PNG Grade 10 Science flashcards
PNG Grade 10 Science · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Osmosis
- The net movement of water molecules through a partially permeable membrane from a dilute (high water) solution to a concentrated (low water) solution.
- Mitochondria
- Rod-shaped organelles in the cytoplasm where aerobic respiration occurs; glucose is broken down with oxygen to release energy for cell activities.
- Photosynthesis equation
- Carbon dioxide plus water, using light energy trapped by chlorophyll in chloroplasts, produces glucose and oxygen: 6CO2 + 6H2O → C6H12O6 + 6O2.
- Mitosis
- Cell division in body cells that produces two genetically identical diploid daughter cells; it is used for growth, repair and asexual reproduction in some organisms.
- Meiosis
- Reduction division producing four haploid gametes with half the normal chromosome number; crossing over and random assortment create genetic variation in offspring.
- Dominant allele
- An allele that is expressed in the phenotype even when only one copy is present, masking the effect of a recessive allele in a heterozygote.
- Artery
- A blood vessel that carries blood away from the heart; thick muscular elastic walls withstand high pressure and there are no valves along its length.
- Enzyme
- A protein biological catalyst that speeds up a specific reaction by lowering activation energy, and is denatured by high temperature or the wrong pH.
- Atomic number
- The number of protons in the nucleus of an atom; it identifies the element and equals the number of electrons in a neutral atom.
- Ionic bond
- A bond formed when a metal atom transfers electrons to a non-metal, creating oppositely charged ions that attract each other, as in sodium chloride.
- Covalent bond
- A bond formed when two non-metal atoms share one or more pairs of electrons, as in water (H2O) and carbon dioxide (CO2).
- Neutralisation
- The reaction between an acid and a base that produces a salt and water only, for example hydrochloric acid plus sodium hydroxide gives sodium chloride plus water.
- pH scale
- A scale from 0 to 14 measuring acidity; below 7 is acidic, exactly 7 is neutral and above 7 is alkaline, tested with universal indicator or a pH meter.
- Reactivity series
- A list of metals in order of decreasing reactivity: potassium, sodium, calcium, magnesium, aluminium, zinc, iron, lead, copper, silver, gold.
- Conservation of mass
- In a chemical reaction the total mass of the reactants equals the total mass of the products, because atoms are rearranged but never created or destroyed.
- Catalyst
- A substance that increases the rate of a reaction by providing an alternative pathway with lower activation energy, and is not used up itself.
- Ohm's law
- For a conductor at constant temperature, voltage equals current multiplied by resistance (V = IR), with current in amperes and resistance in ohms.
- Speed equation
- Speed is the distance travelled divided by the time taken (v = d/t), measured in metres per second; it is a scalar with no direction.
- Weight
- The force of gravity acting on a mass, calculated as W = mg where g is about 9.8 N/kg on Earth; weight is measured in newtons.
- Wave equation
- Wave speed equals frequency multiplied by wavelength (v = fλ); frequency is measured in hertz and wavelength in metres.
- Series circuit
- A circuit with only one path for current, so the current is the same at every point and total resistance is the sum of the resistances.
- Parallel circuit
- A circuit with branches where the voltage across each branch is the same but current divides; total resistance is less than the smallest branch resistance.
- Kinetic energy
- The energy a moving object possesses, calculated as KE = ½mv², where m is mass in kilograms and v is speed in metres per second.
- Conduction
- Transfer of heat through a solid by collisions between particles and the movement of free electrons, without the particles themselves travelling from place to place.
- Plate tectonics
- The theory that Earth's lithosphere is broken into plates that move slowly on the semi-fluid mantle, causing earthquakes, volcanoes and mountain building.
- Divergent boundary
- A plate boundary where two plates move apart, magma rises to fill the gap and new crust forms, as at the Mid-Atlantic Ridge.
- Subduction
- Where a denser oceanic plate sinks beneath a lighter continental plate at a convergent boundary, forming deep ocean trenches and chains of volcanoes.
- Igneous rock
- Rock formed when molten magma or lava cools and solidifies; slow cooling underground gives large crystals while rapid cooling at the surface gives fine crystals.
- Epicentre
- The point on Earth's surface directly above the focus of an earthquake, where the shaking is usually strongest and damage is greatest.
- Earth's rotation
- The spin of Earth on its axis once every 24 hours from west to east, producing day and night and the apparent daily movement of the Sun.
- Cause of seasons
- Seasons occur because Earth's axis is tilted 23.5 degrees, so each hemisphere receives sunlight at a different angle and for different lengths of time during its orbit.
- Solar eclipse
- Occurs at new moon when the Moon passes between the Sun and Earth and casts a shadow, blocking the Sun's light within the umbra.