SVT Chapter 1: The Living Cell and Cell Theory

Vocabulary flashcards covering the foundation and axioms of cell theory, membrane transport mechanisms, the biological status of viruses, microscopy techniques, and the dimensional scales of life.

Cell Theory (Théorie cellulaire)

A biological theory built on three axioms: all living beings are composed of cells, the cell is the basic unit of life, and every cell comes from a pre-existing cell.

Z. Janssen (1590)

The creator of the first optical microscope (MO) in $1590$.

R. Hooke (1665)

The scientist who made the first mention of the term 'cell' ('cellule') in $1665$.

A Von Leeuwenhoek (1678)

The scientist who improved the optical microscope (MO) in $1678$.

MJ. Schleiden and T. Schwann (1837/1839)

The scientists who established the first and second laws of cell theory in $1837/1839$.

R. Virchow (1855)

The scientist who formulated the third law of cell theory in $1855$, stating that every cell arises from a pre-existing cell.

Louis Pasteur (1859)

The scientist who invalidated the theory of spontaneous generation through key experiments in $1859$.

Spontaneous Generation Theory

An ancient theory proposing that living organisms could appear spontaneously from non-living matter without originating from other living organisms.

Electron Microscope (1931)

A microscopy technology invented in $1931$ that allows observation of cellular ultrastructure and nanoscale biological components.

DNA Double Helix (2012)

The structure of Acide Désoxyribo Nucléique of which the first direct photograph was captured in $2012$.

Plasma Membrane

A biological structure composed of two layers of lipids and proteins that forms a barrier between the interior and exterior cellular environments, controlling material exchanges and allowing only small hydrophobic molecules to pass freely between tightly packed lipids.

Osmosis (Osmose)

The passive diffusion of water across a membrane driven by a solute concentration differential, moving from the less concentrated solution to the more concentrated solution.

Aquaporin (Aquaporine)

A protein channel enabling the passage of water molecules between intracellular and extracellular environments at a rate of 3 billion molecules/second ($3 \times 10^9\text{ molecules/second}$).

Paracetamol and Ethanol

Exogenous molecules capable of entering the body, penetrating cells by simple diffusion across the plasma membrane, and altering membrane fluidity; they can be useful or toxic depending on dose and nature.

Metabolism (Métabolisme)

The internal chemical reactions performed by a living organism to exchange matter and energy with its environment.

Living Being (Être vivant)

An entity composed of one or more cells that exchanges matter and energy with its environment, carries out internal chemical reactions (metabolism), reproduces by transmitting genetic information, and evolves over time.

Virus

A biological entity measuring $100\text{ nm}$ possessing genetic material and the ability to evolve, but not classified as a full living being because it lacks cells, has no membrane for environmental exchange, lacks its own metabolism, and requires a host to reproduce.

Resolution (Résolution)

The minimum distance that must separate two points for them to be discernible from one another.

Optical Microscope (MO / MPhotonique)

A low-cost, fast, and easy microscopy tool producing 2D images of living or dead samples with staining capability, but limited by low resolution and magnification where not all cellular components are visible.

Transmission Electron Microscope (MET)

A very high-cost, time-consuming instrument with high resolution and very high magnification that produces 2D false-color images of the cellular interior and ultrastructure using dead, dehydrated samples.

Scanning Electron Microscope (MEB)

A very high-cost, time-consuming instrument with very high resolution and high magnification that visualizes the surface of cells in 3D false-color using dead, dehydrated samples.

Macroscopic Scale of Life (Organism, Organ, Tissue)

The biological scale encompassing the whole organism (m to $1\text{ cm}$), organs ($1\text{ cm}$), and tissues ($1\text{ mm}$).

Microscopic Cellular Scale (Plant and Animal Cells)

The biological scale measuring cell size, specifically $100\,\mu\text{m}$ for a plant cell (cellule végétale) and $10\,\mu\text{m}$ for an animal cell (cellule animale).

Microscopic Sub-Cellular Scale (Bacterium and Virus)

The biological scale representing unicellular organisms and particles, specifically $1\,\mu\text{m}$ for a bacterium and $100\text{ nm}$ for a virus.

Nanoscopic Scale (Protein, Molecule, Atom)

The chemical and molecular scale measuring $10\text{ nm}$ for a protein, $1\text{ nm}$ for a small molecule, and $0.1\text{ nm}$ for an atom.