Term
| What are some benefits of genetic modification? (5) |
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Definition
Increase animal/plant yields
Increase nutrient content of food
Increase resistance to disease/pests
Making vaccines
Producing medicines |
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Term
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Definition
| A more or less self-contained functional unit in ecology made up of all the interacting biotic and abiotic factors in a specific area |
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Term
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Definition
| A group of individuals of the same species in the same habitat. |
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Term
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Definition
| The total number of organisms of all species in a habitat. |
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Term
| What is an ecological niche? |
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Definition
| All conditions and resources required for an organism to survive, reproduce and maintain a viable population. |
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Term
| What are the three factors to consider when using quadrats? |
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Definition
Size of quadrat to use
The number of sample quadrats to record within the study area
The position of each quadrat within the study area |
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Term
| How do you carry out random sampling? |
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Definition
Two long tape measures at right angles along two sides of the study area
Obtain coords using a random number generator
Place the quadrat at the intersection of each pair of coordinates and record the species |
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Term
| What are the assumptions of Mark-Release-Recapture? |
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Definition
Proportions of marked to unmarked in second sample is the same proportion to whole population
The marked individuals distribute themselves evenly and have sufficient time to do so
No immigration or emigration out of the defined boundary
Few deaths/births
Marking method is non-toxic nor makes the animals more conspicuous and more likely to be preyed on
Mark/label does not rub off |
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Term
| What happens in glycolysis? (Basic) |
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Definition
| Splitting of 6C glucose into two 3C pyruvate molecules |
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Term
| What happens in the link reaction? (Basic) |
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Definition
| Conversion of 3C pyruvate into carbon dioxide and 2C molecule called acetylcoenzyme A |
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Term
| What happens in the Krebs cycle? (Basic) |
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Definition
| The introduction of acetyl CoA into a cycle of oxidation-reduction reactions that yield some ATP and a large number of electrons |
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Term
| What are the four main stages of glycolysis? |
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Definition
Activation of glucose by phosphorylation
Splitting of phosphorylated glucose (into TP)
Oxidation of TP
Production of ATP
--> Formation of Pyruvate |
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Term
| What is the product of glycolysis? |
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Definition
Net gain of two ATP molecules
Two molecules of NADH
TWO molecules of Pyruvate |
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Term
| Where are the enzymes for glycolysis found? |
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Definition
| In the CYTOPLASM of cells - does NOT require any organelle or membrane - no oxygen required |
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Term
| Where does the link reaction/Krebs cycle take place in eukaryotic cells? |
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Definition
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Term
| The pyruvate molecules produced in the cytoplasm during __________ are actively transported into the ______ of the ____________ |
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Definition
| glycolysis, matrix, mitochondria |
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Term
| What happens to pyruvate in its conversion to acetyl CoA? |
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Definition
It is oxidised by removing hydrogen (which is accepted by NAD)
Carbon dioxide is lost
The 2C compound (acetyl group) combines with CoA to form Acetyl CoA |
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Term
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Definition
| It works with dehydrogenase enzymes that catalyse the removal of hydrogen ions from substrates and transfer them to other molecules such as the hydrogen carriers involved in oxidative phosphorylation |
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Term
| What's special about the mitochondria of cells that have a high metabolic rate? |
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Definition
| They are more densely packed with cristae |
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Term
| What is the importance of oxygen in respiration? |
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Definition
| To act as the final acceptor of hydrogen atoms. Without its role in removing H atoms at the end of the chain, the protons would 'back up' and respiration would come to a halt. Cyanide is a non-competitive inhibitor of the final enzyme in the ETC |
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Term
| What do organisms need energy for? |
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Definition
| Metabolism, movement, AT, maintenance, repair and division, production of e.g. enzymes and hormones, maintenance of body temperature (WBA) |
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Term
| What are the three ways of synthesising ATP? |
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Definition
Photophosphorylation
oxidative phosphorylation
substrate-level phosphorylation |
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Term
| When and where does photophosphorylaton take place? |
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Definition
| In chlorophyll-containing plant cells during photosynthesis |
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Term
| When and where does oxidative phosphorylation take place? |
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Definition
| In the mitochondria of plant and animal cells during the process of ELECTRON TRANSPORT |
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Term
| Why is ATP better as an immediate energy source than glucose? |
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Definition
Each ATP molecule releases less energy than each glucose molecule (less wastage)
Hydrolysis of ATP to ADP is a single step process - immediate and rapid |
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Term
| What is the effect of the predator-prey relationship on population size? |
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Definition
Predators eat prey --> ↓prey
With fewer prey, predators are in greater competition with each other for prey that are left
↓ predator population as some are unable to obtain enough prey for survival
↓ predators = ↑prey
With more prey, the predator population increases --> cycle |
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Term
| Why are periodic population crashes important? |
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Definition
| They create SELECTION PRESSURES - where only the most fit survive and so adaptation occurs |
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Term
| What factors affect birth rates? |
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Definition
| Economic conditions, cultural and religious backgrounds, social pressures and conditions, birth control, political factors |
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Term
| What is demographic transition? |
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Definition
| Changes in population growth rates over time due to changes in birth and death rates. |
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Term
| What does demographic transition lead to? |
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Definition
| Levelling off of the population and the re-establishment of the typical sigmoid population growth curve |
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Term
| The rate at which plants assimilate (produce) chemical energy is called... |
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Definition
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Term
| What are the two main factors which affect net productivity? |
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Definition
The efficiency of the crop at carrying out photosynthesis. (Improved if all conditions are supplied for PS)
The area of ground covered by the leaves of the crop |
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Term
| How is an agricultural ecosystem prevented from reaching its climax community? |
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Definition
| Most of the species in the community are excluded |
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Term
| In order to suppress unwanted species from an agricultural ecosystem, additional energy is required. What is this energy used for and where does it come from? |
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Definition
Plough fields, sow crops, remove weeds, suppress pests and diseases etc.
The energy comes from food and fossil fuels (from machinery. Energy from fossil fuels requires in an AE is IN ADDITION to solar energy, not instead) |
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Term
| Why is most of the Sun's energy not converted into organic matter? |
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Definition
Over 90% of the SUn's energy is reflected back into space by clouds and dust or absorbed by the atmosphere
Not all wavelengths of light can be absorbed and used for photosynthesis
Light may not fall on a chlorophyll molecule
A factor, such as low carbon dioxide levels, may limit the rate of photosynthesis |
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Term
| Why is there a low percentage of energy transfer in each stage? |
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Definition
Some of the organism is not eaten
Some parts are eaten but cannot be digested and are therefore lost in faeces
Some of the energy is lose in excretory materials, such as urine
Some energy losses occur as heat from repiration and directly from the body to the environment (high in mammals due to being warm blooded) |
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Term
| What happens to lactate after it is produced in Anaerobic respiration. |
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Definition
| Either reoxidised to pyruvate or taken to the liver and converted to glycogen |
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Term
| Where does oxidative level phosphorylation take place? What is it exactly? |
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Definition
| In the ETC. This is the indirect linking of an inorganic phosphate to ADP to produce ATP using hydrogen atoms from glycolysis and the Krebs cycle that are carried on NAD and FAD, cells produce most of their ATP in this way |
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Term
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Definition
| When both allele contribute to the phenotype |
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Term
| Co-dominance can result in a.... |
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Definition
| blend of both features (pink flowers) or expression of both (A and B antigens in AB blood type) |
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Term
| What are features of pioneer species? |
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Definition
Produce wind-dispersed seeds. Why? So they can easily reach isolated situations
Rapid germination
Ability to photosynthesise - no dependency on other species
Ability to FIX NITROGEN
Tolerance to extreme conditions |
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Term
| What are the common features that emerge due to succession? (5) |
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Definition
The non-living environment becomes less hostile
A greater number and variety of habitats
A greater number and variety of habitats
Increased biodiversity
More complex foodwebs --> Increased biomass (esp. during mid-succession) |
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Term
| What is nitrogen used for in living organisms? |
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Definition
| To manufacture proteins and nucleic acids |
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Term
| What is the process of ammonification? |
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Definition
Ammonification --> Production of ammonia from organic ammonium-containing compounds (e.g. urea, proteins, nucleic acids and vitamins (found in faeces))
Saprobiotic microorganisms feed on these materials and release ammonia which then forms ammonium ions in the soil. |
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Term
| What are the two stages of nitrification? |
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Definition
Oxidation of ammonium ions to nitrite ions
Oxidation of nitrite ions to nitrate ions |
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Term
| What will climate change affect? |
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Definition
| The niches that are available in a community. As each organism is adapted to a particular niche, the distribution of species will alter. |
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Term
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Definition
| An organism that competes with humans for food or space, or it could be a danger to health |
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Term
| What makes a good pesticide? |
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Definition
Specific
Biodegradable (but chemically stable for long shelf-life),
Cost-effective
Does not build up in the food chain |
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Term
| What are the advantages to biological control? |
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Definition
Very specific, once introduced, the control organism reproduces itself
Pests do not become resistant |
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Term
| What are the disadvantages to chemical pesticides? |
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Definition
Always have some effect on non-target species
Must be reapplied at intervals, making them very expensive
Pests develop genetic resistance, and new pesticides have to be developed |
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Term
| What are the disadvantages to biological control? |
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Definition
They do not act as quickly
The control organism may itself become a pest
Will not completely get rid of pest, only reduce them. |
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Term
| What does integrated pest-control involve? |
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Definition
Choosing animal or plant varieties that suit the local area and are as pest-resistant as possible
Regularly monitoring the crop for signs of pests so that early action can be taken
Removing pests mechanically (vacuuming!)
Using biological agents if necessary
Using pesticides as a last resort if pest is out of control |
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Term
| What is the purpose of intensive rearing of domestic livestock? |
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Definition
| To produce the maximum yield of meat, eggs and milk at the lowest possible cost. |
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Term
| How does intensive rearing increase the energy-conversion rate? |
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Definition
Movement is restricted and so less energy is used in muscle contraction
The environment can be kept warm (think)
Feeding can be controlled - no waste
Predators excluded |
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Term
| What are the main features of intensive rearing? |
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Definition
| Efficient energy conversion, low cost, quality of food (lowered), use of space, safety, disease, use of drugs, animal welfare, pollution (lots of waste in small area), reduced genetic diversity, use of fossil fuels |
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Term
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Definition
| The evolution of a new species from existing species. |
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Term
What is geographical isolation?
Example? |
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Definition
When a physical barrier prevents two populations from breeding with one another
Oceans, rivers, mountain ranges, deserts |
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Term
| What is the principle of selection? |
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Definition
More offspring produced than environment can support.
Constant population
Competition
Some individuals have advantageous alleles.
Over time, the frequency of advantageous alleles increases , and non advantageous ones decrease |
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Term
| What are the 3 types of selection? |
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Definition
Directional
Disrupted
Stablising |
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Term
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Definition
| All the alleles of all the genes of all the individuals in a population at any one time. |
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Term
| What are the two equations of Hardy-Weinberg? |
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Definition
p + q = 1
p² + 2pq + q² = 1 |
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