Biology

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Define the term Tropic level
The level at which an organism feeds in a food chain
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Define the term Target Cell
Cells that have receptors embedded in the plasma membrane that are complementary in shape to specific hormone molecules. Only these cells will resond to the hormone
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Define the term recombinant DNA
A secetion of DNA often in the form of a plasmid which is formed by joining DNA sections from two different sources
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Define the term Negative feedback
A process in which any change in a paremeter brings about the reversal of that change so the parameter is kept fairly constant
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Define the term Photosynthetic pigment
Chemicals that absorb light energy, Found in thylakoid membranes in photosystems. Each pigment absorbs energy associated with light of a specific wavelength eg chlorophyll a
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What is the ornithine cycle
A process that occurs inside liver cells to convert ammonia to urea
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Define the term endocrine gland
A gland that secretes hormones directly into the blood. Endocrine glands have no ducts eg. Piturity gland, thyroid gland, adrenal glands, testes, ovaries
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Define the term exocrine gland
Gland that secretes molecules into a duct which then carries the molecules to where they are used eg, salivary gland
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What is a local current
Movements of ions along the neurone. The flow of ions is caused by an increase in concentration at one point which causes diffusion away from the region of higher concentration
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What is Vegetative propagation
Production of structures in an organism that can grow into new individual organisms, These offspring contain the same genetic information as the parent so are clones of the parent
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What is xenotransplantation
Transplantation of cell tissues or organs between animals or different species
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Define the term Positive Feedback
A preocess in which any change in a parameter brings about an increase in that change
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Define the term homeostasis
The maintenance of a constant internal environment despite external changes
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Define the term hormone
A molecule released into the blood that acts as a chemical messenger
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Define the term excretion
The removal metabolic waste from the body
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Define the term Ecosystem
All the living organisms and all the non living components in a specific habitat and their interactions
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Define the term decomposer
Organisms that feed on dead organic matter releasing molecules minerals and energy that then become available to other living organisms in that ecosystem
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Define the term producer
Autotrophic organism plants/bacteria that convert light energy to chemical energy which they then supply to consumers
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What is a primer (DNA)
Short stranded sequences of DNA around 10 base pairs. Needed in sequencing reactions and PCR. to bind to a section of DNA.
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What is the posterior pituitary gland
The hind part of the pituitary gland which releases ADH
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What is polyploid
Eukaryotic organisms or cell with more than two sets of chromosomes
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Define the term Tropism
A directional growth response in which the direction of the response is determined by the direction of the external stimulus eg. chemotropsm, phototropism, thigmotropim. geotropism
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What is the function of the medulla obongata
Controls non skeletal muscles ie cardiac and involuntary muscles. Processes such as the cardiac centre and respiratory centre are found here
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What is nitrification
Happens in chemoautotrophic bacteria in the soil that absorb ammonium ions. eg. nitrobacter convert nitrites to nitrates and nitrosomonas convert ammonium ions to nitrites
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What is denitrification
Converts nitrates back to nitrogen gas.
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Define succession
A directional change in a community of organisms over time
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Define the term respiratory substrate
Organic substance that can be used for respiration
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What is epistasis
Interaction of different gene loci so that one gene masks/ suppresses the expression of another gene locus
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Define the term abiotic and biotic factor?
Abiotic factors describe the effects of non-living components eg, pH, temperature and soil types. Biotic - include food supply predation and disease
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What are neurosecretory cells
Specialised cells that act like nerve cells but release a hormone into the blood. ADH is manufactured in the cell body and passes down the axon to be stored in the terminal bulb.
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Other cards in this set

Card 2

Front

Define the term Target Cell

Back

Cells that have receptors embedded in the plasma membrane that are complementary in shape to specific hormone molecules. Only these cells will resond to the hormone

Card 3

Front

Define the term recombinant DNA

Back

Preview of the front of card 3

Card 4

Front

Define the term Negative feedback

Back

Preview of the front of card 4

Card 5

Front

Define the term Photosynthetic pigment

Back

Preview of the front of card 5
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