Biology definitions

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Negative feedback
A process in which any change in a parameter brings about the reversal of that change so the parameter is kept fairly constant
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Positive feedback
A process in which any change in a parameter brings about an increase in that change
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Homeostasis
The maintenance of a constant internal environment despite external changes
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Endocrine gland
A gland that secretes hormones directly into blood capillaries
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Exocrine gland
A gland that secretes substances into a duct
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Hormone
A molecule released into the blood that acts as a chemical messenger
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Endotherms
Organisms that can control production and loss of heat to maintain their body temperature
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Ectotherms
Organisms that rely on external sources of heat and behavioural activities to regulate their body temperature
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Target tissue
Cells of an organ that are affected or stimulated by specific hormones.
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First messenger
A hormone that acts as a message in the bloodstream
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Second messenger
A cheical inside the cell released in response to a hormone binding to the cell surface membrane
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Excretion
The removal of metaolic waste from the body
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Autotrophs
Organisms that use light energy or chemical and inorganic molecules to synthesize complex organic molecules
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Heterotrophs
Organisms that ingest and digest complex organic molecules,releasing the chemical potential energy stored in them
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Photosynthesis
The process in green plants by which carbohydrates are synthesized from carbon dioxide and water using light as an energy source.
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Photosynthetic pigment
Chemical that absorbs light energy.Found in thykaloid membranes,in photosystems
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respiratory substrate
Organic substance that can be used for respiration
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Card 2

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A process in which any change in a parameter brings about an increase in that change

Back

Positive feedback

Card 3

Front

The maintenance of a constant internal environment despite external changes

Back

Preview of the back of card 3

Card 4

Front

A gland that secretes hormones directly into blood capillaries

Back

Preview of the back of card 4

Card 5

Front

A gland that secretes substances into a duct

Back

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