MCQs

The molecule develops dual properties: a hydrophobic domain anchored in the lipid bilayer and a hydrophilic domain exposed to water.

Gangliosides are abundant in nerve cell membranes, where they participate in cell signaling, myelin stability, and synaptogenesis.

Liver cells require protein synthesis to form VLDLs; blocking this prevents lipid export, causing fats to accumulate internally.

N-linked glycosylation targets the nitrogen atom on the side chain of an asparagine residue within a specific consensus sequence.

Even when bound to basic proteins, the dense phosphate backbone of the DNA molecule provides a strong net negative charge to chromatin.

HDL participates in reverse cholesterol transport, clearing excess lipids from blood vessels and carrying them back to the hepatic tissue.

Proteoglycans are mostly carbohydrate by weight (80%–95%), containing long unbranched GAG chains, unlike standard glycoproteins.

Mannose-6-phosphate serves as a specific molecular sorting signal that targets newly synthesized hydrolytic enzymes to the lysosomes.

Human ABO blood group determinants are defined by the structural variations of carbohydrate chains on surface glycolipids and glycoproteins.

The glycocalyx acts as a cellular fingerprint; individual combinations of sugar chains allow immune cells to distinguish self from non-self.

Hydroxyl groups on sugar residues form hydrogen bonds with surrounding water molecules, rendering the region highly hydrophilic.

Lipopolysaccharides (LPS) contain a lipid A anchor component covalently bound to a core oligosaccharide and an O-antigen chain.

Mucus contains mucins, which are heavily glycosylated glycoproteins that trap pathogens and protect delicate mucosal surfaces.

Ribosomes are functional structural complexes consisting of ribosomal RNA (rRNA) and specific ribosomal proteins working together.

Hemoglobin is a metalloprotein containing an iron-porphyrin ring system called a heme group as its functional prosthetic group.

The Golgi apparatus contains specific glycosyltransferase enzymes that trim and add sugar residues to complete glycoprotein processing.

Conjugated molecules like glycoproteins and glycolipids are stable because their components are bound via permanent covalent linkages.

N-linked glycosylation begins in the lumen of the rough endoplasmic reticulum as polypeptides are being translated by ribosomes.

Glycoproteins and glycolipids extend their sugar chains outward to form the glycocalyx, which mediates cellular identification.