An Introduction to Cells Indicator B – 2.1: Recall the three major tenets of cell theory Indicator B – 2.3: Compare the structures and organelles of prokaryotic and eukaryotic cells.

Key Concepts Cell Theory Unicellular vs. Multicellular Organisms Prokaryotes vs. Eukaryotes

It is essential for you to know: All living things are composed of one or more cells. Cells are the basic unit of structure of all living things. All presently existing cells arose from previously existing cells.

Objectives Recall the major tenets of the Cell theory. Compare unicellular organisms and multicellular organisms. Differentiate between prokaryotic cells and eukaryotic cells.

Vocabulary Words Please define the following words: cell theory cytoplasm organelle prokaryotic cell eukaryotic cell

The Cell LIFE IS CELLULAR

Before we begin... ATP (adenosine triphosphate) = Fuel Cells take sugar (glucose) from food and turn it into ATP.

The History of Cell Biology

The History of Cell Biology A person who studies cells is called a cytologist.

The History of Cell Biology Anton van Leeuwenhoek 1600’s Became one of the first people to use a microscope to study nature. Was the first person to see tiny living organisms in a drop of water.

The History of Cell Biology Robert Hooke 1665 Saw “cells” in a cork under a light microscope.

The History of Cell Biology Matthias Schleiden 1838 Concluded that all plants have cells.

The History of Cell Biology Theodor Schwann 1839 Concluded that all animals have cells.

The History of Cell Biology Rudolf Virchow 1855 Studied cell reproduction

The Cell Theory A cell is the basic unit of life. All of the scientists’ work contributed to what is now called the cell theory: All living things are composed of one or more cells. All cells come from previously existing cells. Cells are the most basic units of life.

Prokaryotes & Eukaryotes Biologists divide cells into two categories: Prokaryotes Eukaryotes

Prokaryotes & Eukaryotes No nuclei Have cell membrane, cell wall, plasmid, ribosomes, cytoplasm Smaller and simpler Most bacteria and archae Divide by binary fission

Prokaryotes & Eukaryotes Have a nucleus Usually bigger and more complex Cell membrane, cytoplasm, & organelles. Plants, animals, fungi, and many microorganisms.

Unicellular Organisms Sometimes the cell is the organism. Do everything that you would expect a living thing to do. Include both prokaryotes and eukaryotes. Prokaryotes: bacteria and archae Eukaryotes: some types of algae, protists, fungi.

Multicellular Organisms Made up of more than one cell. Cells in multicellular organisms are specialized to perform particular functions within the organism. This is cell specialization. Think: blood cells, hair cells, digestive cells, etc.

Levels of Organization The levels of organization in a multicellular organism are: individual cells tissues organs organ systems

Levels of Organization Cell: nerve cell Tissue: nerve tissue Organ: the brain Organ System: Nervous System