Cellular biochemistry

Question 1

macromolecules are usually __ that consists of repeating units called __

Answer 1

1. polymers 2. monomer

Question 2

what do we called if a polymer consist of one type of monomer?

Answer 2

homopolymer

Question 3

what do we called if a polymer consists of more than 1 type of monomer?

Answer 3

copolymer/terpolymer/heteropolymer

Question 4

complete statement below:

Protein’s polymer called _. It is monomers of __. there are __ types of amino acids

Answer 4

1. polypeptide
2. amino acid
3. 20

Question 5

amino acids are linked by peptide bond which result in ?

Answer 5

condensation reaction

Question 6

what is peptide bond?

Answer 6

covalent bond that links amino acid via a condensation process (removal/loss of water molecule).

Question 7

how to form protein?

Answer 7

amino acids are linked by dehydration synthesis to form peptide bonds

Question 8

amino acid consists of?

Answer 8

amino group, a carboxylic acid group, hydrogen atom and R group all surrounding C atom (alpha carbon)

Question 9

in glycine, the simplest amino acid, the R-group is

a. oxygen atom
b. hydrogen atom

Answer 9

b

Question 10

which is true about glycine?

1. smallest amino acid
2. side chain is H atom
3. alpha carbon show chiral behavior
4. not flexible

Answer 10

1 and 2

Question 11

which amino acid is acidic: hydrophilic and charged?

Answer 11

aspartic acid (carboxy methyl chain) and glutamic acid(carboxy ethyl chain)

Question 12

which amino acid is basic: hydrophilic and charged?

Answer 12

lysine(amino butyl side chain) and arginine(imidine contain side chain)

Question 13

which amino acid is hydrophilic and not charged?

Answer 13

aspargine(amide side chain), glutamine(Amide side chain), serine(hydroxy methyl side chain), threonine(1-hydroxy ethyl side chain) and tyrosine(p-hydroxy phenyl methyl side chain)

Question 14

why is tyrosine is very hydrophilic and might act as hydrophobic if buried in middle protein

Answer 14

because it has hydroxyl attached to an aromatic ring

Question 15

which amino acid is hydrophobic (nonpolar) with aromatic ring?

Answer 15

phenyl alanine, tryptophan and histidine(but it’s hydrophilic)

Question 16

which amino acid is hydrophobic without aromatic ring?

Answer 16

alanine, valine, leucine, isoleucine

Question 17

which amino acid is contain sulfur?

Answer 17

cysteine(thio methyl side chain) and methionine(methyl thio ethyl side chain) (usually react as unreactive hydrophobic residue)

Question 18

how to form disulphide bridge of cystine and what is the function?

Answer 18

two cystein placed some distance apart along a polypeptide chain/ forming part of different chain can be joined by oxidation. it is sto stabilize protein structure

Question 19

why disulphide bond?

Answer 19

disulphide bond increase the conformational stability mainly by constraining the unfolded conformations of protein and decreasing their conformational entropy

Question 20

what is the function of sulfur atom in methionine?

Answer 20

it is unreactive and serves no function other than imposing a special configuration on aliphatic sidechain but in cytochrome c it form the link between protein and heme iron

Question 21

what is imino acid?

Answer 21

compound that has-NH- group as part of a ring rather than NH2 (proline)

Question 22

at what physiological pH does amino acids have at the zwitterion state?

Answer 22

pH 7.35~7.45

Question 23

what is the functions of protein?

Answer 23

enzyme, storage protein, transport protein, contracting protein(muscle), regulatory protein, toxin, hormone, structural protein

Question 24

what is the level of protein structure?

Answer 24

primary, secondary, tertiary, quaternary

Question 25

explain primary structure of protein

Answer 25

structure due to covalent bonding i.e the sequence of amino acids linked by peptide bond.

Question 26

explain secondary structure of protein

Answer 26

folding of polypeptide chain due to formation of hydrogen bond between peptide group which link amino acid together

Question 27

what are the two types of folding in the secondary structure of protein?

Answer 27

alpha-helix and beta-pleated/sheet (thermodynamically most stable structures)