Module 2

Question 1

Passive role of Water

Answer 1

The structure of biomolecules form in response to interaction with water. For example, protein folding is driven to bury hydrophobic residues

Question 2

Active Role of Water

Answer 2

Water is a participant in many biochemical reactions. For example, peptide bond formation releases a water molecule

Question 3

What do Oxygen and Hydrogen Differ in

Answer 3

ELectonegativhities

Question 4

What is more electronegative

Answer 4

Oxygen is more electronegative than hydrogen, giving water a permanent dipole

Question 5

What abilities does dipole give

Answer 5

Form electrostatic interactions with charged molecules
Form hydrogen bonds (including with other water molecules)

Question 6

Hydrogen Bonds

Answer 6

Electrostatic interactions between an electronegative atom with a hydrogen (donor) covalently linked to another electronegative atom with a free electron pair (Acceptor)

Question 7

Hydrogen bonds

Answer 7

Relatively weak
About double the length of a covalent bond
Strength depends on geometry
Example: Antiparallal beta sheets are stronger than parallel because there is better geometry of hydrogen bonding

Question 8

How many hydrogen bonds can a water molecule donate or accept

Answer 8

2

Question 9

Heat of Vaporization

Answer 9

Amount of heat required to vaporize a liquid at its boiling point

Question 10

Specific Heat Capacity

Answer 10

Amount of hear required to raise the temperature of a substance by one degree

Question 11

Ice

Answer 11

In ice water molecule participates in 4 hydrogen bonds with other water molecules
Ordered arrangement of ice has a lower denser than liquid water as a consequence Ice floats on water

Question 12

Hydrophilic

Answer 12

Water loving (Molecules are polar)

Question 13

Hydrophobic

Answer 13

Water fearing (Molecules are non polar)

Question 14

Amphipatic molecules

Answer 14

Contain both hydrophobic and hydrophilic

Question 15

Non covalent forces influence

Answer 15

Formation and stabilization of structures of biomolecules
Recognition/interactions between biomolecules
Binding reactants to enzymes

Question 16

Non covalent interactions enable

Answer 16

Transient and dynamic interactions
Flexibility of structure and function

Question 17

Non Covalent interactions within biomolecules includes

Answer 17

hydrogen bonds
Ionic (Electrostatic interactions)
Hydrophobic interactions
Van der Waals Interactions

Question 18

Hydrogen Bonds

Answer 18

Many of the functional groups with biomolecules have hydrogen bonding capacity

Question 19

Hydrogen bonds impact on biomolecular structures

Answer 19

Critical for specificity and NOT for Formation of biomolecular structures

Question 20

Hydrophobic effect

Answer 20

Drive to have polar regions to interact with water and non polar regions shielded away from water

Question 21

Thermodynamics of the Hydrophobic effect

Answer 21

Water molecules around hydrophobic molecules are more ordered than they would be in pure water. Such as an introduction of the non polar molecule causes decrease in the entropy of water

The association of non polar molecules released some of the ordered molecules resulting in an increase in entropy of wattle

Question 22

Entropy in a polypeptide

Answer 22

Folding of a polypeptide decreases the entropy of the polypeptide but increases the entropy of the associated water

Question 23

Strong acids and bases

Answer 23

Completely dissociate with water

Question 24

Weak acids and bases

Answer 24

Do not dissociate completely in H20

Question 25

Lower the pKA

Answer 25

The stranger the acids