Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BMSC 200 > Chapter 2 + Quiz Questions > Flashcards

Chapter 2 + Quiz Questions Flashcards

1
Q

What is the most abundant molecule in living organisms?

A

Water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What kind of roles does water play in biochemistry?

A

It plays both active and passive roles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What entails water’s passive role in biochemistry?

A

The structure of biomolecules form in response to interaction with water (hydrophobic/philic responses)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What entails water’s active role in biochemistry?

A

Water is a participant in many biochemical reactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Why is water considered the Matrix of Life?

A

It is so critical to our understanding of the molecular basis of life. It is difficult to imagine life in the absence of water, so much so that its presence on other planets is a critical determinant of their habitability by humans

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the result of oxygen being more electronegative than hydrogen?

A

It gives water a permanent dipole

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Oxygen has a partial ___ charge and each hydrogen has a partial ___ charge.

A

Negative, positive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

The dipole of a water molecule influences its ability to:

A
  1. Form electrostatic interactions
  2. Form hydrogen bonds
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are hydrogen bonds?

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Hydrogen bonding can occur between hydrogen and four other elements, which are they an what are the most common?

A

Oxygen and Fluorine which are the most common, Nitrogen and Carbon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

True or False: oxygen and nitrogen can each serve as hydrogen bond donors and acceptors?

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What does the strength of a hydrogen bond depend on?

A

Its geometry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Compare hydrogen bonds to covalent bonds

A

Hydrogen bonds are relatively weak, only about ~5% the strength of a covalent bond. Hydrogen bonds are also about double the length

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Within water, each water molecule has the potential to participate in ___ hydrogen bonds with four other water molecules

A

four

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Each water can donate and accept how many hydrogen bonds?

A

Two

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

The hydrogen bonds between water molecules confer great internal cohesion which influences what?

A

The properties of water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

The large number of hydrogen bonds within water contributes to the high _____ and _____ of water

A

Heat of Vaporization, Specific Heat Capacity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the definition of Heat of Vaporization?

A

The amount heat required to vaporize a liquid at its boiling temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the definition of Specific Heat Capacity?

A

The amount of heat required to raise the temperature of a substance one degree

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

True or False: water has a lower melting point, boiling point, and heat of vaporization than most common solvents?

A

False, it has a higher melting point, boiling point, and heat of vaporization than most common solvents

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Most living organisms are ___, and what does this mean?

A

Isothermic, they need to regulate and maintain their temperatures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What properties of water help us stay cool?

A

The high composition of water within our bodies, coupled with the high specific heat capacity of water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Why does ice float on water?

A

In ice, each water molecule participated in four hydrogen bonds with other water molecules. This ordered arrangement of ice has a lower density than liquid water, and so it floats

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What was polywater?

A

Polywater was a hypothesized polymerized form of water that was the subject of much scientific controversy during the late 1960s. It had a higher boiling point, a lower freezing point, and much higher viscosity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Water molecules have great versatility in interacting with both positively and negatively charged ions by what virtue?

A

Their small size and permanent dipole

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Why are water molecules ideal hydrogen bonding partners?

A

Their small size and ability to serve as either donors or acceptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Biomolecules have functional groups that can form hydrogen bonds. These groups can hydrogen bond with….

A

Within the same molecule, other biomolecules, or with water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Define Hydrophilic

A

“Water loving,” molecules that are polar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Define Hydrophobic

A

“Water fearing,” molecules that are non-polar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Define Amphipathic

A

Molecules that contain both hydrophobic and hydrophilic parts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Many biologically important gases such as carbon dioxide and O2 have limited solubility in water which presents a challenge for their transport, how is this rectified?

A

There are specialized transport proteins and strategies required for their transport

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

When an amphipathic molecule is mixed with water the hydrophilic regions interact favorably with water but what happens to the hydrophobic portions?

A

The hydrophobic regions cluster together to present the smallest
surface to water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What are hydrophobic interactions?

A

The forces that hold the non-polar regions of the molecule together

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What is a primary driving force in the formation and stabilization of biomolecular structures?

A

The hydrophobic drive

35
Q

Most biomolecules represent what?

A

Stable polymers of covalently linked building blocks

36
Q

The three dimensional structures formed by these stable polymers are largely determined through…?

A

Non-covalent interactions

37
Q

Interactions between biomolecules are largely determined by _____ interactions

A

Non-covalent interactions

38
Q

Non-covalent interactions enable:

A
  1. Transient, dynamic interactions
  2. Flexibility of structure and function
39
Q

What is influenced by non-covalent forces?

A
  1. Formation and stabilization of structures of biomolecules
  2. Recognition and interactions between biomolecules
  3. Binding of reactants to enzymes
40
Q

Non-covalent interactions within biomolecules include:

A
  1. Hydrogen bonds
  2. Ionic (electrostatic) interactions
  3. Hydrophobic interactions
  4. Van der Waals interactions
41
Q

True or False: many of the functional groups with biomolecules have hydrogen bonding capacity?

A

True

42
Q

These functional groups that have hydrogen bonding capacity can form hydrogen bonds with:

A
  1. Water molecules
  2. Groups in the same molecule (intramolecular)
  3. Groups in other molecules (intermolecular)
43
Q

Hydrogen bonds are critical for the ___ of biomolecular interactions but not for the ____ of biomolecular structures

A

Specificity, formation

44
Q

True or False: much is to be gained, from a hydrogen bonding perspective, with formation of higher order structures?

A

False, little is to be gained, from a hydrogen bonding perspective, with formation of higher order structures

45
Q

Define electrostatic interactions

A

Interactions between charged groups that can be attractive or repulsive

46
Q

How is the magnitude of the contribution of ionic interactions to biomolecular structures reduced?

A

By the shielding of these groups by water molecules

47
Q

The strength of electrostatic interactions depends on …?

A

The distance separating the atoms and the nature of the intervening medium

48
Q

Describe van der Waals forces

A

The interaction between permanent and induced dipoles. They are short range and low magnitude

49
Q

When is the attraction maximal in van de Waals forces?

A

When two atoms are separated by the sum of the van der Waals radii

50
Q

When two surfaces of ______ _____ come together, a large number of atoms are brought into van der Waals contact

A

complementary shapes

51
Q

Where are van de Waals forces most abundant?

A

In the core of folded proteins

52
Q

What is the hydrophobic effect?

A

The drive to have polar groups interacting with water and non-polar regions shielded away from water

53
Q

The folding of a protein involves the creation of a more ordered state, which seems to be in contradiction to which law of thermodynamics?

A

The 2nd law

54
Q

The water molecules around hydrophobic molecules are more ordered than they would be in pure water. So the introduction of the non-polar molecules causes a _____ in the entropy of water

A

Decrease

55
Q

The association of non-polar molecules/regions releases some of the ordered water molecules, resulting in an ____ in the entropy of water

A

Increase

56
Q

The folding of a polypeptide ____ the entropy of the polypeptide but ____ the entropy of the associated water

A

Decreases, increases

57
Q

What was the conclusion for the question “does water have a memory?”

A

There is no substantial basis for the claim that water can be imprinted with the memory of past solutes

58
Q

Water has a limited tendency to ionize ___ and ____.

A

Hydrogen ions, hydroxide ions

59
Q

Chemical equation for the ionization of water

A

H2O <—-> H+ + OH-

60
Q

What is the equation and value for the Keq?

A

Keq = [H+][OH -] / [H2O] = 1.8 x 10^(-16) M

61
Q

What is the equation and value for the equilibrium constant for the autoionization of water (Kw)?

A

Kw = [H+][OH-] =1.0 X 10^(-14) M^2

62
Q

What is Kw more known as?

A

The ion product of water

63
Q

What is the equation for pH?

A

pH = -log [H+] = log 1/[H+]

64
Q

Example: [H+] = 1 X 10^(-5) M, what is the pH?

A

pH = -log [10^-5] = 5

65
Q

pH is a log scale such that the difference of 1 pH
unit equals a ___ difference in [H+]

A

10-fold

66
Q

How can you distinguish between a strong and weak acid?

A

A strong acid will completely dissociate in water; whereas weak acids do not, and the extent of the dissociation can be quantified

67
Q

How are Ka values often expressed?

A

Ka values often expressed as pKa’s (pKa = -log Ka)

68
Q

What happens when pH = pKa?

A

Then [A-] = [HA]. And the solution is best able to resist changes in pH

69
Q

What is the buffering region?

A

A region where the pH of a solution remains constant. When a weak acid is titrated against a strong base, the pH of the solution rises, levels off through the buffer zone, and then rises quickly to reach the equivalence point.

70
Q

Where is the buffering region?

A

Extends one pH unit on either side of the pKa point. For example: a weak acid with a pKa point of 4.76 would have a buffering range of 3.76 to 5.76

71
Q

What is the relationship between the value of pKa and strength of acid?

A

The lower the pKa, the stronger the acid

72
Q

Why are buffers important to biological systems?

A

Because organisms need to be able to maintain a constant pH. Any changes to pH could alter the protonation state of biomolecules, potentially changing their structure and function

73
Q

Define protonation state

A

Protonation is the addition of a proton to an atom, molecule, or ion

74
Q

What is compensatory respiratory alkalosis?

A

It serves to maintain the ratio of H2CO3/HCO3- to maintain a constant pH

75
Q

Which relationships does the Henderson-Hasselbalch equation describe?

A
  1. The pH of the solution
  2. The pKa of the weak acid
  3. the relative concentrations of the weak acid (HA) and conjugate base (A-)
76
Q

What is the Henderson-Hasselbalch equation?

A

pH = pKa + log( [A-] / [HA] )

77
Q

Calculate the pH of a mixture of 0.01 M acetic acid and 0.1 M sodium acetate. pKa of acetic acid is 4.76

A

pH = pKa + log [A-] / [HA]
pH = 4.76 + log 0.1 / 0.01
pH = 4.76 + 1.0 = 5.76

78
Q

Calculate the pKa of lactic acid given that a mixture of 0.01 M lactic acid and 0.087 M lactate has a pH of 4.80

A

pH = pKa + log [A-] / [HA]
pKa = pH – log [0.087] / [0.01]
pKa = 4.80 – 0.94 = 3.86

79
Q

Which non-covalent forces contribute to the structure and stability of a biomolecule?

A

Hydrogen bonds, Electrostatic interactions, Hydrophobic interactions, Van der Waals Interactions

80
Q

The folding of a polypeptide into its biologically active conformation serves to ___ the entropy of the polypeptide and ____ the entropy of the associated water

A

decrease, increase

81
Q

What is the Henderson-Hasselbalch equation?

A

pH = pKa + log [A-]/[HA]

82
Q

Which non-covalent force is the primary driver for biomolecules to adopt their biologically active conformations?

A

Hydrophobic interactions

83
Q

Molecules with both polar and non-polar groups are called?

A

Amphipathic

84
Q

True or False: in aqueous solutions, [H+] is always equal to 10-7 M?

A

False

BMSC 200 (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions