Cell Theory and Microscopy Lecture Flashcards

This set of vocabulary flashcards covers the historical development of cell theory, types of microscopy, and the differences between classical and modern cellular concepts.

Theory of Spontaneous Generation

An early scientific belief that living organisms could arise from non-living matter.

Jan Baptist van Helmont

A 17th-century proponent of spontaneous generation who claimed to have generated mice from wheat and a sweaty shirt.

Francesco Redi

A scientist who challenged spontaneous generation by demonstrating that maggots on decaying meat came from flies, not the meat itself.

John Needham

A scientist whose experiment involved heating chicken broth in a sealed flask; he interpreted the appearance of microorganisms as evidence of spontaneous generation.

Lazzaro Spallanzani

A scientist who disproved Needham by demonstrating that microorganisms arise from pre-existing microorganisms and do not grow in heated, sealed flasks.

Louis Pasteur

The scientist who established the principle of biogenesis using swan-neck flasks to show that microorganisms come from other microorganisms in the environment.

Biogenesis

The principle that life arises only from pre-existing life.

Cell

Derived from the Latin 'cella' meaning 'small room', it is the basic structural, functional, and biological unit of all known organisms.

Cytology

The study of cells, also known as cell biology or cellular biology.

Surface area-to-volume ratio

An explanation for small cell size; if the radius increases by $10$ times, the surface area increases by $100$ times, but the volume increases by $1000$ times.

Robert Hooke

The first person to see cell walls in dead oak bark (cork) in 1665 using an early microscope.

Anton van Leeuwenhoek

The first person to observe living cells using a microscope in the late 1600s.

Light Microscope (LM)

An instrument that passes visible light through a specimen and refracts it through glass lenses to magnify the image.

Bright-field microscope

A type of light microscopy where light is transmitted through a specimen, often requiring staining (which fixes/kills the cells) to improve contrast.

Dark-field microscope

A microscope that directs light onto a specimen at an angle, resulting in a light specimen against a dark background.

Phase-contrast microscope

A microscope that brings light waves out of phase to produce differences in contrast and brightness in live specimens.

Confocal microscope

A microscope that uses a laser to scan a fluorescently stained specimen in two directions, producing clear 3-D images by excluding light from other planes.

Scanning Electron Microscope (SEM)

A microscope that focuses a beam of electrons onto the surface of a specimen to provide 3-D images.

Transmission Electron Microscope (TEM)

A microscope that focuses a beam of electrons through a specimen to study internal cell structures.

Cell Fractionation

A technique using an ultracentrifuge to take cells apart and separate major organelles from one another.

Dujardin

The scientist who in 1835 described the internal substance of the cell as 'sarcode'.

Schleiden and Schwann

The mid-19th century scientists who formulated Classical Cell Theory, proposing that all plants and animals are made of cells.

Omnis cellulla e cellula

A phrase by Rudolf Virchow (1858) meaning all living cells come from other living cells by the process of cell division.

Modern Cell Theory

The theory that incorporates DNA replication, energy flow (metabolism), and chemical composition into the understanding of cellular life.

Somatic Cells

Body cells like skin or muscle that are diploid ($2n$) and divide through mitosis.

Gametes

Sex cells (sperm and egg) that are haploid ($n$) and produced through meiosis.

Plasmodesmata

Openings in plant cell walls that allow cytoplasmic continuity between neighboring cells.

Totipotence

The power of regeneration where whole new individuals can be cultured from isolated cells.

Organismal Theory

A theory suggesting that some organisms are non-cellular or supracellular, where the whole organism is the basic unit of life rather than independent cells.

Supracellular

A state where cellular units are continuous with each other, making the whole plant or tissue the basic unit of life, such as in plants or multinucleated skeletal muscle cells.

Cell Body

In the context of organismal theory, the nucleus and associated microtubules that serve as the basic unit of life due to their capacity for self-organization.

Cell Periphery

The membrane and other cytosol structures that support and protect the cell body but do not directly contribute to reproduction.

De novo membrane synthesis

A recent finding that challenges existing cell theory, showing that membranes do not necessarily need a pre-existing membrane template to form.