CELL BIOLOGYMrs. Stewart

Central Magnet SchoolHonors Biology

THE DISCOVERY OF CELLS Robert Hooke

Used an “early” Light Microscope to observe dead “cells” in bark of a Cork Oak tree He coined the

term “cells” because he described what he saw as “many little boxes” that reminded him of the cubicles, or cells, where monks live.

THE DISCOVERY OF CELLS Anton Van

Leeuwenhoek-Made

microscopes – able to grind lenses to increase magnification to 10x Hooke’s microscope

First to observe living cells Spyrogyra genus

– type of algae Termed them

Animalcules (protists)

THE CELL THEORY

All living organisms are composed of one or more cellsMatthias Schleiden – plantsTheodor Schwann – animals

Cells are the basic units of structure and function in an organism

Cells come only from the reproduction of existing cellsRudolf Virchow

TIMELINE – HISTORY OF CELL BIOLOGY

MICROSCOPES Microscopes are why scientists were

able to stop speculating and start observing and exploring the “unseen” world of living and non-living things.

Microscopes helped scientists clarify our definition of life

CHARACTERISTICS OF LIFE Consist of cells Cells display organization Obtain and use energy to perform

chemical reactions (metabolism) Change through time (adapt) Respond to their environment/stimulus Reproduce Growth and development Homeostasis

CELLULAR ORGANIZATION

CELL DIVERSITY

Shape Cell

shapes reflect the different functions of cells

CELL DIVERSITY Size

A few cells are large enough to be seen by the “naked” eye

Surface area-to-volume ratio determines cell size. All materials needed by the cell must enter

and exit through the surface (cell membrane/wall) Nutrients come in Wastes are excreted out

As a cell becomes larger, the volume increases more than the surface area. There is a point where there is not enough surface area to sustain transport in/out of necessary materials to keep up with volume of cell.

PROKARYOTE VS EUKARYOTE

Pro = NO Eu = DO

Prokaryotes Smaller No nucleus, but a

nucleoid DNA is in one circular

chromosome No plasma

membrane No membrane bound

organelles

Eukaryotes Larger Nucleus Plasma membrane Membrane bound

organelles Organelles carry out

life processes within cell

DNA in multiple chromosomes within nucleus

CHARACTERISTICS THAT DISTINGUISH PLANT CELLS FROM ANIMAL CELLS Cell wall Large central vacuole plastids