Yr 8 Science Exam Cheat Sheet

Sedime­ntary rocks are formed from particles of sand, shells, pebbles. Gradually, the sediment accumu­lates in layers and over a long period of time hardens into rock. Sedime­ntary rock are fairly soft and may break apart or crumble easily. Contains fossils

Igneous rocks are formed when magma cools and hardens. Sometimes the magma cools inside the earth, and other times it erupts onto the surface from volcanoes. When lava cools very quickly, no crystals form and the rock looks shiny and glasslike. Sometimes gas bubbles are trapped in the rock during the cooling process, leaving tiny holes and spaces in the rock.

Enzymes are biological catalysts - catalysts are substances that increase the rate of chemical reactions without being used up.

Metamo­rphic rocks are formed under the surface of the earth due to intense heat and pressure. The rocks that result from these processes have layers and may have shiny crystals, formed by minerals growing slowly over time, on their surface.

transport nutrients (such as amino acids and electr­oly­tes), oxygen, carbon dioxide, hormones, and blood cells to and from the cells in the body to provide nouris­hment and help in fighting diseases, stabilize temper­ature and pH, and maintain homeos­tasis

Once in the lungs, oxygen is moved into the bloods­tream. Blood carries the oxygen through the body to where it is needed. blood cells collect carbon dioxide from the body’s cells and transports it back to the lungs.e­xc­hange of oxygen and carbon dioxide takes place in the alveoli, small structures within the lungs. The carbon dioxide, a waste gas, is exhaled and the cycle begins again with the next breath.The diaphragm is a dome-s­haped muscle below the lungs that controls breathing. The diaphragm flattens out and pulls forward, drawing air into the lungs for inhala­tion. During exhalation the diaphragm expands to force air out of the lungs.