1.6 Stereoisomers are ________ 1. nonsuperimposable mirror-image molecules. 2. m

Question

1.6 Stereoisomers are ________

1. nonsuperimposable mirror-image molecules.

2. molecules with very little free rotation around single bonds.

3. molecules with a well-defined three-dimensional shape.

4. compounds with more than three carbon atoms.

1.7 The Henderson-Hasselbalch equation___________

1. allows the graphic determination of the molecular weight of a weak acid from its pH alone.

2. does not explain the behaviour of d- or tri- basic acids.

3. relates the pH of a solution to the pKa and the contraction of acid and conjugate base.

4. is equally useful with solutions of acetic acid and of hydrochloric acid.

1.8 In a mixture of proteins below, which one would elute second using gel-filtration chromatography?

1. Cytochrome c (Mr = 13 kDa)

2. Immunoglobulin G (Mr = 145 kDa)

3. Haemoglobin (subunit Mr = 16 kDa)

4. Serum albumin (Mr = 68.5 kDa)

1.9 Which of the following is a phospholipid?

1. Lecithin

2. Cholesterol

3. Sterol

4. Steroid

1.10 High content of triacylglycerides are seen in:

1. LDL

2. HDL

3. VLDL

4. Chylomicrons

Explanation / Answer

1.6

Incorrect: The molecules with the non-super impossible mirror image are called as enantiomers. These molecules are the chiral molecules. The molecules with the very little free rotation around the single bonds are not the sterioisomers.

The compounds with the more than three carbon atoms can be named as oligo compounds. Hence the options (1), (2), and (4) are incorrect.

Correct: sterioisomers are the molecules consisting the same molecular formula but differ in the three dimensional orientation. Hence, the option (3) is correct.

1.7

Incorrect: Henderson-Hasselbalch equation uses the pH along with the pKa value to determine the molecular weight of the weak acid. This equation also explains the behavior of di and tri basic acids. This equation is useful to estimate the pH of the buffer solutions. The equation is not suitable for the solutions containing the only acids. Hence, the options (1), (2), and (4) are incorrect.

Correct: Henderson-Hasselbalch equation uses the pH along with the pKa value to determine the equilibrium or to estimate the pH of a buffer solution. Hence, the option (3) is correct.

1.8

Incorrect: gel-filtration chromatography works on the principle of the diffusion of molecules. The pores of the beads in the gel-filtration chromatography allow the slow movement of the smaller molecules or molecules with the less molecular weight.

So, the cytochrome c having very less molecular weight and will elute at the end. The hemoglobin will elute at the third number and immunoglobulin at the first according to their molecular weight. Hence, the options (1), (2), and (3) are incorrect.

Correct: the movement of molecules in the gel-filtration chromatography is according to their size and molecular weight. The smaller molecules or molecules with the less molecular weight will move slowly. So, according to the molecular weight, serum albumin will elute second. Hence, the option (4) is correct.

1.9

Incorrect: a class of lipids that contain phosphate group in its molecule is termed as phospholipid. Cholesterol does not contain the phosphate group. The sterol is also a type of cholesterol. Both cholesterol and sterol are not the phospholipids. These molecules only help to maintain the integrity of the eukaryotic cell membrane.

Steroids are not the ideal phospholipids. This is because they do not resemble the other lipids. Steroids are hydrophobic in nature and this is the reason that they are grouped with the lipids. Hence, the options (2), (3), and (4) are incorrect.

Correct: Lecithins are the phospholipids. The main source of lecithin is the soybean. The molecule of lecithin contain phosphate group and this is also hydrophobic in nature. Hence, the option (1) is correct.

1.10

Incorrect: triglyceride derived from the glycerol and is an ester with the three fatty acid. The body fat mainly contains the triglyceride. The LDL and VLDL contain the enough amounts of triglycerides. The triglyceride associated with the LDL and VLDL is bad for the health. The amount of triglyceride is low in both LDL and VLDL as compare to chylomicrons.

The HDL is good for health as it contain high density lipoprotein cholesterol. The amount of triglyceride is low in HDL as compare to the LDL. Hence, the options (1), (2), and (3) are incorrect.

Correct: the small globules of the fat that are composed of the lipid and protein are called as chylomicrones. Chylomicrons contain very high amount of triglycerides. The amount of triglycerides in the chylomicron is around 85 to 92%. Hence, the option (4) is correct.

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.