Year 8 Science
Christmas Exam
Revision List
Revision Notes - Cells
Cells
All living things (organisms) are made up of cells. Cells are very small. Cells can be magnified by observing them under a microscope.
A stain (Iodine) can be added to the specimen on slide to help make the cell visible.
The slide is placed on the stage and viewed through the eyepiece lens.
The stage is moved up and down using the Focus wheel to sharpen the image.
Animal v Plant Cells
Animal and Plant cells all have at least
a Nucleus, Cell Membrane and Cytoplasm.
Plant cells can have 3 extra organelles that Animal cells do not have; Vacuole, Cell Wall and Chloroplasts.
Cell Specialisation
Cells have particular shapes and parts to help them do their job in the Animal or Plant.
This makes them specialised:
· Cells in the windpipe might have Cilia to help move mucus and dust out of the lungs. (bottom left)
· Cells in leaves have Chloroplasts to make food in Photosynthesis. (bottom right)
Revision Notes - Levels of Organisation
Animals and Plants are multicellular organisms – they are built from many cells. There is a level or organisation from Cell up to Organism:
Cells build Tissues, Tissues build Organs, Organs build Organ Systems and Organ Systems all work together to build a living Organism.
Organ Systems
As cells have specialised shapes and jobs, they build organs and organ systems with their own specific shapes and jobs. Here are the main organ systems in the Human Body and their Function:
Skeletal System – Built from Bone tissue for Structure and Support.
Muscular System – Built from Muscle tissue for Movement.
Digestive System – Built from many different organs for the breakdown and absorption of food into the blood.
Respiratory System – Built from Lung tissue for Breathing.
Nervous System – Built from Nerve tissue for Co-ordination and Control.
Circulatory System – Built from Heart and Blood Vessels for transport of blood around body.
Other systems include:
Reproductive System – built from Male Testes and Female Ovaries.
Excretory System – built from the Kidneys and Bladder. (right diagram)
Revision Notes - Solids, Liquids & Gases
All matter is made from very small particles (atoms). The particles are arranged in such as way that they can form Solid, Liquid or Gas materials. These are the 3 States of Matter:
Depending on their arrangement of particles; Solids, Liquids & Gases can have particular properties, as seen in the table.
By adding or removing energy (heat) the particles in can gain or lose energy and change state from one state to another.
Some substances can exist in all 3 states. Water can be in the form of Solid Ice, Liquid Water or Gas Steam.
These 3 states can change back and forward by adding heat or cooling.
· Water Freezes below 0oC
· Ice Melts above 0oC
· Water Boils (evaporates) at 100oC
· Steam Condenses below 100oC
On a warm day water evaporates and forms water vapour which condenses to form clouds.
Revision Notes - Printable Copy
Year 8 - Assessment 2 Revision List and Notes.pdf