BCH 400 Exam 1

hydrophobic a. a.

leu

Which of the following subcellular organelles is the largest? nucleus golgi apparatus mitochondria ribosome

nucleus

hydroxyl containing a. a.

ser

In the central dogma of biology, only one of the process involves a change in language. It is the process of replication translation transcription reverse transcription

translation

side chain has a carboxylic acid group

glu

In the last decade, our understanding of the mechanism of oxidative phosphorylation has become much better understood as some of the key enzymes involved had had they x-ray crystal structures solved. Which of the following cell fraction would you find in these proteins? 10,000 xg for 20 min pellet 105,000 xg for 90 min pellet 105,000 xg supernatant None

10,000 xg for 20 min pellet

Drug metabolism, complex lipid synthesis and protein synthesis would be associated with which fraction? 10,000 xg for 20 min pellet 105,000 xg for 90 min pellet 105,000 xg for 90 min supernatant None

105,000 xg for 90 min pellet

The pKa values for glutamic acid are 2.1, 4.1, and 9.5. what is the pI glutamic acid? 3.1 6.8 7.85 2.1 4.1

3.1 (2.1+4.1/2)

How may peptide bonds are in a pentapeptide? 3 4 5 6 none of the answers

4

By adding too much ash from his fireplace, Blomquist allowed the [OH-] to reach 1 x 10-5. What is the pH at this hydroxyl ion concentration? 3.0 5.0 7.0 9.0 none

9.0

Which of the following amino acids has a hydrophobic side chain? Phe Lys Glu Ser none of the above

Phe

You are using cysteine (pKa=8.3) to buffer at pH 7.5. Would cys buffer best against added acid added base same against acid or base

added base

The peptide ala-phe-leu-met-set-pro was subjected to one round Edman degradation. Which amino acid would be cleaved from the peptide and analyzed as a PTH derivative? pro ala phe leu met

ala

The membrane spanning portion of a protein must interact with the fatty acid chains of phospholipids. Which group of amino acids would you most likely find associated with a membrane spanning portion of a membrane spanning protein? glu, asp, lys, arg tyr, ser, thr ala, phe, val, ile gly, cys, his

ala, phe, val, ile

Which of the following organelles is surrounded by two membranes? nucleus mitochondria chloroplasts all the organelles

all the organelles

Which of the following amino acids contains the most number of oxygens? ala asp trp cys

asp

What is the net charge on dipeptide Aspartame (asp-phe-methyl ester) at the pH of coca cola (2.53), assuming the pKa of the asp side chain carboxyl group is 3.53? close to +1 close to 0 close to -1

close to +1

Which of the following types of bonds is not used to stabilize quaternary structure? covalent bonds hydrophobic bonds interactions of apolar side chains of amino acids

covalent bonds

Which of the following three amino acids all have ionizable side chains? ser, thr, tyr cys, lys, tyr ala, leu, val phe, tyr, trp

cys, lys, tyr

Denaturing and renaturing a protein requires heat requires breaking and reforming disulfide bridges demonstrates that the primary structure of a protein determines the tertiary structure always results in a protein regains its function

demonstrates that the primary structure of a protein determines the tertiary structure

Which statement does not pertain to a peptide bond? it is an amide bond it is rigid and planar it is between amino acids in a protein it connects the side chains of acidic and basic amino acids

it connects the side chains of acidic and basic amino acids

Which of the following statements about Edman automated protein sequencing is not true? it sequences from the N-terminal end it sequences from the C-terminal end it requires high efficiency at each chemical step one can get up to 50 amino acids in a protein in a single automated run

it sequences from the C-terminal end

side chain contains an amino group

lys

Which of the following ways of denaturing proteins deal primarily with breaking disulfide bonds? urea mercaptoethanol SDS high temperature

mercaptoethanol

Which of the following is in a most reduced state? carbon dioxide formic acid methanol methane

methane

Which of the following amino acids has the highest molecular weight? ala gly cys phe

phe

The shape of hair is determined in part by the pattern of disulfide bonds. Which of the following procedures could be involved in inducing curling in hair. oxidation of disulfide bonds, putting the hair in the shape you want, followed by reduction reduction of disulfide bonds putting the hair in the shape you want, followed by oxidation use of SDS to denature proteins adding oil to change hydrophobic bonds

reduction of disulfide bonds putting the hair in the shape you want, followed by oxidation

Which of the following statements about peptide bonds is not true? the four atoms in a peptide bond and the attached alpa-carbons are in a plane the hydrogen on the nitrogen and the carbonyl carbon are trans the R groups on adjacent amino acid residues are cis in the peptide bond, the bond between the carbonyl carbon and the nitrogen has partial double bond character

the R groups on adjacent amino acid residues are cis

Which of the following amino acids have more than one chiral center? thr and ile ala phe gly

thr and ile

Which of the following amino acid changes in protein would least likely to change the function of the protein val for glu val for ile asp for lys his for cys

val for ile