Practice Questions

While cellulose is built by plasma membrane enzymes, non-cellulose wall polysaccharides are synthesized in the Golgi and shipped out via vesicles.

Six connexin proteins assemble to form a hemichannel called a connexon; when aligned with a neighbor, it creates a functional gap junction.

The phragmoplast is an array of microtubules and filaments that forms during late mitosis, guiding Golgi vesicles to the cell plate site.

Cholesterol inserts its rigid steroid ring core between phospholipid tails, stabilizing the membrane and regulating fluid properties.

Cutin is a complex macromolecular lipid polymer that coats the outer surfaces of land plants, reducing non-stomatal transpirational water loss.

The central vacuole maintains an acidic internal pH and houses a variety of hydrolytic enzymes to break down and recycle macromolecules.

Animal cells rely on an intricate network of specialized junctional complexes to bind cells structurally and coordinate tissue-wide communication.

Intermediate filaments (like keratins, lamins, and vimentin) possess high tensile strength, protecting animal cells from stretching and tearing.

Peroxisomes host amino acid and fatty acid oxidation reactions that generate hazardous H2​O2​, which is immediately neutralized by catalase.

Hydrostatic turgor pressure pushes cells tightly against one another, providing mechanical structural support to non-woody plant organs.