science

• Biochemical cycle (system)


  Succession of interrelated chemical reactions that occur within an organism or environment
• Inputs


  Molecules, substrates, or energy sources that start or feed the cycle, often obtained from the environment or other metabolic processes
• Outputs


  Products or intermediates generated as a result of the cycle's activity, serving various purposes within the organism
• Growing system


  Has more inputs than outputs
• Declining system


  Has less inputs than outputs
• Negative feedback systems


  • Help to preserve stability by compensating for any deviation from the set point
  • When a change in a parameter is recognised, the system launches an opposing response, bringing the parameter back to the set point
• Positive feedback systems


  • Improve or support parameter changes rather than opposing them
  • Can result in a cascade effect, where the parameter continues to deviate from the set point until an external factor breaks the loop
• Blood clotting<|>Release of oxytocin during labour

  • Examples of positive feedback
• Nitrogen cycle


  Biogeochemical process that describes the movement and transformation of nitrogen within ecosystems

  
• Nitrogen is an essential element for the formation of proteins, nucleic acids, and other organic molecules crucial for life
• Atmosphere is abundant in nitrogen (78%)
• Nitrogen fixation


  The nitrogen (N2) in the air gets absorbed by the soil, where nitrogen-fixing bacteria convert it to ammonia (NH3)

  
• Nitrogen cycle


  1. Nitrogen fixation

  2. Nitrification

  3. Assimilation

  4. Ammonification

  5. Denitrification

  
• Nitrification


  Nitrifying bacteria in the soil convert ammonia (NH3) into nitrites (NO2) and then into nitrates (NO3)
• Assimilation


  Primary producers/plants take in the nitrates from the soil through root absorption, incorporating nitrogen into their bodies
• Ammonification


  When an animal/plant dies, decomposers release the nitrogen in the form of ammonia, which can then re-enter the nitrogen cycle
• Denitrification


  Denitrifying bacteria convert excess ammonia (NH3) into nitrogen (N2) and release it into the atmosphere
• Carbon cycle


  Important natural process that details how carbon moves through the atmosphere, oceans, land, and living creatures

  
• Carbon cycle


  1. Plants absorb carbon from the atmosphere and use it to create food (glucose) and oxygen through photosynthesis

  2. Carbon is passed through the food chain as organisms consume each other

  3. Decomposition of living cells releases carbon, which can turn into fossil fuels over time

  4. Humans extract and burn fossil fuels, releasing carbon dioxide into the atmosphere

  
• Human interference


  Cutting down trees, burning fossil fuels, and poor waste management can disrupt the balance of the carbon cycle, leading to an increase in atmospheric carbon dioxide and enhanced greenhouse effect

  
• Water cycle


  Continuous movement of water on, above, and below the surface of the Earth, crucial for the distribution of water across the planet

  
• Water cycle


  1. Evaporation

  2. Transpiration

  3. Condensation

  4. Precipitation

  5. Infiltration

  6. Runoff

  7. Sublimation

  8. Deposition

  
• Eutrophication


  Process where a body of water becomes overly enriched with nutrients, leading to excessive growth of algae and other aquatic plants, often resulting in oxygen depletion and harm to other organisms

  
• Eutrophication


  1. Nutrient input

  2. Algal bloom

  3. Oxygen depletion

  4. Impact on aquatic life

  5. Ecosystem changes

  
• Elements

  Pure substances made up of only one type of atom, represented by unique chemical symbols
• Molecules


  Formed when two or more atoms join together chemically through covalent bonds, can be composed of atoms of the same element (diatomic molecules) or different elements (compounds)
• Atoms


  Basic building blocks of matter, consisting of a nucleus containing protons and neutrons, surrounded by a cloud of electrons
• Compounds


  Substances that contain atoms of more than one kind joined together, can be broken down into simpler substances
• Chemical formulas


  Represent the fixed amount of atoms in each compound, using capital and lowercase letters correctly

  
• Decomposition reactions


  Breaking up compounds requires a lot of energy and chemical change, can occur through thermal or electrical means
• Chemical changes


  Involve the formation of new substances, can be identified by gas/solid formation, color changes, and energy changes
• Physical changes


  Do not involve the formation of new substances, generally just involve changes in the state or mixing of substances
• Chemical changes


  When the substance will get changed to another substance
• Chemical reactions in the laboratory

  • Gas/solids formed
  • Color being changed
  • Energy change (heat increase/decrease)
• Effervescence


  When a chemical reaction fizzes because it is producing gas
• Precipitation


  • Between solutions produce a solid
  • The solid is a precipitate
• Color Change


  When the formation of a new product is indicated by color change
• Endothermic reaction


  Heat energy is not released during a change, and is taken away
• Exothermic reaction


  Heat energy is released
• Chemical Changes


  • No substances are formed
  • Generally the states of the substance changes of 2 substances are mixed with each other