Biochem test 2 quizzes

Positive cooperativity means that binding of one molecule of substrate _____ binding affinity of the _____ molecule of substrate.

1. Option A

   increases, 2nd

2. Option B

   decreases 2nd

3. Option C

   increases,  1st

4. Option D

   decreases,  1st

A

Heme groups are common cofactors in redox and O₂ binding proteins. What are the primary components of these cofactors?

1. Option A

   Fe and Cu ions

2. Option B

   Fe ions and porphyrin rings

3. Option C

   Cu ions and porphyrin rings

4. Option D

   Fe ions, Cu ions and quinones

B.

Which of the following describes the difference between hemoproteins involved in redox reactions and those involved in O₂ transport?

1. Option A

   They are actually identical.

2. Option B

   Redox hemoproteins have both axial positions on the Fe ion coordinated.

3. Option C

   Hemoproteins are not involved in redox reactions.

4. Option D

   Hemoproteins involved in O2 transport have one axial position of the Fe ion unligated.

B and D

What is one unique feature about the position of the heme group in redox active hemoproteins?

1. Option A

   The heme groups is completely buried in the core of the protein and not accessible.

2. Option B

   All hemes in redox active proteins must be accompanied by a pair of non-heme Fe ions.

3. Option C

   Hemes in redox active hemoproteins must be of the 'S" heme type.

4. Option D

   One edge of the heme porphyrin ring is generally accessible for electron transfer.

D

When a protein is caught in a local folding minima such as that shown at point B or C in the diagram below, it can be rescued by which of the following systems?

1. Option A

   disulfide isomerase

2. Option B

   prolyl isomerase

3. Option C

   sulfide:quinone oxidoreductase

4. Option D

   two of these

5. Option E

   chaperones

E

Which of the following is a requirement for proteins destined for the periplasmic space in prokaryotes?

1. Option A

   Quarternary structure in the mature protein.

2. Option B

   High hydropathy

3. Option C

   An appropriate leader sequence in the gene sequence

4. Option D

   A high % of alpha helix

C

at pH = 7.0, which of the following groups of amino acids should result in the highest surface charge on a fully folded protein?

1. Option A

   Gly, Trp, Ala

2. Option B

   Leu, Glu, Tyr

3. Option C

   Glu, Gln, Asp

4. Option D

   His, Phe, Ala

C

The 3D structure of a protein is composed of 2 spherical regions. If the protein is composed of a single polypeptide, the structures are known as _____. If the protein is 2 polypeptides, they are known as ___.

1. Option A

   domains, domains

2. Option B

   subunits, domains

3. Option C

   subunits, subunits

4. Option D

   domains, subunits

D

Disulfide linkages may occur between which of the following?

1. Option A

   cysteine and cysteine

2. Option B

   cysteine and cystine

3. Option C

   methionine and cysteine only

4. Option D

   methionine and any other amino acid

A

Which of the following represents an aldose?

a.

b.

c.

d.

C

Which of the structures in question #1 represents a pentose?

1. Option A

   a

2. Option B

   b

3. Option C

   c

4. Option D

   d

C

In answer a of question #1, what is the numbering for the carbon designated by the arrow?

1. Option A

   1

2. Option B

   2

3. Option C

   3

4. Option D

   4

5. Option E

   other

C

Which of the following represents the b (beta) anomer?

a.

b.

c.

d. none of the above

B

Which of the following represents N-acetyl glucosamine?

a.

b.

c.

d.

C

Biological organisms are generally considered to be an _____ system.

1. Option A

   isolated

2. Option B

   sealed

3. Option C

   closed

4. Option D

   open

D

According to the 2nd law of thermodynamics, naturally occurring processes tend towards ________.

1. Option A

   reactants

2. Option B

   equilibrium

3. Option C

   products

4. Option D

   low entropy

B

Which of the following conditions would be involved in defining the standard state ?

1. Option A

   37 degrees Celsius(372K)

2. Option B

   298K

3. Option C

   any concentration

4. Option D

   1M concentration

5. Option E

   gas state only

B and D

What does the following equation represent?

1. Option A

   Hemholtz correction

2. Option B

   Energy corrected for nonstandard state concentrations

3. Option C

   Entropy corrected for nonstandard  state concentrations

4. Option D

   Enthalpy corrected for nonstandard state concentrations

B

Why do biological systems not normally utilize standard state concentrations when referring to pH? What is used instead?

1. Option A

   A standard state of 1 x 10-7 M H+ is pH =0. Use pH =7 instead.

2. Option B

   A standard state of 1 x 10-7 M H+ is pH =7. Use pH =0 instead.

3. Option C

   A standard state of 1M H+ is pH =7. Use pH =0 instead.

4. Option D

   A standard state of 1M H+ is pH =0. Use pH =7 instead.

D

How are energetically unfavorable reactions made possible in biological systems?

1. Option A

   They are not. They cannot occur.

2. Option B

   They are coupled to energetically favorable reactions.

3. Option C

   They are temperature dependent. They only occur at extremely high temperatures.

4. Option D

   Equilibrium can be shifted towards products by removal of products (Ex. - exhalation of CO2 after a CO2 producing reaction).

B and D

Why is non-enzymatic hydrolysis of ATP pH dependent?

1. Option A

   Enzymes are pH dependent.

2. Option B

   Increases in ionization state based on the pKa of phosphate increases the entropy contribution.

3. Option C

   Decreases in ionization state based on the pKa of phosphate increases the entropy contribution.

4. Option D

   It isn't.

not a not B. it’s D

A single long chain fatty acid forming an ester bond with a single long chain alcohol is known as a(n) _____.

1. Option A

   terpene

2. Option B

   wax

3. Option C

   phospholipid

4. Option D

   diacyl glycerol

B

Lipids that spontaneously form micelles, monolayers and bil;ayers have which of the following properties?

1. Option A

   amphipathic

2. Option B

   polar

3. Option C

   waxy

4. Option D

   zwitterion

Option A

amphipathic

Which of the following lipids is correctly defined?

1. Option A

   cholesterol: the primary component of "saturated" fats

2. Option B

   phospholipid: contains glycerol with 2 fatty acids and a phosphate, very often forms bilayers

3. Option C

   triacylglycerol: formed from glycerol and 3 fatty acids, primary lipid of membranes

4. Option D

   wax: contains a fatty acid and alcohol, used primarily for energy storage

phospholipid: contains glycerol with 2 fatty acids and a phosphate, very often forms bilayers

Lipids formed from molecules other than fatty acids generally use _____ as a precusor molecule(s).

1. Option A

   acetic acid

2. Option B

   amino acids

3. Option C

   glucose

4. Option D

   isoprene

5. Option E

   two of these

Option D

isoprene

Which of the following functions involve lipids?

1. Option A

   anchor of proteins to cell membranes

2. Option B

   storage of energy within cells

3. Option C

   transport of energy between organs

4. Option D

   pigmentation of cells

5. Option E

   all of these are possible

Option E

all of these are possible

Which of the below bands represents the phi bond angle?

Option A

A

1. Option B

   B

2. Option C

   both A and B

3. Option D

   neither A nor B

Option A

What is pKa1 of the alpha amino group of the 2nd amino acid in a peptide?

1. Option A

   It is 1pH unit lower than in the free amino acid.

2. Option B

   It is 1 pH unit higher than in the free amino acid.

3. Option C

   It is equivalent to the free amino acid.

4. Option D

   It has no pKa1.

D

How are amino acids such as hydroxyproline incorporated into peptides and proteins?

1. Option A

   They have their own codon.

2. Option B

   They ar only found in proteins as a result of oxidative damage.

3. Option C

   They are the result of post-translational modifications.

4. Option D

   They are never found in proteins.

C

In the Ramachandran plot below, in which region would we NOT expect to find a proline in the local amino acid sequence?

A. alpha

B. beta

C. La

D. none of the above

A, B, and C