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Discovering Cells…. Anton van Leenwenhoek Dutch scientist Dutch scientist The first person to look at water using a single-lens microscope in the mid-1600’s.

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Presentation on theme: "Discovering Cells…. Anton van Leenwenhoek Dutch scientist Dutch scientist The first person to look at water using a single-lens microscope in the mid-1600’s."— Presentation transcript:

1 Discovering Cells…

2 Anton van Leenwenhoek Dutch scientist Dutch scientist The first person to look at water using a single-lens microscope in the mid-1600’s. The first person to look at water using a single-lens microscope in the mid-1600’s. He was surprised to see the water was full of living things: He was surprised to see the water was full of living things:“animalcules”

3 van Leenwenhoek Microscope

4 Robert Hooke English scientist English scientist Studied cork using a compound light microscope. Studied cork using a compound light microscope.

5 Hooke Microscope

6 CELLS He observed tiny geometric shapes and named them “cells” because they reminded him of the small rooms monks lived in at the monastery. He observed tiny geometric shapes and named them “cells” because they reminded him of the small rooms monks lived in at the monastery.

7 Robert Hooke published 'Micrographia' in It is his most famous work, and is notable for the stunning illustrations, drawn by Hooke himself. Robert Hooke published 'Micrographia' in It is his most famous work, and is notable for the stunning illustrations, drawn by Hooke himself.

8 The picture of the flea shown is one of his most famous images; the original is 18 inches across. The picture of the flea shown is one of his most famous images; the original is 18 inches across.

9 Additional Hooke drawings

10 Matthias Schleiden German scientist German scientist Observed different plants and concluded that all plants are composed of cells in the 1830’s. Observed different plants and concluded that all plants are composed of cells in the 1830’s.

11 Theodore Schwann German scientist German scientist Made observations that all animals are composed of cells. Made observations that all animals are composed of cells.

12 Robert Brown Scottish scientist Scottish scientist Observed that all cells contained a prominent structure that appeared to be a “blob” in the center of the cell…the nucleus. Observed that all cells contained a prominent structure that appeared to be a “blob” in the center of the cell…the nucleus.

13 Rudolf Virchow Concluded that the nucleus was the structure responsible for cell division. Concluded that the nucleus was the structure responsible for cell division.

14 Together, these men developed The Cell Theory:

15 The Cell Theory 1. All organisms are composed of one or more cells. 2. The cell is the basic unit of organization of organisms. 3. All cells come from preexisting cells.

16

17 Compound Light Microscopes Uses 2 or more glass lenses to magnify objects. Uses 2 or more glass lenses to magnify objects. Can magnify up to 1500 times. Can magnify up to 1500 times.

18 Compound Light Microscopes

19 Scanning Electron Microscope Sweeps a beam of electrons over the surface of a specimen causing electrons to be emitted from the specimen. Sweeps a beam of electrons over the surface of a specimen causing electrons to be emitted from the specimen. Produce a realistic, 3D image…but only on the surface. Produce a realistic, 3D image…but only on the surface. Can magnify about 60,000 times. Can magnify about 60,000 times.

20 Scanning Electron Microscope

21 Transmission Electron Microscope Aims a beam of electrons through a specimen Aims a beam of electrons through a specimen Two-dimensional images are used to study details of cells Two-dimensional images are used to study details of cells Can magnify hundreds of thousands of times. Can magnify hundreds of thousands of times.

22 Transmission Electron Microscope

23 Blood Cells Compound Microscope TEM SEM

24 LOOKING AT CELLS FORM DEFINES FUNCTION FORM DEFINES FUNCTION A cell’s shape reflects its function. A cell’s shape reflects its function. VARIOUS SHAPES VARIOUS SHAPES Branched Branched Flat Flat Round Round Rectangular Rectangular Irregular Irregular Change shapes Change shapes

25 CELL SIZE Cell size is limited by a cell’s surface area-to-volume ratio Cell size is limited by a cell’s surface area-to-volume ratio Cells get larger…need more nutrients…release more waste. Cells get larger…need more nutrients…release more waste. The substances have to move farther to reach their destination The substances have to move farther to reach their destination

26 CELL FEATURES (Venn Diagram?) ALL cells share common structural features: ALL cells share common structural features: Cell membrane Cell membrane Cytoplasm Cytoplasm Ribosomes Ribosomes DNA DNA

27 Two Types of Cells Prokaryotes Prokaryotes Lacks a nucleus Lacks a nucleus Pro = before Pro = before Karyon = nucleus Karyon = nucleus Eukaryotes Eukaryotes Has a nucleus Eu = true Karyon = nucleus

28 Two Types of Cells Prokaryotes Prokaryotes Small, simple, single-celled organisms Small, simple, single-celled organisms BACTERIA BACTERIA Eukaryotes Eukaryotes Complex, multi-celled organisms PLANTS & ANIMALS

29 Two Types of Cells Prokaryotes Prokaryotes Do NOT have: Do NOT have: Eukaryotes Eukaryotes DO have: Internal compartments (membrane-bound organelles)

30 Eukaryotic cells can carry out more specialized functions because of their complex organization (organelles).

31 DNA Cell Division Cell Membrane Ribosomes Small, simple, single-celled organisms Nucleus No Nucleus Complex, multi- celled organisms No Internal Compartments— membrane-bound organelles Has Internal Compartments— membrane-bound organelles Earliest cells Smaller ribosomes Larger ribosomes Cells evolved later Cell Division— Binary Fission Cell Division— Mitosis


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