MCQs

The rigid cell wall prevents pinching; instead, the phragmoplast guides Golgi vesicles to fuse at the equator, forming a new cell plate from the inside out.

Animal cells form a contractile ring of actin and myosin filaments that pinches the plasma membrane inward, creating a cleavage furrow.

Leukoplasts are non-pigmented plastids found in non-photosynthetic plant tissues (like roots or tubers) that store starches (amyloplasts) or fats.

The rigid, box-like cellulose cell wall forces plant cells to maintain structured, geometric, or rectangular morphologies.

The development of a massive, turgid central vacuole forces the cytoplasm and the nucleus to the periphery against the plant cell wall.

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.

Plant cells possess an extracellular, rigid cell wall made primarily of cellulose that protects the cell from mechanical stress and osmotic lysis.

Animal cells lack a cell wall entirely; their outermost living boundary is the selectively permeable phospholipid bilayer known as the plasma membrane.

Triple-stranded H-DNA forms when a third single strand winds into the major groove of a duplex, binding via alternative Hoogsteen hydrogen bonds.

Hypoxanthine pairs with cytosine, meaning the original template A-T pair becomes a G-C pair after a few rounds of replication, causing a transition mutation.