Name the four key inorganic ions in living organisms.
Magnesium ions (Mg2+)
Ironions (Fe2+)
Calcium ions (Ca2+)
Phosphateions (PO43-)
What is the role of Mg2+ in plants?
Mg2+ is used to produce chlorophyll.
What is the role of Fe2+ in animals
Fe2+ is found in haemoglobin and is involved in the transport of oxygen.
What is the role of PO43- in living organisms?
PO43- is used to produce ADP and ATP
What is the role of Ca2+ in living organisms?
Ca2+ is used to strengthen tissues such as bones and teeth in animals and cell walls in plants.
Why is water a polar molecule?
O is more electronegative than H, so attracts the electron density in the covalent bond more strongly. forms O 𝛿- (slight negative charge) & H 𝛿+ (slight positive charge).
Describe hydrogen bonding between water molecules.
Weak intermolecular forces of attraction form between a lone pair on a δ- O and a δ+ H on an adjacent molecule.
What is a metabolite?
A molecule formed or used in metabolic reactions.
Describe the role of water as a metabolite.
Water is a reactant in photosynthesis and hydrolysis reactions. Water is a product in aerobic respiration and condensation reactions.
Why is water's high specific heat capacity important for organisms?
Water acts as a temperature buffer, enabling endotherms to resist fluctuations in core temperature and to maintain optimum enzyme activity.
Why is water's high latent heat of vaporisation important for organisms?
When water evaporates, it has a cooling effect. This is important in homeostasis; organisms can lose heat through sweating or panting.
Why is water an important solvent for organisms?
Water is a polar universal solvent. It enables chemical reactions to take place within cells, the transport of materials in the plasma and the removal of metabolic waste.
Why does water have a high surface tension?
Due to the ordered arrangement and cohesion of molecules at the surface of water.
Why is the high surface tension of water important for organisms?
- Enables the transport of water and nutrients through plant stems and small blood vessels in the body.
- Allows small insects to walk on water.
What is a monosaccharide?
- Simple Sugar
- General formula Cn(H2O)n
Give some examples of monosaccharides.
Glyceraldehyde, Ribose, Deoxyribose, α- and β-glucose, Fructose, Galactose.
What is the name of the bond formed when two monosaccharides react?
Glycosidic Bonds
What is a disaccharide?
- Molecule formed by the condensation of two monosaccharides, forming a glycosidic bond.
- Formula C12H22O11
Give some examples of disaccharides and their monosaccharide constituents.
- Sucrose (Glucose-Fructose)
- Maltose (Alpha glucose- Alpha glucose)
- Lactose (Glucose-Galactose)
What is a polysaccharide?
A polymer of many monosaccharides, formed by condensation reactions.
Give some examples of polysaccharides.
starch, glycogen, cellulose, chitin
What is the function of starch?
energy storage in plants.
Describe the structure of starch.
- Polymer of a-glucose monomers
- Two forms: Amylose and Amylopectin
- Amylose: a-1,4 glycosidic bonds, unbranched
- Amylopectin: a-1,4 and a-1,6 glycosidic bonds, branched
What is the function of glycogen?
Energy storage in animals.
How does the structure of glycogen relate to its function?
It is highly branched enabling the rapid hydrolysis of glucose molecules.
Describe the structure and function of cellulose.
- Linear polysaccharide that is the main component of the cell wall in plants.
- Consists of many beta-glucose molecules joined by beta- 1,4- glycosidic bonds.
How do LDL's contribute to the risk of cardiovascular disease?
The high blood cholesterol level caused by LDL's leads to formation of atherosclerosis plaques.
Describe the general structure of an amino acid.
- Amine group (-NH2)
- Variable side chain (R)
- Carboxyl group (-COOH)
- H atom
How are polypeptides formed?
Many amino acid monomers join together in condensation reactions, forming peptide bonds (-CONH-).
What is the primary structure of a protein?
The individual sequence of amino acids in a protein.
Describe the secondary structure of a protein.
The local interactions of the amino acids in the polypeptide chain resulting in alpha-helices or beta-pleated sheets. Hydrogen bonds hold the arrangements in place.
Describe the tertiary structure of a protein.
Folding of a protein to make a three-dimensional structure held in place by various interactions and bonds