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Biomolecules 11-08-19 > amino acids > Flashcards

amino acids Flashcards

1
Q

The unique cyclic structure of which of the following amino acids plays a central role in the formation of alpha helices and beta sheets?

A

proline.

Proline plays a central role in the FORMATION of alpha helices and beta sheets. While proline’s unique structure may also disrupt both alpha helixes and beta sheets, it’s ability to make sharp turns facilitates the FORMATION of both structures, with proline commonly being found at the beginning of alpha helices or at the turns in beta sheets.

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2
Q

Electrophoretic separation of leucine from a protein sample would be least effective at which of the following pH values?

A

7.4

At physiological pH, leucine exists as a zwitterion.

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3
Q

DNA and RNA are made up of _____. Proteins are made up of _____.

A

nucleotides/nucleic acids.

amino acids

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4
Q

what is epigenetics?

A

epigenetics is the study of heritable phenotype changes that do not involve alterations in the DNA sequence.

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5
Q

physiological pH of histidine

A

side chain = 6.5 so exists in both protonated and deprotonated since it about the same as physiological pH of 7

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6
Q

proline has a _____ amino group

A

secondary

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7
Q

glycine does not have a ____

A

chiral carbon

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8
Q

proline and glycine are known as _____

A

alpha helix breakers

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9
Q

cysteine has a ____ group

A

thiol

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10
Q

thiols in cysteine are in a ____ environment

A

reducing

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11
Q

a disulfide bridge occurs between cysteines in the _____ environment

A

extracellular; oxidized environment

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12
Q

antioxidants keep the intracellular space a _____ environment

A

reducing (so nothing becomes oxidized)

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13
Q

cysteine turns into ____ when it is oxidized

A

cystine

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14
Q

amino acids are chiral and can rotate light (optical activity) except the amino acid _____

A

glycine

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15
Q

what is a zwitterion?

A

has both negative and positive charges

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16
Q

name the alkyl amino acids

A

glycine, alanine, valine, methionine, leucine, isoleucine, proline

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17
Q

aromatic amino acids

A

phenylalanine, tryptophan

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18
Q

polar neutral amino acids

A

serine, threonine, asparagine, glutamine, cysteine, tyrosine

19
Q

acidic amino acids

A

aspartic acid and glutamic acid

20
Q

basic amino acids

A

arginine, lysine and histidine

21
Q

primary protein structure is the ____

A

peptide bonds

22
Q

secondary protein structure are the ____

A

H-bonds, alpha helix, and B-pleated sheets

23
Q

tertiary structure are the ____

A

V.d waals forces, disulfide bridges and hydrophobic interactions

24
Q

quaternary structure are the ____

A

subunit interactions

25
Q

increased temperature affects the _____ structures

A

2, 3 and 4

not the primary!

26
Q

pH disrupts the ____bonds

A

ionic, which affects the tertiary and quaternary structure

27
Q

chemicals affect the _____ structures

A

2, 3 and 4

28
Q

enzymes affect the ____

A

peptide bonds

29
Q

what are the 4 catalytic strategies that enzymes use to make reactions go faster?

A
  1. acid/base
  2. covalent
  3. electrostatic
  4. proximity/orientation
30
Q

what are coenzymes?

A

organic carrier molecules ex. NADH is an electron carrier

31
Q

cofactors _____ in catalysis

A

participate

32
Q

what is vitamin B3?

A

niacin which is a precursor for NAD

33
Q

minerals are ____

A

inorganic cofactors ex. magnesium

34
Q

amylase is found in the ____ and pepsin is found in the _____

A

mouth (functions at pH=7); stomach (functions at low pH)

35
Q

A ____ catalyzes the formation of a single bond between two substrates through the elimination of water.

A

ligase

36
Q

_______ catalyzes the first committed step of glycolysis

A

Phosphofructokinase 1

37
Q

_____ are inactive enzymes that require covalent modification to become active

A

zymogens

38
Q

covalent modifications for enzymes

A
  1. small post translational
  2. zymogens
  3. suicide inhibitors
39
Q

deoxyribose is missing an ____

A

oxygen

40
Q

purines have ___ rings

A

2

41
Q

pyrimidines have ___ ring(s)

A

1

42
Q

what does telomerase do

A

lengthens telomeres

43
Q

you can only had nucleotides going from the ____ direction

A

5’ to 3’

44
Q

helices breaks the ____

A

hydrogen bonds between nitrogenous bases

Biomolecules 11-08-19 (1 decks)

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