MID UNIT TEST

• Biotic = are all the living things in an environment 

  EXAMPLES -> Animals, plants, soil
• Abiotic = are all the non-living things in an environment

  EXAMPLES -> Sun, water, rocks
• Predation : relationship between two organisms, where one kills and eats the other
• Parasitic : relationship between two organisms, where one lives on or in the other and feeds off it. One is benefited and the other is harmed.
• Competition : relationship between two organisms that are trying to use the same limited resource.  In extreme cases it can cause extinction. 
• Pollinators : A pollinator is anything that helps carry pollen from the male part of the flower (stamen) and carries it to another flower with the female part of the flower (stigma).
• Mutualism : relationship between two organisms living closely together, where each benefits the other.
• Commensalism : relationship between two organisms, where one is benefited, and the other is unharmed.
• FOSSIL FUELS : an unrenewable source of energy that is formed within the Earth's crust from biological remains.
• 3 types of fossil fuels : Oil, natural gas, coal
• How do humans use these fossil fuels ?

  Oil = petrol for cars , natural gas = cooking and heating, coal = generates electricity in factories
• Effects of burning fossil fuels on the ecosystem

  - Air pollution, oil spills, coral bleaching and enhanced greenhouse effect 
• Where is carbon stored on earth ?

  -  Rocks and sediments (fossils)
• Photosynthesis = The process by which green plants and certain other organisms transform light energy into chemical energy.
• Word equation for photosynthesis = Carbon dioxide + water + sunlight -> oxygen + glucose
• Producers = organisms that get their energy through photosynthesis
• Consumers = feed on other organisms to obtain food, the food provides energy needed to power all the processes in the organism
• Function of the endocrine system = to produce hormones to control the body in response to stimuli to maintain homeostasis 
• Organs and their hormones (endocrine system) = pituitary gland, thyroid gland, pancreas, adrenal gland, ovaries, testes
• Function of the nervous system = carry messages to and from the brain and controls movement throughout the body
• Components of the nervous system : cell body, dendrites, nucleus, axon, myelin sheath, axon terminal
• Dendrites -> receive and pass message to the cell body
• Cell body : receives message from dendrites + contains nucleus 
• Axon : carries electrical impulses away from cell body to axon terminal , myelin sheath protects axon + increase neutral transmission speed
• Axon terminal : receives electrical impulse and this then stimulates the neurotransmitters to be released into synapse 
• Reflex : an involuntary response (not consciously controlled) that protects the body. They are extremely fast.
• Reflex arc : the pathway a reflex follows to make it extremely quick
• Reactions : a voluntary response (consciously controlled)
• Reflexes = Not consciously controlled, faster than reactions,

  use the spinal cord to produce the response
• Reactions = Consciously controlled, slower than reflexes, use the brain to produce the response 
• READING THE PERIODIC TABLE

      8     <-- Atomic number (always the smaller number)

      O    <-- Symbol

  Oxygen  <-- Name

  15.999   <-- Atomic mass (always the larger number)
• CALCULATING SUMBATOMIC PARTICLES

  • Protons = atomic number
  • Neutrons = atomic mass (rounded) - atomic number
  • Electrons = number of protons
• Define combustion : chemical process in which a substance reacts rapidly with oxygen and gives off heat
• Word equation of combustion : hydrocarbon + oxygen -> carbon dioxide + water 
• Nuclear energy : released from the nucleus of an atom when nucleus undergoes fission (break apart) or fusion (join)
• Nuclear decay : breakdown of an unstable atomic nucleus resulting in the release of energy and/or matter
• Radioisotope : elements that undergo nuclear decay
• 3 types of nuclear decay 

  1.     Alpha 

  2.     Beta

  3.     Gamma 
• Effects of high levels of nuclear radiation on humans 

  • Burning and redness of the skin
  • Changes to a person's DNA (genetic code)
  • Cause people to become fertile
  • Cancer of the blood, bone and glands
• Medical uses of nuclear decay

  - Radioisotopes are injected into the body to release their energy as light, giving an image (brain PET)

  - A beam of subatomic particles is focused on cancer cells, causing them to die