Biology

• What is the nervous system?

  The nervous system coordinates its actions by transmitting signals to and from different parts of its body. The nervous system includes the brain, spinal cord and a network of nerves.
• What is a stimulus response pathway?

  A stimulus response pathway is the mechanism that the body uses to coordinate responses to maintain homeostasis.
• What are positive and negative feedback loops?

  Positive feedback loops reinforce the stimulus causing the body to be temporarily out of balance and not maintain homeostasis (E.g. childbirth, blood clotting). Negative feedback loops counteract the stimulus to maintain homeostasis (E.g. Heating up and trying to cool down)
• The order of the stimulus response pathway:

  Stimulus, Receptor, Control center, Effector, Response
• What is the different type of receptors?

  Chemoreceptors detect chemical changes, photoreceptors detect light and vision, mechanoreceptors detect touch and movement, thermoreceptors detect temperature changes, nociceptors detect pain, Baroreceptors detect pressure.
• What is homeostasis?

  homeostasis helps maintain constant internal conditions in the body despite constant external changes.
• What is a Signal Transduction Pathway?

  A Signal transduction pathway is the process of converting the original signal into a response through a signaling cascade of biochemical reactions.
• Signal Transduction Pathways occur in 3 stages:

  1. A hormone binds to a receptor making it change shape and signal to other molecules.
  2. Relay molecules are produced to relay the signal into the cell as one molecule triggers the next.
  3. Signal Transduction Cascade activates a process making the body respond to the stimulus.
• What is a Hormone

  A Hormone is a chemical messenger that can only act on target cells which control many of the functions within a living organism. The chemical messenger is used by the endocrine system which binds to complementary receptor to eventually trigger a response.
• What is a sensory neuron

  Sensory neurons transmit signals from the peripheral nervous system to the central nervous system, they are responsible for sensing stimulus.
• What is a motor neuron?

  Motor neurons transmit signals from the central nervous system to the peripheral nervous system to trigger them to respond.
• What is an interneuron?

  Interneurons connect the sensory and motor neurons together to allow signals to pass on.
• How does the sensory, motor and interneurons work?

  Sensory, motor and interneurons all work together to allow the nervous system to communicate.
• What is a neuron?

  A neuron is a specialized nerve cell that allows the nervous system to send signals. It is made up of dendrites that have branches and axons that carry signals.
• What are the two different types of nervous systems?

  the nervous system is split into the central nervous system and peripheral nervous system and uses neurons to send signals. The CNS consists of the brain and spinal cord while the PNS consists of branching nerves which receives and send signals to and from the CNS.
• What is endocrine signalling?

  Endocrine signalling allows long distance communication between cells in different areas of the body. The secreting cell releases hormones which diffuse into the bloodstream and get carried around the body to reach their target cell.
• What is paracrine signalling?

  paracrine signalling is used for local cell to cell communication as the secreting cell releases hormones and chemical signals bind to receptors on neighboring target cells to trigger a response.
• What is autocrine signalling?

  Autocrine signaling targets the same cell that released the chemical signal to trigger the response when it binds to a receptor on the same cell.
• What is osmoregulators?

  osmoregulators can change their internal osmic concentration via various physiological mechanisms to ensure constant internal osmotic balance despite what is occurring to the external osmotic concentration
• What are osmoconformers?

  Osmoconformers are organisms that don't have the ability to regulate their internal water balance so instead their internal osmotic concentration conforms to that of their surroundings.
• What is Anti-diuretic hormone (ADH)?

  ADH controls water retention in the body. When there is increased water levels in the body, less ADH is released from the pituitary gland which decreases permeability of the kidneys which then means less water is reabsorbed by the kidneys where it gets transported to the bladder and forms dilute urine.
• What is hormone aldosterone?

  Aldosterone regulates sodium and potassium levels in and out of the cell. When blood volume decreases due to low water level, aldosterone causes sodium and potassium levels to increase which draws water out of the cell into the blood through osmosis.
• What are xerophytes?

  Xerophytes are plants that can only survive in extreme temperatures, like hot, dry conditions. They have structural adaptations (fewer stomata and extensive root systems) that reduce water loss since it can be hard to find in those environments.
• What are halophytes?

  Halophytes are plants that are adapted to survive in high-salt environments. Meaning they have physiological adaptations to withstand the salinity such as compartmentalization of ions within cells and shedding leaves that have excessive salt.
• What are Mesophytes?

  Mesophytes are plants that grow in moist environments with aerated soils or moderate to warm and humid conditions. These types of plants don't have many adaptations for their environment however they have a few structural adaptations like fibrous roots and food storage compartments.
• What are hydrophytes?

  Hydrophytes are plants that grow in aquatic environments, so they don't have to adapt to minimising water loss. They usually have stomata on the topside of the leaf to maximise photosynthesis since water loss isn't an issue
• What are structural mechanisms for thermoregulations?

  Structural mechanisms are the physical characteristics that an organism has to assist it with heating and cooling. E.g Insulation like fur, feathers and blubber
• What are physiological mechanisms for thermoregulation?

  Physiological mechanisms are internal responses that occur at a metabolic level to change how the body operates and how it uses its energy resources. E.g vasomotor control
• What are behavioural mechanisms for thermoregulation?

  Behavioural mechanisms are behaviours that an organism display that are designed to help it regulate temperature.
• What are the first line barriers made up of?

  First line barrier defenses are the first step in innate immunity and can be classified as either chemical or physical. The physical barriers stop pathogens from entering the body by blocking or trapping them using the skin, mucous or cilia (small hairs found on top of the skin)
• what are the 3 types of immunity innate?

  There is the non-specific immune response, adaptive immune response (Specific) and the passive immune response (borrowed/specific). These innate immunities can illicit one of two responses: the non-specific response (everything is a target) or the specific response (particular target).
• What is a mechanical vector?

  A mechanical vector is when an animal spreads a pathogen from one host to another without being infected itself, E.g. a fly landing on faecal matter and then spreads the pathogen from the faeces to the food it lands on that is then eaten by another organism.
• what is a biological vector?


  A biological vector is a living thing that is the carrier of disease-causing agents from reservoirs to the host, E.g, when a mosquito bites an organism and infects them with malaria.
• How can disease spread within a community?

  It can spread faster depending on population density, personal or community hygiene issues, Immunity factors (or lack of), environmental factors, mechanism of transmission, or the type of pathogen being spread.
• What is innate immunity?

  Innate immunity is the first response of the body's immune sustem to a harmful foreign substance. when these foreign substances like bacteria or virus's enter the body, certain cells are able to respond to the threat and destory them.
• How can non-infectious diseases occur?

  They can be caused genetically caused by abnormalities in the genome. They can be caused environmentally by exposure to carcinogens, radiation or chemicals if they have the genetic pre-disposition. Lastly, they can be caused nutritionally by either inadequate or excess intake of nutrients or kilojules.
• what are non-infectious diseases?

  Non-infectious diseases are diseases that cannot be transmitted as they are not caused by pathogens but more to do with genetics and DNA.
• What are infectious diseases?

  Infectious disease are diseases that can be transmitted to an organism through infectious agents known as pathogens.
• what are the results of genetic mutation?

  There are 2 results to genetic mutation: The first being a chromosomal abnormality and it is caused by incorrect number of chromosomes an organism is born with or it can be the result of structural mutations. The second genetic mutation is single gene mutation, and it is caused by changes to a single base either through deletion, insertions or additions.
• What are the chromosomal structural mutations?

  Deletion: one part of a chromosome gets deleted so genes are missing, Translocation: part of a chromosome adds onto another chromosome, Duplication: part of a chromosome copies itself so more genes are present.