water

Question 1

you are running your first marathon on a warm day. you start to sweat heavily and realize that you may be in danger of dehydration. why is severe dehydration potentially life threatening

Answer 1

• water is a solvent for many biomolecules
• water is a chemical participant in many biological reaction
• water is necessary for buffering action in the body
• water’s attraction to itself drives hydrophobic interactions

Question 2

hydrogen bonds

Answer 2

the attraction between the oxygen atom of the water molecule and the hydrogen atom of molecule constitute a hydrogen bond

Question 3

pH is

Answer 3

varying the pH of a solution will alter the degree of ionization of an ionization group in that solution

Question 4

consider a weak acid in a solution with pH of 5.0. the [H+] is

Answer 4

10^-5 M

Question 5

water derives all its special properties from its

Answer 5

polarity and hydrogen - bonding capacity

Question 6

the pka values for three ionizable groups on tyrosine are pka(-COOH)= 2.2, pka(-NH3)= 9.11 and pka(-R)=10.07. in which pH ranges will this amino acid have the greatest buffering capacity

Answer 6

at pH between 9 and 10

Question 7

in a typical eukaryotic cell the pH is usually around 7.4. what is the [H+] in a typical eukaryotic cell

Answer 7

4*10^-8

Question 8

carbonic acid has a Ka of 1.7010^-4 and acetic acid has a Ka of 1.7410^-5 then acetic acid is a weaker acid and has tendency to

Answer 8

lose its proton compared to carbonic acid

Question 9

as climber approach a summit of a mountain they usually increase the rate of breathing to compensate for the thinner air due to the lower oxygen pressure at higher elevation. this increased ventilation rate results in a reduction in levels of CO2 dissolved in the blood. it will result in

Answer 9

an increase in the association of H^+ +HCO3———- H2CO3 and increase in pH

Question 10

you mix 100 ml of solution of pH 1 with 100 ml of a solution of pH 3. the pH of the new 200 ml solution will be

Answer 10

between pH 1.0 and pH 2.0

Question 11

the pH of the sample of blood is 7.4 , the pH of the sample of gastric juice is 1.4. the blood sample has an [H+]

Answer 11

a million times lower than that of gastric juice

Question 12

peptide bond is

Answer 12

a substituded amide linkage

formed in condensation reaction