1. Cell Structure and Function

2. Robert Hook 1665 - Hook used a primitive microscope to view cork. What he saw (cell walls) he described as “cells” because they looked like rooms in a monastery.

3. The Cell Theory (1835-1855) Schleiden, Schwann, and Virchow 1. All living things are composed of cells. 2. Cells are the basic units of structure and function in living things. 3. New cells are produced from existing cells.

4. Two categories of cells Eukaryotes (eu “true”; karyon “nucleus”) are cells that have a nucleus. Prokaryotes (pro “before”) do not contain nuclei. Nucleus – large membrane-enclosed structure that contains the cell’s genetic material in the form of DNA.

5. Comparison

6. Prokaryotes Smaller and simpler than eukaryotes Genetic material not contained in nucleus Carry out activities associated with living things: grow, reproduce, respond to environment and some move Example: bacteria

7. Eukaryotes Contain a nucleus in which their genetic material is separated from the rest of the cell. Can be unicellular: amoeba, protozoa Can be multicellular: animals, plants, fungi Contain organelles – “little organs”

8. 2 Parts of Eukaryotic Cell Nucleus and the cytoplasm Cytoplasm is the portion of the cell outside the nucleus.

9. Nucleus Contains almost all DNA and with it the coded instructions for making proteins and other important molecules. Surrounded by nuclear envelope (double membrane) dotted with nuclear pores; allows movement of info into & out of nucleus Contains chromatin (granular material) – consists of DNA bound to protein; cell divisions, forms chromosomes: genetic info passed on

10. Ribosomes Formed in the nucleolus (small region of nucleus) Very small dot- like structures Make proteins

11. Vacuoles Round membrane storage sac for holding food, water, or waste

12. Mitochondria Double membrane structures, where cellular respiration (the break down of sugar) occurs to release energy

13. Chloroplast Double membrane structure, where photosynthesis takes place (making of carbohydrates or sugars), contains green pigment called chlorophyll

14. Cell Membrane aka Plasma Membrane Thin, flexible barrier that surrounds the cell Regulates which molecules enter and leave Provides protection and support

15. Cell Wall Rigid structure around cell, outside of cell membrane Provides support and protection Plant cells: mostly cellulose