Brainscape's Knowledge GenomeTM

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


See full index

BIOL 2421 - Cellular Biochem > 1. Water and bonding > Flashcards

1. Water and bonding Flashcards

1
Q

what type of elements make up 97% of the weight in most organisms? What is another name for them?

A

nonmetallic elements

called bulk elements

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

how many bulk elements are there? What are they?

A

there are 6:

C, H, N, O, P, S

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

what are the elements called that make up the remaining 3% of weight in living organisms?

A

they’re called trace elements

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

list the 5 essential trace elements

A

Ca2+, K+, Na+, Mg2+, Cl-

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

what are three possible shapes of covalently linked carbon chains

A

linear, branched, cyclic

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

how are macromolecules assembled

A

assembled from smaller and simper monomeric precursors

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

how are monomeric units usually held together

A

via covalent bonds

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

T or F: Supramolecular complexes are held together by covalent bonds

A

False! They’re held together via non-covalent interactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

List the non-covalent interactions that hold together supramolecular complexes

A

hydrogen bonds, ionic interactions, hydrophobic effect, and van der Waals forces

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

what is the role of a functional group

A

functional groups help confer the chemical properties of a molecule

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

describe “conformation”

A

conformations are due to bond rotation of a molecule. No bonds are broken, but different spatial arrangement creates stereoisomers

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

define stereoisomers

A

molecules with the same chemical formula and bonds, but different fixed arrangements of atoms

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

describe “configuration”

A

a configuration is a different arrangement of the atoms in a molecule, due to the breakage of bonds

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

T or F: a double bond cannot rotate

A

true

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

since double bonds cannot rotate, can geometric (cis/trans) isomers have different conformations?

A

No, only configurations, because we cannot rotate so bonds would have to be broken

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

what is a chiral carbon

A

a carbon bound to 4 different groups

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

for each chiral carbon, how many stereoisomers can there be

A

2

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

define enantiomers

A

two molecules that are mirror images of each other (non superimposable)

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

define diastereomers

A

molecules are diastereomers if they are not enantiomers

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

how much mass does water account for in most cells

A

60-90%

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

what about water molecules influence the cell structure and properties of all cell components?

A

the attractive forces between water molecules and the tendency of water to ionize

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

T or F: water’s strength as a solvent influences the strength and specifics of interactions between biomolecules

A

true

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

how does water as a solvent differ from other solvents?

A

water has the highest mp, bp, heat of vaporization, and specific heat

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

define specific heat

A

specific heat is the energy input required to raise the temperature by 1 degree

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

what are the four types of weak interactions that are important for the function and structure of water

A

hydrogen bonds, charge-charge interactions, Van der Waals forces, and hydrophobic effect

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

what are 3 important functions of water for life on earth

A

cohesion, density, solvent

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

how many electrons does a water molecule have

A

8

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

where are the 8 electrons of a water molecule located within the molecule

A

the oxygen has 6, and these are in the outer shell, each H has 1

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

what orbitals do the 6 oxygen electrons occupy

A

four sp3 hybrid orbitals

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

what is the shape of a water molecule? why?

A

a tetrahedron; formed by the four sp3 hybrid orbitals

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

describe the corners of a tetrahedron water molecule

A

two corners have H’s, two corners have lone paired electrons

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

what are the bond angles of a perfect tetrahedron?

A

109.5 degrees

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

what are the bond angles of a water molecule tetrahedron

A

104.5 degrees

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

why are the bond angles of water smaller than that of a perfect tetrahedron?

A

the oxygen nucleus attracts electrons more strongly than the hydrogen nucleus. The shared electrons in the O-H bonds spend more time near O than near H, so this unequal sharing results in two electric dipoles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

what charge does each atom in a water molecule have due to the dipoles

A

oxygen has a partial negative charge (g-) and hydrogens have a partial positive charge (g+)

36
Q

what makes a molecule polar

A

the presence of a net dipole

37
Q

in what directions on the periodic table does electronegativity increase

A

increases to the right and up

38
Q

T or F: hydrogen bonds are weaker than covalent bonds

A

true! they’re ~20 times weaker

39
Q

T or F: hydrogen bonds are shorter than covalent bonds

A

false! they’re ~2 times longer

40
Q

describe the lifetime of a hydrogen bond

A

lasts 10-12 seconds, constantly associating and disassociating (ie flickering)

41
Q

T or F: the sum of all the hydrogen bonds confers great internal strength to liquid water

A

true

42
Q

how many hydrogen bonds can water form in ice

A

4

43
Q

why is there a high melting point of water

A

because water in ice can form 4 hydrogen bonds, and it requires much thermal energy to break so many

44
Q

T or F: it is very easy to break the 4 hydrogen bonds of ice to melt it

A

false! it requires much thermal energy to break these bonds and melt ice

45
Q

how many hydrogen bonds are formed in liquid water

A

3.4, because water is less organized and in continuous motion

46
Q

why does liquid water form only 3.4 hydrogen bonds as compared to ice which forms 4?

A

liquid water is less organized and in continuous motion, so it only forms 3.4 hydrogen bonds

47
Q

what structure does ice have

A

a lattice structure

48
Q

T or F: water atoms are more spread out in a lattice structure

A

true

49
Q

since water atoms are more spread out in a lattice structure (ice), what does this mean about the density

A

ice is less dense than water

50
Q

describe a hydrogen bond

A

it’s a bond between an electronegative atom and hydrogen (but the hydrogen must be COVALENTLY bound to it’s own electronegative atom)

51
Q

in a hydrogen bond, what does it mean that the H needs to be covalently bound to it’s own electronegative atom before it can create the hydrogen bond?

A

the H must be covalently bound to its own electronegative atom, meaning it must have a partial positive charge (must be POLAR)

52
Q

in what shape are hydrogen bonds the strongest

A

strongest when they’re linear

53
Q

why are hydrogen bonds strongest when they’re linear

A

this maximizes the electrostatic attraction between the atoms

54
Q

T or F: there is a stronger interaction between water molecule’s at the water-air interface

A

true

55
Q

explain why there’s a stronger interaction between water molecules at the water-air interface

A

water molecules that aren’t at the surface form hydrogen bonds in all directions. Water molecules at the surface only have hydrogen bonds in 3 directions, so they become more strongly bound to the water molecules beside them

56
Q

what is the result of water molecules having a stronger interaction at the water-air interface?

A

surface tension

57
Q

what are charge-charge interactions

A

these are electrostatic interactions between two charged particles (including ionic bonds)

58
Q

T or F: charge-charge interactions are the weakest noncovalent forces

A

false! they’re potentially the strongest noncovalent forces

59
Q

T or F: charge-charge interactions extend over greater distances than other noncovalent forces

A

true

60
Q

how are salt bridges formed in many proteins

A

formed when there are charge-charge interactions between oppositely charges protein side chains (R groups)

61
Q

T or F: most biomolecules are either polar or charged

A

true

62
Q

what are examples of biomolecules that are polar/charged

A

sugars and amino acids

63
Q

what solvent easily dissolves most biomolecules

A

water

64
Q

how does water dissolve salts?

A

does so by hydrating the ions, which weakens the electrostatic interactions between them

65
Q

T or F: salts have a greater entropy when dissolved

A

true; when dissolved, they have much greater freedom of movement = greater entropy

66
Q

T or F: water is effective at screening electrostatic interactions as a solvent

A

true

67
Q

what is the outcome of water being effective of screening electrostatic interactions as a solvent

A

it is good at dissolving salts and hydrophilic biomolecules

68
Q

why is water effective at screening electrostatic interactions as a solvent?

A

it has a high dielectric constant (ε)

69
Q

what is the formula for strength of ionic interactions in a solution? what does each part mean

A 
F=(Q1Q2)/er2
F=strength of ionic interactions in a solution
Q=magnitude of charges
e=dielectric constant of the solvent
r=distance between charged groups
70
Q

T or F: as the dielectric constant of the solvent gets larger (ie in water it’s large), F gets smaller

A

true; the higher the dielectric constant, the weaker the ionic interactions in a solution

71
Q

what are the 3 key gases in this course

A

N2, O2, and CO2

72
Q

do N2, O2, or CO2 have net dipoles

A

no net dipole

73
Q

are N2, O2, and CO2 soluble in water?

A

no, they’re poorly soluble in water

74
Q

how does maximizing the entropy of water help drive substrate-enzyme interactions

A

when water=ordered, molecules surround both substrate and enzyme, blocking them from joining. When water is unordered, it becomes displaced so the enzyme and substrate can interact

75
Q

what types of bonds help stabilize an enzyme-substrate complex

A

hydrogen bonds, ionic bonds, and hydrophobic interactions

76
Q

describe the hydrophobic effect

A

non-polar segments constrain adjacent water molecules into a highly ordered cage, reducing entropy

77
Q

is entropy high or low due to the hydrophobic effect

A

low entropy (water is assembled into a highly ordered cage)

78
Q

what happens to enthalpy due to the hydrophobic effect? how is this caused

A

enthalpy increases; the non-polar segments disrupt hydrogen bonds between water molecules

79
Q

what happens when an amphipathic molecule is in water

A

it tends to assemble in the manner which will shield the non-polar regions as much as possible from water, keeping entropy as high as possible

80
Q

describe 3 ways amphipathic molecules can assemble in water

A

dispersion of lipids, clusters of lipids, or micelles

81
Q

describe Van der Waals interactions

A

when two uncharged atoms are brought close together, the surrounding electron clouds influence each other and can form transient electric dipoles in adjacent molecules

82
Q

how does distance affect Van der Waals forces

A

if the two nuclei are too far apart, electron clouds won’t influence each other, and if they’re too close the electron clouds will repel each other

83
Q

T or F: Van der Waals forces are very strong

A

false; they’re weak

84
Q

use radii to explain why covalent bonds are stronger than Van der Waals forces

A

when two atoms are covalently joined, the atomic radii are shorter than the Van der Waals radii

short radii=stronger attraction

85
Q

why are water molecules essential for a substrate to bind properly to an active site of an enzyme

A

water molecules help connect components of the active site (ie sugar) to certain amino acid residues on the substrate

86
Q

why is water important to cells in regards to temperature

A

water has a high specific heat, so it takes a lot of energy to raise or lower the temperature. Since cells contain a huge amount of water, the temperature of cells stays more consistent

BIOL 2421 - Cellular Biochem (21 decks)

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