Question

Identify the components labelled a, b, c, d, e and f in the given figure from the list (i) to (vi) given below.
Components:
(i) Glycoprotein
(ii) Cholesterol
(iii) Extrinsic protein
(iv) Glycolipid
(v) Intrinsic protein
(vi) Carbohydrate
The correct components are

• A. a-(iv), b-(i), c-(vi), d-(ii), e-(iii), f-(v)
• B. a-(i), b-(iv), c-(vi), d-(ii), e-(v), f-(iii)
• C. a-(iv), b-(i), c-(ii), d-(vi), e-(v), f-(iii)
• D. a-(iv), b-(i), c-(vi), d-(ii), e-(v), f-(iii)

Answer 1

Answer: (B)

a-(i), b-(iv), c-(vi), d-(ii), e-(v), f-(iii)

(a)Glycoproteins are proteins which contain oligosaccharide chains covalently attached to amino acid side chains. The carbohydrate is attached to the protein in a cotransitional or posttransitional modification. This process is called glycosylation.

(b)The basic structure of a glycolipid consists of a mono or oligosaccharide group attached to a sphingolipid or a glycerol group (can be acetylated or alkalyted) with one or two fatty acids. Synthesis of glycolipids proceed by a series of enzymes that sequentially add sugars to lipid.

(c)Carbohydrates consists of carbon,hydrogen and oxygen. The general emirical structure for carbohydrates is (CH2O)n. The building blocks of carbohydrates are simple sugar called monosaccharides. They are polyhydroxy aldehyde or polyhydroxy ketone.

(d)Cholesterol is a lipid with a unique structure consisting of four linled hydrocarbon rings forming the bulky steroid structure. There is a hydrocarbon tail linked to one end of the steroid and a hydroxy group linked to the other end.

(e)Intrinsic proteins,as their name implies are firmly embedded within the phospholipid bilayers.

(f)Extrinsic proteins are attached externally with the membrane.They are embedded within the membrane and permanently attached.

So,the correct option is (B).