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Science Definitions A-Z

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Science







A | B | C | D | E | F | G | H | I | J | K | L | M
N | O | P | Q | R | S | T | U | V | W | X | Y | Z

Physics | Chemistry

Biology

A

Absorption: This is the movement of food into the bloodstream.

Alkaline pyrogallol: This is used to absorb oxygen.

Amylase: This is an enzyme. It is found in saliva. It breaks starch down into maltose.

Antagonistic muscles: A pair of skeletal muscles that work together. When one contracts the other relaxes, e.g. the biceps and triceps.

Asexual reproduction: Reproduction that does not involve gametes.

Assimilation: This is the using of the food by the cells of the body after absorption.

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B

Benedict's solution: This is used to test for a reducing sugar e.g. glucose. If a reducing sugar is present it turns brick red after being heated in a boiling water bath.

Breathing: This is a physical process of taking in oxygen and breathing back out carbon dioxide.

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C

Carnivore: An animal that only eats other animals.

Carpel: The female part of the flowering plant. It is made up of the stigma, style and ovary.

Catalyst: A chemical that speeds up or slows down chemical reactions.

Cell wall: Structure found outside the cell membrane in plant cells. Cell walls are absent in animal cells.

Chlorophyll: The green pigment found in the chloroplasts of plant cells. It is used in photosynthesis.

Competition: This is the struggle between organisms to gain a sufficient supply of a scarce resource e.g. Grasses and dandelions compete for water.

Conservation: This is the wise use of the environment:

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D

Digestion: This is the breaking down of food into small soluble pieces.

Dispersal: The dispersal of seeds is the scattering of seeds. The advantage of dispersal is that it helps reduce competition.

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E

Egestion: The getting rid of unused, undigested and unabsorbed food material

Endocrine glands: A ductless gland that releases hormones directly into the bloodstream, e.g. the pancreas (it releases insulin which controls blood sugar level).

Excretion: This is the getting rid of waste products from chemical reactions in the body.

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F

Food chain: A food chain is a feeding relationship between organisms through which energy is transferred.

Food web: A food web is a number of interconnected food chains.

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G

Gamete: A gamete is a sex cell. The male gamete is the sperm and the female gamete is the egg.

Genetics: This is the study of inheritance.

Geotropism: The growth of a plant in response to gravity.

Germination: Germination is the growth of a seed into a new plant. The requirements are warmth, moisture and oxygen.

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H

Habitat: The place where a plant or animal lives is called its habitat.

Haemoglobin: The red pigment in red blood corpuscles. It is involved in transporting oxygen.

Herbivore: An animal that eats only plants.

Hormone: A chemical substance that is released by an endocrine gland.

Humus: The organic material of soil. It is formed from decomposing plants and animals.

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I

Implantation: This is when the embryo attaches itself to the womb wall.

Ingestion: This is the taking in of food into the mouth.

Iodine solution: This is used to test for starch. If starch is present it turns blue-black.

Iris: The iris controls the amount of light entering the eye.

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J

Joint: This is where two or more bones meet.

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L

Leaching: The washing of minerals out of the soil.

Ligaments: Fibres that connect bone to bone.

Lime water: This is used to test for the presence of carbon dioxide. If carbon dioxide is present the lime water turns milky.

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M

Motor nerve: A nerve that carries messages away from the brain and spinal cord.

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N

Nutrient agar: This is used as a food supply for bacteria and fungi in the lab.

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O

Omnivore: An animal that eats plants and animals.

Organ: A group of tissues working together e.g. heart.

Ovulation: This is the release of an egg from an ovary.

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P

Phloem: This is a plant transport tissue. It transports food from where it is made to other parts of the plant.

Photosynthesis: This is the process in which green plants make food.

Phototropism: The growth of a plant in response to light.

Placenta: The structure that binds the developing baby to the wall of the womb. It allows nutrients and waste to be exchanged.

Pollination: This is the transfer of pollen from the anther of the stamen to the stigma of the carpel.

Pollution: This is where things such as oil, sewage, slurry, sulphur dioxide, nitrogen oxides and litter damage the environment.

Pooter: A piece of equipment used to collect small animals.

Producer: An organism that can make its own food.

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R

Respiration: This is a chemical process where energy is released from food.

Retina: The light sensitive layer at the back of the eye.

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S

Sensory nerve: A nerve that carries messages to the brain and spinal cord.

Soda lime: This is used to absorb carbon dioxide.

Stamen: The male part of the flowering plant. It is made up of the anther and filament.

Stomata: These are pores (openings) in the leaves of a plant, which allows gases to diffuse.

Synovial fluid: A lubricating fluid found at a joint. It helps reduce friction.

System: A group of organs working together e.g. digestive system.

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T

Tendons: Fibres that attach muscle to bone.

Tissue: A group of similar cells e.g. muscle.

Transpiration: This is the loss of water vapour from the surface of a plant. It is highest when there is a gentle breeze, sun and low humidity.

Trophic level: The position an organism occupies in a food chain.

Tropism: A growth response to a stimulus.

Tullgren funnel: A piece of equipment used to extract small animals from leaf litter or soil.

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X

Xylem: This is a plant transport tissue. It transports water and minerals from the roots to other parts of the plant.

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Z

Zygote: The cell, which results from the fusion of a male and female gamete.

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