Microscopes and the Cell Theory All About Cells Microscopes and the Cell Theory

Microscopes of Today At lot of times, when we think of a object, we think of it as it is today. For example, a cell phone.

Cell Phones So when we think of cell phones, we think of the ones we see today. The ones that we know and many of us use. But what about the original cell phones?

Microscopes Just as there are difference between the cell phones we use now and the original cell phones, there are also differences in the microscopes we use today and what the original scientists who first looked at cells had available to them.

1723 1764

1770 1800

1839 1856

1865 1876

1905 1914

1926 1959

Historical microscope images, and more, can be found at: http://www Historical microscope images, and more, can be found at: http://www.techinst.com/ antiquecollection.html

The observations and conclusion of many scientists helped to develop the current understanding of the cell. Robert Hooke Anton van Leeuwenhoek Matthias Schleiden Theodor Schwann Rudolph Virchow

The Discovery of the Cell Early Scientists Robert Hooke (1665) Observed a cork slick and saw that it seemed to be made up of tiny, empty chambers. Hooke called these chambers cells, because they resembled the tiny rooms of a monastery.

The Discovery of the Cell Early Scientists Anton van Leeuwenhoek (1674) Used a single-lense microscope to observe pond water Saw tiny living organisms, which he called “animalcules” and we know today as bacteria

Matthias Schleiden (1838) – concluded that all plants are made up of cells

Theodor Schwann (1839) – concluded that all animals are made up of cells

Rudolph Virchow (1855) – proposes that all cells come from preexisting cells, completing the cell theory

The Cell Theory Cells are the basic unit of life. The cell theory states that: All living things are composed of cells Cells are basic units of structure and function in living things New cells are produced from existing cells

The Cell Theory Remember, before the Cell Theory, we had Spontaneous Generation – that life can arise from nonliving matter. The scientists who worked to disprove this idea are: Redi Spallanzani Pasteur

Redi’s Experiment

Spallanzani’s Experiment

Pasteur’s Experiment

Exploring the Cell Common Microscope Types: Light microscope – living organisms, but low resolution Electron microscopes - view details 1000 times smaller than visible in light microscopes. Non-living specimens. Requires vacuum. Scanning Probe microscopes – Can operate in air, and can show DNA, protein molecules, and even single atoms.

Light Microscope

Electron Microscopes Transmission Electron microscopes – requires thin specimens, can view cell structures and large protein molecules. Organelles in a pollen grain of tobacco (Nicotiana tabacum; AF = Actin filaments; G = Golgi apparatus; Mi = Mitochondrion; Mt = Microtubule).

Electron microscopes Scanning Electron microscopes – 3D

Scanning Probe Microscopes

PROKARYOTES EUKARYOTES DNA Cells that have genetic material that is not contained in a nucleus; called a nucleoid region Cells that contain a nucleus in which their genetic material is separated from the rest of the cell Size 0.2-10μm 5-100μm Organization Usually single-celled; generally smaller than Eukaryotes Can be single celled, but often multicellular Examples Bacteria Plants, animals, protists, fungi

Prokaryote Cells

Eukaryotes Cells