Biological molecules (water) 2.1.2 Flashcards
Organic molecules
- Contain hydrogen and carbon
- Either macromolecules (Molecules containing a large number of atoms) or small molecules
Polymers and monomers
Polymers are a chain of repeating units (monomers) joined togther by covalent bonds and formed through a condensation reaction. Monomers are molecules that are covalently bonded to eachpther to form a polymer.
What are the biomolecules?
Lipids, nucleic acids, carbohydrates and proteins.
How many bonds can the elements carbon, nitrogen, oxygen and hydrogen form?
- carbon atoms can form 4 bonds
- nitrogen atoms can form 3 bonds
-Oxygen can form 2 bonds
-Hydrogen forms 1 bond
Important cations
- Sodium ion (Na +) necessary for nerve impulse transmission and kidney function.
- Potassium ion (K+) nerve impulse transmission and stomatal opening.
- Calcium ion (Ca 2+) nerve impulse transmission and muscle contraction
- Hydrogen ion (H+ aka a proton) catalysis of reactions and pH determinations
- Ammonium ion (NH4) production of nitrate ions by bacteria
Important anions
- Chloride (Cl-) balances charge of sodium and potassium ions in cells
- Hydroxide (OH-) catalysis of reactions and pH determinations
- Nitrate (NO3-) nitrogen supply to plants for amino acids and protein production.
- Phosphate (H2PO4-) cell membrane formation, nucleic acid and ATP formation, bone formation.
- Hydrogen carbonate (HCO3-) maintainence of blood pH
The living composition of a cell
70% water, (about)1% inorganic substances, 29% organic polymers and macromolecules, 0-1% organic monomers and other organic molecules.
what is an ion?
An atom or molecule in which the total number of electrons are not equal to the number of protons.
Carbohydrates
Polymer = Polysaccarides
Name of bond between polymers = Glycosidic bond
Monomer = Monosaccarides
Elements = C, H, O
Fats/Lipids
Polymer = Triglycerides
Name of bond between polymers = Ester bond
Monomer = 3 fatty acids + glycerol
Elements = C, H, O
Proteins
Polymer = Polypeptide
Name of bond between polymers = Peptide bond
Monomer = Amino acids
Elements = C, H, N, O, S
Nucleic acids
Polymer = Polynucleotides
Name of bond between polymers = Phosphodiester bond
Monomer = Nucleotides
Elements = C, H, O, N, P
Elements in carbohydrates, fats, proteins and nucleic acids
CHO
CHO
CHNOS
CHONP
Hydrolysis
- All polymers are broken down/hydrolysed into their respective monomers by the addition of water to break the covalent bond.
- A catabolic/exothermic reaction so releases energy.
-(look at diagram on powerpoint)
Condensation reaction
- All monomers are joined condensed into their respective polymers by the removal of water to form a covalent bond.
- An anobolic reaction (endothermic) requires an input of energy.
The water molecule
- An oxygen atom bonded to 2 hydrogen
- Oxygen is delta negative (s-) whereas oxygen is delta positive (s+)
- It’s a polar molecule as theres an uneven distribution of charge
- Hydrogen bonds are weak
- Hydrogen bonding gives water it’s unique characteristics.
Characteristics of water
- Has an unusually high BP
-A small molecule much lighter than carbon dioxide and water. - A liquid at room temp due to the hydrogen bonds
- When water turns into ice it becomes less dense.
- ## As water is cooled below 4 degrees the hydrogen bonds fix in the positions of the polar molecules slightly further apart then the average distance in the liquid state.
Important functional groups in biological molecules
These are all polar (hydrophyllic)
- Hydroxyl (many in carbohydrates)
- carbonyl
- carboxylic acids (present in amino and fatty acids)
- amino
- Sulfhydryl (involved in protein structure)
- Ester
- Phosphate
Except for:
- methyl/hydrocarbon(non polar/hydrophobic)