Bio and Chem Half Yearly

• How do organisms survive in changing environments?

  1. Abiotic vs biotic features
  2. Cycles in ecosystems
  3. Flow of energy through food webs and chains
  4. Conservation of ecosystems
• How does the human body respond to infection?

  1. Types of diseases
  2. Lines of defence
  3. Immune system
  4. Vaccination
• Cell Hierarchy?

  Cells -> Tissues -> Organs -> Organ System -> Organism

  Intestinal Cells -> Intestinal Tissue -> Intestines -> Part of Digestive System -> Part of a Human Body
• We are?

  Multicellular organisms made up of a number of body systems that work together
• Why is it vital for your cells to communicate with each other?


  This is essential so that your cell requirements are met and a stable internal environment is maintained.
• Your cells communicate with each other using?


  1. Electrical impulses
  2. Neurotransmitters
  3. Hormones
• Stimuli relating to body temperature

  A) +

  B) -

  C) -

  D) +

  E) heating process activated

  F) cooling process activated

  
• What are some examples of ABIOTIC chemical features in an ecosystem?

  pH of Soil and water

  Salinity

  Availability of gases
• What is the optimum range?

  Each species has a tolerance range for each abiotic factor.

  The optimum range is the zone within the tolerance range in which it functions best.
• What cycles can you find in an ecosystem? (there are 7 common ones)

  • Rock Cycle
  • Life cycle
  • Cycling of matter and energy
  • Water cycle
  • Food webs
  • Nitrogen cycle
  • Carbon cycle
• How do matter and energy flow through an ecosystem?

  The members of every community within an ecosystem can be identified as producers, consumers, and decomposers.

  The feeding relationships can be identified through food webs and these groups.
• Nitrogen Cycle

  A) Nitrates

  B) Nitrites

  C) Decomposition

  D) N-fixing bacteria

  E) N-fixing bacteria

  F) ammonia

  
• What are consumers?

  Consumers, also known as heterotrophs are unable to make their own food source since they obtain their nutrients from eating other organisms.

  Consumers are divided into different types based on how they obtain it.
• What is an atom?


  An atom is the basic unit of matter that consists of a nucleus containing protons and neutrons, surrounded by electrons.
• What is an element?

  There are over a hundred different types of atoms, and these are called elements.

  
  

  Each element has a special name e.g. Gold, Neon, Sulfur

  E.g.- Hydrogen gas is only made up of hydrogen atoms
• What is inside an atom?

  The centre of the atom is the nucleus which is made up of protons and neutrons.

  The nucleus is surrounded by electrons.

  In the first orbit, there is always only two electrons
• How do we use the periodic table?

  The periodic table contains every known element (118)

  Each element has a unique atomic number

  ^This represents the number of protons in the nucleus

  Each element has a unique atomic weight

  ^This represents the number of protons + neutrons

  Each element also has a symbol represented by 1 or 2 letters

  Atomic mass = number of protons + neutrons
• Protons are not always equal to number of neutrons
• Don't include electrons in the atomic mass
• Round atomic mass to the nearest whole number
• The number of protons equals to the amount of electrons
• What are ions?

  An ion is formed when an atom gains or loses electrons.

  All atoms aim to have a valence shell. (outer shell)

  A neutral atom holds the same amount of protons and electrons

  When an atom loses electrons it turns into a cation (positive)

  When an atom gains electrons it turns into an anion (negative)
• The elements in group 18 are called inert gases or noble gases

  This is because they are chemically unreactive and stay stable
• What makes elements different from eachother?

  Physical properties

  Magnetic properties

  Chemical properties
• Physical properties of an element

  • Colour
  • Shape
  • Density
  • Mass
  • Volume
  • Melting point and boiling point
  • Temperature
• Magnetic properties of an element


  It does not involve any chemical changes to the molecule
• Chemical properties of an element

  • Flammability
  • Reaction with oxygen
  • Reaction with water
  • Reaction with acids
• Properties in the periodic table

  • At room temperature (25`C)

  -> Most elements are solids

  -> All of group 18 are gases

  -> Bromine and mercury are liquids
• Active Metals


  The far left side of the periodic table (except for Hydrogen) contains unique metals

  • These are very malleable, soft and have low density
  • They are very chemically active - this means that they can ignite and burn violently
• Transition Metals


  • The centre block of the Periodic Table contains common metals (gold, iron, silver, and copper)
  • Most are hard, shiny and have high melting points.
  • Goes from Group 3-12
• How do metals react with acids?


  Metal + acid -> salt + hydrogen gas

  E.g. Magnesium + hydrochloric acid -> magnesium chloride + hydrogen gas
• The quickness of the reaction (between acid and metal) depends on how the metal is used and how high it is in the reactivity series
• More reactive metals have a greater tendency to lose electrons and form positive ions.
• The vaccine does not cause the disease. it stimulates the immune system to produce white blood cells. This allows the body to quickly develop immunity and provide a fast response to infection.
• Reasons for vaccination

  • Wanting immunity against diseases
  • Encouragement from friends and family
  • Believing that it will protect them against the disease
  • Travel and entry requirements
  • For the protection of loved ones
  • Scientific trust and research
• Electron configuration refers to the arrangement of electrons within an atom, molecule, or ion. It describes how electrons are distributed among the various energy levels (or electron shells) and subshells (or orbitals) around the nucleus of an atom. This follows three rules which include Aufbau Principal, Hund Rule and Pauli Exclusion Principal.
• Introduced in 1869, Mendeleev's periodic table organized known elements based on their atomic weights and chemical properties, arranging them in rows (periods) and columns (groups) that highlighted recurring trends and patterns. He left gaps for undiscovered elements and predicted them based on the periodic patterns. Examples of elements he predicted include Gallium and Manganese.
• Radiation refers to the emission and transmission of energy through space or a material medium in forms of waves or particles. There is ionising and non-ionising radiation. Examples of non-ionising radiation include infared radiation and microwaves. Examples of ionising radiation include x-rays and gamma rays.
• Electromagnetic spectrum is the complete range of all the types of radiation that has both electric and magnetic fields and travels in waves.
• An isotope is an atom that has the same number of protons but a different number of neutrons in its nucleus. E.g, Carbon usually has 6 protons and 6 neutrons but Carbon-13 (isotope) has 6 protons and 7 neutrons.