Bell Question 9/13 What is a cell?

Transcription

1 Bell Question 9/13 What is a cell? So you missed your test yesterday. You need to come in and take it before or after school or at lunch. Retakes..must be done on your own time and finished by Wednesday

2 Section 1: The invention of the microscope led to the discovery of cells. K What I Know W What I Want to Find Out L What I Learned

3 Essential Questions How are the advances in microscope technology related to discoveries about cells? What are the similarities and differences between compound light microscopes and electron microscopes? What are the principles of the cell theory? What are the differences between a prokaryotic cell and a eukaryotic cell? Vocabulary Review organization New cell cell theory plasma membrane organelle eukaryotic cell nucleus prokaryotic cell

4 History of the Cell Theory A cell is the basic structural and functional unit of all living organisms. Cells are so small that their existence was unknown before the invention of microscopes. The cell theory is one of the fundamental ideas of modern biology, and includes the following three principles: All living organisms are composed of one of more cells. Cells are the basic unit of structure and organization of all living organisms. Cells arise only from previously existing cells, with cells passing copies of their genetic material on to their daughter cells.

5 Microscope Technology Compound light microscopes Use a series of glass lenses and visible light to magnify images Magnify images up to ~1000 actual size Electron microscopes Create an image by illuminating a sample with a beam of electrons and collecting the electrons that are reflected back from the sample Magnify images up to 500,000 actual size

6 Basic Cell Types All cells have at least one physical trait in common: a plasma membrane. A plasma membrane is a special boundary that helps control what enters and leaves the cell. Most cells contain genetic material in some form. Most cells break down molecules to generate energy. There are two basic kinds of cells: eukaryotic and prokaryotic.

7 Eukaryotic cells contain a nucleus and other organelles. Organelles are specialized structures that perform specific cell functions. The nucleus is the distinct central organelle that contains the cell s genetic material. Eukaryotic cells are generally much larger than prokaryotic cells. Prokaryotic cells are cells without a nucleus or other membrane-bound organelles. Smaller and simpler than eukaryotes. May be similar to the first organisms that lived on Earth.

8 Basic Cell Types Origin of cell diversity Eukaryotic cells may have evolved from prokaryotic cells. The endosymbiont theory proposes that a symbiotic relationship formed between two prokaryotic cells, one of which lived inside the other. Eventually the symbiotic relationship led to the two cells becoming one. Because eukaryotic cells are larger and more complex, they developed specific functions. These specific functions led to cell diversity, and thus organismal diversity.

9 Cell Specialization BrainPOP FPO Add link to BrainPOP from page 186 here.

10 Review Essential Questions How are the advances in microscope technology related to discoveries about cells? What are the similarities and differences between compound light microscopes and electron microscopes? What are the principles of the cell theory? What are the differences between a prokaryotic cell and a eukaryotic cell? Vocabulary cell cell theory plasma membrane organelle eukaryotic cell nucleus prokaryotic cell