Sells Unit

Sells Middle SchoolPrincipal: Matt Sachtleben

150 West Bridge StreetDublin, Ohio 43017

Phone: 614.764.5919Fax: 614.764.5923

Hours: 8:28 AM - 3:08 PM

Cells

Motorola introduced firsthand held cell phone in 1973.It cost $4,000

Cells

Cells

• Cells are the basic unit of structure and function in living things.– Form all organisms’ parts– Carry out all organisms’ processes/functions

• Everything/anything an organism does starts in the cells!

Cells

• Organisms are vastly different– Trees, humans, eels, etc.– Cells combine in vastly different ways to make all of

these different organisms• Functions are what keep organisms alive and

reproductive.– Getting oxygen, food, eliminating waste, growth, etc.– Different cells enable all of these function to work

(properly one hopes!).• Most cells are microscopic.

Cells

• Microscopes made it possible to see, except for eggs, for the first time.

• Microscopes make small objects look larger through magnification.

• Robert Hooke was one of the first to see cells after he built

his own compound microscope.

• In 1663 Hooke to a look (get it) at this: a thin slice of cork taken from the bark of a cork tree.

• He thought the tiny spaces looked like rectangular rooms.

• Cells means small rooms – so Hooke named them cells!

Anton Van Leeuwenhoek

• Around the same time as Hooke, Anton used the microscopeand discovered that there were organisms that were made ofjust ONE cell!

• He observed many of these organisms moving.• His microscope magnified objects up to 266x

Cell Theory

• Scientists all over were excited and inspired by the microscope and Bob’s/Anton’s work.

• In 1838 Matthias Schleiden determined that all plants were made of cells.

• In 1839 Theodor Schwann determined that all animals were made of cells. So, based on Schleiden and his own work Teddy said all living things were made of cells!

• In 1855 Rudolf Virchow thought that “All cells come from cells.”, which ended the theory that living things could come from non-living things.

• Their work led to the formation of the cell theory.

Cell Theory

How the book states cell theory (different words – same meaning!1. All living things are composed of cells.2. Cells are the basic units of structure and function in living things.3. All cells are produced from other cells.

NO MATTERHOW BIG OR SMALLTHE ORGANISM, CELLTHEORY HOLDS!

Microscopes

• Microscopes help to enlarge (magnify) and make things clear (resolve). Magnification and resolution are

key.• Magnification

– The lenses in light microscopes bend the light that passes through them causes objects to look magnified (larger).

– The lenses are curved (convex) with a thicker center.– Compound Microscopes use two lenses. The magnification of the lenses is

increased by the multiplier effect.• Resolution – keeps specimens under the scope from being blurry.

Magnified blurry cells are no use.• Electron microscopes – use beam of electrons to magnify instead of

light. Much stronger magnification (up to 5,000,000x) and better resolution!