Lecture 1/ Medicinal Biochem

Question 1

the study of the chemistry of life processes

Answer 1

biochemistry

Question 2

____ are constructed from simple building blocks

Answer 2

macromolecules

Question 3

monomeric subunits (building blocks)

Answer 3

amino acids, nucleotides, carbohydrates, acetate

Question 4

biological macromolecules

Answer 4

proteins, DNA/RNA, polysaccharides, lipids

Question 5

each amino acid has an ____ to which ____ different groups are attached

Answer 5

alpha carbon; four

Question 6

4 groups attached to alpha carbon

Answer 6

hydrogen atom, acidic carboxyl group, basic amino group, and side chain

Question 7

the amino acid ____ has two hydrogen atoms connected to the alpha carbon

Answer 7

glycine

Question 8

each amino acid has it’s own properties based on it’s ______

Answer 8

side chain (–R)

Question 9

side chain determines:

Answer 9

structure of proteins, function of proteins, electrical charge of the protein

Question 10

properties of the side chain (–R) are important for:

Answer 10

methods of analysis, purification, and identification

Question 11

amino acids that have nonpolar, aliphatic R groups, from least hydrophobic to most hydrophobic

Answer 11

Glycine (Gly) G, Alanine (Ala) A, Valine (Val) V, Leucine (Leu) L, Isoleucine (Ile) I

Question 12

amino acids that have nonpolar, aromatic R groups

Answer 12

phenylalanine (Phe) F, Tyrosine (Tyr) Y, Tryptophan (Trp) W

Question 13

____ is highly hydrophobic

Answer 13

phenylalanine

Question 14

the hydrophobic character of tyrosine and tryptophan is tempered somewhat by the presence of _____ in their side chains

Answer 14

polar groups

Question 15

amino acids with uncharged, polar R groups

Answer 15

threonine (Thr) T, Serine (Ser) S, Asparagine (Asn) N, Glutamine (Gln) Q

Question 16

amino acids with acidic R groups

Answer 16

aspartic acid (Asp) D, Glutamic acid (Glu) E

Question 17

aspartic acid and glutamic acid are decidedly ____, and therefore ____; you would expect to find these residues on the ____ of a protein molecule, in contact with the surrounding ____

Answer 17

polar; hydrophilic; surface; water

Question 18

amino acids with basic R groups

Answer 18

Histidine (His) H, Lysine (Lys) K, Arginine (Arg) R

Question 19

the basic amino acids are strongly ____; they are normally found on the ____ surface of proteins, where they can be _____ by the surrounding environment

Answer 19

polar; exterior; hydrated

Question 20

amino acids with sulfur containing R groups

Answer 20

cysteine (Cys) C, Methionine (Met) M

Question 21

the amino acids with sulfur containing R groups are generally more ____than their aliphatic analogs due to their weakly polar side chains; however, ____ is fairly _____;

Answer 21

hydrophilic; methionine; hydrophobic

Question 22

____ is a cyclic amino acid

Answer 22

proline

Question 23

proline does not form a conventional _____; it is very ____ compared to other amino acids; the side chain is ____ with no functional groups; the side chain covalently bonds to the ____ eliminating the opportunity for _____ at that position; it’s alpha-imino group is bonded to it’s side chain

Answer 23

peptide bond; constrained; aliphatic; amide nitrogen; hydrogen bonding

Question 24

proline is difficult to fit into any category, but it shares properties with the ____ amino acids

Answer 24

aliphatic

Question 25

all amino acids except ____ contain at least one _____ carbon atom and are therefore _____

Answer 25

glycine; asymmetric; optically active

Question 26

optically active amino acids exist in two isomeric forms:

Answer 26

L- (levorotatory) or D- (dextrorotatory) depending on the direction they rotate plane-polarized light

Question 27

proteins contain only ____

Answer 27

L- amino acids (Not D-)

Question 28

D-amino acids are found in ____ and ____

Answer 28

bacterial cell wall; peptide antibiotics

Question 29

amino acids have ____ properties; they are able to react as both a base and an acid

Answer 29

amphoteric

Question 30

At ____ pH, the carboxyl group accepts a ____ and becomes uncharged, and the overall charge on the molecule is ____

Answer 30

low; proton; positive

Question 31

At ___ pH, the amino group loses its ____ and becomes uncharged, and the overall charge on the molecule is ____

Answer 31

high; proton; negative

Question 32

in aqueous solution, the amino acid exists as a ____ or _____ and has both negative and positive charges

Answer 32

dipolar molecule; zwitterion

Question 33

in aqueous solution, the alpha-carboxyl group is ____ and ____ charged; the alpha-amino group is ____ and ____ charged; the molecule is electrically ____

Answer 33

dissociated; negatively; protonated; positively; neutral

Question 34

describes the derivation of pH as a measure of acidity in biological and chemical systems

Answer 34

henderson-hasselbach equation

Question 35

HH equation also useful for estimating the pH of a ____

Answer 35

buffer solution

Question 36

HH equation widely used to calculate the ____ of proteins (the point at which a protein neither ___ nor ___ proton)

Answer 36

isoelectric point; accept; yield

Question 37

the linking together of amino acids produces _____

Answer 37

peptide chains

Question 38

the peptide bond is formed between the ____ group of one amino acid and the ____ group of the other

Answer 38

alpha-carboxyl; alpha-amino

Question 39

the pH at which a molecule has no net charge

Answer 39

pI (isoelectric point)

Question 40

primary structure of proteins

Answer 40

sequence of a chain of amino acids

Question 41

secondary structure of proteins

Answer 41

• alpha helix sexondary structure with H bonds between backbone
• parallel beta sheet secondary structure; backbone of polypeptide chain in zigzag structure (pleats)

Question 42

tertiary structure of proteins

Answer 42

-have disulfide bonds, hydrogen bonds, salt bridges, and hydrophobic interactions

Question 43

quaternary structure

Answer 43

assembly of multiple polypeptide chains into intact, tetrameric protein