Discovering Cells Chapter 3.1

I. An Overview of Cells Cells: the basic unit of structure and function. TPS: What does basic mean?

A. Structure and Function The structure of a cell is complementary to its function. TPS: What are the functions of these cells?

B. Cells and Functions Example functions: –Absorbing O 2 gas –Absorbing food –Detoxifying –Releasing waste –Producing energy –Signaling to other cells –Protection

C. Size of Cells Cells are measured in microns. 1 micron = one millionth of a meter. Cool Facts: - One cm 2 of your skin contains 100,000 cells. - An adult human is made of trillion cells.

II. First Observations of Cells Cells discovered around Made possible by the invention of the microscope.

A. Robert Hooke Observed cork under a microscope. Coined the term “cells” because they looked like tiny rooms.

III. Development of Cell Theory Cell Theory 1.All living things are made of cells. 2.Cells are the basic units of structure and function. 3.All cells are produced from other cells.

IV. Unicellular and Multicellular Unicellular: Organisms made of one cell. “uni” = one Examples: Bacteria, rotifers, parameceum. Rotifer Paramecium

Multicellular: Organisms made of many cells. Examples: Human, slug, sunflower.

☼ In multicellular organisms, cells are organized into tissues, organs, and organ systems.

Tissue: A group of similar cells working together to serve a common function. Organ: A group of tissues working together to serve a common function. Organ System: A group of organs working together to serve a common function.

Levels of Organization Tissue Organ Organ System Nervous Brain Nervous System Muscle Heart Cardio- pulmonary System