Chemical elements are joined together to form biological compounds Flashcards
What are 4 main inorganic ions? what are their functions in living organisms?
Magnesium (II) : Needed to produce chlorophyll
Iron (II) : A constituent of haemoglobin
Phosphate ion : Used to make nucleotides and is found in phospholipids in cell membranes.
Calcium ion: Used to strengthen Bones and teeth in animals and used to make the cell wall in plants
Why is water polar?
The difference in electronegativity between the slightly positive Hydrogen and slightly negative Oxygen creates a permanent dipole.
Describe how water forms Hydrogen bonds?
Weak attraction between the slightly negative lone pair on the oxygen in one water molecule and the slightly
What is water’s high specific heat capacity and latent heat of vaporisation?
High specific heat capacity : High amount of heat energy required to heat 1 gram of water by 1 degree. It prevents huge temperature fluctuations.
High latent heat of vaporisation : High amount of energy required to vaporise 1 gram of water. Water can have a cooling effect.
How is water a metabolite?
Water is a product of a condensation reaction and reactant in a hydrolysis reaction.
What is the role of water as a solvent?
Water is a universal solvent and it can dissolve polar molecules which is useful for transport. Water is a useful medium for reactions in the cytoplasm.
What is cohesion and adhesion?
Cohesion - Attraction between water molecules caused by Hydrogen bonding
Adhesion - Attraction between polar hydrophilic molecules and water.
Give some examples of monossacharides and their dissacharide constituents
Lactose = Glucose + Galactose Sucrose = Fructose + Glucose Maltose = Glucose + Glucose
Explain how the structure of starch relates to its role in plants?
- Compact molecule, so more energy can be stored.
- Starch is insoluble so it has no osmotic effect.
What are the 2 forms of starch? What are their structures.
Amylose - 1,4 glycosidic bonds and has a helical structure; Unbranched.
Amylopectin - 1,4 and 1.6 glycosidic bonds; branched.
How does the structure of glycogen relate to its function?
- Highly branched
- Allows for rapid hydrolysis of glucose for quick energy release.
Describe the structure and function of cellulose
- Consists of β glucose units joined by 1,4 glycosidic bonds
- Alternate β glucose molecules rotated 180* to allow hydrogen bonding between parallel chains to form myrofibrils.
- Main component of the cell wall in plants.
Describe the structure and function of chitin.
- Component of the cell wall in fungi; found in the exoskeleton of
plants. - Consists of many β glucose molecules joined by 1,4 glycosidic
bonds, but with amino acid side chains. - They also have myrofibrils.
Explain how the structure of a triglyceride and relates to its function as an energy store
- High energy to mass ratio so less of it can be carried around by animals
- They have no osmotic effect as they are insoluble in water
What are the uses for triglycerides in animals?
- Non-polar hydrocarbon chain repels water so it can be used for waterproofing.
- Used for thermal insulation in animals
- Buoyancy for aquatic animals because they are less dense than water
- Protection of internal organs.
What are the uses of triglycerides in respiration?
- Triglycerides can be broken down into glycerol and fatty acids which can be used in respiration.
- Triglycerides release a lot of energy due to the large no. of C-H bonds being broken down.
- Triglycerides are a good source of metabolic water.
What is the structure of a phospholipid?
2 Phospholipids and 1 phosphate molecule attached to a glycerol molecule.
What is the structure of a triglyceride?
- 3 fatty acids attached to 1 glycerol molecule.
Explain how the structure of phospholipids relate to its role in biological membranes
- Phospholipids have a Hydrophilic head and two hydrophobic tails.
- This allows it form a phospholipid bilayer with the hydrophobic tails facing inwards and the hydrophillic heads facing towards the water with the middle being a non-aqueous area.
What is the difference between saturated and unsaturated fats?
- Saturated fats have no C = C bonds and have a straight chain so they are solid at room temp.
- Unsaturated fats have C = C bonds and have a kink in their fatty acid chains so they are liquid at room temp.
What are the implications of unsaturated fat intake on human health?
- Increase in unsaturated fat intake increases the LDL (Low density lipoprotein) cholesterol level.
- This can cause the atheroma to be formed in the coronary arteries which contributes to coronary heart disease.
Describe the general structure of an amino acid
- They ALWAYS contain, C, H, N and O
- They SOMETIMES contain K and S
Attached to the central C atom they have:
- An NH₂ group
- A COOH group
- An R group
- A Hydrogen atom
What are the roles of proteins in the body?
- They have structural roles as they make up muscles and tendons
- They have metabolic roles; enzymes catalyse reactions by breaking down substrates to form products
- The have transport roles; Haemoglobin transports 0₂ the body in the blood.
What is the primary and secondary structure of protiens?
- The primary structure of a protein is the arrangement of amino acids in a polypeptide chain.
- The secondary structure of a protein is the folding or curling of the polypeptide chain into α - helix or a β - pleated sheet due to the formation of hydrogen bonds.
