Cell Theory

Cell

The basic building block of life.

Tissue

A group of cells that work together to perform a function.

Organ

A group of tissues that work together to perform a function.

Organ System

A group of organs that work together to perform a function.

Cell Membrane (Plasma Membrane)

A surrounding boundary that allows substances to move in and out of the cell.

Protoplasm

The thick fluid that contains all the contents of a cell.

Organelles

Structures within the cell that perform specific functions.

DNA (Deoxyribonucleic Acid)

The control center of the cell, carrying genetic instructions.

Cell Theory Postulate 1

All known living things are made up of one or more cells.

Cell Theory Postulate 2

All living cells arise from pre-existing cells by division.

Cell Theory Postulate 3

The cell is the fundamental unit of structure and function in all living organisms.

Cell Theory Postulate 4

The activity of an organism depends on the total activity of its independent cells.

Cell Theory Postulate 5

Energy flow occurs within cells.

Cell Theory Postulate 6

Cells contain DNA and RNA.

Cell Theory Postulate 7

All cells are basically the same in chemical composition in organisms of similar species.

Cell Theory Postulate 8

Heredity information is passed from cell to cell.

Zaccharias Janssen (1590)

Invented a primitive microscope.

Robert Hooke (1663–1665)

First observed cells in cork.

Marcelo Malpighi & Nehemiah Grew (1665–1676)

Investigated plant cells independently.

Anton van Leeuwenhoek (1670)

Discovered mobile organelles, or “animalcules.”

Robert Brown (1663)

Discovered the nucleus.

Matthias Schleiden (1676)

Found that plant parts are made of cells.

Theodor Schwann (1839)

Declared animals are composed of cells.

Albrecht von Roelliker (1840)

Stated that egg and sperm are made of cells.

Luis Pasteur (1849)

Developed fermentation and pasteurization.

Robert Remak (1855)

Tried proving cell division by hardening the cell membrane.

Rudolf Virchow (1858)

Coined "Omnis cellula e cellula," meaning all cells come from other cells.

Nutrition

Intake of nutrients.

Digestion

Breaking down food for use.

Absorption

Transporting substances into cells.

Biosynthesis

Building new cellular components.

Excretion

Removing cellular waste.

Egestion

Expelling undigested materials.

Secretion

Releasing useful substances.

Movement

Changing position or location.

Irritability

Responding to stimuli.

Respiration

Converting food into energy.

Reproduction

Producing new cells or organisms.