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Biochemistry Lippincott 7th Edition > Chapter 1 Amino Acids > Flashcards

Chapter 1 Amino Acids Flashcards

1
Q

there are less that 300 different amino acids described in nature, how may are found in as constituents of mamalian proteins ?

A

20

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2
Q

Non standard amino acids are produced by modification of ?

A

standard amino acids

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3
Q

the only amino acids encoded by DNA

A

standard amino acids

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4
Q

has a secondary amino group

A

proline

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5
Q

at what pH is when the carboxyl group is dissociated, forming the negatively charged carboxylate ion, and then the amino group is protonated

A

7.4

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6
Q

in protein terms

  1. what groups are combined through peptide linkages ?
  2. proteins are not available for chem rxn except for ?
A

carboxyl and amino groups are combined through peptide linkages and not available for chemical reaction; except for hydrogen bond formation

  1. carboxyl and amino groups
  2. hydrogen bond formation
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7
Q

Amino Acids with NON-polar side chains

  1. name reactions that they do not participate in
A
  • do not gain or lose protons
  • do not participate in hydrogen or ionic bonds
  • has an oily and lipid like property
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8
Q
  1. the side chains of NON-POLAR** amino acids tend to **CLUSTER in the interior of the protein
A
  1. proteins found in a polar environment (aqueous solution)
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9
Q

name all the uncharged POLAR SIDE CHIANS

Nemonic

Sorry, The , Time, And Game Ceased

A
  • Serine
  • Threonine
  • Tyrosine
  • Aspargine
  • Glutamine
  • Cysteine
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10
Q

Acidic side chains

A

Aspartic acid

Glutamic acid

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11
Q

name the “Basic” Side chains

BASE dominant

A

Histidine

Lysine

Arginine

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12
Q
  • side chain and alpha amino nitrogen form rigid five membered ring
  • has a secondary rather than primary amino group
  • referred to as an IMINO acid
  • contributes to the structure of collagen
  • interupts alpha-helices in globular proteins
A

Proline

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13
Q

Amino Acids with uncharged polar side chains

Serine, Threonine, Tyrosine, Aspargine, Glutamine Cysteine

A
  • have zero at physiologic pH
  • Serine Threonine and Tyrosine contain a polar hyhdroxyl group that can play a role in hydrogen bond formation
  • Aspargine and Glutamine contain both carboxyl and amide groups that can participate in hydrogen bonds.
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14
Q

Disulfide bond:

  1. the side chain of CYSTEINE contains what ?
  2. i_mportant component of the active site_ of _enzymes_?
  3. -SH group of two cysteine can be oxidized to form a covalent cross-link is called what ?
  4. Two disulfide-linked cysteins are referred to as ?
A
  1. sulfhydryl
  2. thiol group (-SH)
  3. disulfide bond
  4. CystINE
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15
Q

page 4.

Side chains as attachment sites for other compounds

  1. what A.A. can serve as a site of attachment for structures like phosphate groups?
  2. the amide group of Aspargine, as well as Hydroxyl group of Serine and Threonine can serve as a site of attachment to what ?
A
  1. the polar hydroxyl grp of serine, threonine and rarely tyrosine
  2. Oligosaccharide chains in glycoproteins
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16
Q

<strong><u>page 5. </u></strong>

Amino Acids with Acidic Side Chains

  1. name the two acidic A.A.
  2. are they proton donors or proton acceptors ?
  3. describe these AA’s a physiologic pH
  4. what are the fully IONIZED forms called
A
  1. Aspartic and Glutamic acid
  2. proton donors
  3. side chains are fully ionized containing a negatively charged carboxylate group (-COO- )
  4. Aspartate and Glutamate
17
Q
  1. Amino acids with a chiral alpha carbon exist in two isomeric forms, what are these two forms ?
  2. All amino acids in mammals are in what form ?
  3. what form is found in antibiotics

page 5.

A
  1. D and L
  2. L form
  3. D form (cell bacterial walls)
18
Q

<strong><u>page 6.</u></strong>

B. Buffers

  1. what is a buffer ?
  2. buffers can be created by ?
  3. when HCL is added into a buffer
  4. when does maximum buffer capacity happen ?
  5. If the amounts of HA and A- is equal; then the pH is equal to the?
  6. at pH values less than pKa, the protonated acid in the (CH3-COOH) is the
  7. what is the predominant specie at pH values greater than pKa?
  8. overall, what can serve as buffers ?
A
  1. a solution that resist pH following an addition of an acid or base.
  2. mixing weak acid (HA) with its conjugate base A<u><span>-</span></u>
  3. converted to HA in the process by A- neutralized
  4. at a pH equal to pKa
  5. pKa = maximum buffer
  6. predominant specie in the solution
  7. (CH3-COO-)
  8. free amino acids, plus charged amino acids in peptide chains.
19
Q

Understanding the Henderson-Hasselbalch

  1. A drug passes through more readily if ?
  2. explain these simple drug penetration
  • weak acid (aspirin)
  • weak base (morphine)
  1. what equation is useful in determining how much drug is found on either side of the membrane ?(separates two components that differ in pH ?
A
  1. the drug is uncharged
  2. aspirin ( uncharged HA CAN A- cannot) ———–morphine (uncharged B CAN BH+ cannot)
  3. Henderson -Hasselbalch equation
20
Q

page 8. and pag 9.

Net Charge at Neutral pH

  1. Negatively charged COO- and positively charged NH3+ happens at ?
  2. what are they called if they can either act as an acid or a base ?
  3. what is another term for amphoteric ?
A
  1. at physiologic pH (7.4)
  2. Amphoteric
  3. Ampholytes ( amphoteric electrolytes)
21
Q

Essential Amino Acid

I Love Lisa For Trying To Make Vicky Happy

A

Isoleucine

Leucine

Lysine

Phenylalanine

Threonine

Tryptophan

Methionine

Valine

Histidine

22
Q

All molecules with a chiral center is optically ACTIVE or INACTIVE ?

A

Optically Active

23
Q

Name the three nonpolar (hydrophobic) A.A.

-they can all participate in hydrophobic interactions

A
  1. Phenylalanine
  2. Tyrosine
  3. Tryptophan
24
Q
  1. Weak bases: what can it release ?

BH+ ——-→ B + H+

  1. however the protonated form of basic drugs is usually ? charged or uncharged ?
  2. the loss of a proton produces what ?
A
  1. hydrogen
  2. charged
  3. uncharged base
25
Q

The effective concentration of the permeable form of a drug at its absorption site is determined by ?

A

the relative concentrations of the charged and uncharged forms

26
Q

Permeable or Impermeable

charged forms cause

uncharged forms cause

A

impermeability

permeability

27
Q

Proteins located in a hydrophobic environment such as the membrane protein- where would the non polar R groups found ?

A

on the outside surface of the protein –interacting with the lipid environment

28
Q
  1. The concentration of protons [H+] in a solution is expressed as ?
  2. The quantitive relationship between the pH** of the solution **and concentration of a weak acid (HA) and it’s conjugate base (A<u>-</u>) is described by ?
A
  1. pH
  2. The Henderson-Hasselbalch equation
29
Q

Acidic drugs release ?

A

H+ to cause a charged molecule

30
Q

at physiologic pH amino acids have a negatively charged group (COO-) and a … ?

A

positively charged (NH3+) group

31
Q

Amino Acids that can either act as an acid or a base are defined as what?

A

amphoteric

32
Q

Henderson Hasselbalch application:

Bicarbonate as a BUFFER

  • what causes the pH to rise in the blood ?
  • what causes the increase in CO2
  • when CO2 increases it causes a rise or fall in pH ?
  • the falling levels of pH results in what condition
A

-an increase in HCO<u>3 </u><u>_</u> causes the pH to rise

  • Pulmonary obstruction
  • fall in pH
  • respiratory acidosis
33
Q

Amphoteric properties.

Amino acids are amphoteric molecule

  1. what does amphoteric mean ?

Monoamino-monocaboxylic amino acids exist in aequeous solution as dipolar molecules, which means? they have both positive and negative charges and the overall molecules is electrically neutral.

  1. At low pH, the carboxyl group ?
  2. At high pH, the amino group loses its proton and becomes uncharged (neutral) , thus the overall charge on the molecule is negative.

pH at which an amino acid is electrically neutral is known as the isoelectric point for the molecule and the symbol is pI.

A
  1. (dipolar ions), that is they have both basic and acidic groups.
  2. they have both positive and negative charges and the overall molecules is electrically neutral
    1. accepts a proton** and **become uncharged, so that the overall charge on the molecule is positive.
  4. loses its proton** and **becomes uncharged (neutral) , thus the overall charge on the molecule is negative.
  5. isoelectric point for the molecule and the symbol is pI.
34
Q
  1. describe protein denaturation ?
  2. structures of proteins are dependent on weak secondary forces; give examples
A
  1. unfolding and loss of natural function
  2. pH, radiation, temperature, detergents, heavy metals etc..

Biochemistry Lippincott 7th Edition (24 decks)

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