Practice Questions

Lysosomes function as the cell's recycling center under acidic conditions; typical plant cells rely instead on their central vacuole for hydrolytic breakdown.

Gap junctions are protein channels made of connexins that bridge the gap between adjacent animal cells, playing a role similar to plasmodesmata.

Plasmodesmata are microscopic channels crossing the plant cell wall, lining up the plasma membrane and endoplasmic reticulum of neighboring cells.

Glycogen, a highly branched glucose polymer, serves as the primary multi-branched energy storage polysaccharide in animal tissues.

Plants store excess photosynthetic carbohydrates as insoluble starch (amylose and amylopectin), while animals store energy as glycogen.

Higher plant cells completely lack centrioles, utilizing alternative microtubule-organizing centers (MTOCs) to manage spindle formation during division.

Chloroplasts are specialized green plastids containing chlorophyll pigments that execute the light and dark reactions of photosynthesis in plants.

The tonoplast is the specialized semi-permeable membrane enclosing the plant vacuole, containing active transport pumps to maintain cell turgidity.

Mature plant cells feature a massive central vacuole that maintains turgor pressure, whereas animal cells contain multiple small, transient vacuoles.

Cellulose is a linear polymer of β-D-glucose units that organizes into microfibrils to give the plant cell wall its high tensile strength.