Cell Structure and Function Quiz

Overview of Cells

• Cells are the fundamental units of life, either unicellular (single-celled organisms) or multicellular (composed of multiple cells).
• Cells can be envisioned as building blocks, forming tissues, organs, and entire organisms like Lego blocks.

Cell Membrane and Cytoplasm

• The cell membrane is a double layer of phospholipids that protects the cell and separates it from the extracellular environment.
• Cytoplasm, also called cytosol, is a gelatinous substance within the cell that houses organelles.

Nucleus

• The nucleus is a prominent organelle containing the nuclear membrane, regulating cellular functions, and storing genetic information.
• The nucleolus, within the nucleus, is responsible for ribosome production, essential for protein assembly.

Metabolic Organelles

• Mitochondria are the powerhouses, facilitating cellular respiration and breaking down glucose for energy.
• Plastids, found in photosynthetic organisms, capture sunlight energy to synthesize glucose.

Endoplasmic Reticulum (ER)

• The rough ER, studded with ribosomes, synthesizes proteins; whereas the smooth ER lacks ribosomes and synthesizes other cellular products.

Golgi Apparatus

• The Golgi apparatus receives, processes, and distributes cellular products from the ER via vesicles, temporary storage and transport units.

Lysosomes

• Lysosomes are membrane-bound vesicles in animal cells containing enzymes for breaking down waste and invasive organisms, aiding in cellular cleanup.

Cytoskeleton and Locomotory Organelles

• The cytoskeleton provides structural support, allowing for cell shape alterations and the formation of organelles like cilia, pseudopodia, and flagella.

Centrioles

• Centrioles, located near the nucleus, maintain cell shape and organization during cell division and are collectively known as the centrosome.

Central Vacuole

• Plant cells feature a large central vacuole for storage and pressure regulation, substituting for lysosomes found in animal cells.

Cell Wall

• Certain cells possess a rigid outer cell wall made of various substances: cellulose in plants and algae, chitin in fungi, peptidoglycan in bacteria, and pseudopeptidoglycan in archaea.

Unique Features of Plant vs. Animal Cells

• Plant cells: contain cell walls, plastids (e.g., chloroplasts), and central vacuoles.
• Animal cells: have lysosomes and centrioles, but lack cell walls, central vacuoles, and plastids.

Implications for Classification

• The presence and type of cellular features significantly inform the classification schemes utilized by biologists.