibodies that are all same, and specific to one antigen. They are used, for example, in pregnancy test kits or in targeting drugs to cancer cells.
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One of many similar smaller molecules that join together to form a polymer.
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A single sugar, such as glucose or fructose.
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Myobacterium Tuberculosis
The name of the bacterium that causes TB.
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Myocardial Infarction
The name for a heart attack. This happens when the coronary artery is blocked by a blood clot or atheroma, so the heart muscle is starved of oxygen and some of the heart muscle cells die.
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This describes the cardiac muscle, which can contract on its own without any impulses from the nervous system.
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Non-Competitive Inhibitor
This fits into an enzyme, but not at its active site. However, it changes the shape of the active site so that substrate no longer fits.
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Non-Reducing System
A sugar that gives a negative result with Benedict's test but a positive result with Benedict's test after it has been hydrolysed by boiling with acid and neutralised by adding an alkali, eg sucrose
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An organelle that contains the cell's genetic information, in the form of DNA, that controls the activities of the cell.
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Part of the gut that carries food from the mouth to the stomach.
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Optical Microscope
This uses light rays that pass through lenses to produce a magnified image of an object.
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This refers to the temperature or pH at which the rate of enzyme activity is highest.
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Oral Rehydration Solution
This is a means of treating dehydration by giving a person a drink containing a balanced concentration of salts and glucose, that stimulates the gut to reabsorb water.
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A membrane-bound structure in the cytoplasm of a cell, eg mitochondria.
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The passage of water from a region where there is a higher water potential across a partially permeable membrane.
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A process that does not require energy from ATP
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Any microorganism that causes disease
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A solid layer forming in a test tube after a suspension has been spun in a centrifuge.
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The bond formed when two amino acids join together.
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Co-ordinated waves of contraction and relaxation of the smooth muscle making up the gut wall, which propel the gut contents along the digestive tract.
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Mechanism by which cells engulf particles to form a vesicle or vacuole. E.g. how a macrophage engulf pathogens.
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This is a type of lipid found in the cell membrane. It consists of glycerol with 2 fatty acids and a phosphate group.
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A small circle of DNA found in some bacteria. It contains genes additional to those in the main DNA of the cell.
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Large molecule made of many repeating smaller molecule (monomeres)
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Other cards in this set

Card 2


Activation Energy


The minimum amount of kinetic energy needed for a reaction to occur

Card 3


Active Site


Preview of the front of card 3

Card 4


Active Transport


Preview of the front of card 4

Card 5


Aerobic Respiration


Preview of the front of card 5
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