biology

• The nucleus is the control center of the cell, containing the genetic material (DNA).
• The nucleus contains the genetic material (DNA) that controls all cellular activities.
• Changes in matter has 3 main changes e.g physical change, Nuclear change & chemical change
• physical change is when the substance changes but the composition of the substance remains the same.
• nuclear change is the change in the number of protons and neutrons in the nucleus of an atom
• chemical change is a change in the composition of a substance, but not in its physical state
• there are 2 energy in reactions which are; endothermic and exothermic
• endothermic reaction absorbs heat from surroundings to react
• exothermic reaction releases heat into surroundings as it reacts
• the rate of a chemical reaction can be affected by temperature, concentration, surface area and catalysts
• temperature affects the speed of a reaction because molecules have more kinetic energy at higher temperatures so they collide with greater force causing them to react faster
• catalysts affect the speed of a reaction because they lower activation energy making it easier for particles to react