Macromolecules

Question 1

Macromolecule

Answer 1

very large molecule that consists of many structural units with similar chemical properties
Except for lipids, macromolecules are polymers

Question 2

Polymers

Answer 2

A large molecule composed of multiple
repeating (chemically similar) subunits, called monomers –
that are attached to each other through covalent bonds.
monomer polymer
(chemically similar)
covalent bon

Question 3

NAs

Answer 3

Nucleic acids are formed from four kinds of nucleotide monomers
(adenine, guanine, thymidine, cytosine) linked together by covalent bonds in
long chains

Question 4

Proteins

Answer 4

formed from 20 kinds of amino acid monomers linked
together by covalent bonds in long chains.
amino acids protein
Proteins
(polymers)

Question 5

Carbs

Answer 5

formed from monosaccharide (sugar)
monomers linked together by covalent bonds in giant structures.

Question 6

Lipids
(not polymers)

Answer 6

formed from a small set of smaller molecules, but in
this case noncovalent forces maintain the interactions between
the fatty acid monomers.

Question 7

Condensation reactions form polymers from monomers
(polymerization).

Answer 7

Hydrolysis reactions break down polymers into monomers.
monomerH OH monomerH OH
H2O
monomerH monomer OH
+
 Molecular basis of polymer break down.

Question 8

How many bonds does carbon form?

Answer 8

4 covalent bonds

Question 9

What’s a covalent bond

Answer 9

Covalent bonds are formed when elements share electrons

Question 10

Why do elements form bonds

Answer 10

To become stable.
They want to have a full outer shell.

Question 11

Single pair of e-

Answer 11

Single covalent bond

Question 12

2 pairs of e-

Answer 12

double bond

Question 13

3 pairs of e-

Answer 13

triple bond

Question 14

Carbon-carbon bond types

Answer 14

alkane
alkene
alkyne

Question 15

Saturated Molecules

Answer 15

Alkanes are carbon-based molecules with single covalent bonds
between carbons. These are called saturated molecules.
There is a SINGLE covalent bond between
carbons.
This is a SATURATED molecule.
You cannot possibly add more H atoms to
this molecule
Single bonds = saturated

Question 16

Unsaturated molecules

Answer 16

alkenes and alkynes are unsaturated molecules – alkenes have double bonds; alkynes have triple bonds. Unsaturated molecules

There are DOUBLE/TRIPLE
covalent bonds between carbons.
These are UNSATURATED
molecules.

These double or triple bonds can
be broken, and more hydrogen
atoms can be added to these
molecules.

Double/triple bonds = unsaturated

Question 17

Why is electronegativity/polarity important in biology?

Answer 17

Polarity enables molecules to form hydrogen bonds.

Question 18

Polar Molecules

Answer 18

Polar molecules have slightly more positive or negative
regions that can interact with water through hydrogen
bonding
These molecules are called ‘hydrophilic’ molecules

Question 19

Non polar molecules

Answer 19

In non-polar molecules charge is equally
distributed throughout the molecule. =
They DO NOT HAVE slightly more
negative/positive regions that can interact
with water.
 These molecules are called
‘hydrophobic’ molecules.
 Non-polar molecules CANNOT form
hydrogen bonds with water.

Question 20

How do functional groups confer hydrophobicity/
hydrophilicity?

Answer 20

in general, a functional group will make a macromolecule more
hydrophilic because most functional groups have polarity
(charge).

Question 21

What’s a functional group

Answer 21

Groups of atoms in organic molecules that determine the
physical and chemical properties of molecules

Question 22

Aromatic ring Structured hydrocarbons

Answer 22

typically
hydrophobic.
example: Benzene structure

Question 23

Electronegativity

Answer 23

measure of the tendency of an atom to attract a bonding pair of electrons

Question 24

Summary of electronegativity

Answer 24

*The higher the electronegativity, the more the atom likes to keep
hold of electrons.
* Electronegativity creates polar bonds (positive charge at one end,
negative charge at the other).
* Molecules that have polar covalent bonds can interact with water
through hydrogen bonding. These are hydrophilic molecules.
* Molecules that do not have polar bonds cannot interact with water
through hydrogen bonding. These are hydrophobic molecules

Question 25

FGs on hydrophobicity etc

Answer 25

• Functional groups typically confer hydrophilic characteristics.
• Aromatic structures typically confer hydrophobic characteristics

Question 26

Isomerism

Answer 26

The atoms in a functional group can be arranged differently –
which will result in differences in structural, functional and
chemical properties

Question 27

Structural

Answer 27

Structural isomers are compounds that have the
same molecular formulae but different structural formulae.
Example 1: Butane and isobutane - C4H10

Question 28

Geometric (cis-trans) isomers

Answer 28

cis- and trans- isomers are compounds that have the same atoms
connected to each other, however the atoms are differently
arranged in space.

Example 1: cis-2-Butene and trans-2-Butene - C4H8

Question 29

2b- Optical isomerism

Answer 29

Optical isomerism occur when a carbon atom has four different
atoms or groups of atoms attached to it. This carbon is called the
chiral carbon (chiral centre).
Optical isomers are also known as ‘enantiomers’.

Question 30

Chiral Carbon

Answer 30

Chiral carbon will have 4 different atoms/groups
attached to it.

Question 31

How do we distinguish between optical isomers (enantiomers)?

Answer 31

By using light polarization.

Question 32

D form (RHS) e.g Natural Sugars

Answer 32

D-form of the chiral sample (for example D-glucose)
(rotates the plane of polarized light to right - clockwise)
D comes from dextrorotary

Question 33

L- Form (LHS) e.g AAs

Answer 33

L-form of the chiral sample (for example L-glucose)
(rotates the plane of polarized light to left - anticlockwise)
L comes from levorotary.

Question 34

Summary of Plane Polarised Light

Answer 34

• Solutions of chiral chemical compounds
  change the plane in which the light is
  polarized.
• Each enantiomer of a pair rotates the plane
  of the light by the same amount, but the
  directions of rotation are opposite.
• If one enantiomer rotates the plane of the
  light to the right (D-form), the other rotates
  it to the left (L-form).