Unit 1 Cell Theory Study Guide Cells ● Cells are the smallest unit of life that can be considered alive. ● Cells are the basic structural and functional unit of all organisms ● Cells all come from preexisting cells. ● Organisms can be made of one cell (unicellular) or many cells (multicellular). ● Multicellular organisms are more complex. ● Unicellular organisms are less complex. ● Both multicellular organisms and unicellular organisms need food, water, waste disposal, and an environment to live in. ● The two main types of cells are prokaryotic and eukaryotic. ● Functions of cells include obtaining energy, bringing in nutrients and water, and getting rid of wastes. ● Other functions of the cell are providing the ability to grow and reproduce. Cell Theory ● In 1665, English scientist Robert Hooke built his own microscope to observe nature. ● Hooke thought that the empty spaces that he saw in tree bark looked like tiny rooms that the monks lived in, so he named them “cells”. ● In 1674, Dutch businessman Anton van Leeuwenhoek was the first person to observe living cells through a microscope. He named them “animalcules”, or little animals. ● In 1838, Matthias Schleiden, a scientist working with plants, noticed that all plants were made of cells. ● A year later, Theodore Schwann came to the conclusion that animals are made of animal cells. ● Schleiden and Schwann are credited with the development of cell theory. ● Cell theory is a widely accepted explanation of the relationship between cells and living things. The three core principles are: ○ All living things are made of cells. ○ Cells are the basic unit of structure and function in living things. ○ All new cells are produced from existing cells. ● The cell theory holds true for all living things, no matter how or how small they are. Microscopes ● A microscope is an instrument that makes small objects look larger. ● The advanced technology in the modern microscope provides far greater detail for much closer observations. ● Light microscopes focus light through lenses to produce a magnified image. ● Electron microscopes are more complex. To create an image, electron microscopes use beams of electrons that scan the surface of the specimen. Level of Organization ● Cells form tissues ● Tissues form organs ● Organs for organ systems ● Without cells to form the tissues, the body would not function. Vocabulary ● Cell - The basic structural and functional unit of living organisms ● Cell Theory - A theory that states the following: ❖ All life is made up of cells ❖ Cells are the fundamental unit of life ❖ All cells come from preexisting cells ● Organism - A self-contained living thing ● Multicellular - A category of organisms made up of more than one cell and of different types of cells ● Unicellular - A category of organisms made up of ONE cell ● TIssue - A mass of similar cells that perform a specific function ● Organ - A collection of similar tissues joined together into a structure that performs specialized functions ● Virus - A nonliving particle dependent on host cells for replication of genetic material` **Vocabulary will be tested two different ways. One-they will match the definition to** the word. Two- they will apply the definition to a sentence. .