Definitions Unit 4 Flashcards
(237 cards)
1
Q
Autotrophic
A
Organisms that make complex organic compounds from simple compounds in the environment
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
3
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Heterotrophic
A
Organisms that obtain complex organic molecules by feeding on other living organisms or their dead remains
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
5
Q
ATPase
A
The enzyme which catalyses the formation and breakdown of ATP, depending on the conditions
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
7
Q
Reduction/oxidation reactions (redox reactions)
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Reactions in which one reactant loses electrons (is oxidised) and another gains electrons (is reduced)
8
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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
9
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Chloroplast envelope
A
The outer and inner membranes of a chloroplast including the intermembrane space
10
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Grana
A
Layers of thylakoid membranes within a chloroplast
11
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Thylakoids
A
Membrane discs found in the grana of a chloroplast
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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
13
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Stroma
A
The matrix which surrounds the grana and contains all the enzymes needed to complete the process of photosynthesis and produce glucose
14
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Chlorophyll α
A
A blue-green photosynthetic pigment, found in all green plants
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Chlorophyll β
A
A yellow-green photosynthetic pigment
16
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Carotenoids
A
Photosynthetic pigments consisting of orange carotene and yellow xanthophyll
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Phaeophytin
A
A grey pigment which is produced by the breakdown of the other photosynthetic pigments
18
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Absorption spectrum
A
A graph showing the amount of light absorbed by a pigment against the wavelength of the light
19
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action spectrum
A
A graph demonstrating the rate of photosynthesis against the wavelength of light
20
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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
21
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Photosystem l (PSI)
A
A combination of chlorophyll pigments which absorbs light of wavelength 700nm and is involved in cyclic and non-cyclic photophosphorylation
22
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Photosystem ll (PSII)
A
A combination of chlorophyll pigments which absorbs light of wavelength 680nm and is involved only in non-cyclic photophosphorylation
23
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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
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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Photochemical reaction
A reaction initiated by light
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Cyclic photophosphorylation
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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Non-cyclic photophosphorylation
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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Photolysis
The breaking down of a molecule into smaller units using light
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Calvin cycle
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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Ribulose bisphosphate (RuBP)
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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Ribulose bisphosphate carboxylase/oxygenase (RUBISCO)
A rate-controlling enzyme that catalyses the reaction between carbon dioxide/oxygen and ribulose bisphosphate
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Glycerate 3-phosphate (GP)
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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Glyceraldehyde 3-phosphate (GALP)
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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Photorespiration
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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Gluconeogenesis
The synthesis of glucose from non-carbohydrates
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Limiting factor
The faster needed for a reaction to progress that is closest to its minimum value
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Abundance
The relative representation of a species in a particular ecosystem
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Ecosystem
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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Habitat
The place where an organism lives
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Microhabitat
A small area of a habitat
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Population
A group of organisms of the same species, living and breeding together in a habitat
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Population
A group of organisms of the same species, living and breeding together in a habitat
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Community
All the populations of all the different species of organisms living in a habitat at any one time
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Niche
The role of an organism within the habitat in which it lives
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Predator
An organism which hunts and eats other organisms
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Predator
An organism which hunts and eats other organisms
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Abiotic factors
The non-living elements of the habitat of an organism
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Biotic factors
The living elements of a habitat that affect the ability of a group of organisms to survive there
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Prey
An organism which is hunted and eaten by other organisms
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Prey
An organism which is hunted and eaten by other organisms
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Biosphere
All of the areas of the surface of the Earth where living organisms survive
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Biomes
The major ecosystems of the world
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Succession
The process by which the communities of organisms colonising an area change over time
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Succession
The process by which the communities of organisms colonising an area change over time
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Colonisation
The process by which new species spread to new areas
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Opportunists/pioneer species
Species which are the first to colonise new or disturbed ecosystems
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Climax community
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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Climatic climax community
The only climax community possible in a given climate
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Plagioclimax
A climax community that is at least in part the result of human intervention
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Microclimate
A small area with a distinct climate that is different from the surrounding area
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Edaphic factors
Factors that relate to the structure of the soil
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Leaching
The loss of minerals from soil as water passes through rapidly
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Density-independent factors
Factors affecting the number of organisms occupying a niche which are the same regardless of population size
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Density-dependent factors
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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Intraspecific competition
Competition between members of the same species for a limited resource
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Interspecific competition
Competition between different species within a community for the same resources
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Abundance
The relative representation of a species in a particular ecosystem
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Distribution
Where a species of organism is found in the environment and how it is organised
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Quadrat
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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Individual counts
A measure of the number of individual organisms in an area
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Percentage cover
The area covered by the above-ground parts of a particular species
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ACFOR scale
A simple scale used to describe the abundance of a species in a given area
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Line transect
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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belt transect
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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Spearman’s rank correlation coefficient
A statistical tool used to test whether two variables are significantly correlated
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Student’s t-test
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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Chi squared test
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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Null hypothesis
The hypothesis that any differences between data sets are the result of chance
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Significant
Not due to chance
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Food chain
A simple way of modelling the feeding relationships between a series of organisms in an ecosystem
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Trophic level
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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Producers
Organisms that make food by photosynthesis or chemosynthesis
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Primary consumers
Organisms that eat producers, either plants or algae
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Secondary consumers
Animals that feed on primary consumers
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Tertiary consumers
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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Decomposers
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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Pyramid of numbers
A model of feeding relationships that represents the numbers of organisms at each trophic level in a food chain
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Pyramid of biomass
A model of feeding relationships that represents the biomass of the organisms at each trophic level in a food chain
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Pyramid of biomass
A model of feeding relationships that represents the biomass of the organisms at each trophic level in a food chain
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Pyramid of energy
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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Secondary production
The process of making new animal biomass from plant material that has been eaten
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Gross primary productivity (GPP)
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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Net primary productivity (NPP)
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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Carbon cycle
A series of reactions by which carbon is constantly recycled between living things and the environment
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Carbon sink
A reservoir where carbon dioxide is removed from the atmosphere and locked into organic or inorganic compounds
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Greenhouse gases
Gases found in the atmosphere, including carbon dioxide, methane and water vapour, which are involved in the greenhouse effect
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Greenhouse effect
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
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Global warming
A measurable increase in the temperature of the Earth’s atmosphere or temperature at the surface of the Earth
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Climate
The average weather in a relatively large area (such as a country) over a long period of time
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Weather
The conditions in the atmosphere at a particular time (for example, if it is sunny or windy or rainy when you go outside)
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Climate change
A large-scale change in global or regional weather patterns that happens over a period of many years
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Interglacials
The relatively warm periods between ice ages
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Dendrochronology
The dating of past events using tree ring growth
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Calibration
Checking the measurement values given by one system of measurement against another of known accuracy
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Anthropogenic
Produced by people
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Correlation
A strong tendency for two sets of data to vary together
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Causal relationship
One event happens as a direct result of another, with a clear mechanism by which one factor causes a given change
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Extrapolate
Apply already known trends to unknown situations to predict what will happen
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Temperature coefficient (Q10)
A coefficient showing the effect of temperature on the rate of a reaction
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Optimum temperature
The temperature at which an enzyme works most efficiently
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Denature
To cause permanent changes in a protein by too high a temperature
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Allopathic speciation
An evolutionary process that occurs when populations become physically or geographically isolated
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Sympatric speciation
An evolutionary process that occurs when organisms become reproductively isolated by mechanical, behavioural or seasonal changes
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Sustainability
The production of a decent standard of living for everyone now, without compromising the needs of future generations or the ecosystems around us
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Sustainable resources
Resources which can be grown and used in a sustainable way
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Biofuels
Fuels produced directly or indirectly from biomass
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Reforestation
The replanting of trees in an area where trees have been lost
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Pathogens
Microorganisms that cause disease
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Tobacco mosaic virus (TMV)
A virus that infects the leaves of tobacco plants and other closely related species, and causes a mosaic patterning which can reduce the yield
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Capsid
The protein coat of a virus
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Capsomeres
The repeating protein units that make up the capsid of a virus
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Virus attachment particles (VAPs)
specific proteins (antigens) that target proteins in the host cell surface membrane
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Envelope
A coat around the outside of a virus derived from lipids in the host cell
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DNA viruses
Viruses that have DNA as the genetic material
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RNA viruses
Viruses that have RNA as the genetic material
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Retrovirus
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
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Reverse transcriptase
an enzyme synthesised in the life cycle of a retrovirus which makes DNA molecules corresponding to the viral RNA genome
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Human immunodeficiency virus (HIV)
A retrovirus that causes AIDS
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Plasmid
small, circular piece of DNA that codes for a specific characteristic of the bacterial phenotype
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Vector
Living organisms or environmental factors which transmit pathogens from one host to another
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Provirus
The DNA that is inserted into the host cell during the lysogenic pathway of reproduction in viruses
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Latent
The state of the non-virulent virus within the host cell
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Lysogeny
The period when a virus is part of the reproducing host cell, but does not affect the host adversely
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Exocytosis
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
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Binary fission
Asexual reproduction in bacteria in which the bacteria split in half
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Generation time
The time span between bacterial divisions
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Lag phase
When bacteria are adapting to a new environment and are not reproducing at their maximum rate
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Log phase/ exponential phase
When the rate of bacterial reproduction is close to or at its theoretical maximum, repeatedly doubling in a given time period
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Stationary phase
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
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Death phase/ decline phase
When reproduction has almost ceased and the death rate of cells is increasing so that the population number falls
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Sterile
A term used to describe something that is free from living microorganisms and their spores
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Nutrient medium
A substance used for the culture of microorganisms, which can be in liquid form (nutrient broth) or in solid form (usually nutrient Agar)
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Nutrient broth
A liquid nutrient for culturing microorganisms, commonly used in flasks, test tubes or bottles
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Liquid culture
Growing microorganisms in a nutrient broth in a flask or test tube rather than on an agar plate
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Nutrient agar
A jelly extracted from seaweed and used as a solid nutrient for culturing microorganisms, commonly used in Petri dishes
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Selective medium
A growth medium for microorganisms containing a very specific mixture of nutrients, so only a particular type of microorganisms will grow on it
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Inoculation
The process by which microorganisms are transferred into a culture medium under sterile conditions
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Haemocytometer
A thick microscope slide with a rectangular indentation and engraved (marked) grid of lines that is used to count cells
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Turbidimetry
A method of measuring the concentration of a substance by measuring the amount of light passing through it
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Turbid
A term used to describe something that is opaque because of suspended matter
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Dilution plating
A method used to obtain a culture plate with a countable number of bacterial colonies
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Total viable cell count
A measure of the number of cells that are alive in a specific volume of a culture
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Communicable
Diseases caused by pathogens which can be passed from one organism to another
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Bacterial flora
The combination of different species of microorganisms found in or on a specific region of the body
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Sebum
An oily substance produced by the skin which contains chemicals that inhibit the growth of microorganisms
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Lysozymes
Enzymes found in tears and other body secretions that are capable of destroying microbial cell walls
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Endotoxins
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
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Exotoxins
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
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Lipopolysaccharides
Chemicals made up of a combination of lipids and polysaccharides (complex carbohydrates)
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Primary infection
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
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Tubercule
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
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Acquired immunodeficiency syndrome (AIDS)
The disease which results from the destruction of the T helper cells as a result of infection with HIV
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Human immunodeficiency virus (HIV)
A retrovirus that causes AIDS
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HIV positive
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
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Anti-retroviral drugs
Drugs which are effective against retroviruses such as HIV
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Antigens
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
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leucocytes
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
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granulocytes
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
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neutrophils
the most common type of leucocyte; they engulf and digest pathogens by phagocytosis
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eosinophils
leucocytes important in the non-specific immune response against parasites, in allergic reactions and inflammation, and in developing immunity to disease
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basophils
leucocytes with a two-lobed nucleus; they produce histamines involved in inflammation and allergic reactions
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agranulocytes
leucocytes with round nuclei but without granules in their cytoplasm; they are involved in the specific immune response to infection
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monocytes
the largest of the leucocytes, they can pass from the blood into the tissues to form macrophages
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macrophages
cells that engulf pathogens by phagocytosis as part of the specific immune system
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lymphocytes
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
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inflammation
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
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mast cells
cells found in the connective tissue below the skin and around blood vessels; they release histamines when the tissue is damaged
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histamines
chemicals released by the tissues in response to an allergic reaction
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antibodies
glycoproteins that are each produced in response to a specific antigen
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fever
a raised body temperature, often in response to infection
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phagocytosis
the process by which a cell engulfs another cell and encloses it in a vesicle to digest it
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phagocyte
cell which engulfs and digests other cells or pathogens
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phagosome
the vesicle in which a pathogen is enclosed in a phagocyte
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cytokines
molecules which signal between cells; they have several roles in the immune system, including stimulating other phagocytes to move to the infection site
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interferons
chemicals produced by cells in very small amounts when invaded by viruses; interferons act to prevent the viruses invading other cells
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immune response
the specific response of the body to invasion by pathogens
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B cells
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
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immunoglobulins
antibodies
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B effector cells
lymphocytes that are made and mature in the bone marrow which divide to form the plasma cell clones
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plasma cells
cells that produce antibodies to particular antigens at a rate of around 2000 antibodies per second
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B memory cells
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
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T cells
lymphocytes made in the bone marrow that mature and become active in the thymus gland
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T killer cells
lymphocytes that mature in the thymus gland and produce chemicals that destroy pathogens
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T helper cells
lymphocytes that mature in the thymus gland and are involved in the process that produces antibodies against the antigens on a particular pathogens
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opsonins
chemicals which bind to pathogens and label them so they are more easily recognised by phagocytes
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T memory cells
very long-lived cells which constitute part of the immunological memory
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major histocompatibility complex (MHC) proteins
proteins that display antigens on the cell surface membrane
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antigen-presenting cell (APC)
a cell displaying an antigen/ MHC protein complex
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clone
a group of genetically identical cells which are all produced from one cell
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clonal selection
the selection of the cells that carry the right antibody for a specific antigen
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plasma cell clones
clones of identical plasma cells that all produce the same antibody
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agglutination
the grouping together of cells caused when antibodies bind to the antigens on pathogens
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opsonisation
a process that makes a pathogen more easily recognised, engulfed and digested by phagocytes
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neutralisation
the action of antibodies in neutralising the effects of bacterial toxins on cells by binding to them
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Natural active immunity
When the body produces its own antibodies to an antigen encountered naturally
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Natural passive immunity
When antibodies made by the mother are passed to the baby via the placenta or mother’s milk
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Immunisation
The process of protecting people from infection by giving them passive or active artificial immunity
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Vaccination
The introduction of harmless forms of organisms or antigens by injection or mouth to produce artificial immunity
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Artificial passive immunity
When antibodies are extracted from one individual and injected into another ( e.g. one form of the tetanus vaccine)
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Artificial active immunity
When the body produces its own antibodies to an antigen acquired through vaccination
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Attenuated pathogens
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
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Herd immunity
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
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Antibiotic
A drug that either destroys microorganisms or prevents them from growing and reproducing
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Selective toxicity
A substance that is toxic against some types of cells or organisms but not others
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Penicillin
The first antibiotic discovered; it is a bactericidal and affects the formation of bacterial cell walls
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Bacteriostatic
the inhibits the growth of bacteria
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Tetracycline
A bacteriostatic antibiotic that inhibits protein synthesis
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Bactericidal
Kills bacteria
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Antibiotic resistant
A microorganism that is not affected by an antibiotic (even one that may have been effective in the past)
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Methicillin-resistant Staphylococcus aureus (MRSA)
a strain of S.aureus that is resistant to several antibiotics, including methicillin
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Clostridium difficile
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
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Hospital-acquired infections (HAIs)
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
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Nitrogen cycle
The recycling of nitrogen between living things and the environment by the actions of microorganisms
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Forensic science
The application of scientific techniques to the investigation of a crime
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Rigor mortis
Temporary muscle contraction causing the body to become rigid after death
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Forensic entomology
The study of insect life relating to crime
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Exons
The coding regions of DNA (the genes)
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Introns
The large, non-coding regions of DNA that are removed before messenger RNA is translated into proteins
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DNA sequencing/ gene sequencing
The analysis of the individual base sequence along a DNA strand or an individual gene
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DNA profiling
The identification of repeating patterns in the non-coding regions of DNA
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Polymerase chain reaction (PCR)
The process used to amplify a sample of DNA (to make more copies of it very rapidly)
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Amplified
The process by which DNA is replicated repeatedly (using the polymerase chain reaction) to produce a much bigger sample
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Micro-satellite
A section of DNA with a 2-6 base sequence repeated 5 to 100 times
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Mini-satellite
A section of DNA with a 10-100 base sequence repeated 50 to several hundred times
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Restriction endonucleases
Enzymes used to cut up strands of DNA at particular points in the intron sequences
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Recognition site
Specific base sequences where restriction endonucleases cut the DNA molecule
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Short tandem repeats
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
