(M) Peptides and Proteins part 2 (ppt and lec based)

Question 1

enumerate the levels of protein structures

Answer 1

primary (1°)
Secondary (2°)
Tertiary (3°)
Quaternary (4°)

Question 2

this is the linear sequence of amino acids, primary structure of insulin

Answer 2

primary

Question 3

this is the simplest level of complexity describing the structure of protein

Answer 3

primary

Question 4

the primary protein structure refers to

Answer 4

quantitative aa composition

sequence of aa

number of peptide chains

Question 5

how many dipeptides are possible from 20 protein derived aa?

Answer 5

There are 20 x 20 = 400 dipeptides possible

Question 6

how many tripeptides are possible from the 20 protein derived aa?

Answer 6

There are 20 x 20 x 20 = 8000 tripeptides possible

Question 7

T or F
the number of peptides possible fo a chain of n amino acid is 20xN

Answer 7

F (20^n)

Question 8

T or F
the most abundant amino acid proteins are Trp, Cys, Met, and His

Answer 8

F (rarest)

Question 9

T or F
The most abundant amino acid in proteins are Leu, Ala, Gly, Ser, Val, Met and Glu

Answer 9

F (remove Met)

Question 10

protein structure created by the formation of hydrogen bonds between peptide bonds

Answer 10

secondary protein structure

Question 11

who proposed the two secondary structures in proteins

Answer 11

Pauling and Corey

Question 12

two types of secondary structures

Answer 12

alpha-helix
beta-sheet

Question 13

types of secondary structures of protein:

Rod-like structure (phonecord)

Answer 13

alpha-helix

Question 14

T or F in alpha helix, aa R groups extend inward from the helix

Answer 14

F (outward)

Question 15

T or F

main chain atoms are outside

Answer 15

F inside

Question 16

T or F
Helices can be right or left-handed

Answer 16

T

Question 17

how is the carbonyl of each amino acid in alpha helix bonded to the amide

Answer 17

H-bonded

Question 18

Why does proline destabilize alpha helices

Answer 18

its rigid ring prevents the n-c bond from rotating

Question 19

Why is it important that the n-c bond rotate?

Answer 19

so that an amide group will b able to form intrachain hydrogen bonds

Question 20

example of bulky r groups that destabilize alpha helices

Answer 20

val, ile, leu, pro, met (branched amino acids)

Question 21

T or F

presence of parallel similarly charged amnio acids destabilize alpha helices

Answer 21

F (adjacent)

Question 22

Second most commonly occurring protein 2° structure

Answer 22

beta pleated sheet

Question 23

formed when 2 or more polypeptide chains are linear and stacked at top of each other

Answer 23

beta pleated sheet

Question 24

where does r groups lie within the pleated sheet

Answer 24

above or below the zigzagging planes

Question 25

in what orientation does the r group lie in relation to the pleated sheet

Answer 25

perpendicular to the pleated sheet

Question 26

how is the carbonyl of each amino acid in beta pleated sheet bonded to the amide

Answer 26

H-bonded (parehas lang sila akshwally sa alpha helix)

Question 27

two types of beta pleated sheet

Answer 27

antiparallel and parallel

Question 28

T or F parallel beta pleated sheets are more stable than the antiparallel

Answer 28

F (less stable)

Question 29

this type of beta pleated sheet is composed of : one strand of NH and carbonyl group, h-bonded to carbonyl group and N-H group of the opposing amino acid on the other strand

Answer 29

Anti-parallel beta sheet

Question 30

5 ways that tertiary structures are stabilized

Answer 30

covalent bonds hydrogen bonds salt bridges hydrophobic interactions metal ion coordination

Question 31

5 ways that tertiary structures are stabilized: this stabilizes the native conformation of the protein

Answer 31

covalent bonds

Question 32

5 ways that tertiary structures are stabilized: these are bonds in the interior of the protein

Answer 32

hydrogen bonding

Question 33

5 ways that tertiary structures are stabilized: attracts the NH3+ group and the -COO- group

Answer 33

salt bridges

Question 34

5 ways that tertiary structures are stabilized: these are interaction between nonpolar side chains

Answer 34

hydrophobic interaction

Question 35

5 ways that tertiary structures are stabilized: major force stabilizing tertiary structure

Answer 35

hydrophobic interaction

Question 36

5 ways that tertiary structures are stabilized: linkage via metal ion

Answer 36

metal ion coordination

Question 37

if you see this card, familiarize yourself with the tertiary protein structure visual aid

Answer 37

thanks mwah galingan mo bading

Question 38

This is the highest level of protein organization

Answer 38

quaternary (4°) protein structure

Question 39

in which proteins are quaternary structures found?

Answer 39

in proteins that have 2 or more polypeptide chains (subunits)

Question 40

escribes the characteristic manner in which the individual , folded polypeptide chains fit each other or interact with one another so that they can act as one single molecule

Answer 40

quaternary structure

Question 41

how are the chains held together in a quaternary structure

Answer 41

hydrogen bonds salt bridges hydrophobic interactions

Question 42

quaternary levels: has 2 polypeptide chains / subunits

Answer 42

dimer

Question 43

quaternary levels: 3 polypeptide chains / subunits

Answer 43

trimer

Question 44

quaternary levels: has 4 polypeptide chains / subunits

Answer 44

tetramers

Question 45

quaternary levels: has 5 polypeptide chains / subunits

Answer 45

pentamer

Question 46

Process by which a protein structure assumes its functional shape or conformation

Answer 46

Protein Folding

Question 47

process in which a protein chain acquire its 3-dimensional structure from a random coil

Answer 47

Protein Folding

Question 48

what is the native state of the protein

Answer 48

folded protein

Question 49

what assists proteins in folding and prevents it from associating with inappropriate molecules

Answer 49

chaperones

Question 50

example of chaperone protein discovered from E.coli bacterium

Answer 50

-hsp 70

Question 51

T or F Allergies develops from failure of protein to fold into a native structure

Answer 51

T

Question 52

T or F Failure of proteins to fold can cause improved memore

Answer 52

F (can lead to Parkinson's and Alzheimer's)

Question 53

T or F The protein will be more active if it failed to fold properly to compensate

Answer 53

F (inactive)

Question 54

The process of destroying the native conformation of a protein by chemical or physical means

Answer 54

denaturation

Question 55

denaturing agent: disrupts hydrogen bonding

Answer 55

heat and 6M Aqueous urea

Question 56

denaturing agent for hydrophobic regions

Answer 56

detergents

Question 57

denaturing agent for salt bridges and h bonds

Answer 57

acids and bases

Question 58

denaturing agent for disulfide bonds

Answer 58

reducing agents and heavy metal ions

Question 59

basic amino acids with an overall positive charge

Answer 59

lys, arg, and his

Question 60

acidic amino acids with overall negative charge

Answer 60

glu, asp

Question 61

T or F Proteins to be insoluble should be able to interact as much as possible with the solvent

Answer 61

F (should be soluble)

Question 62

what is the charge of proteins at the isoelectric point

Answer 62

net zero charge

Question 63

what is the net charge of protein above pI

Answer 63

negative

Question 64

what is the net charge of protein below pI

Answer 64

positive