Science S1 word lists

word lists

atomic number

An integer that identifies an element uniquely, equal to the number of protons in nucleus

Mass number

The sum of neutrons and protons in atoms nucleus

Element

A substance that cannot be broken down into simpler substances by chemical means

Molecule

Particle consisting of two or more atoms chemically bonded

Compound

A substance consisting of two or more different elements chemically combined in a fixed ratio

Proton

Particle in nucleus of an atom, positive charge

Neutron

Particle in the nucleus with neutral charge

Electron

Negatively charged particle that orbits the nucleus of an atom

Nucleus

Small, dense centre of an atom consisting of protons and neutrons

group

vertical column of the periodic table where each element has similar chemical properties

period

a horizontal row of periodic table

Alkali Metal

Elements in group I

Alkaline earth metal

Elements in group II

Halogen

Elements in group VII

Noble/inert gases

Elements in group VIII, not chemically reactive as they have a full outer shell

Ion

A charged particle formed by loss or gain of electrons

Polyatomic Ion

Charged particle consisting of many atoms

Valency

Measure of combining power of a particle with other atoms when it forms chemical compounds or molecules

Electron Configuration

Shorthand form describing the ordered arrangement of a particle’s electrons into defined energy levels (shells)

Covalent Bond

Chemical bond that involves the sharing of electron pairs between atoms

Ionic bond

Chemical bond that involves the electrostatic attraction between oppositely charged ions

Isotope

Atoms with the same number of protons in the nucleus, but different amount of neutrons

Transition Metal

Group of metals between group III and IV of the periodic table

Reactants

Substance that takes part in and undergoes a chemical change during a reactionpr

products

The substance(s) that form as a result of a chemical reaction

combustion

chemical reaction where a fuel combines with oxygen quickly releasing large amounts of energy and forming an oxide of the fuel

Corrosion

slow chemical reaction where a fuel combines with oxygen to form a more stable metal oxide

precipitation

chemical reaction where two or more dissolved ionic compounds react to form a solid ionic compound

Neutralisation

Chemical reaction where an acid reacts with a base to form neutral products

Insoluble

Unable to dissolve in a named solvent

Soluble

Able to dissolve in a named solvent

Central nervous system (CNS)

a part of the nervous system consisting of brain and spinal cord

Peripheral nervous system (PNS)

connects CNS to sensory organs, other organs, muscles, blood vessels and glands.

cerebrum

largest part of the brain, responsible for conscious functions

cerebellum

smaller part of brain, located at the rear, regulates movement, coordination, balance

hypothalamus

functions as main control centre, regulates sleep cycles, body temperature, appetite, blood pressure, thirst

brain stem

connects cerebellum and spinal cord

Stimulus

change in environment that may be detected by an organism

receptor

cell or group of cells that detects stimuli

effector

organ becomes responsive in response to nerve impulses

neuron (or neurones)

cells conduct impulses, make up nerves, CNS. types: (motor, sensory, interneurons)

Motor neurons

sends impulses to effector organs

sensory neurons

carries messages from sensory organs to CNS

Interneurons

connects dendrites of sensory to dendrites of motor neurons

dendrite

part of neuron that receives nerve impulses

Myelin

fatty sheath that protects and covers neurons

synapse

small gap separating neurons

homeostasis

process which organisms maintain a stable internal environment

endocrine system

body system, consists of endocrine glands, secreting hormones into blood stream

hormone

chemical secreted by glands which affects metabolism or behaviour of target cells

Pituitary

small endocrine gland at base of brain, secretes hormones, regulates growth & metabolism (also called master gland)

Thyroid

small butterfly shaped gland in neck which produces hormones maintaining metabolism

Adrenal gland

glands above kidneys, secrete hormones that control blood pressure and heart rate

Pancreas

Large, elongated gland which secretes hormones (insulin & glucagon) which regulate blood sugar

Ovaries

Two small, oval shaped organs on either side of uterus in which ova develop and release ovum during ovulation. Secretes hormones oestrogen and progesterone

Testes

Produces and stores sperm and testosterone

Adrenaline

Hormone produced by adrenal gland, used in “fight or flight” response

Insulin

Hormone from pancreas, regulates blood sugar

Testosterone

male hormone from testes, causes changes in puberty, and associated with male characteristics

Oestrogen

Make changes in pubert and provides female characteristics

Progesterone

Female hormone involved in menstrual cycle and pregnancy

Ovulation

Release of ovum from ovary

Menstruation

Periodic shedding of lining, approx. every 28 days

In vitro fertilisation

ova removed from woman’s ovary and fertilised with sperm in lab. Fertilised egg returned to woman’s uterus

Pathogen

Disease causing organism

Inflammation

Immune response to a pathogen or foreign body involving increased blood flow to site, swelling, redness.

Phagocytosis

Process which white blood cell (phagocyte) engulfs & digests debris & invading micro-organisms

Immunity

protected from pathogen, from exposure to pathogen or vaccination

vaccination

process of gaining immunity

Antigen

Substance that induces immune response

Antibody

Protein produced in response to antigen

Lymphocyte

White blood cells involved in the immune response