Definitions:Topic 1 Flashcards
What is an anion?
A negative ion.
What is a cation?
A positive ion.
What are ionic bonds?
Bonds formed when atoms give or receive electrons; they result in charged particles called ions.
What are covalent bonds?
Bonds formed when atoms share electrons; covalent molecules may be polar if the electrons are not shared equally
Define dipole.
The separation of charge in a molecule when the electrons in covalent bonds are not evenly shared
What is a polar molecule?
A molecule containing a dipole.
Define dissociation.
Splitting of a molecule into smaller molecules, atoms, or ions, especially by a reversible process
What are hydrogen bonds?
Weak electrostatic intermolecular bonds formed between polar molecules containing at least one hydrogen atom
What is a monomer?
A small molecule that is a single unit of a larger molecule called a polymer
What is a polymer?
A long-chain molecule made up of many smaller, repeating monomer units joined together by chemical bonds
What is a macromolecule?
a very large molecule often formed by polymerisation
Define starch.
A long-chain polymer formed of glucose monomers
What is sucrose?
a sweet-tasting disaccharide formed by the joining of glucose and fructose by a 1,4-glycosidic bond
What is glucose?
A hexose sugar.
What is a monosaccharide?
A single sugar monomer.
What is a disaccharide?
A sugar made up of two monosaccharide units joined by a glycosidic bond, formed in a condensation reaction
What is a polysaccharide?
a polymer consisting of long chains of monosaccharide units joined by glycosidic bonds
What is a triose sugar?
A sugar with 3 carbon atoms.
What is a pentose sugar?
A sugar with 5 carbon atoms.
Define ribose.
A pentose sugar that is part of the structure of RNA.
Define deoxyribose.
A pentose sugar that is part of the structure of DNA.
Define deoxyribonucleic acid (DNA)
A nucleic acid that is the genetic material in many organisms.
What is ribonucleic acid (RNA)?
A nucleic acid which is the genetic material in some organisms and is involved in protein synthesis
What is a hexose sugar?
A sugar with 6 carbon atoms
What are isomers?
Molecules that have the same chemical formula, but different molecular structures
Define a condensation reaction.
A reaction in which a molecule of water is removed from the reacting molecules as a bond is formed between them
What is a glycosidic bond?
A covalent bond formed between two monosaccharides in a condensation reaction, which can be broken down by a hydrolysis reaction to release the monosaccharide units
Define reducing sugars.
Sugars that react with blue Benedict’s solution and reduce the copper(I) ions giving an orangey-red precipitate
What are non-reducing sugars?
These are sugars that do not react with Benedict’s solution
What are oligosaccharides?
molecules with between 3 and 10 monosaccharide units
Define hydrolysis.
A reaction in which bonds are broken by the addition of a molecule of water
What is ATP?
Adenosine triphosphate, the molecule that acts as a universal energy supply molecule in all cells
What are end products?
the final products of a chemical reaction
Define amylose.
Complex carbohydrate containing only
a-glucose monomers joined together by 1,4-glycosidic bonds so the molecules form long unbranched chains
Define amylopectin.
A complex carbohydrate made up of
a-glucose monomers joined by 1,4-glycosidic bonds with some 1,6-glycosidic bonds so the molecules branch repeatedly
Define glycogen.
A complex carbohydrate with many
a-glucose units joined by 1,4-glycosidic bonds with many 1,6-glycosidic bonds, giving it many side branches
What are lipids?
Large family of organic molecules that are important in cell membranes and as an energy store in many organisms; they include triglycerides, phospholipids and steroids
What are fatty acids?
Organic acids with a long hydrocarbon chain.
What is glycerol?
Propane- 1,2,3-triol, an important component of triglycerides.
What are ester bonds?
Bonds formed in a condensation reaction between the carboxyl group (-COOH) of a fatty acid and one of the hydroxyl groups (-OH) of glycerol
Define a saturated fatty acid.
Fatty acid in which each carbon atom is joined to the one next to it in the hydrocarbon chain by a single covalent bond
What is an unsaturated fatty acid?
A fatty acid in which the carbon atoms in the hydrocarbon chain have one or more double covalent bonds in them
What is a monosaturated fatty acid?
A fatty acid with only one double covalent bond between carbon atoms in the hydrocarbon chain
What is a polysaturated fatty acid?
Fatty acid with two or more double covalent bonds between carbon atoms in the hydrocarbon chain
Define esterfication.
The process by which ester bonds are made.
What is haemoglobin?
A red pigment that carries oxygen and gives the erythrocytes their colour
What are amino acids?
The building blocks of proteins consisting of an amino group (-NH,) and a carboxyl group (-COOH) attached to a carbon atom and an R group that varies between amino acids
What is a peptide bond?
the bond formed by condensation reactions between amino acids
Define dipeptide.
two amino acids joined by a peptide bond
Define polypeptide.
A long chain of amino acids joined by peptide bonds.
What is a disulfide bond?
A strong covalent bond produced by an oxidation reaction between sulfur groups in cysteine or methionine molecules, which are close together in the structure of a polypeptide
What are fibrous proteins?
Proteins that have long, parallel polypeptide chains with occasional cross-linkages that produce fibres; they have little tertiary structure
What is denaturation?
the loss of the 3D shape of a protein (e,g. caused by changes in temperature or pH)
What is a collagen?
A strong fibrous protein with a triple helix structure
What are globular proteins?
Large proteins with complex tertiary and sometimes quaternary structures, folded into spherical (globular) shapes
Define hydrophobic.
A substance that tends to repel water and that will not mix with or dissolve in water
Define hydrophillic.
A substance with an affinity for water that will readily dissolve in or mix with water
What does colloid?
A suspension of molecules that are not fully dissolved.
What is a prosthetic group?
The molecule incorporated in a conjugated protein
What is conjugated protein?
Protein molecules joined with or conjugated to another molecule called a
prosthetic group
What are lipoproteins?
Conjugated proteins with a lipid prosthetic group
What are glycoproteins?
Conjugated proteins with a carbohydrate prosthetic group
Define proteases.
Protein-digesting enzymes
Define diffusion.
The movement of the particles in a liquid or a gas down a concentration gradient from an area where they are at a relatively high concentration to an area where they are at a relatively low conc.
What is conc. gradient?
Change in the concentration of solutes
present in a solution between two regions; in biology, this typically
means across a cell membrane
What is SA:Vol?
The relationship between the surface area of an organism and its volume
What are vertebrates?
Animals with a backbone or spinal column; they include mammals, birds, reptiles, amphibians and fish
What is a mass transport system?
An arrangement of structures by which
substances are transported in the flow of a fluid with a mechanism for moving it around the body
Define single circulation system.
Circulation in which the heart pumps the
blood to the organs of gas exchange and the blood then travels on around the body before returning to the heart
What is a double circulation system?
A circulation that involves two separate
circuits, one of deoxygenated blood flowing from the heart to the gas exchange organs to be oxygenated before returning to the heart, and one of oxygenated blood leaving the heart and flowing around the body, returning as deoxygenated blood to the heart
What is systemic circulation?
Carries oxygenated blood from the heart
to the cells of the body where the oxygen is used, and carries the deoxygenated blood back to the heart
Define oxygenated blood.
blood that is carrying oxygen
Define deoxygenated blood.
Blood that has given up its oxygen to the cells in the body
What is pulmonary circulation?
Carries deoxygenated blood to the lungs and oxygenated blood back to the heart
What is the cardiovascular system?
The mass transport system of the body made up of a series of vessels with a pump (the heart) to move blood through the vessels
What is circulation?
The passage of blood through the blood vessels
What is active transport?
The movement of substances into or out of the cell using ATP produced during cellular respiration
What is a buffer?
A solution which resists changes in pH
What are leucocytes?
White blood cells there are several different types which play important roles in defending the body against the entry of pathogens and in the immune system
What are platelets?
Cell fragments involved in the clotting mechanism of the blood
What are megakaryocytes?
Large cells that are found in the bone marrow and produce platelets
What is oxyhaemoglobin?
the molecule formed when oxygen binds to haemoglobin
What is carbaminohaemoglobin?
The molecule formed when carbon dioxide combines with haemoglobin
What is carbonic anyhydrase?
The enzyme that controls the rate of the reaction between carbon dioxide and water to produce carbonic acid
What is the Bohr effect?
The name given to changes in the oxygen dissociation curve of hemoglobin that occur due to a rise in carbon dioxide levels and a reduction of the affinity of haemoglobin for oxygen
Define fetal haemoglobin?
A form of haemoglobin found only in the developing fetus with a higher affinity for oxygen than adult haemoglobin
What is serotonin?
A chemical that causes the smooth muscle of the blood vessels to contract, narrowing them and cutting off the blood flow to the damaged area
What is thromboplastin?
An enzyme that sets in progress a cascade of events that leads to the formation of a blood clot
What is prothrombin?
A large, soluble protein found in the plasma that is the precursor to an enzyme called thrombin
What is thrombin?
An enzyme that acts on fibrinogen, converting it to fibrin during clot formation
Define the term precursor.
A biologically inactive molecule which can be converted into a closely related biologically active molecule when needed
Define fibrinogen.
A soluble plasma protein which is the precursor of the insoluble protein fibrin
What is fibrin?
An insoluble protein formed from fibrinogen by the action of thrombin that forms a mesh of fibres that trap erythrocytes and platelets to form a blood clot
What are arteries?
vessels that carry blood away from the heart
What are veins?
vessels that carry blood towards the heart
What are capillaries?
tiny vessels that spread ihrouphout the tissues of the body
What is the lumen?
the central space inside the blood vessel
What is the arterial system?
The system of arteries in the body
What are artioles?
the very smallest branches of the arterial system, furthest from the heart
What are peripheral arteries?
arteries further away from the heart but before the arterioles
What are venules?
the very smallest branches of the venous system, furthest from the heart
Define the inferior vena cava.
The large vein that carries the returning blood from the lower parts of the body to the heart
Define the superior vena cava.
The large vein that carries the returning blood from the upper parts of the body to the heart
What is the venous system?
The system of veins in the body.
What are the semilunar valves?
Half-moon shaped, one-way valves found at frequent intervals in veins to prevent the backflow of blood
What is the septum?
The thick muscular dividing wall through the centre of the heart that prevents oxygenated and deoxygenated blood from mixing
What is the septum?
The thick muscular dividing wall through the centre of the heart that prevents oxygenated and deoxygenated blood from mixing
What is the cardiac muscle?
The special muscle tissue of the heart, which has an intrinsic rhythm and does not fatigue
Define myoglobin.
A respiratory pigment with a stronger affinity for oxygen than haemoglobin.
What is the right atrium?
The upper right-hand chamber of the heart that receives deoxygenated blood from the body
What is the right ventricle?
The lower chamber that receives deoxygenated blood from the right atrium and pumps it to the lungs
What is a tricuspid valve( atrioventricular valve)?
The valve between the right atrium and the right ventricle that prevents backflow of blood from the ventricle to the atrium when the ventricle contracts
What are tendinous cords(valve tendons,heartstrings)?
Cord-like tendons that make sure the valves are not turned inside out by the large pressure exerted when the ventricles contract
What are the pulmonary arteries?
The blood vessels that carry deoxygenated blood from the heart to the lungs
What are the pulmonary veins?
the blood vessels that carry oxygenated blood back from the lungs to the heart
What is the left atrium?
The upper left-hand chamber of the heart that receives oxygenated blood from the lungs
What is the left ventricle?
The chamber that receives oxygenated blood from the left atrium and pumps it around the body
What is a bicuspid valve(atrioventricular valve)?
The valve between the left atrium and the left ventricle that prevents backflow of blood into the atrium when the ventricle contracts
What is the aorta?
The main artery of the body; it leaves the left ventricle of the heart carrying oxygenated blood under high pressure
Define systole.
the contraction of the heart
Define atrial systole.
when the atria of the heart contract
Define ventricular systole.
when the ventricles of the heart contract
Define diastole.
when the heart relaxes and fills with blood
What is a cardiac cycle?
The cycle of contraction (systole) and relaxation (diastole) in the heart
Define cardiovascular diseases.
Diseases of the heart and circulatory system, many of which are linked to atherosclerosis
What is atherolosclerosis?
A condition in which yellow fatty deposits build up (increase in amount) on the lining of the arteries, causing them to be narrowed and resulting in many different health problems
What are plaques?
Yellowish fatty deposits that form on the inside of arteries in atherosclerosis
What is an atheroma?
another term for a plaque formed on the arterial lining
What is an aneurysm?
A weakened, bulging area of artery wall that results from blood collecting behind a blockage caused by plaques
Define angina.
A condition in which plaques are deposited on the endothelium of the arteries and reduce the blood flow to the cardiac muscle through the coronary artery; it results in pain during exercise
Define myocardial infarction(heart attack).
The events which take place when atherosclerosis leads to the formation of a clot that blocks the coronary artery entirely and deprives the heart muscle of oxygen, so it dies; it can stop the heart functioning
What is anaerobic respiration?
Cellular respiration that takes place in the absence of oxygen
What is a stent?
A metal or plastic mesh tube that is inserted into an artery affected by atherosclerosis to hold it open and allow blood to pass through freely
What is thrombosis?
A clot that forms in a blood vessel
What is a stroke?
An event caused by an interruption to the normal blood supply to an area of the brain which may be due to bleeding from damaged capillaries or a blockage cutting off the blood supply to the brain, usually caused by a blood clot
Define non-communicable conditions.
Diseases which are not caused by
pathogens and cannot be spread from one person to another
What is a risk?
The probability that an event will take place
Define probability.
A measure of the chance or likelihood that an event will take place
What are risk factors?
Factors which affect the risk of an event happening
Define a multifactorial disease.
A disease which results from the interactions of many different factors - not from one simple cause
Define epidemiology.
The study of patterns of health and disease, to identify causes of different conditions and patterns of infection
What is correlation?
A strong tendency for two sets of data to change together
What is causation?
When a factor directly causes a specific effect
Define logitudinal studies.
Scientific studies which follow the same group of individuals for many years
Define metadata analysis(meta-analysis)
When data from all the available studies in a particular area are analysed
Define the term valid.
An investigation which is well designed to answer the question being asked
What is precision?
measurements with only slight variation between them
Define the term reliable.
Evidence which can be repeated by several different scientists
Define biased.
When someone is unfairly for or against an idea (e.g. when a scientist is paid by someone with a vested interest in a specific result they may receive benefit from the outcome)
What is meant by the term evaluate?
To assess or judge the quality of a study and the significance of the results
What is high blood pressure?
Blood pressure that is regularly more than 140/90 mmHg; this increases your risk of developing CVDs
What is hypertension?
High blood pressure, regularly measuring over 140/90 mmHg, which increases your risk of developing CVDs
Define body mass index (BMI).
A calculation to determine if you are a are a healthy weight by comparing your weight to your height in a simple formula
Define low-density lipoproteins(LDLs).
Lipoproteins which transport lipid for around the body
Define high-density lipoproteins(HDLs).
Lipoproteins which transport cholesterol from body tissues to the liver and can help reduce risks of CVDs
What are antioxidants?
Molecules that inhibit the oxidation of other molecules which can lead to chain reactions that may damage cells
What is an antihyperintensive?
Drug which reduces high blood pressure
What are diuretics?
Drugs which increase volume of urine produced
What are beta blockers?
Drugs which block the response of the heart to hormones such as adrenaline
What are sympathetic nerve inhibitors?
Drugs which inhibit sympathetic nerves, keeping arteries dilated
What are ACE inhibitors?
Drugs which block the production of angiotensin.
Define the term side-effect.
A secondary, usually undesirable effect of a drug or medical treatment
What are statins?
Drugs that lower the level of cholesterol in the blood
Define a placebo.
An inactive substance resembling a drug being trialled which is used as an experimental control.
Define plant stanols and sterols.
Similar in structure to cholesterol, these compounds can help reduce blood cholesterol in those consuming them.
What is an anticoagulant?
A substance that interferes with the manufacture of prothrombin in the body.
What are platelet inhibitory drugs?
Drugs used to prevent blood clots forming by preventing platelets clumping together.
