Cells & Particles
What is a cell?
The smallest unit of life
What unit is used to measure energy?
Joules (J)
What is a force?
A push or a pull
What structure carries genes inside the nucleus?
Chromosomes
What is a chemical reaction?
A process where substances change into new substance
What is the nucleus?
The part of the cell that controls its activities and contains genetic information.
What is the law that states energy cannot be created or destroyed?
Conservation of energy
What force pulls objects towards the Earth?
Weight (gravity)
What type of variation is inherited from parents?
Genetic variation
What are substances called before and after a chemical reaction?
Reactants and products
Explain why gases are compressible using the particle model.
Particles are far apart with lots of empty space so they can be pushed closer together
What are the three methods of heat transfer?
Conduction, convection, radiation
What force opposes motion between two surfaces rubbing together?
Friction
What is the process where male and female gametes fuse?
Fertilisation
What is the difference between an element and a compound?
An element contains one type of atom; a compound contains two or more elements chemically bonded
How are particles arranged and how do they move in a solid?
Because the particles are far apart with lots of empty space
Why are dull black surfaces good emitters of radiation?
They absorb and emit infrared radiation very effectively
Why can liquids flow but solids cannot?
Liquid particles can move past each other, but solid particles are fixed in place
What do we call an allele that is not expressed when paired with a dominant one?
Recessive
Name one sign that a chemical reaction has occurred.
Examples: colour change / gas produced / temperature change / light produced
Explain how heating a gas increases its pressure.
Particles move faster, collide more often and with greater force, increasing pressure
A 500 W appliance transfers 10,000 J of energy. How long was it on?
20 seconds
A car is moving at a constant speed along a straight road. Explain what this tells you about the forces acting on the car, and describe what would happen if the driving force became larger than the resistive forces.
A Bb parent is crossed with bb. What is the phenotypic ratio of offspring?
1:1 (50% dominant, 50% recessive)
Magnesium reacts with sulphuric acid to form a salt and a gas. Write this as a word equation, naming the salt and the gas.
Magnesium + Sulphuric acid -> Magnesium Sulphate + Hydrogen