CCEA AS Biology 1.1 (Molecules) – Study Guide & Practice Questions
What does polar mean? - ANS ✔✔Charges in a compound are unevenly distributed
Is water polar or non-polar? - ANS ✔✔Polar
What are the disadvantages of hydrogen bonding? - ANS ✔✔- The bonds are not strong
- The bonds are easily broken
What does hydrophobic mean? - ANS ✔✔Repelled by water/Not soluble in water
What does hydrophilic mean? - ANS ✔✔Attracted to water/Soluble in water
Why is it vital that water is a good solvent? - ANS ✔✔- Most chemical reactions in cells take
place in an aqueous solution
- It is able to act as a transport medium in living organisms
What are the main roles of inorganic ions in living organisms? - ANS ✔✔They are important in
osmotic and buffering systems
What is osmosis? - ANS ✔✔Net movement of water molecules across a partially permeable
membrane from a region of higher water concentration to a region of lower water
concentration
What is a buffer? - ANS ✔✔A chemical that resists changes to pH and ensures a particular
environment maintains a particular pH
, What is the biological importance of Calcium (Ca^2+) ions? - ANS ✔✔- In plants calcium pectate
is an essential component of the middle lamella of plant cell walls
- In animals is is an essential component of bones and teeth and is required during blood
clotting and muscle contraction
What is the biological importance of Iron (Fe^2+) ions? - ANS ✔✔- Part of the haem group of
haemoglobin in animals
- Important constituent of electron carriers in respiration
What is the biological importance of Magnesium (Mg^2+) ions? - ANS ✔✔- Part of the
chlorophyll molecule in plants (essential for it's light absorbing property)
What is the biological importance of Potassium (K^+) ions? - ANS ✔✔- Important in maintaining
electrical gradients across neurons in animals
What is the biological importance of Nitrate (NO^3-) ions? - ANS ✔✔- A component of all amino
acids, nucleic acids and chlorophyll
What is the biological importance of Phosphate (PO4^3-) ions? - ANS ✔✔- A component of
phospholipids and others vital biological molecules like ATP and nucleic acids
What is the biological importance of Hydrogen Carbonate (HCO^3-) ions? - ANS ✔✔- Important
as a natural buffer
What are organic molecules? - ANS ✔✔Complex carbon-containing molecules
What are the smaller molecules which make up polymers known as? - ANS ✔✔Monomers
What are long chain molecules made up of monomers known as? - ANS ✔✔Polymers
What does polar mean? - ANS ✔✔Charges in a compound are unevenly distributed
Is water polar or non-polar? - ANS ✔✔Polar
What are the disadvantages of hydrogen bonding? - ANS ✔✔- The bonds are not strong
- The bonds are easily broken
What does hydrophobic mean? - ANS ✔✔Repelled by water/Not soluble in water
What does hydrophilic mean? - ANS ✔✔Attracted to water/Soluble in water
Why is it vital that water is a good solvent? - ANS ✔✔- Most chemical reactions in cells take
place in an aqueous solution
- It is able to act as a transport medium in living organisms
What are the main roles of inorganic ions in living organisms? - ANS ✔✔They are important in
osmotic and buffering systems
What is osmosis? - ANS ✔✔Net movement of water molecules across a partially permeable
membrane from a region of higher water concentration to a region of lower water
concentration
What is a buffer? - ANS ✔✔A chemical that resists changes to pH and ensures a particular
environment maintains a particular pH
, What is the biological importance of Calcium (Ca^2+) ions? - ANS ✔✔- In plants calcium pectate
is an essential component of the middle lamella of plant cell walls
- In animals is is an essential component of bones and teeth and is required during blood
clotting and muscle contraction
What is the biological importance of Iron (Fe^2+) ions? - ANS ✔✔- Part of the haem group of
haemoglobin in animals
- Important constituent of electron carriers in respiration
What is the biological importance of Magnesium (Mg^2+) ions? - ANS ✔✔- Part of the
chlorophyll molecule in plants (essential for it's light absorbing property)
What is the biological importance of Potassium (K^+) ions? - ANS ✔✔- Important in maintaining
electrical gradients across neurons in animals
What is the biological importance of Nitrate (NO^3-) ions? - ANS ✔✔- A component of all amino
acids, nucleic acids and chlorophyll
What is the biological importance of Phosphate (PO4^3-) ions? - ANS ✔✔- A component of
phospholipids and others vital biological molecules like ATP and nucleic acids
What is the biological importance of Hydrogen Carbonate (HCO^3-) ions? - ANS ✔✔- Important
as a natural buffer
What are organic molecules? - ANS ✔✔Complex carbon-containing molecules
What are the smaller molecules which make up polymers known as? - ANS ✔✔Monomers
What are long chain molecules made up of monomers known as? - ANS ✔✔Polymers
