Brainscape's Knowledge GenomeTM

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


See full index

Biochemistry Exam 1 > L2&3 Amino Acids and pH > Flashcards

L2&3 Amino Acids and pH Flashcards

1
Q

Chiral

A

C atom with four different substituents

All alpha Cs of AA are chiral except glycine

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

Nonpolar

A

Uncharged
Hydrophobic
Aggregate in aqueous solitons

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

Polar

A

Hydrophilic
Posses electronegative O, N, or S atom
Can form H, ionic, or covalent bonds
Charged or uncharged

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

Hydrophobic

A

Water fearing

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

Hydrophilic

A

Water loving

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

Electronegative atom

A

Measure of tendency of an atom to attract a bonding pair of electrons

O, N, S have strong pull on electrons

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

Hydrophobic effect/interaction

A

When AA side chains are uncharged and repel water

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

Covalent bond

A

Shared electrons

Peptide bonds, disulfide bonds

Much stronger than noncovalent

Used to make polymers from monomers

Requires enzyme to break bond

Polar or nonpolar

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

Polar covalent

A

Electrons shared by atoms of differing electro negativity

Creates partial pos and partial neg which creates permanent dipole

Basis of H bond

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

Permanent dipole

A

Partial neg and pos charge that occurs when electrons are not shared equally

Allows molecules to interact through electrostatic forces

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

Peptide bond

A

Bond between amino and carboxyl group of AA

forms protein backbone but also between side chains in special cases

Covalent

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

Disulfide bond

A

Joins 2 sulfhydryl groups

Covalent

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

H-bond

A

Sharing of H atom between 2 electronegative groups

Weaker than ionic because a full charge is not shared

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

Ionic bond

A

Transfer of electrons

Attractive forces gold two ions together

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

Van der Waals interactions

A

Weak forces between molecules in close contact

Arise from transient dipole interactions

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

pH

A

Negative log of hydrogen ion concentration

pH=-log[H+]

Inversely related to [H+]

Small changes in pH = large changes in [H+]

2pH changes = 100 fold changes in [H+]

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

pKa

A

pH at which a weak acid will be 50% dissociated

Proportional to affinity of weak acid for its proton

Low pKa = H+ easily dissociable, strong weak acid

High pKa= H+ bound more tightly, weak weak acid

18
Q

pI

A

Isoelectric point

At pH=pI one group completely dissociated and one is completely associated

19
Q

Amino group and pKa

A

+NH3

pka > 7

Termed basic

20
Q

Carboxyl group and pKa

A

-COOH

pKa < 7

Termed acidic

21
Q

R-group

A

Variable group for AA

22
Q

Conjugate base

A

Dissociated form of a weak acid

23
Q

Weak acid

A

Molecule that contain dissociable hydrogen ion

24
Q

Noncovalent

A

Determines shape polymer will assume within cell and how it interacts with other biomolecuels

Weaker but more quantity

Hydrophobic interactions
Ionic
H bonds
Van der Waals

25
Q

Basic AA structure

A

Alpha C bonded to an amino group, a carboxyl group, a hydrogen atom and a variable side group

26
Q

Nonpolar AA interactions

A

Side chains uncharged and only contain hydrocarbons except tryptophan and methionine
Tryptophan- 1N among 9Cs acts hydrophobic
Methionine- S sandwiched btw hydrocarbon masks electronegativity

Participate in hydrophobic interactions, exclude water

NOT a bond

27
Q

Polar uncharged AA side chain interactions

A

Contain electronegative atom

Participate in H bonds

Noncovalent interaction which H is shared by 2 electronegative atoms

28
Q

Cysteine interactions

A

Only AA with sulfhydryl group
Polar and uncharged

Forms ionic and disulfide bonds

29
Q

Polar charged AA with acidic side chains interactions between

A

Contain COOH that dissociated and negatively charged at physiological pH

Proton donors

Participate in H bonds and ionic bonds

30
Q

Polar charged AA with basic side chains

A

Side chains positively charged at physiological pH

Accept protons

Participate in H bonds and ionic bonds

31
Q

Ka

A

Ka=[H+][A-]/[HA]
Products/reactants

Measure of the extent of the reaction ( how much product produced) at equilibrium

Measure of strength of acid

a lot of products=a lot of dissociation=high Ka= stronger acid

32
Q

Henderson-Hasselbalch equation

A

Estimates extent of dissociation (balance btw [HA] and [A-])

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

pka is -log of Ka

33
Q

What happens when [A-] = [HA]

A

pH=pKa

Acid is 50% dissociated

34
Q

pka

A

Low pKa=high ka=easily dissociable=strong weak acid

High pKa=low ka=more tightly bound= weak weak acid

35
Q

Henderson-hasselbalch rule of thumb

A

pH is 1 pH unit above pKa the acid is 91% dissociated

pH is 1 pH unit below pKa the acid is 9.1% dissociated

36
Q

Buffers

A

Weak/acid conjugate base pairs that release or absorb H+ according to the pKa and laws of mass action to minimize changes in pH

37
Q

Maximum buffering range

A

Runs from one pH unit below to one pH unit about the pKa of the weak acid/conjugate base pair

38
Q

Buffering capacity

A

Measure of efficiency in resisting pH changes

Amount of base that must be added to solution to change pH by one unit

39
Q

Best buffering region is

A

50/50 mix of protons and conjugate base

40
Q

When looking at titration curve

A

Look at where a lot of base was added and where there was a little change in pH

Biochemistry Exam 1 (9 decks)

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