Science Notes-2024 Term 1

• The acronym "MRS GREN" represents the seven attributes that enable an organism to be defined as "living":

  • Movement
  • Respiration
  • Sensitivity
  • Growth
  • Reproduction
  • Excretion
  • Nutrition
• Movement is defined as a change in position or place
• Respiration is the process that breaks down food to release the energy the body needs
• Sensitivity refers to the ability to sense and respond to environmental changes, usually done by using our five senses
• Growth is a lasting size increase caused by more cells
• Reproduction involves creating non-identical copies of the same organism
• Excretion is the elimination of harmful substances from the body, necessary when there's excess of a dangerous material
• Nutrition involves absorbing nutrients and minerals to grow and repair the organism's body
• The digestive system functions to take in food, digest it into smaller molecules, absorb nutrients, and remove indigestible food from the body
• The circulatory system's function is to transport materials to and from cells
• The nervous system gathers and interprets information, responds to that information, and helps maintain homeostasis
• The excretory system removes waste products from cellular metabolism and filters blood
• The respiratory system takes in oxygen and removes carbon dioxide and water
• The skeletal system protects organs, provides support/shape, stores materials, produces blood cells, and allows movement
• The muscular system allows for movement by contracting
• The endocrine system regulates body activities using hormones, with a slow response and long-lasting effects
• The immune system fights off foreign invaders in the body
• The integumentary system acts as a barrier against infection, regulates body temperature, removes waste, protects against the sun's UV rays, and produces vitamin D
• The lymphatic system stores and carries white blood cells
• Phagocytes are white blood cells that engulf and digest foreign particles in a non-specific manner
• Lymphocytes are white blood cells that directly attack and destroy infected or abnormal cells in the body
• 1. Cells identify pathogens by their antigens, while B-cells produce antibodies that bind to antigens on a pathogen
• Vaccination or immunisation is the giving of a vaccine to produce a type of immunity called artificial immunity
• Vaccination or immunisation is the giving of a vaccine to produce a type of immunity called artificial immunity
• Sensory neurons carry information from sensory organs to the central nervous system (CNS)
• Motor neurons transmit signals from the brain and spinal cord to muscles and glands
• Synapses are tiny gaps where neurons communicate using chemical signals (neurotransmitters), facilitating communication within the nervous system
• Axon transmits electrical impulses away from a neuron's cell body to communicate with other neurons or target cells
• Dendrite receives incoming signals and transmits them toward the cell body of a neuron for further processing
• Myelin Sheath insulates and speeds up the transmission of electrical impulses along the axon of a neuron
• Axon Branch extends from the main axon, allowing a neuron to communicate with multiple target cells or other neurons
• Muscle Fibres contract in response to signals from motor neurons, facilitating movement and muscle function
• Receptor detects and responds to specific stimuli, converting them into electrical signals that can be processed by the nervous system
• Interneurons are only found in the central nervous system (CNS) and act as a link between sensory and motor neurons
• Influenza (the flu) is caused by a virus and is transmitted through respiratory droplets (e.g., coughing, sneezing, or talking)
• Effects of influenza include fever, muscle aches, fatigue, respiratory symptoms, headache, and gastrointestinal symptoms
• When analysing markets, a range of assumptions are made about the rationality of economic agents involved in the transactions
• The Wealth of Nations was written

  1776
• Rational


  (in classical economic theory) economic agents are able to consider the outcome of their choices and recognise the net benefits of each one
• Consumers act rationally by


  Maximising their utility