Biological Molecules

• What does polarity mean?

  Region of postive charge and regions of negative charge which overall leads to an uneven distrubution of charge
• Describe the formation of hydrogen bonds between 2 molecules of water and explain how water can form these bonds

  Waters polarity allow hydrogen bonds to form between δ+ Hydrogen and δ- Oxygen of two different water moleculesSee an expert-written answer!We have an expert-written solution to this problem!
• Outline 4 functions of water

  Coolant, Transport Medium, Habitat, Solvent
• Explain how water has a high specific heat capacity and relate to function

  the hydrogen bonds can absorb a lot of energy so it takes a lot of energy to heat it up

  This means water temperature doesn't experience rapid temperature changes thats make it a good habitat (stable
• Explain how waters is a transport medium in plant and animal cells

  Animal cell - Blood (plasma) water makes up 55%

  
  

  Plant cells - Transpiration stream (Xylem)

  There are hydrogen bonds in between the water molecules (Cohesion) and there is also hydrogen bonds that form from the water molecules and the surface wall of the xylem (adhesion) this allows the water molecules to be transported upwards. The bonds in between allow the water to pull the next one up and the bonds on the surface keep it there as it moves up the stream
• Explain how water polarity makes it a solvents

  A lot of substances in biological reactions are ion (e.g Salt) This means there made from one positively charged atom/molecule and one negatively charged. Since water is polar the slight positive and negative ends will attract to the negative and positive end of the ion.

  ions will get surrounded by water molecules ( they dissolve)

  In humans ions can dissolve in blood and be transported around.
• Explain how hydrogen bonds give water a high latent heat of evaporation

  Requires lot of energy to break bond

  So lot of energy used up when water evaporates. Good for cooling when sweat evaporates it cools surface of skin
• Explain water's function as a habitat


  Water is less dense when solid as molecules held further apart in ice (reason it floats) then liquid as each water molecules form 4 H bonds to other water molecules making lattice shape.

  ice forms insulating layer so organisms in water doesn't freeze and can move around
• What is a polymer?


  long chain of repeating units (monomers)
• What are the monomers that make up Carbohydrates?

  monosaccharides (simple sugars)
• what type of monomer is glucose

  monosaccharide - 6 carbon atoms (hexrose)
• What are the 2 forms of glucose?

  alpha and beta. Both have a ring structure
• How is glucose's structure related to its function as the main energy sources of plants and animals?

  Structure makes it soluble so it can be easily transported.

  Its chemical bonds contain lots of energy.
• What type of monomer is Ribose?

  Monosaccharide - pentose sugar
• Which biological molecules are ribose found in?

  Ribonucleic acid (RNA)

  ATP
• What is the general formula for monasaccarides?

  (CH₂O)n
• What do monosaccharides join together and form?

  disaccharides and polysaccharides
• What type of bond occurs when 2 alpha glucose monosaccharides react together

  1,4 Glycosidic bond
• What is formed when 2 alpha glucose molecules react?


  Maltose
• When making a disaccharide how is a water molecule formed?

  water molecule is formed when a hydrogen atom from one of the monosaccharides bonds with a hydroxyl from the other group (Condensation reaction)
• What is the reverse of the condensation reaction?

  hydrolysis
• What happens in a hydrolysis reaction?

  a water molecule is added to a disaccharide to break the glycosidic bond converting back into monosaccharide
• How is the disaccharide sucrose formed?

  by condensation of the monosaccharides α-glucose and fructose
• How is the disaccharide lactose formed?

  by condensation of the monosaccharides either α/β-glucose and galactose
• Name 3 polysaccharides


  starch, glycogen, cellulose
• What is starch used for?

  main energy storage material in plants.

  Plants store excess glucose as starch
• What is the structure of starch

  mixture of two alpha-glucose polysaccharides

  Amylose - long, unbranched ( has one 1.6 bond every 25 alpha glucose molecules)

  coiled structure makes it compact and good for storage.

  Amylopectin - long branched chain,

  side branches allow enzymes to get at the glycosidic bond easily meaning glucose can be released easily
• How does starch being insoluble in water help?

  Doesn't cause water to enter cells by osmosis which wont make them swell this makes good for storage.
• What is glycogen used for?

  Animal store excess glucose as glycogen - another polysaccharide of alpha glucose
• Describe the function of Glycogen


  Similar to amylopectin but has more side branches so that the stored glucose can be released quickly important for energy release in animals

  very compact molecule good for storage
• What is the purpose of cellulose in plant cells?

  major component of cell wall
• What is the structure of cellulose?

  cellulose consists of a long,unbranched and straight chain of β glucose

  Cellulose chain linked together by hydrogen bonds to form strong fibres (microfibrils) these provide structural support for cells
• What is a protein?


  sequence of amino acids ( made up of one or more polypeptides)
• What is the variable group in amino acids

  R group
• What are the different parts in amino acids

  Amino

  R

  Carboxyl
• What type of bond holds amino acids together?

  peptide bonds (covalent bonds)
• What type of reaction happens in a peptide bond?

  Condensation

  ( water molecule formed)
• What are the two amino acid joined up?

  dipeptide
• What is a polypeptide?

  chain of amino acids
• What is the primary structure of a protein?

  The sequence in which amino acids are joined together -made by peptide bonds

  
  

  The particular amino acid sequence will influence how the polypeptides fold to give protein final shape.