Chapter 16 Amino acids, proteins,

Question 1

what is hemoglobin and myoglobin an example of?

Answer 1

proteins that transport oxygen in the blood

Question 2

what is found in an amino acid?

Answer 2

central atom bonded to an ammonium group(NH3+) and a carboxylate group (COO-)

Question 3

can amino acids be polar or non polar?

Answer 3

both

Question 4

when is an amino acid nonpolar?

Answer 4

when the R group is H, alkyl, or aromatic (ex: attached to benzine ring or chain of carboxyl groups)

Question 5

when is an amino acid polar?

Answer 5

when the R group is an alcohol, a thiol, or an amide (ex: anything with Oxygen or SH or O=C-NH2 at the end)

Question 6

what is sickle-cell anemia caused by? What does it cause to happen?

Answer 6

an abnormality in one of the subunits (an amino acid) of the hemoglobin protein. This changes the shape of the blood cell to change form like a sickle shape, leaving it unable to adequately transport oxygen

Question 7

what building blocks are proteins made of?

Answer 7

amino acids

Question 8

are nonpolar amino acids water soluble? what’s the name for this?

Answer 8

no; hydrophobic

Question 9

are polar amino acids water soluble? what’s the name for this?

Answer 9

yes; hydrophilic

Question 10

what makes a polar amino acid neutral, acidic, or basic?

Answer 10

Neutral: contains neutrally charged ions in the R group of the amino acid
Acidic: contains negatively charged oxygen in the R group of the amino acid (a carboxylic acid)
Basic: contains positively charged Nitrogen in the R group of the amino acid (an amine)

Question 11

Answer 11

Question 12

are the alpha amino acids chiral or achiral?

Answer 12

all a-amino acids are chiral with exception for glycine

Question 13

how do you tell if you are looking at the L or D enantiomer of a amino acid?

Answer 13

L: NH3+ appears on the left
D: NH3+ appears on the right

Question 14

Answer 14

Question 15

what are essential amino acids?

Answer 15

amino acids that cannot be produced in the body and need to come from our diet

Question 16

what are examples of foods that contain complete proteins of all the essential amino acids?

Answer 16

meat, milk, eggs and fish

Question 17

what are examples of foods that contain incomplete proteins of only some of the essential amino acids?

Answer 17

grains, beans, and nuts

Question 18

Answer 18

Question 19

Answer 19

Question 20

amino acids can exist as positive ion or negative ion, how would you know which is it?

Answer 20

positive ion: if a solution is more acidic; lower pH than its pI
negative ion: if a solution is more basic; higher pH than its pI

Question 21

what is the definition of pI?

Answer 21

Isoelectric point: when an amino acid with positive and negative charges is overall neutral in charge

Question 22

would this have a pH higher or lower than 6?

Answer 22

lower than 6

Question 23

what is another name for peptide bonds?

Answer 23

amide bonds

Question 24

what is a peptide?

Answer 24

linking of two or more amino acids via peptide (amide) bonds

Question 25

Where does a peptide (amide) bond form?

Answer 25

between one amino acid's COO- group and another amino acid's NH3+ group gets ride of a water molecule (one oxygen from the COO- and two hydrogens from the NH3+)

Question 26

what is the name of two/three/four amino acids bonded by peptide bonds?

Answer 26

dipeptides tripeptides tetrapeptides

Question 27

Answer 27

Question 28

what is the name of the reaction that forms di/tri/tetrapeptides?

Answer 28

amidation reaction

Question 29

Since amino acids are the building blocks of proteins, how many amino acids does it take to form a functioning protein?

Answer 29

a protein is a polypeptide of 50 or more amino acids

Question 30

which protein was the first to have its primary structure determined?

Answer 30

insulin

Question 31

what does the primary structure of insulin contain?

Answer 31

two polypeptide chains linked by disulfide bonds

Question 32

how many amino acids are used to build proteins in the body and how many can be synthesized within it?

Answer 32

20 11 9 are essential amino acids that are obtained through diet

Question 33

what is the difference in appearance between primary and secondary structures of polypeptides?

Answer 33

primary: straight line secondary: helix spiral or pleated sheet

Question 34

what are the differences of types of bonds found in primary vs secondary structures?

Answer 34

primary: only peptide bonds secondary: peptide and hydrogen bonds

Question 35

where do hydrogen bonds form within the helix structure?

Answer 35

between the oxygen of C=O groups and the hydrogen of N-H groups of the amide bonds

Question 36

what holds the chains together within a triple helix? what important function does this have?

Answer 36

hydrogen bonds added strength (as in with collagen and connective tissue)

Question 37

which amino acids will have salt bridges in tertiary structures?

Answer 37

only ones with positive NH3+ bonds

Question 38

what are examples of triple helixes in proteins? what type of structure are they?

Answer 38

collagen, connective tissue, skin, tendons, and cartilage secondary struture

Question 39

what vitamin is important for the production of collagen?

Answer 39

vitamin C

Question 40

what are the five characteristics of tertiary proteins?

Answer 40

hydrophobic interactions hydrophilic interactions salt bridges hydrogen bonds disulfide bonds

Question 41

where do hydrophobic interaction occur within tertiary proteins? polar or nonpolar?

Answer 41

between two nonpolar amino acids at the center of the protein molecule

Question 42

where do hydrophilic interactions occur within tertiary proteins?

Answer 42

between the external aqueous environment and the R groups of the polar amino acids

Question 43

where do salt bridges occur within tertiary proteins?

Answer 43

between ionized R groups of basic and acidic amino acids (NH3+)

Question 44

where do hydrogen bonds occur within tertiary proteins?

Answer 44

between H of a polar R group and the O or N of another amino acid

Question 45

where do disulfide bonds occur between tertiary proteins?

Answer 45

between the SH groups of cysteine amino acids

Question 46

myoglobin is a ___________ structure protein

Answer 46

tertiary

Question 47

hemoglobin is a ____________ structure protein

Answer 47

quaternary

Question 48

what force is important in the primary structure of a protein?

Answer 48

peptide bond

Question 49

a-helix and b-sheet are in the ________ structure category of proteins?

Answer 49

secondary

Question 50

which amino acid forms disulfide bonds to stabilize the tertiary structure of a protein?

Answer 50

cysteine

Question 51

quaternary structure are made up of?

Answer 51

two or more protein subunits

Question 52

hemoglobin is made up of what?

Answer 52

two a-chains and two b-chains

Question 53

what kind of interactions are found in quaternary structures?

Answer 53

the same ones as with tertiary structures (hydrophilic/phobic, salt bridges, hydrogen bonds, and disulfide bonds

Question 54

when does denaturation occur within proteins?

Answer 54

when there is a change that disrupts the interactions that stabilize the secondary, tertiary, or quaternary structure

Question 55

Under what conditions can denaturation of proteins occur?

Answer 55

heat, organic compounds, acids and bases, heavy metals, and mechanical agitation (such as whipping a solution)

Question 56

the cooking of an egg is an example of ?

Answer 56

denaturation

Question 57

what are the bonds divided when heat is applied to proteins?

Answer 57

hydrogen bonds and hydrophobic interactions

Question 58

what are the bonds disrupted when acids or bases denature proteins?

Answer 58

hydrogen bonds between polar R groups (salt bridges are disrupted)

Question 59

what bonds are denatured when organic compounds are applied?

Answer 59

hydrogen bonds FORM and hydrophobic interactions are disrupted

Question 60

what bonds are disrupted when heavy metals denature proteins?

Answer 60

disulfide bonds (instead it forms ionic bonds)

Question 61

what bonds are disrupted when mechanical agitation denature proteins?

Answer 61

hydrogen bonds and hydrophobic interactions

Question 62

Answer 62

Question 63

Answer 63

Question 64

Answer 64

Question 65

Answer 65