MCQs

Unlike template-driven translation, carbohydrate assembly depends on local enzyme concentrations and kinetics, resulting in glycan variations.

The dense, charged sugar chains of the lipopolysaccharide layer form a hydrophilic shield that resists the entry of hydrophobic toxic compounds.

LHCs are pigment-protein chromoprotein complexes where chlorophylls and carotenoids are precisely bound to a protein matrix to capture light.

Without N-linked oligosaccharide chains, nascent polypeptides inside the ER lumen cannot fold properly, triggering the unfolded protein response.

The central axis of a proteoglycan monomer is a core protein, from which numerous long glycosaminoglycan chains extend outwards.

Ferritin is a hollow metalloprotein shell that stores iron atoms safely as ferric oxide mineral cores, preventing oxidative cellular damage.

Many nucleoporins are modified with single O-linked N-acetylglucosamine (O-GlcNAc) residues, which are essential for pore function and transport regulation.

Lipidation, such as prenylation or palmitoylation, adds a hydrophobic lipid tail to a protein, anchoring it into a lipid bilayer.

Genetic variations dictate which glycosyltransferase is active, determining whether an extra N-acetylgalactosamine (A) or galactose (B) is added.

Spliceosomes are specialized ribonucleoproteins; they require small nuclear RNAs to recognize splice sites on pre-mRNA transcripts.

Lipoprotein lipase hydrolyzes the triacylglycerols inside circulating chylomicrons and VLDLs, releasing free fatty acids for tissue uptake.

Cancer cells alter their surface glycosylation profiles, which helps them evade immune detection and metastasize to other tissues.

Horseradish peroxidase is a complex conjugated enzyme; it contains an iron-bearing heme group and carries structural carbohydrate chains.

Lipoteichoic acids span the thick peptidoglycan layer and use their lipid tails to anchor the wall assembly into the cytoplasmic membrane.

Non-polar triacylglycerols and cholesterol esters aggregate in water; lipoproteins shield them to allow smooth transport through the blood.

Enveloped viruses use host-derived lipids embedded with viral glycoproteins to form a shield that facilitates membrane fusion.

Chaperones like calnexin bind to glycoproteins carrying a single terminal glucose, ensuring the protein folds properly before moving on.

Proteins are denser than lipids (1.3 g/mL vs. 0.9 g/mL). Particles containing more protein and less lipid exhibit a higher overall density.

Sulfated and carboxylated sugars carry negative charges, creating electrostatic fields that draw in water molecules to form a resilient gel.