Cell Biology and Structure

Genes are specific segments of DNA that are organized and packaged into structures called chromosomes within the cell nucleus.

Lysosomes are single-membrane-bound organelles containing digestive enzymes. Mitochondria, chloroplasts, and the nucleus are all double-membrane-bound organelles.

A gland is a group of cells or an organ that synthesizes and secretes substances such as hormones or enzymes.

Fibroblasts are the most common type of cell in connective tissue; they produce the extracellular matrix and collagen fibers.

Meristematic cells are undifferentiated plant cells that are actively dividing, allowing for growth in length and girth.

Chondrocytes are the only cells found in healthy cartilage; they produce and maintain the cartilaginous matrix.

Necrosis is the premature death of cells in living tissue caused by factors such as injury, infection, or toxins. Neurosis refers to a class of mental disorders.

Ribosomes are the cellular machinery responsible for translating mRNA into proteins. They are found in the cytoplasm, either free-floating or attached to the endoplasmic reticulum.

Chlorophyll is a pigment molecule used for photosynthesis, not a membrane-bound organelle. E.R., ribosomes, and mitochondria are all considered organelles.

The cell membrane (or plasma membrane) is the biological membrane that separates the interior of all cells from the outside environment, effectively surrounding the organelles within the cytoplasm.

An egg cell of a hen is a single cell that is large enough to be seen with the naked eye, unlike most other microscopic cells.

Robert Brown discovered the cell nucleus in 1831 while observing the cells of orchid roots.

All cells, whether prokaryotic or eukaryotic, are bounded by a cell membrane (plasma membrane) that regulates the passage of substances in and out of the cell.

Centrioles are cylindrical structures involved in cell division and are typically found in animal cells, but they are absent in most higher plant cells.

Muscle cells require significant amounts of energy for contraction, therefore they contain a very high density of mitochondria to produce the necessary ATP.