Cell Theory, Cytology, and Protein Structure

Vocabulary flashcards covering key terms, scientists, and concepts from the lecture notes on cell theory, cytology, and protein structure.

Cell

The basic structural and functional unit of all living organisms, capable of independent existence and performing essential life functions.

Cytology

The branch of biology that studies the structure, function, and chemistry of cells.

Cell Theory

Principle stating that all living organisms are composed of cells and cell products, and that new cells arise only from pre-existing cells.

Unicellular Organism

A living organism composed of a single cell that carries out all life processes independently.

Multicellular Organism

A living organism made up of many specialized cells working together.

Fundamental Unit of Life

Concept asserting that the cell is the smallest entity that can exhibit all characteristics of life.

Prokaryotic Cell

A cell lacking a membrane-bound nucleus; its genetic material is a single, circular DNA molecule.

Eukaryotic Cell

A cell possessing a membrane-bound nucleus and other membrane-bound organelles.

Robert Hooke

English scientist who first observed dead cork cells in 1665, coined the term “cell,” and is called the father of cytology.

Cellula

Latin word used by Robert Hooke in Micrographia to describe the box-like structures he saw in cork; later shortened to “cell.”

Anton van Leeuwenhoek

Dutch microscopist who first saw and described living cells such as bacteria, protozoa, yeast, and sperm.

Robert Brown

Scottish botanist who discovered the cell nucleus in 1831.

Nucleus

Dense, membrane-bound organelle in eukaryotic cells that houses chromosomes and genetic material (DNA).

Matthias Schleiden

German botanist who co-formulated the original cell theory, stating that plants are composed of cells.

Theodor Schwann

German zoologist who co-formulated the original cell theory, extending it to animals.

Rudolf Virchow

German pathologist who in 1855 stated that new cells arise from pre-existing cells, completing cell theory.

Omnis cellula e cellula

Latin maxim meaning “every cell from a cell,” summarizing Virchow’s contribution to cell theory.

Reductionist Biology

Physico-chemical approach that explains physiological and behavioral processes by analyzing cellular and molecular components.

Biomolecule

Any organic molecule present in living organisms, such as carbohydrates, proteins, lipids, or nucleic acids.

G. N. Ramachandran

Indian structural biologist who discovered the triple-helical structure of collagen and developed the Ramachandran plot.

Triple Helical Structure of Collagen

Three-stranded, rope-like conformation of collagen elucidated by G. N. Ramachandran in 1954.

Ramachandran Plot

Graphical representation that maps the allowed φ (phi) and ψ (psi) angles of amino-acid residues in protein structures.

Conformational Analysis

Study of the spatial arrangement of atoms in biomolecules and the energy associated with their shapes.

Collagen

The most abundant structural protein in animals, characterized by a triple-helical structure that provides tensile strength to tissues.

Onion Cell

Typical plant cell with a rigid cell wall; shows nucleus and cytoplasm when viewed microscopically.

Human Cheek Cell

Typical animal cell lacking a cell wall; shows plasma membrane, cytoplasm, and nucleus under the microscope.