Project #72420 - organic chemistry quiz

1

Marks: 1
A complete turn of the A-DNA helix occurs at which distance?
Choose one answer.
 
Question 2
Marks: 1
A pentapeptide has the following proportions of amino acids: gly (1), leu (1), val (1), phe (2). Treatment of the pentapeptide with chymotrypsin gave the following fragments: gly-val, leu, phe. Which is the structure of the pentapeptide?
Choose one answer.
 
Question 3
Marks: 1
Karl Nessler received the patent for the so-called “hot procedure” for a permanent (hair) in 1906. The hair was treated with a basic solution (NaOH in water, pH approx. 10) and then heated for several hours on the curler. The result was often extremely curly hair. What kind of bonds was/were actually (partially) broken and reformed?

a. hydrogen bonds
b. ionic bonds
c. disulfide-bridges
d. dipolar bonds
Choose one answer.
 
Question 4
Marks: 1
The first known procedures to bend straight hair into curls dates from 3000 B.C.: Hot Curlers made from clay were used. The hair was apparently dry. What kind of bonds was/were actually broken and reformed?
Choose one answer.
 
Question 5
Marks: 1
The structure of vasopressin is very similar to that of oxytocin (primary sequence of vasopressin: cysteine - tyrosine - phenylalanine - glutamine - asparagine - cysteine - proline - arginine - glycine), which is also a nonapeptide with a disulfide bridge. One of the most important roles of vasopressin is to regulate the body's retention of water; it is released when the body is dehydrated and causes the kidneys to conserve water, thus concentrating the urine, and reducing urine volume. In addition, it has a variety of neurological effects on the brain. What are the differences in the structures of vasopressin and oxytocin?

a. residue #3: isoleucine (oxytocin) vs. phenylalanine (vasopressin)
b. residue #7: isoleucine (oxytocin) vs. phenylalanine (vasopressin)
c. residue #8: leucine (oxytocin) vs. arginine (vasopressin)
d. residue #4: asparagine (oxytocin) vs. cysteine (vasopressin)
Choose one answer.
 
Question 6
Marks: 1
The tertiary structure of proteins depends primarily on which property of amino acids?
I) disulfide bonds
II) hydrogen bonds
III) amide bonds
VI) polar side chains
Choose one answer.
 
Question 7
Marks: 1
Transfer RNA (tRNA) is a small RNA molecule (usually less than 100 nucleotides) that transfers defined amino acids to a growing peptide chain at the ribosomal site during translation. tRNA contains unusual bases, such as, pseudouridine and inosine. Which sequence of ribonucleosides is correct?

Choose one answer.
 
Question 8
Marks: 1
Tyrosine has an isoelectric point of 5.63. What charge does tyrosine have at pH 7 and toward which electrode would it migrate during electrophoresis?
Choose one answer.
 
Question 9
Marks: 1
What are the differences between polyamides and proteins ?
I) Polyamides are unable to undergo hydrogen bonding between individual polymer chains.
II) Polyamides usually do not have hydroxyl- or thiol-groups as side chains.
III) Proteins and polyamides can be partially crystalline.
IV) Polyamides have a more stable bond between their monomers than proteins have between the individual amino acids.
Choose one answer.
 
Question 10
Marks: 1
Which amino acid has a nonpolar side chain?
Choose one answer.
 
Question 11
Marks: 1
Which are types of RNA?
I) ribosomal
II) histonal
III) helix
IV) transfer
Choose one answer.
 
Question 12
Marks: 1
Which describes the isoelectric point of an amino acid?
Choose one answer.
 
Question 13
Marks: 1
Which is the key to in vitro DNA replication?
Choose one answer.
 
Question 14
Marks: 1
Which is the predominate form of lysine in blood plasma at pH 7.4?
Choose one answer.
 
Question 15
Marks: 1
Which nucleotides are named correctly?
Choose one answer.
 
Question 16
Marks: 1
Which statement about the base mole-percent composition of DNA is true?
Choose one answer.
 
Question 17
Marks: 1
Which statements about differences between DNA and RNA are true?
I) The sugar unit is β-D-ribose in RNA and β-2-deoxyribose in DNA.
II) The pyrimidine bases are uracil and thymine in RNA and cytosine and thymine in DNA.
III) RNA is single stranded, DNA double stranded.
IV) The phosphodiester groups join the 3' to 5' ends of sugars in RNA, and join the 5' to 3' ends in DNA.
Choose one answer.
 
Question 18
Marks: 1
Which statements about mRNA codons are correct?
I) Each amino acid is coded by only one codon.
II) Codons code for several amino acids.
III) UAA, UAG, UGA are stop codons.
IV) Several amino acids are coded by more than one codon.
Choose one answer.
 
Question 19
Marks: 1
Which statements about restriction endonucleases are true?
I) Each cleave DNA at the same site, but leave different fragment lengths.
II) Each recognizes 4 to 8 nucleotides, and cleaves at all sites containing the sequence.
III) Approximately 1000 restriction endonucleases have been isolated and characterized.
IV) Each cleaves the DNA strand by reducing the base off at the sugar 1' position.
Choose one answer.
 
Question 20
Marks: 1
Which structure is a nucleoside?
Choose one answer.

21

Marks: 1
Polysorbate 80 (Tween 80) is a non-ionic surfactant and emulsifier (w+x+y+z=20). A typical application is in ice cream, where it hinders the milk proteins from completely coating the fat droplets. This allows for a firmer texture, which is associated with high quality ice cream. Which of the following statements is true?
Choose one answer.
 
Question 22
Marks: 1
The following are key steps in fatty acid metabolism. What is the best description for the first step (A)?
Choose one answer.
 
Question 23
Marks: 1
Today, palm oil or palm kernel oil is often used for the production of soap. The main components of palm kernel oil are glycerol esters of lauric acid (48%), myristic acid (16%) and palmitic acid (14%). What are the chemical components of soap from palm kernel oil?
Choose one answer.
 
Question 24
Marks: 1
Which are agents for energy storage and transport?
I) ATP
II) ADP
III) NAD+ / NADH
IV) FAD / FADH2
Choose one answer.
 
Question 25
Marks: 1
Which are oxidation / reduction reagents in the metabolism of fatty acids?
I) ATP
II) ADP
III) NAD+ / NADH
IV) FAD / FADH2
Choose one answer.
 
Question 26
Marks: 1
Which are the most common fatty acids found in phospholipids?
Choose one answer.
 
Question 27
Marks: 1
Which describes the effect of lactate fermentation of glucose on blood pH and CO2 concentration?
Choose one answer.
 
Question 28
Marks: 1
Which is the best description of the second step (B) of the biosynthesis of prostaglandins?  
Choose one answer.
 
Question 29
Marks: 1
Which is the key intermediate in the enzyme catalyzed reverse-aldol reaction of fructose 1,6-bisphosphate to two trioses?
Choose one answer.
 
Question 30
Marks: 1
Which of the following structures represents coenzyme A?

Choose one answer.
 
Question 31
Marks: 1
Which of the following structures represents GTP?

Choose one answer.
 
Question 32
Marks: 1
Which physical property of triacylglycerols rich in saturated fatty acids is responsible for the higher melting point than the corresponding unsaturated compounds?
Choose one answer.
 
Question 33
Marks: 1
Which property of phospholipids accounts for their ability to form micelles?
Choose one answer.
 
Question 34
Marks: 1
Which saturated fatty acids have the correct name?
I) CH3(CH2)10COOH – stearic acid
II) CH3(CH2)14COOH – palmitic acid
III) CH3(CH2)16COOH – lauric acid
IV) CH3(CH2)18COOH – arachidic acid
Choose one answer.
 
Question 35
Marks: 1
Which statement is true concerning the balanced half reaction for the oxidation of glucose to pyruvate?
Choose one answer.
 
Question 36
Marks: 1
Which statements about steroids are false?
I) The fusion of all rings is cis.
II) Sex hormones, adrenocorticoid hormones, bile acids and vitamin D are derived from cholesterol.
III) The biosynthesis of cholesterol produces several isomers.
IV) Steroids are tetracyclic ring systems
Choose one answer.
 
Question 37
Marks: 1
Which statements about vitamins are true?
I) Vitamins A, D, E and K are fat soluble.
II) Vitamins A, D, E and K are derived from cholesterol.
III) Vitamins A, D, E and K each contain 4 isoprene units.
IV) Vitamins A, D, E and K have distinct physiological activities.
Choose one answer.
 
Question 38
Marks: 1
Which structure is vitamin A?
Choose one answer.
 
Question 39
Marks: 1
The citric acid cycle oxidizes acetyl-CoA to CO2, producing NADH and FADH2.
Answer:
 
Question 40
Marks: 1
The cleavage of fructose-1,6-bisphosphate to two triose phosphates (reaction 4 of the glycolysis sequence) is an example of an aldol reaction.
Answer:

Subject Science
Due By (Pacific Time) 06/01/2015 11:00 pm
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