Warmup

1. Warmup A complete sentence expresses a thought. Can a thought be expressed by less than a complete sentence? Can that thought be divided … And divided again? What is the smallest piece of that original thought that has any meaning at all? How would you describe the size of the smallest piece, and what relationship does it have with the original thing?

2. Cell Theory October 3, 2011

3. Overview: Understanding Cells Cell Theory Materials Transportation History of Discovery Metabolism Hierarchies of Organization Cells Organelles Differentiation and Specialization Reproduction Students understand cell theory, metabolisms, and categories of organic compounds. Students know the functions organelles carry out (nucleus, ribosome, mitochondria, chloroplast, mitochondria) Students can differentiate between plant eukaryote, animal eukaryote, and prokaryotic cells, and between stem and specialized cells, and between haploid and diploid cells, and understand the difference between types of cell division, sexual reproduction, and asexual reproduction.

4. Cell Description Cells are so small (measurable in micrometers, or 1/1,000,000th of a meter) they were not discovered until after the invention of the microscope. 1663 – Robert Hooke observes cork, calls empty boxes “cells”. 1674 – Anton van Leeuwenhoek observes living microorganisms.

5. Cell Description 2 Cells are self-contained by a wall or a membrane, which allows some materials to move in and out. Some cells are multi-purpose, while others perform only one special job. Cells divide in half to create two daughter cells.

6. Cell Theory • 1855 – Schleiden, Schwann, Virchow propose a theory based on continued evidence from experiments and observations of cells. • Cell Theory states: • All living things are composed of cells. • Cells are the basic units of form and function in living things. • All cells are produced from other cells.

7. A scientist puts nutritious broth in a jar, and weeks later observes it under a microscope. She sees many cells. According to cell theory: • The cells were created from the broth. • The broth was originally lifeless. • Individual cells have no real structure or organization. • At least one cell must have started out in the jar. • The individual cells will eventually combine forces into a larger creature. • None of the above.

8. The first scientist to use a microscope to discover cells was: • Anton van Leeuwenhoek • Matthias Schleiden • Rudolf Virchow • Theodor Schwann • Robert Hooke • Charles Darwin • Gregor Mendel

9. Cell Hierarchies