Biological molecules

Question 1

Peptide bonds vs Tertiary structure bonds

Answer 1

peptide bond and disulfide bond are covalent bonds ;
differences
tertiary structure bonds are between, R groups / side chains, (of different amino acids ;
H bond / ionic bond / hydrophobic interaction, versus covalent peptide bond ;
A tertiary structure bonds apart from disulfide are not covalent
peptide bond, stronger / more thermostable, than, tertiary structure bonds / two named bonds;
peptide bond is between, carboxylic acid / COOH, and, amino / NH2, group (of the adjacent amino acid) ;

Question 2

What is a macromolecule?

Answer 2

A large biological molecule such as a protein,nucleic acid or carbohydrate

Question 3

What is a monomer?

Answer 3

A relative simple molecule which is used as a basic building block for the synthesis of a polymer.
many monomers are joined together in condensation reactions.
e.g nucleotides,amino acids and monomers

Question 4

What is a polymer?

Answer 4

A giant molecule made from many similar repeating sub units joined together in a chain.
The sub-units are monomers.
E.g polysaccharides,proteins and nucleic acid

Question 5

Define polysaccharide

Answer 5

A polymer whose sub-units are monosaccharides joined together by glycosidic bonds.

Question 6

Define monosaccharide.

Answer 6

A molecule consisting of a single sugar unit with the general formula (CH2O)n

Question 7

Define disaccharide.

Answer 7

A sugar molecule consisting of 2 monosaccharides joined together by a glycosidic bond.

Question 8

What are isomers?

Answer 8

2 forms of the same chemical

Question 9

Monosaccharides of maltose

Answer 9

glucose + glucose

Question 10

Monosaccharides of sucrose

Answer 10

glucose + fructose

Question 11

Monosaccharides of lactose

Answer 11

glucose + galactose

Question 12

What is a glycosidic bond?

Answer 12

a C-O-C link between two monosaccharides formed by a condensation reaction

Question 13

Define primary structure.

Answer 13

The sequence of amino acids in a polypeptide or protein

Question 14

Describe secondary structure.

Answer 14

The structure of a protein molecule resulting from the regular coiling and folding of the chain of amino acids
e.g alpha helices,beta pleated sheets

Question 15

Describe Tertiary structure.

Answer 15

The compact structure of a protein molecule resulting from the 3D coiling of the already folded chain of amino acids.

Question 16

Describe Quarternary structure.

Answer 16

The 3D arrangement of 2 or more polypeptides or of a polypeptide and non-protein component such as Haem,in a protein molecule

Question 17

Hydrophobic interactions occur between?

Answer 17

R groups which are non polar or hydrophobic

Question 18

Disulfide bonds occur between?

Answer 18

Two cysteine molecules,which contain sulfur molecules.

Question 19

What groups form Ionic bonds?

Answer 19

Ionised amine groups(NH3+)

Ionised carboxylic acid(COO)

Question 20

Non-polar vs polar

Answer 20

Polar-differences in electronegativity between bonded atoms

Non-polar-when electrons are shared equal between atoms

Question 21

What breaks down Ionic bonds?

Answer 21

pH changes

Question 22

What breaks down disulfide bonds?

Answer 22

Reducing agents

Question 23

Describe the structure of a globular protein

Answer 23

Non-polar hydrophobic R groups point to the centre of the molecule away from watery surroundings.
The polar,hydrophilic R groups-outside molecule

Question 24

What is responsible for maintaining the solubilty of haemoglobin?

Answer 24

The outward pointing hydrophilic R groups.

Question 25

Which polar amino acid is replaced by Valine( Valine causes sickle cell anemia)?

Answer 25

Glutamic acid

Question 26

Describe the structure of haemoglobin

Answer 26

4 polypeptide chains.
2 B-chains-made of beta globin.
2 A-chains-alpha globin
Each polypeptide chain contains a haem group.
Each haem group contains an Iron atom.
1 oxygen molecule can bind with each iron atom.

Question 27

A complete haem group with 4 haem groups can carry 4 oxygen molecules at a time. How many oxygen atoms can it carry?

Answer 27

8

Question 28

A collagen molecule consists of how many polypeptide chains?

Answer 28

3,each in the shape of a helix(NOT AN A-HELIX)

Question 29

Every 3rd amino acid in a collagen strand is

Answer 29

glycine

Question 30

Three helices are wound together to form a

Answer 30

collagen molecule

Question 31

What are fibrils?

Answer 31

Cross-links holding many collagen molecules side by side.

Question 32

Name the advantages of collagen.

Answer 32

• Flexible

- Tensile strength

Question 33

Why is water important?

Answer 33

-acts a solvent
-transport mechanism
-high specific heat capacity
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