The Cell Theory Biology 11 Cell Biology Chapter

The Cell Theory Biology 11 Cell Biology Chapter 1

The Cell pages 8 -10 • • smallest living unit Basic building block of organisms Human body – 100 trillion cells Different cells are specialized to preform different tasks

Nerve Cells • Transmit messages to the body about our surroundings and enable us to respond. • Vision, hearing, taste, smell and touch all depend on nerves.

Muscle Cells • Capable of rapid contraction. • Grouped together to form our muscle groups.

Red Blood Cells • Transport of Oxygen

White Blood Cells • Defense against disease.

Special Receptor Cells • Communicate messages to nerves for relay to nerve centres like the brain.

Our Body – a living ecosystem of cells • E. coli bacteria in our “gut”. • We breathe in plant spores and pollen. • Microbes and microscopic animal eggs on the food we eat. • All made of cells! • Outside has cells too – fungus and bacteria.

Cells in Daily Life • • • Yogurt bacteria Sour milk bacteria Cheese processing Yeast cells for bread and beer making Leather tanning processes

All cells ……… • • Digest nutrients Excrete wastes Synthesize needed chemicals reproduce

Cells are…. • The basic unit of all living things! • Grouped together to form tissues and organs.

Cell History • • Robert Hooke, 1665, borrowed the word cell (reminded him of the “cells” in a monastery) to describe the honeycomb shape and structure of a thin slice of cork he observed under a primitive microscope. Robert Hooke Neglected Hooke Anton Van Leeuenhoek, 1674 An Unlikely Scientist, made microcsopes and observed blood cells, bacteria and single celled organisms. Robert Brown, 1831, described the nucleus Theodor Schwann and Mathias Schleiden, 1838, plant and animal tissue composed of cells Louis Pasteur, – Very Important Person! studied microorganisms. Rudolph VIrchow, 1858, “All cells come from preexisting cells. ”

Modern Cell Theory • All living things are composed of one or more cells. • The cell is the smallest entity that retains the properties of life. • New cells arise only from cells that already exist. • An expansion…. More to the story!