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Biology A-Level IAL Edexcel > Definitions Unit 4 > Flashcards

Definitions Unit 4 Flashcards

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1
Q

Autotrophic

A

Organisms that make complex organic compounds from simple compounds in the environment

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2
Q

Photosynthesis

A

The process by which living organisms, particularly plants and algae, capture the energy of the Sun using chlorophyll and use it to convert carbon dioxide and water into simple sugars

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3
Q

Heterotrophic

A

Organisms that obtain complex organic molecules by feeding on other living organisms or their dead remains

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4
Q

Adenosine triphosphate (ATP)

A

A nucleotide that acts as the universal energy supply in cells. It is made up of the base adenine, the pentose sugar ribose and three phosphate groups

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5
Q

ATPase

A

The enzyme which catalyses the formation and breakdown of ATP, depending on the conditions

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6
Q

Adenosine diphosphate (ADP)

A

A nucleotide formed when a phosphate group is removed from ATP, releasing energy to drive reactions in the cell

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7
Q

Reduction/oxidation reactions (redox reactions)

A

Reactions in which one reactant loses electrons (is oxidised) and another gains electrons (is reduced)

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8
Q

Electrón transport chain

A

A series of electron-carrying compounds along which electrons are transferred in a series of oxidation/ reduction reactions, driving the production of ATP

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9
Q

Chloroplast envelope

A

The outer and inner membranes of a chloroplast including the intermembrane space

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10
Q

Grana

A

Layers of thylakoid membranes within a chloroplast

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11
Q

Thylakoids

A

Membrane discs found in the grana of a chloroplast

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12
Q

Lamellae

A

Extensions of the thylakoid membranes which connect two or more grana and act as a supporting skeleton in the chloroplast; they maintain a working distance between the grana so that these receive the maximum light and function as efficiently as possible

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13
Q

Stroma

A

The matrix which surrounds the grana and contains all the enzymes needed to complete the process of photosynthesis and produce glucose

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14
Q

Chlorophyll α

A

A blue-green photosynthetic pigment, found in all green plants

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15
Q

Chlorophyll β

A

A yellow-green photosynthetic pigment

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16
Q

Carotenoids

A

Photosynthetic pigments consisting of orange carotene and yellow xanthophyll

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17
Q

Phaeophytin

A

A grey pigment which is produced by the breakdown of the other photosynthetic pigments

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18
Q

Absorption spectrum

A

A graph showing the amount of light absorbed by a pigment against the wavelength of the light

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19
Q

action spectrum

A

A graph demonstrating the rate of photosynthesis against the wavelength of light

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20
Q

Rf value

A

The ratio of the distance travelled by the pigment to the distance travelled by the solvent alone when pigments are separated by chromatography

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21
Q

Photosystem l (PSI)

A

A combination of chlorophyll pigments which absorbs light of wavelength 700nm and is involved in cyclic and non-cyclic photophosphorylation

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22
Q

Photosystem ll (PSII)

A

A combination of chlorophyll pigments which absorbs light of wavelength 680nm and is involved only in non-cyclic photophosphorylation

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23
Q

Light-dependent reactions

A

The reactions that take place in the light on the thylakoid membranes of the chloroplasts; the reactions produce ATP and break down water molecules in a photochemical reaction, providing hydrogen ions to reduce carbon dioxide and produce carbohydrates

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24
Q

Light-independent reactions

A

The reactions that use the reduced NADP and ATP produced by the light-dependent stage of photosynthesis in a pathway known as the Calvin cycle; this occurs in the stroma of the chloroplast and results in the reduction of carbon dioxide from the air to cause the synthesis of carbohydrates

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25
Q

Photochemical reaction

A

A reaction initiated by light

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26
Q

Cyclic photophosphorylation

A

A process that drives the production of ATP; light-excited electrons from PSI are taken up by an electron acceptor and transferred directly along an electron transport chain to produce ATP, with the electron returning to PSI

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27
Q

Non-cyclic photophosphorylation

A

A process involving both PSI and PSII in which water molecules are broken into smaller units using light energy to provide reducing power to make carbohydrates and at the same time produce more ATP

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28
Q

Photolysis

A

The breaking down of a molecule into smaller units using light

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29
Q

Calvin cycle

A

A series of enzyme-controlled reactions that take place in the stroma of chloroplasts and result in the reduction of carbon dioxide from the air to bring about the synthesis of carbohydrate

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30
Q

Ribulose bisphosphate (RuBP)

A

A 5-carbon compound that combines with carbon dioxide from the air in the Calvin cycle to fix the carbon dioxide and form a 6-carbon compound

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31
Q

Ribulose bisphosphate carboxylase/oxygenase (RUBISCO)

A

A rate-controlling enzyme that catalyses the reaction between carbon dioxide/oxygen and ribulose bisphosphate

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32
Q

Glycerate 3-phosphate (GP)

A

A 3-carbon compound thought to be the result of breakdown of a theoretical highly unstable 6-carbon compound formed as a result of the reaction between RuBP and carbon dioxide in the Calvin cycle

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33
Q

Glyceraldehyde 3-phosphate (GALP)

A

A 3-carbon sugar produced in the Calvin cycle using reduced NADP and ATP from the light-dependent stage; GALP is the key product of photosynthesis and is used to replace the RuBP needed in the first step of the cycle, in glycolysis and the Krebs cycle, and in the synthesis of amino acids, lipids, etc. for the plant cells

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34
Q

Photorespiration

A

The alternative reaction catalysed by RUBISCO in a low carbon dioxide environment which uses oxygen and releases carbon dioxide, making photosynthesis less efficient

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35
Q

Gluconeogenesis

A

The synthesis of glucose from non-carbohydrates

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36
Q

Limiting factor

A

The faster needed for a reaction to progress that is closest to its minimum value

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37
Q

Abundance

A

The relative representation of a species in a particular ecosystem

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38
Q

Ecosystem

A

An environment including all the living organisms interacting within it, the cycling of nutrients and the physical and chemical environment in which the organisms are living

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39
Q

Habitat

A

The place where an organism lives

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40
Q

Microhabitat

A

A small area of a habitat

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41
Q

Population

A

A group of organisms of the same species, living and breeding together in a habitat

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42
Q

Population

A

A group of organisms of the same species, living and breeding together in a habitat

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43
Q

Community

A

All the populations of all the different species of organisms living in a habitat at any one time

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44
Q

Niche

A

The role of an organism within the habitat in which it lives

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45
Q

Predator

A

An organism which hunts and eats other organisms

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45
Q

Predator

A

An organism which hunts and eats other organisms

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46
Q

Abiotic factors

A

The non-living elements of the habitat of an organism

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47
Q

Biotic factors

A

The living elements of a habitat that affect the ability of a group of organisms to survive there

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48
Q

Prey

A

An organism which is hunted and eaten by other organisms

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48
Q

Prey

A

An organism which is hunted and eaten by other organisms

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49
Q

Biosphere

A

All of the areas of the surface of the Earth where living organisms survive

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50
Q

Biomes

A

The major ecosystems of the world

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51
Q

Succession

A

The process by which the communities of organisms colonising an area change over time

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52
Q

Succession

A

The process by which the communities of organisms colonising an area change over time

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53
Q

Colonisation

A

The process by which new species spread to new areas

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54
Q

Opportunists/pioneer species

A

Species which are the first to colonise new or disturbed ecosystems

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55
Q

Climax community

A

A self-sustaining community with relatively constant biodiversity and species range. It is the most productive group of organisms that a given environment can support long term

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56
Q

Climatic climax community

A

The only climax community possible in a given climate

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57
Q

Plagioclimax

A

A climax community that is at least in part the result of human intervention

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58
Q

Microclimate

A

A small area with a distinct climate that is different from the surrounding area

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59
Q

Edaphic factors

A

Factors that relate to the structure of the soil

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60
Q

Leaching

A

The loss of minerals from soil as water passes through rapidly

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61
Q

Density-independent factors

A

Factors affecting the number of organisms occupying a niche which are the same regardless of population size

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62
Q

Density-dependent factors

A

Factors affecting the number of organisms occupying a niche which are dependent on the number of organisms in a specific area

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63
Q

Intraspecific competition

A

Competition between members of the same species for a limited resource

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64
Q

Interspecific competition

A

Competition between different species within a community for the same resources

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65
Q

Abundance

A

The relative representation of a species in a particular ecosystem

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66
Q

Distribution

A

Where a species of organism is found in the environment and how it is organised

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67
Q

Quadrat

A

A sample area used in practical ecology, often measured using a square frame divided into sections that you lay on the ground

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68
Q

Individual counts

A

A measure of the number of individual organisms in an area

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69
Q

Percentage cover

A

The area covered by the above-ground parts of a particular species

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70
Q

ACFOR scale

A

A simple scale used to describe the abundance of a species in a given area

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71
Q

Line transect

A

A way of collecting data more systematically; a tape is stretched between two points and every individual plant (or animal) that touches the tape is recorded

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72
Q

belt transect

A

When two tapes are stretched out and the ground between them surveyed or a tape stretched out and quadrats are taken at regular intervals

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73
Q

Spearman’s rank correlation coefficient

A

A statistical tool used to test whether two variables are significantly correlated

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74
Q

Student’s t-test

A

A statistical test that allows you to judge whether any difference between the means of the two sets of data is statistically significant

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75
Q

Chi squared test

A

A statistical test that enables you to determine whether there is a statistically significant association between the distribution of two species

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76
Q

Null hypothesis

A

The hypothesis that any differences between data sets are the result of chance

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77
Q

Significant

A

Not due to chance

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78
Q

Food chain

A

A simple way of modelling the feeding relationships between a series of organisms in an ecosystem

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79
Q

Trophic level

A

A term which describes the position of an organism in a food chain or web and its feeding relationship with other organisms

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80
Q

Producers

A

Organisms that make food by photosynthesis or chemosynthesis

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81
Q

Primary consumers

A

Organisms that eat producers, either plants or algae

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82
Q

Secondary consumers

A

Animals that feed on primary consumers

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83
Q

Tertiary consumers

A

Animals that feed on secondary consumers (i.e they eat other carnivores); they are usually the top predators in an area

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84
Q

Decomposers

A

The final trophic level in any set of feeding relationships; these are the microorganisms such as bacteria and fungi that break down the remains of animals and plants and return the mineral nutrients to the soil

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85
Q

Pyramid of numbers

A

A model of feeding relationships that represents the numbers of organisms at each trophic level in a food chain

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86
Q

Pyramid of biomass

A

A model of feeding relationships that represents the biomass of the organisms at each trophic level in a food chain

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87
Q

Pyramid of biomass

A

A model of feeding relationships that represents the biomass of the organisms at each trophic level in a food chain

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88
Q

Pyramid of energy

A

A model of feeding relationships that represents the total energy store of the organisms at each trophic level in a food chain

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89
Q

Secondary production

A

The process of making new animal biomass from plant material that has been eaten

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90
Q

Gross primary productivity (GPP)

A

In plants, the rate at which light from the Sun catalyses the production of new plant material, measured as gm -2 year-1, gCm -2 year-1or kJm-2 year -1

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91
Q

Net primary productivity (NPP)

A

The material produced by photosynthesis and stored as new plant body tissues; that is, NPP=GPP - R (where R = losses due to respiration)

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92
Q

Carbon cycle

A

A series of reactions by which carbon is constantly recycled between living things and the environment

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93
Q

Carbon sink

A

A reservoir where carbon dioxide is removed from the atmosphere and locked into organic or inorganic compounds

94
Q

Greenhouse gases

A

Gases found in the atmosphere, including carbon dioxide, methane and water vapour, which are involved in the greenhouse effect

95
Q

Greenhouse effect

A

The process by which gases in the Earth’s atmosphere absorb and re-radiate the radiation from the Sun, which has been reflected from the Earth’s surface, maintaining a temperature at the surface of the Earth that is warm enough for life to exist

96
Q

Global warming

A

A measurable increase in the temperature of the Earth’s atmosphere or temperature at the surface of the Earth

97
Q

Climate

A

The average weather in a relatively large area (such as a country) over a long period of time

98
Q

Weather

A

The conditions in the atmosphere at a particular time (for example, if it is sunny or windy or rainy when you go outside)

99
Q

Climate change

A

A large-scale change in global or regional weather patterns that happens over a period of many years

100
Q

Interglacials

A

The relatively warm periods between ice ages

101
Q

Dendrochronology

A

The dating of past events using tree ring growth

102
Q

Calibration

A

Checking the measurement values given by one system of measurement against another of known accuracy

103
Q

Anthropogenic

A

Produced by people

104
Q

Correlation

A

A strong tendency for two sets of data to vary together

105
Q

Causal relationship

A

One event happens as a direct result of another, with a clear mechanism by which one factor causes a given change

106
Q

Extrapolate

A

Apply already known trends to unknown situations to predict what will happen

107
Q

Temperature coefficient (Q10)

A

A coefficient showing the effect of temperature on the rate of a reaction

108
Q

Optimum temperature

A

The temperature at which an enzyme works most efficiently

109
Q

Denature

A

To cause permanent changes in a protein by too high a temperature

110
Q

Allopathic speciation

A

An evolutionary process that occurs when populations become physically or geographically isolated

111
Q

Sympatric speciation

A

An evolutionary process that occurs when organisms become reproductively isolated by mechanical, behavioural or seasonal changes

112
Q

Sustainability

A

The production of a decent standard of living for everyone now, without compromising the needs of future generations or the ecosystems around us

113
Q

Sustainable resources

A

Resources which can be grown and used in a sustainable way

114
Q

Biofuels

A

Fuels produced directly or indirectly from biomass

115
Q

Reforestation

A

The replanting of trees in an area where trees have been lost

116
Q

Pathogens

A

Microorganisms that cause disease

117
Q

Tobacco mosaic virus (TMV)

A

A virus that infects the leaves of tobacco plants and other closely related species, and causes a mosaic patterning which can reduce the yield

118
Q

Capsid

A

The protein coat of a virus

119
Q

Capsomeres

A

The repeating protein units that make up the capsid of a virus

120
Q

Virus attachment particles (VAPs)

A

specific proteins (antigens) that target proteins in the host cell surface membrane

121
Q

Envelope

A

A coat around the outside of a virus derived from lipids in the host cell

122
Q

DNA viruses

A

Viruses that have DNA as the genetic material

123
Q

RNA viruses

A

Viruses that have RNA as the genetic material

124
Q

Retrovirus

A

A special type of RNA virus that controls the production of DNA corresponding to the viral RNA, and inserts it into the host cell DNA

125
Q

Reverse transcriptase

A

an enzyme synthesised in the life cycle of a retrovirus which makes DNA molecules corresponding to the viral RNA genome

126
Q

Human immunodeficiency virus (HIV)

A

A retrovirus that causes AIDS

127
Q

Plasmid

A

small, circular piece of DNA that codes for a specific characteristic of the bacterial phenotype

128
Q

Vector

A

Living organisms or environmental factors which transmit pathogens from one host to another

129
Q

Provirus

A

The DNA that is inserted into the host cell during the lysogenic pathway of reproduction in viruses

130
Q

Latent

A

The state of the non-virulent virus within the host cell

131
Q

Lysogeny

A

The period when a virus is part of the reproducing host cell, but does not affect the host adversely

132
Q

Exocytosis

A

The energy-requiring process by which a vesicle fuses with the cell surface membrane so the contents are released to the outside of the cell

133
Q

Binary fission

A

Asexual reproduction in bacteria in which the bacteria split in half

134
Q

Generation time

A

The time span between bacterial divisions

135
Q

Lag phase

A

When bacteria are adapting to a new environment and are not reproducing at their maximum rate

136
Q

Log phase/ exponential phase

A

When the rate of bacterial reproduction is close to or at its theoretical maximum, repeatedly doubling in a given time period

137
Q

Stationary phase

A

When the total growth rate is zero as the number of new cells formed by binary cells is equal to the number of cells dying due to factors including competition for nutrients, lack of essential nutrients, an accumulation of toxic waste products and possibly lack of, competition for, oxygen

138
Q

Death phase/ decline phase

A

When reproduction has almost ceased and the death rate of cells is increasing so that the population number falls

139
Q

Sterile

A

A term used to describe something that is free from living microorganisms and their spores

140
Q

Nutrient medium

A

A substance used for the culture of microorganisms, which can be in liquid form (nutrient broth) or in solid form (usually nutrient Agar)

141
Q

Nutrient broth

A

A liquid nutrient for culturing microorganisms, commonly used in flasks, test tubes or bottles

142
Q

Liquid culture

A

Growing microorganisms in a nutrient broth in a flask or test tube rather than on an agar plate

143
Q

Nutrient agar

A

A jelly extracted from seaweed and used as a solid nutrient for culturing microorganisms, commonly used in Petri dishes

144
Q

Selective medium

A

A growth medium for microorganisms containing a very specific mixture of nutrients, so only a particular type of microorganisms will grow on it

145
Q

Inoculation

A

The process by which microorganisms are transferred into a culture medium under sterile conditions

146
Q

Haemocytometer

A

A thick microscope slide with a rectangular indentation and engraved (marked) grid of lines that is used to count cells

147
Q

Turbidimetry

A

A method of measuring the concentration of a substance by measuring the amount of light passing through it

148
Q

Turbid

A

A term used to describe something that is opaque because of suspended matter

149
Q

Dilution plating

A

A method used to obtain a culture plate with a countable number of bacterial colonies

150
Q

Total viable cell count

A

A measure of the number of cells that are alive in a specific volume of a culture

151
Q

Communicable

A

Diseases caused by pathogens which can be passed from one organism to another

152
Q

Bacterial flora

A

The combination of different species of microorganisms found in or on a specific region of the body

153
Q

Sebum

A

An oily substance produced by the skin which contains chemicals that inhibit the growth of microorganisms

154
Q

Lysozymes

A

Enzymes found in tears and other body secretions that are capable of destroying microbial cell walls

155
Q

Endotoxins

A

Lipopolysaccharides that are an integral part of the outer layer of the cell wall of Gram-negative bacteria and act as toxins to other cells

156
Q

Exotoxins

A

Soluble proteins produced and released into the body by bacteria as they metabolise and reproduce in the cells of their host; these proteins act as toxins in different ways

157
Q

Lipopolysaccharides

A

Chemicals made up of a combination of lipids and polysaccharides (complex carbohydrates)

158
Q

Primary infection

A

The initial stage of tuberculosis, when M. Tuberculosis has been inhaled into the lungs, invaded the cells of the lungs and multiplied slowly, often causing no obvious symptoms of disease

159
Q

Tubercule

A

A localised mass of tissue containing dead bacteria and macrophages formed as a result of a healthy immune response to an infection by M. tuberculosis

160
Q

Acquired immunodeficiency syndrome (AIDS)

A

The disease which results from the destruction of the T helper cells as a result of infection with HIV

161
Q

Human immunodeficiency virus (HIV)

A

A retrovirus that causes AIDS

162
Q

HIV positive

A

Someone who has antibodies to HIV in their blood, indicating that they have been infected with the virus and so are at risk of passing it on to other people

163
Q

Anti-retroviral drugs

A

Drugs which are effective against retroviruses such as HIV

164
Q

Antigens

A

Glycoproteins, proteins or carbohydrates on the surface of cells, toxins produced by bacterial and fungal pathogens, and some whole viruses and bacteria that are recognised by white blood cells during the specific immune responses to infection; they stimulate the production of an antibody

165
Q

leucocytes

A

white blood cells which are larger than erythrocytes and can squeeze through tiny blood vessels as they can change their shape; there are around 4000-11000 leucocytes per mm3 of blood and there are several different types which carry out different functions in the body

166
Q

granulocytes

A

leucocytes with granules that absorb stain in the cytoplasm of the cells; this makes them visible under the microscope; they have lobed nuclei and are involved in the non-specific responses to infection

167
Q

neutrophils

A

the most common type of leucocyte; they engulf and digest pathogens by phagocytosis

168
Q

eosinophils

A

leucocytes important in the non-specific immune response against parasites, in allergic reactions and inflammation, and in developing immunity to disease

169
Q

basophils

A

leucocytes with a two-lobed nucleus; they produce histamines involved in inflammation and allergic reactions

170
Q

agranulocytes

A

leucocytes with round nuclei but without granules in their cytoplasm; they are involved in the specific immune response to infection

171
Q

monocytes

A

the largest of the leucocytes, they can pass from the blood into the tissues to form macrophages

172
Q

macrophages

A

cells that engulf pathogens by phagocytosis as part of the specific immune system

173
Q

lymphocytes

A

small leucocytes with very large nuclei that are vitally important in the specific immune response of the body; they make up the main cellular components of the immune system; they are made in the white bone marrow of the long bones

174
Q

inflammation

A

a common, non-specific response to infection involving the release of histamines from mast cells and basophils; this causes the blood vessels to dilate producing local heat, redness and swelling

175
Q

mast cells

A

cells found in the connective tissue below the skin and around blood vessels; they release histamines when the tissue is damaged

176
Q

histamines

A

chemicals released by the tissues in response to an allergic reaction

177
Q

antibodies

A

glycoproteins that are each produced in response to a specific antigen

178
Q

fever

A

a raised body temperature, often in response to infection

179
Q

phagocytosis

A

the process by which a cell engulfs another cell and encloses it in a vesicle to digest it

180
Q

phagocyte

A

cell which engulfs and digests other cells or pathogens

181
Q

phagosome

A

the vesicle in which a pathogen is enclosed in a phagocyte

182
Q

cytokines

A

molecules which signal between cells; they have several roles in the immune system, including stimulating other phagocytes to move to the infection site

183
Q

interferons

A

chemicals produced by cells in very small amounts when invaded by viruses; interferons act to prevent the viruses invading other cells

184
Q

immune response

A

the specific response of the body to invasion by pathogens

185
Q

B cells

A

lymphocytes that are made and mature in the bone marrow; once they are mature, they are found in the lymph glands and free in the body

186
Q

immunoglobulins

A

antibodies

187
Q

B effector cells

A

lymphocytes that are made and mature in the bone marrow which divide to form the plasma cell clones

188
Q

plasma cells

A

cells that produce antibodies to particular antigens at a rate of around 2000 antibodies per second

189
Q

B memory cells

A

lymphocytes that are made and mature in the bone marrow and that provide the immunological memory to a specific antigen; they allow the body to respond very rapidly to the same pathogen carrying the same antigen a second time

190
Q

T cells

A

lymphocytes made in the bone marrow that mature and become active in the thymus gland

191
Q

T killer cells

A

lymphocytes that mature in the thymus gland and produce chemicals that destroy pathogens

192
Q

T helper cells

A

lymphocytes that mature in the thymus gland and are involved in the process that produces antibodies against the antigens on a particular pathogens

193
Q

opsonins

A

chemicals which bind to pathogens and label them so they are more easily recognised by phagocytes

194
Q

T memory cells

A

very long-lived cells which constitute part of the immunological memory

195
Q

major histocompatibility complex (MHC) proteins

A

proteins that display antigens on the cell surface membrane

196
Q

antigen-presenting cell (APC)

A

a cell displaying an antigen/ MHC protein complex

197
Q

clone

A

a group of genetically identical cells which are all produced from one cell

198
Q

clonal selection

A

the selection of the cells that carry the right antibody for a specific antigen

199
Q

plasma cell clones

A

clones of identical plasma cells that all produce the same antibody

200
Q

agglutination

A

the grouping together of cells caused when antibodies bind to the antigens on pathogens

201
Q

opsonisation

A

a process that makes a pathogen more easily recognised, engulfed and digested by phagocytes

202
Q

neutralisation

A

the action of antibodies in neutralising the effects of bacterial toxins on cells by binding to them

203
Q

Natural active immunity

A

When the body produces its own antibodies to an antigen encountered naturally

204
Q

Natural passive immunity

A

When antibodies made by the mother are passed to the baby via the placenta or mother’s milk

205
Q

Immunisation

A

The process of protecting people from infection by giving them passive or active artificial immunity

206
Q

Vaccination

A

The introduction of harmless forms of organisms or antigens by injection or mouth to produce artificial immunity

207
Q

Artificial passive immunity

A

When antibodies are extracted from one individual and injected into another ( e.g. one form of the tetanus vaccine)

208
Q

Artificial active immunity

A

When the body produces its own antibodies to an antigen acquired through vaccination

209
Q

Attenuated pathogens

A

Viable pathogens tat have been modified so that they do not cause disease but still cause an immune response that results in the production of antibodies and immunity

210
Q

Herd immunity

A

When a high proportion of a population is immune to a pathogen, usually through vaccination, thus lowering the risk of infection to all, including those not vaccinated

211
Q

Antibiotic

A

A drug that either destroys microorganisms or prevents them from growing and reproducing

212
Q

Selective toxicity

A

A substance that is toxic against some types of cells or organisms but not others

213
Q

Penicillin

A

The first antibiotic discovered; it is a bactericidal and affects the formation of bacterial cell walls

214
Q

Bacteriostatic

A

the inhibits the growth of bacteria

215
Q

Tetracycline

A

A bacteriostatic antibiotic that inhibits protein synthesis

216
Q

Bactericidal

A

Kills bacteria

217
Q

Antibiotic resistant

A

A microorganism that is not affected by an antibiotic (even one that may have been effective in the past)

218
Q

Methicillin-resistant Staphylococcus aureus (MRSA)

A

a strain of S.aureus that is resistant to several antibiotics, including methicillin

219
Q

Clostridium difficile

A

A type of bacterium that often exists in the intestines and causes no problems unless it becomes dominant as a result of antibiotic treatment that has removed or damaged the normal gut flora

220
Q

Hospital-acquired infections (HAIs)

A

Infections that are acquired by patients while they are in hospitals or care facilities; these infections may be the result of poor hygiene or the result of antibiotic treatment; the pathogens may be antibiotic resistant

221
Q

Nitrogen cycle

A

The recycling of nitrogen between living things and the environment by the actions of microorganisms

222
Q

Forensic science

A

The application of scientific techniques to the investigation of a crime

223
Q

Rigor mortis

A

Temporary muscle contraction causing the body to become rigid after death

224
Q

Forensic entomology

A

The study of insect life relating to crime

225
Q

Exons

A

The coding regions of DNA (the genes)

226
Q

Introns

A

The large, non-coding regions of DNA that are removed before messenger RNA is translated into proteins

227
Q

DNA sequencing/ gene sequencing

A

The analysis of the individual base sequence along a DNA strand or an individual gene

228
Q

DNA profiling

A

The identification of repeating patterns in the non-coding regions of DNA

229
Q

Polymerase chain reaction (PCR)

A

The process used to amplify a sample of DNA (to make more copies of it very rapidly)

230
Q

Amplified

A

The process by which DNA is replicated repeatedly (using the polymerase chain reaction) to produce a much bigger sample

231
Q

Micro-satellite

A

A section of DNA with a 2-6 base sequence repeated 5 to 100 times

232
Q

Mini-satellite

A

A section of DNA with a 10-100 base sequence repeated 50 to several hundred times

233
Q

Restriction endonucleases

A

Enzymes used to cut up strands of DNA at particular points in the intron sequences

234
Q

Recognition site

A

Specific base sequences where restriction endonucleases cut the DNA molecule

235
Q

Short tandem repeats

A

Micro-satellite regions that are widely used in DNA identification of suspects; statistically, the chance of two people matching on 11 or more sites is so small that it is considered to be reliable evidence in court

Biology A-Level IAL Edexcel (4 decks)

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