Lesson 2: Review: Organic Compounds

Question 1

Carbon

Answer 1

Carbon is unique in several
ways;

Carbon has 4 available
binding sites

Carbon can form single,
double or triple covalent
bonds

Carbon is able to bond
covalently with a large
number of elements

Carbon can form both long
chains and rings of atoms

Tetrahedral structure
when bound allows for
isomerism

Question 2

Organic Compounds

Answer 2

Compounds containing carbon found in living organisms

Not including carbonates, hydrogen carbonates, CO2 or CO

Often based upon a skeleton of carbon

Evolution has chosen a few for use in living organisms

There are four principal groups: sugars, fatty acids, amino acids and nucleotides

Question 3

Carbohydrates

Answer 3

Organic molecules commonly referred to as
sugars.

Made up of carbon, hydrogen and oxygen. The
general formula is C(H2O)n

There are three types of carbohydrates

Monosaccharides

Disaccharides

Polysaccharides

Question 4

Monosaccharides

Answer 4

Monosaccharides are the simplest form of carbohydrates.

Contain a carbonyl group and at least two hydroxyl groups.

Empirical formula is CH2O.

6 carbon monosaccharides include glucose, fructose and galactose. (hexose
sugars)

5 carbon monosaccharides include ribose and deoxyribose (pentose sugars)
All hexose sugars have the
molecular formula C6H12O6.
However, there are many
isomers.

Question 5

Straight Chain and Cyclic
Structure

Answer 5

The previous slide contained the straight chain structure of three
monosaccharides.

The carbons are numbered starting at the carbonyl group.

However, in aqueous solution monosaccharides adopt a ring structure.

This occurs as a result of an intermolecular reaction between the
aldehyde group on C1 and the OH group on C5

Question 6

Ring Structure Isomers

Answer 6

The intermolecular reaction that
causes the ring structure to from
in aqueous solution produces an
asymmetric carbon at C1.

Therefore, there are two ring
structure isomers of glucose called
α-glucose and β-glucose.

The difference has an effect on the
properties of their polymer.

Question 7

Condensation Reactions

Answer 7

Monosaccharides undergo condensation reactions in order to from
disaccharides and polysaccharides.

Hydroxide groups on adjacent monosaccharides react to form a bond, known as
a glycosidic link, and a molecule of water.

Two molecules of α-glucose condense to form a 1-4 glycosidic link which
produces the disaccharide maltose.

Question 8

Disaccharides

Answer 8

Disaccharides are composed of two monosaccharides joined together.

Combining different monosaccharides produces different disaccharides.

Disaccharides are soluble molecules that can be broken down into their
component monosaccharides through acid hydrolysis or by enzyme catalysed
reactions (digestion)

Question 9

Polysaccharides

Answer 9

Polysaccharides are long chains of monosaccharides held together by glycosidic
bonds.

Have large molar mass, are not sweet, are insoluble or slightly soluble in water
and are non-reducing.

Polysaccharides differ in the nature of their recurring monosaccharide, their
bonds, the length of their chains and the degree of branching.

Question 10

Glucose Based Polysaccharides

Answer 10

There are three common glucose based polysaccharides.

Starch

Glycogen

Cellulose