Chapter 7 “Cell Structure & Functions” Objectives n Students will learn about cell theory and the scientists who discovered it. n Students will also learn about the structure of a cell and its organelles, important cellular functions and the basic organization of cells into a living organism.
Microscope Handling 1. Carry microscope properly having one hand beneath the base and the other hand grasping the arm 2. Place arm of microscope facing you 3. Move objectives all the way up 4. Rotate and lock (clicking sound) low power objective into position. 5. Turn on the light
6. Place slide onto stage, use stage clips to hold slide in place (make sure that the specimen is centered) 7. Move low power objective lens, using the course adjustment knob, until almost touching the slide. 8. Now, looking through the ocular lens, move the objective (10X) until the image is in focus 9. Switch to high power carefully, rotate and lock into place. Use only the fine-adjustment knob, because you could damage or break the slide
Discovery of Cells n 1600s Anton von Leeuwenhoek - 1st person to observe & describe microorganisms & living cells. n n 1st person to construct a microscope to view microorganisms
Robert Hooke n Robert Hooke 1600s observed dead plant cells from cork. n In fact, it was Hooke who coined the term "cells": the box-like cells of cork reminded him of the cells of a monastery n In fact, it was Hooke who coined the term "cells": the box-like cells of cork reminded him of the cells of a monastery.
1833 Robert Brown n Observed that many cells to have a dark structure near the center of a cell. We now call this structure a nucleus
1838 Matthias Scheleiden n German botanist n Studied plants & concluded that all plants are made of cells n Studied plants & concluded that all plants are made of cells.
1839 Theodor Schwann n a German cytologist and physiologist n Concluded that all animals are made up of cells.
1855 Rudolf Virchow n Researched and concluded that all cells arise from preexisting cells n example: skin cells develop into new skin cells.
Cell Theory n The combined work of these scientists developed what we know today as the Cell Theory. n The cell theory states: 1. all living things are composed of cells. 2. cells are the basic unit of structure and function in living things 3. all cells come from preexisting cells 3. all cells come from preexisting cells.
1970 Lynn Margulis n Proposed the idea that certain organelles were once free-living cells themselves. n Ex: Chloroplasts were once free-living photosynthetic bacteria that were incorporated into plant cells and formed a symbiotic relationship.