L5 Amino Acids and Proteins

Question 1

Monomeric units are joined by what type of bonds to form what?

Answer 1

Monomeric units are joined by covalent bonds to form macromolecules

Question 2

Macromolecule/complexes are held together what kind of interactions

Answer 2

by non covalent interactions

Question 3

The formation of macromolecules an complexes involve what type of interaction

Answer 3

weak interaction

Question 4

What does multiple weak interaction’s in the formation of macromolecules and complexes do to the stability of these complexes?

Answer 4

multiple weak interactions increases the stability of these complexes

Question 5

What does breaking these interactions in the formation of macromolecules and complexes do

Answer 5

loss of function and structure

Question 6

solubility depends on what

Answer 6

the ability to form hydrogen bonds

Question 7

Polar biomolecules form what kind of bonds?

Answer 7

H bonds

and are water soluble

Question 8

Can non polar biomolecules form H bonds? and are they soluble in water?

Answer 8

NO
Insoluble in water

Question 9

Amphipathic Molecule

Answer 9

An amphipathic molecule is a molecule that has both polar and non-polar parts.

Question 10

How do the hydrophobic and hydrophilic regions of Amphipathic Molecules react?

Answer 10

Hydrophobic regions cluster together

Hydrophilic regions interact with water

Question 11

micelle

Answer 11

A micelle is a spherical structure that forms in water by the aggregation of surfactant molecules, with their hydrophobic (water-hating) tails inward and hydrophilic (water-loving) heads outward.

Question 11

proteins play crucial roles in virtually all
biological processes, as:

Answer 11

Catalysts – enzymes

Transporters (e.g. O2
, Fe)

Structural support (e.g., collagens in skin
and bone)

Machines (e.g., muscular contraction and
motion)

Immune protection (e.g. immunoglobulins)

Ion channels

Receptors (for hormones,
neurotransmitters, etc.)

Ligands in cell signalling (growth factors
etc.)

Question 12

Key features of proteins

Answer 12

proteins are macromolecules composed of amino acids that are joined covalently to give the sequence of the protein

Question 13

the amino acid sequence of a protein is encoded by what

Answer 13

a gene

Question 14

The nucleotide sequence of a gene determines…

Answer 14

The amino acid sequence of
a protein

Question 15

The polypeptide chain folds into:

Answer 15

complex and highly specific three dimensional structure, determined by the sequence of amino acids

Question 16

The folding of proteins depends on

Answer 16

the chemical and physical
properties of the amino acids

Question 17

The three-dimensional shape of a protein dictates

Answer 17

the properties and
function of the protein

Question 18

proteins are polymers of

Answer 18

amino acids

Question 19

what does an amino acid consist of

Answer 19

Amino acids consist of a central carbon atom (the α-carbon)

covalently bonded to:
* an amino group (-NH2)
* a carboxyl group (COOH)
* a hydrogen atom (-H)
* a distinctive R group (side chain)

Question 20

What isomer is the only isomer found in proteins?

Answer 20

L isomer

Question 21

Peptide bond formation

Answer 21

When two amino acids form a dipeptide through a peptide bond, it is a type of condensation reaction.

Question 22

Peptide bonds are

Answer 22

planar

Question 23

What makes a peptide bond planar ?

Answer 23

The C-N within the CONH peptide bond has partial
‘double bond’ characteristics. This makes the peptide
bond rigid and planar

Question 24

Trans and Cis peptide bonds

Answer 24

TRANS
C alpha on opposite sides of peptide bond

CIS
C alpha on the same side of peptide bond can lead to steric clashes and hence
cis peptide bonds are rare

Question 25

How are amino acids classified?

Answer 25

Classified according to the chemical properties of R groups

Question 26

Classification of amino acids - 20 amino acids

Answer 26

Subcatergorised by
non polar amino acids (Hydrophobic)

Polar uncharged amino acids (hydrophillic)

Polar charged amino acids (hydrophillic)

Question 27

Ionization states of amino acids

Answer 27

Unionised form of and amino acid (NH2) (COOH)

Zwitterion form of an aa (NH3+) (COO-)

Question 28

Non-polar

Answer 28

Nonpolar refers to a substance whose molecules do not have opposite positive and negative poles

Question 29

Polar Molecule

Answer 29

A polar molecule is a molecule containing polar bonds where the sum of all the bond’s dipole moments is not zero.

Question 30

What is an isomer

Answer 30

each of two or more compounds with the same formula but a different arrangement of atoms in the molecule and different properties.

Question 31

ionize meaning

Answer 31

convert (an atom, molecule, or substance) into an ion or ions, typically by removing one or more electrons

Question 32

At certain pH (called ‘pI’), the aa will exist as a Zwitterion - what is the overall charge

Answer 32

and the overall charge will be zero (-1 + 1 = 0)

Question 33

Base accepts or donates proton

Answer 33

Base accepts proton

Question 34

Acid donates or accepts proton

Answer 34

Acid donates proton

Question 35

Types of Bonds between biomolecules

Answer 35

Hydrogen Bonds - bonds between neutral groups or between peptide bonds

Ionic interactions: attraction and repulsion

hydrophobic interaction

van der Waals interaction