Test 1

Question 1

What makes carbon such an abundant element in biomolecules?

Answer 1

it forms stable covalent bonds by electron pair sharing

Question 2

Which of the following is true for the polymerization reactions that produce proteins, polysaccharides and nucleic acids.

Answer 2

They involve bond formation by the elemination of water

Question 3

Which of the following is a true statement about non-covalent bonds?

Answer 3

Hydrogen bonds, ionic bond and hydrophobic interactions

all carry a degree of

specificity while van der Waals interactions are induced.

Question 4

Which of the following is the correct order of the molecular organization in the cellular hierarchy?

Answer 4

water, pyruvate, amino acids, proteins, ribosomes

Question 5

When the relative strengths of non-covalent bonds are

determined by the size of the

atoms as well as the distance between them, this describes:

Answer 5

Van der Waals interactions

Question 6

All of the statements about structural complementarity are true EXCEPT.

Answer 6

produces strong irreversible interactions.

Question 7

Rank the following bonds in order of increasing bond strength.

Answer 7

Van der Waals, electrostatic, hydrogen bond, covalent single bond

Question 8

Membrane structures are maintained primarily by:

Answer 8

hydrophobic interactions.

Question 9

Which of the following characteristics is specific for prokaryotic cells, but NOT eukaryotic cells?

Answer 9

Prokaryotic cells lack a cytoskeleton.

Question 10

What ionic forms of phosphoric acid are present at pH 7.0.

The pKas of phosphoric acid are 2.1, 7.2, and 12.4.

Answer 10

H2PO4^- and HPO4^-2

Question 11

Addition of ethanol to a solution of magnesium chloride would result in all the following except

Answer 11

A decrease in the electrostatic force between the Mg 2+ and the Cl-ions

Question 12

When nonpolar molecules are dissolve in water, which of the following is true

Answer 12

the nonpolar molecule produces a reorganization of water surrounding the molecule, effectively decreasing the hydrogen bonding network in water

Question 13

Addition of glucose to water results in all of the following effects EXCEPT.

Answer 13

The lowering of the boiling point of the solution.

Question 14

Which of the following is true about buffer systems?

Answer 14

They will have an area on their titration curve where the greatest buffering capacity exists

Question 15

Intracellular pH is maintained primarily by the ________ and __________ buffer systems, and the extracellular pH by the ____________ buffer system.

Answer 15

HPO42-/ H2PO4-, histidine, HCO3-/ H2CO3

Question 16

Which statment is incorrect about macromolecules?

Answer 16

Carbohydate polymers are compsed of monosaccarides linked by ester bonds

Question 17

All of the following activities require the presence of ATP or NADPH EXCEPT.

Answer 17

none, they are all energy-requiring activities

Question 18

All will cause the denaturation of a protein EXCEPT.

Answer 18

Refrigeration.

Question 19

All of the following characteristics are associated with the solvent water EXCEPT:

Answer 19

low heat capacity.

Question 20

Thermodynamics does NOT:

Answer 20

provide information on the rate of a reaction.

Question 21

Living systems are:

Answer 21

open systems exchanging both energy and matter with their surroundings.

Question 22

An example of an open system would be:

Answer 22

a gas burner/ a pot of boiling water

Question 23

Which example has the greatest increase in entropy, Triangle S?

Answer 23

sublimation of CO2

Question 24

Calorimeter measures ______________ by a biochemical process.

Answer 24

heat absorbed or given off

Question 25

The second law of thermodynamics states that:

Answer 25

Naturally occurring processes proceed to a state of minimum potential energy

Question 26

The enthalpy of a system may not change from state 1 to 2 by a change in

Answer 26

entropy

Question 27

When are enthalpy internal energy equivalent?

Answer 27

When there is no PV work accomplished

Question 28

If △G for a reaction is negative, then

Answer 28

△ S can be either negative or positive

Question 29

Which of the following sentence about spontaneity is correct?

Answer 29

A reaction with a negative △G will be spontaneous

Question 30

The reaction A+B→C+D is to be at equilibrium when

Answer 30

Its energy charge △G is zero

Question 31

What is the energy change of a solution when a salt, such as MgCl2, is dissolved in water?

Answer 31

Decrease

Question 32

An important characteristic of living system is that they

Answer 32

Are never at equilibrium

Question 33

Which of the following processes has a negative change in entropy?

Answer 33

the hydration of Na+ion

Question 34

The subunits of many oligomeric proteins associate as the temperature is increase from 4 °C to room temperature. Which of the following is best explanation for this effect?

Answer 34

The term –T ΔS becomes more negative at higher temperatures making the ΔG of association more negative

Question 35

ATP exhibits which of the following characteristics

Answer 35

It is a thermodynamically stable molecule

Question 36

Consider the following reaction which has a △G of +0.64 kj/mol succinate + Q <——>fumarate + QH2. These four compounds are mixed at 0.01M each and allowed to equilibrium. Which statement is correct about the resulting concentration of Q at equilibrium?

Answer 36

[QH2] < [Q]

Question 37

Thermodynamic parameters (entropy, enthalpy, free energy, and internal energy) are given for an unknown enzyme. Explain which results would be expected for the breaking of hydrogen bonds and the exposure of hydrophobic groups from the interior during the unfolding process of a process of a protein.

Answer 37

enthalpy change, △H, is positive

Question 38

All of the statements below about metabolism are true except:

Answer 38

Metabolism occurs in the mitochondria of prokaryotes

Question 39

Which of the following statements about water is false:

Answer 39

Pure liquid water consist of H2O molecule in a highly ordered three dimensional network of hydrogen bonds

Question 40

For a weak acid solution pH=pKa when

Answer 40

[A-]=[HA]

Question 41

Buffers have all of the following characteristics except they:

Answer 41

Buffer best for polyprotic acids halfway between the two pKa values

Question 42

An example of a system at equilibrium would be:

Answer 42

death of a fucking living system fuck this shit

Question 43

Which of the following cannot function as a hydrogen bond donor to water at pH 3.0?

Answer 43

Acetylaldehyde

Question 44

Which of the following weak acid would makes the beat buffer at pH = 5.0?

Answer 44

Acetic acid (ka= 1,7 x 10^-5