Bio

Front 1

Negative Feedback

Back 1

a process in which any change in a parameter brings about the reversal of that change so the parameter is kept fairly constant

Front 2

Positive Feedback

Back 2

a process in which any change detected by the receptors in a parameter brings about an increase in that change

Front 3

Homeostasis

Back 3

the maintenance of a constant internal environment despite external changes

Front 4

Endocrine gland

Back 4

a gland that secretes hormones directly into the blood. Have no ducts

Front 5

Exocrine gland

Back 5

secretes molecules into a duct that carries the molecules to where they are used

Front 6

Hormone

Back 6

a molecule released into the blood that acts as a chemical messenger

Front 7

Target Cells

Back 7

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

Front 8

First messenger

Back 8

a hormone that acts as a message in the bloodstream, e.g. adrenaline

Front 9

Second messenger

Back 9

a chemical inside the cell released in response to a hormone binding to the cell surface membrane, e.g. cAMP

Front 10

Excretion

Back 10

the removal of metabolic waste from the body

Front 11

Autotroph

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organism that makes its own food using simple inorganic molecules, such as CO2 and water, and enery.

Photoautotrophs use light as a source of energy.

Chemoautotrophs use chemical energy.

Front 12

Heterotroph

Back 12

organism that gains its nutients from complex organic molecules. It digests them into simpler, soluble molecules and then respires some of them to obtain energy, or uses the products of digestion to synthesise the organic molecules it needs

Front 13

Photosynthetic pigments

Back 13

chemicals that absorb light energy. Found in thylakoid membranes in photosystems. Each pigment absorbs energy associated with light of a specific wavelength, e.g. chlorophyll a