AS BIOL1 definitions


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  • Created on: 20-06-11 21:07
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Unit 1 | Causes of Disease
1.1 Pathogens
Interface ­ a surface or boundary which links the two systems, i.e. the external environment with the
internal environment of the body (skin); these are common types of entry for pathogenic microorganisms
Microorganism ­ single-celled organism that is too small to be seen without a microscope
Pathogen ­ a disease-causing microorganism that gains entry to the host and damages its tissues or
producing toxins (bacteria, virus and fungi)
Transmission ­ When a pathogen is transferred from one individual to another
1.2 Data and Disease
Correlation ­ occurs when a change in one of two variables is reflected by a change in the other variable
Causal link ­ experimental evidence and compelling studies carried out that prove a certain factor is the
cause of disease
Epidemiology ­ the study of the incidence and pattern of disease in order to find the means of preventing
and controlling it
1.3 Lifestyle and Health
Risk ­ a measure of the probability that damage to health will occur as a result of a given hazard
Unit 2 | Enzymes and the Digestive System
2.1 Enzymes and digestion
Absorption ­ taking soluble molecules into the body
Assimilation ­ the process by which molecules are incorporated into body issues and/or used in processes
within the body
Hydrolysis ­ splitting up of molecules by adding water to the chemical bonds that hold them together
Peristalsis ­ waves of muscle contractions
Sphincter muscles ­ control the entry and exit of substances
Chyme ­ acidic fluid food is turned into in the stomach
2.2 Carbohydrates ­ monosaccharides
Monomer ­ each of the individual molecules that combine to form a larger one
Monosaccharide ­ a single monomer in carbohydrates; sweet-tasting, soluble substances with
formula (CH2O) n
Polymer ­ longer chains of repeating monomer units

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Reduction ­ a chemical reaction involving the gain of electrons
2.3 Carbohydrates ­ disaccharides and polysaccharides
Condensation ­ giving out of water in reactions; a glycosidic bond is formed
Disaccharide ­ a pair of monosaccharides combined together by a peptide bond
Polysaccharide ­ monosaccharides combined in much larger numbers; insoluble polymers used
for storage and structural support (in plant cells)
2.4 Carbohydrate digestion
Digestion ­ process in which large molecules are hydrolysed by enzymes into small molecules
which can be absorbed and assimilated
2.…read more

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Enzyme inhibition
Metabolic pathway ­ a series of reactions in which each step is catalysed by an enzyme
End-product inhibition ­ maintenance of the level of any chemical at a relatively constant level
by making the same chemical act as an inhibitor of an enzyme at the start of a reaction
Competitive inhibitors ­ substances that bind to the active site of the enzyme
Non-competitive inhibitors ­ substances that bind to the enzyme at a position other than the
active site
Unit 3 | Cells…read more

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Rough Endoplasmic reticulum (RER) ­ covered in ribosomes; folds and processes proteins that have
been made at the ribosomes
Golgi apparatus ­ a group of fluid-filled sacs; processes and packages new lipids and proteins; also makes
Microvilli ­ found on cells involved in processes like absorption; increase the surface area of the
Mitochondrion ­ site of aerobic respiration; matrix inside which contains enzymes involved in respiration;
they're found in large numbers in cells that are very active and require a lot of energy…read more

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Active Transport
Active Transport ­ the movement of molecules or ions into or out of a cell from a region of lower
concentration to a region of higher concentration using energy and carrier molecules
3.9 Absorption in the small intestine
Villi ­ finger-like projections with thin walls lined with epithelial cells which increase the surface area of the
small intestine therefore accelerate the rate of absorption
3.…read more

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Pulmonary ventilation (dm3 min-1) ­ total volume of air that is moved into the lungs during one minute
Tidal volume (dm3) ­ volume of air normally taken in at each breath when the body is at rest
Ventilation rate (min-1) ­ number of breaths taken in one minute
4.4 Lung disease ­ pulmonary tuberculosis
Pulmonary tuberculosis ­ infectious disease that can be fatal; bacteria destroy lung tissue, resulting in
cavities and scars
4.…read more

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Myogenic (cardiac muscle) ­ contraction initiated from within the muscle itself rather than by nerve
SAN (Sinoatrial node) ­ distinct group of cells that determine the rhythm of the heart beat by passing a
wave of electrical activity
AVN (Atrioventricular node) ­ second group of cells that lie between the atria; convey a wave of electrical
activity after a short delay
Bundle of His ­ series of specialised muscle fibres that conduct the wave through the atrioventricular
septum to the base of the ventricles…read more

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Phagocytes ­ type of white blood cells that ingest and destroy the pathogen by phagocytosis
Histamine ­ causes dilation of the blood vessels and speeds up delivery of phagocytes to the site of
6.…read more


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