MCQs

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.

Phytochrome is a chromoprotein with a light-sensitive bilin prosthetic group that acts as a molecular switch for plant photomorphogenesis.

Collagen is a structural glycoprotein; its triple-helix structure contains short carbohydrate chains attached to hydroxylysine residues.

ABCA1 is required to load cholesterol onto ApoA-I to form HDL; its absence causes HDL deficiency and lipid buildup in tissues.

GPI anchors use a complex bridge made of a phospholipid linked via a phosphodiester bond to an oligosaccharide, which then binds the protein.

This structural packaging arranges DNA strands systematically inside the eukaryotic nucleus, compacting the genetic material.

Ovalbumin is a storage glycoprotein that makes up the bulk of egg white, providing essential amino acids and attached carbohydrates.

The carbohydrate arrays on glycoprotein hormones are essential for maintaining proper folding, structural stability, and receptor activation.