1.1 - Biological Compounds Flashcards
(a)
Name the four key inorganic ions and their roles in living organisms
Magnesium ions (Mg2+):
Used to produce chlorophyll
Iron ions (Fe2+):
Manufacture of haemoglobin
Calcium ions (Ca2+):
Strengthening/hardens bones and teeth
in animals; cell walls in plants.
Phosphate ions (PO43-):
Used to produce ADP and ATP
1.1- Biological compounds
Structure of water
Water has the chemical formula of H2O.
Water consists of one oxygen atom joined to two hydrogen atoms by covalent bonds.
The molecule is a dipole.
The oxygen atom has a slight negative charge / δ-, the hydrogen atoms have a slightly positive charge δ+.
(b)
The importance of water in terms of its polarity
O is more electronegative than H. O attracts the electron density in the covalent bond more strongly, forming δ- O and δ+ H
(b)
The importance of water in terms of its ability to form hydrogen bonds
Weak intermolecular forces of attraction form between a lone pair on a δ- O and a δ+ H on an adjacent molecule
(b)
The importance of water in terms of its surface tension and as a solvent
Surface tension:
Support and buoyancy.
Solvent:
Polar molecules dissolve in water and are able to be transported.
(b)
Why is the high surface tension of water important for organisms?
Enables the transport of water and nutrients through plants stems and small blood vessels in the body Allows small insects to ‘walk’ on water
(b)
The importance of water in terms of its thermal properties and as a metabolite
Thermal properties:
High specific heat capacity- a lot of energy is required to change the temperature of water so aquatic/cellular environments remain stable.
High latent heat of vaporisation- evaporative cooling.
Metabolite:
Water is a reactant in photosynthesis and hydrolysis, produced in aerobic respiration and condensation reactions.
(b)
Properties of water
Ice is less dense than water which means ice floats insulating the water below allowing organisms to survive.
Cohesive/forms hydrogen bonds allowing the movement of water
(c)
Condensation reaction
A chemical reaction in which two molecules combine to form a larger molecule, with the elimination of a small molecule, usually water.
(c)
Hydrolysis reaction
A chemical reaction in which a molecule is broken down into smaller molecules by the addition of water.
(c)
What are monosaccharides?
Monosaccharides are the simplest form of carbohydrates, made up of a single sugar unit.
(c)
Name three types of monosaccharides based on the number of carbon atoms.
Triose (3 carbons), pentose (5 carbons), and hexose (6 carbons).
Role of triose, pentose and hexose sugars in cells
Triose:
Important in respiration and
photosynthesis.
Pentose:
Important in nucleotides.
Hexose:
It is used in respiration.
(c)
Give an example of a hexose sugar.
Glucose is an example of a hexose sugar.
(c)
What are disaccharides?
Disaccharides are carbohydrates made of two monosaccharide units bonded together.
(c)
Name three common disaccharides.
Sucrose, lactose, and maltose.
(c)
Which monosaccharides make up sucrose?
Glucose and fructose linked in a condensation reaction where one molecule of water is lost and a glycosidic bond is formed.
(c)
Which monosaccharides make up lactose?
A dimer formed from glucose and galactose.
(c)
Which monosaccharides make up maltose?
.α−glucose and α−glucose linked in a condensation reaction where one molecule of water is lost and a glycosidic bond is formed.
(c)
What are polysaccharides?
Polysaccharides are polymers made up of hundreds of monosaccaharide units.
(c)
Name four examples of polysaccharides.
Starch, glycogen, cellulose, and chitin.
(c)
Starch
Function:
Compact energy storage in plants with little osmotic effect.
Strucure:
A polymer of α−glucose (composed of straight-chain amylose and branched
amylopectin).
(c)
Glycogen
Function:
Energy storage in animals.
Structure:
A polymer of α−glucose.
(c)
Cellulose
Function:
A strong structure for plant cell walls.
Structure:
A polymer of β−glucose, adjacent monomers twisted through 180° to each other, allowing hydrogen bonds between chains, forming microfibrils.
