Discovering Cells

Chapter 3.1

I. An Overview of CellsCells: 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 O2 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 cm2 of your skin contains 100,000 cells.

- An adult human is made of 10-50 trillion cells.

II. First Observations of Cells

• Cells discovered around 1600.

• 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 MulticellularUnicellular: 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