Water And Ph

Question 1

Water balance is regulated by

Answer 1

Hypothalamus (controls thirst)
ADH
Kidneys
Evaporative loss

Question 2

The acidity of aqeous solutions is generally reportd using the

Answer 2

Logarithmic pH scale

Question 3

Acid base imbalances are verified by measuring

Answer 3

pH of arterial blood

Co2 content of venous blood

Question 4

Causes of metabolic acidosis (ph

Answer 4

Diabetic ketosis

Lactic acidosis

Question 5

Causes of metabolic alkalosis

Answer 5

Vomiting of gastric contents

Question 6

Inability to concentrate urine or adjust to subtle changes in extracellular fluid osmolarity

Answer 6

Nephrogenic diabetes insipidus

Cause: unresponsiveness of renal tubular receptors to ADH

Question 7

Water forms a high dielectric constant

Answer 7

Water greatly decreases the force of attraction between charged and polar species

Enables water to dissolve large quantities of charged compounds such as salt

Question 8

Hydrogen bonding profoundly influences the physical properties of water and accounts for water’s

Answer 8

High viscosity
Surface tension
Boiling point

(These hydrogen bonds are weak transient - requires only 4.5kcal/mol)

Question 9

Enables water to dissolve many organic biomolecules that contain functional groups wc can participate in Hydrogen bonding.

Answer 9

Hydrogen bonding

Question 10

The o2 atoms of -, -, and - provide lone pairs of electrons that can serve as hydrogen acceptors.

Answer 10

Aldehydes
Ketones
Amides

Question 11

Can serve both as hydrogen acceptors and as donors of unshielded hydrogen atoms for formation of hydrogen bonds

Answer 11

Alcohol
Carboxylic acid
Amines

Question 12

Is a link between two atoms in which electrons are being SHARED between them; STRONGEST force that holds molecules together

Answer 12

COVALENT BOND

Question 13

Does not involve the sharing of pairs of electrons but rather involves more dispersed variations of electromagnetic interactions

Answer 13

Non covalent bond

4 types
Hydrogen bond
Ionic bonds
Van der Waals
Hydrophobic interactions

Question 14

Groups interact w each other to extrude water molecules

Answer 14

Hydrophobic forces

Question 15

Fluctuations in electron clouds around molecules oppositely polarize neighboring atoms

Answer 15

Van der Waals

Question 16

Attraction between opposite charges

Answer 16

Electrostatic forces

Question 17

Fxns of non covalent bond

Answer 17

Holds together the 2 strands of DNA in the double helix

Stabilizes secondary and tertiary structures of proteins

Enables enzyme-substrate binding and antibody antigen association

Question 18

Non covalent bonds can either be

Answer 18

Attractive or repulsive

Question 19

Biomolecules fold to

Answer 19

Position polar and charged groups on their sufaces

Question 20

Have both hydrophilic and hydrophobic groups

Answer 20

Amphipathic molecules

Question 21

Amphipathic molecules fold with _____ side chains in the interior

Answer 21

Hydrophobic

Aa w charged or polar chains - hydrophilic - surface

Question 22

Dictate that macromolecules expose the polar (hydrophilic) regions to an aqueous interface and bury the non polar (hydrophobic) regions

Answer 22

ENTROPIC FORCES

Question 23

Maximizes formation of charge-dipole, dipole-dipole and hydrogen bonding bet polar groups on the biomolecule and water

Answer 23

Phospholipid bilayer

Question 24

Tendency of non polar compounds to self associate in an aqueous environment

Answer 24

Hydrophobic interaction

Question 25

The optimal free energy of a hydrocarbon water mixture is a fxn of both

Answer 25

Maximal enthalpy (from hydrogen bonding)
Minimum entropy (max degrees of freedom)

Question 26

Any attractive forces that are due to the presence of ionized chemical entities and to the electronegative and electropositive properties of these atoms ….

Answer 26

ELECTROSTATIC INTERACTIONS

Question 27

Electrostatic interactions between oppositely charged groups

Answer 27

Salt bridges

Almost same w hydrogen bonds but act over LONGER DISTANCES

Question 28

Electrostatic interactions bet charged group

Answer 28

Help shape biomolecular structures

Question 29

Sum of the attractive/repulsive forces bet molecules, also called totality of intermolecular forces

Answer 29

Van der Waals forces

-weaker than hydrogen bonds, act over short distances

Question 30

Van der waals forces arise from

Answer 30

Attractions between transient dipoles

Question 31

Illustrates the contribution of multiple forces to the structure of biomolecules

Answer 31

DNA DOUBLE HELIX

each individual strand of DNA - covalent bond

Question 32

Interaction bet stacked purine and pyrimidine

Answer 32

Van der Waals

Question 33

Interaction bet nucleotide base (watson- crick base pairing)

Answer 33

Hydrogen bonding

Question 34

Helix presents the

Answer 34

Charged phosphate groups and polar ribose sugars

Question 35

Protein catalysts that accelerate the rate of hydrolytic rxns

Answer 35

Enzymes (proteases and nucleases)

Proteases - catalyze hydrolysis of proteins into their component amino acids

Nucleases- phosphoester bonds- DNA

Question 36

Group transfer reactions responsible for the synthesis of macromolecules involved the

Answer 36

Unfavored formation of covalent bonds

Question 37

Is of central importance to life

Answer 37

Ability of water to ionize

Water acts both as an acid and as a base

Question 38

May represented as an intermolecular proton transfer that forms a hydronium ion and hydroxide ion

Answer 38

Ionization of water

Question 39

Introduced by sorensen in 1909

Answer 39

pH

Question 40

Water is a dipole: a molecule with electric charge distributed symmetrically. TRUE OR FALSE

Answer 40

FALSE. ASYMMETRICALLY