Cell Structure and Tissue Quiz

Cell Structure

The foundation of life is found in cells, fundamental units that carry out various tasks required for survival. At their simplest, cells consist of a single membrane enclosing a fluid interior called cytoplasm. Within this environment, organelles perform specialized roles, such as mitochondria generating energy through cellular respiration, ribosomes synthesizing proteins, endoplasmic reticulum folding those proteins, Golgi apparatus packaging proteins for export, lysosomes breaking down waste products, and nucleus storing genetic information in the form of DNA.

Cell walls provide structural support and protection while preventing excessive water loss in plant cells, whereas animal cells lack walls due to their constantly changing shapes. Additionally, cells communicate with each other via signaling molecules called hormones and chemicals, enabling coordinated responses to environmental changes.

Tissue

Tissues are groups of similar cells working together to serve specific purposes. Animal tissues fall into three major categories: epithelial, connective, and muscle tissues. Plants exhibit simpler tissues, mainly consisting of vascular tissue, ground tissue, and dermal tissue.

Epithelial tissues cover surfaces, line cavities, and compose glands. Connective tissues bind structures together, store fat, and transport nutrients. Muscle tissues contract, allowing movement. Vascular tissues found in plants deliver nutrients and remove waste, while ground tissues provide mechanical support and storage for food reserves.

In multicellular organisms, cells move, divide, grow, and die in response to internal signals and external stimuli. Prokaryotes, like bacteria, represent a primitive group without nuclear membranes in their cells, while eukaryotic organisms feature true nuclei containing DNA wrapped in protein.