Paper 2

Cards (27)

  • What is the function of the nervous system
    It enables humans to react to their surroundings and to coordinate their behaviour-this includes both voluntary and involuntary actions
  • What is the structure of the nervous systems
    It is made up of the central nervous system (CNS) and a network of nerves. The CNS comprises the brain and spinal cord
  • What are the 5 parts of a reaction for the nervous system
    Stimulus, Receptor, Coordinator, Effectors, Response
  • What is the stimulus in a nervous system response
    It is a change in the environment which is detected by the receptors
  • What does the receptors do in the nervous system response
    Information from receptors passes along cells (neurones) to the CNS as electrical impulses
  • What does the coordinator do in the nervous system response
    The CNS coordinates the body’s response to the stimulus
  • What does the effector do in the nervous system response
    They bring about a response, such as glands secreting hormones or muscles contracting
  • What does the response do in the nervous system response
    The body responds to the stimulus
  • What are factors affecting reaction time
    Tiredness, Distractions, Caffeine, Alcohol
  • What is homeostasis
    It is the regulation of internal conditions (of a cell or whole organism) in response to internal or external changes, to maintain optimum conditions for functioning
  • What is maintained for optimum function
    Blood glucose concentration
    Body temperature
    Water levels
  • What 2 responses are involved of homeostasis
    Nervous response and chemical response
  • What are all the control systems involved in homeostasis
    -Receptor cells, which detect stimuli
    -Coordination centres(like the brain, spinal cord and pancreas)which receive and process information from the receptors
    -Effectors(muscles or glands), which produce responses to restore optimum conditions
  • What is a reflex arc 

    They are reflex actions of the nervous system that are automatic and rapid-they do not involve the conscious part of the brain
  • Why are reflex actions importation
    they are important for survival because they prevent damage to the body
  • What are neurones
    They carry electrical impulses around the body - relay neurones connect sensory neurones to motor neurones
  • What are synapses
    they are gaps between neurones, which allow electrical impulses in the nervous system to cross between neurones
  • What is variation
    The differences in the characteristics of individuals in a population
  • What can be the difference for variation
    The genes they have inherited e.g. eye colour
    The environment they grew up in e.g. language
    A combination of gene and environment
  • What is a mutation
    It is a change in a DNA sequence
  • What is selective breeding
    It is the process by which humans breed plants and animals for particular genetic characteristics
  • What are the processes of selective breeding
    1.Choose parents with the desired characteristics from a mixed population
    2.Breed them together
    3.Choose offspring with the desired characteristics and breed them together
    4.Continue over many generations until all offspring show the desired characteristics
  • What are the benefits of selective breeding
    Disease resistant in food crops
    animals produce more milk or meat
    domestic dogs with gentle nature
    larger or unusually flowers
  • Disadvantages of selective breeding
    Can lead to inbreeding, where some breeds are particularly prone to inherited defects or disease
    Reduces variation, meaning all members of a species could be susceptible to certain diseases
  • What is Genetic engineering
    It is a process that involves changing the genome of an organism by introducing a gene from another organism to produce a desired characteristic
  • What are the benefits of Genetic engineering
    -Potential to overcome some inherited human disease
    -can lead to higher value of crops as GM crops have a bigger yields than normal
    -crops can be engineered to be resistant to herbicides
  • What are the risks of Genetic engineering
    -Genes from GM plants and animals may spread to other wildlife, which could have devastating effects on an ecosystem
    -Potential negative impacts on population of wild flowers and insects
    -Ethical concerns, like people could manipulate the genes of get used for certain characteristics
    -Health concerns as eating crops that are GM have not been fully explored