Chapter 7 “Cell Structure Chapter 7 “Cell Structure & Functions” Objectives& Functions” Objectives

Students will learn about cell theory Students will learn about cell theory and the scientists who discovered it.and the scientists who discovered it.

Students will also learn about the Students will also learn about the structure of a cell and its organelles, structure of a cell and its organelles, important cellular functions and the important cellular functions and the basic organization of cells into a basic organization of cells into a living organism.living organism.

Microscope HandlingMicroscope Handling

1.1. Carry microscope properly having Carry microscope properly having one hand beneath the base and one hand beneath the base and the other hand grasping the armthe other hand grasping the arm

2.2. Place arm of microscope facing youPlace arm of microscope facing you3.3. Move objectives all the way upMove objectives all the way up4.4. Rotate and lock (clicking sound) Rotate and lock (clicking sound)

low power objective into position.low power objective into position.5.5. Turn on the lightTurn on the light

6.6. Place slide onto stage, use stage clips to Place slide onto stage, use stage clips to hold slide in place (make sure that the hold slide in place (make sure that the specimen is centered)specimen is centered)

7.7. Move low power objective lens, using the Move low power objective lens, using the course adjustment knob, until almost course adjustment knob, until almost touching the slide.touching the slide.

8.8. Now, looking through the ocular lens, Now, looking through the ocular lens, move the objective (10X) until the image move the objective (10X) until the image is in focusis in focus

9.9. Switch to high power carefully, rotate Switch to high power carefully, rotate and lock into place. Use only the fine-and lock into place. Use only the fine-adjustment knob, because you could adjustment knob, because you could damage or break the slidedamage or break the slide

Discovery of CellsDiscovery of Cells

1600s 1600s Anton von Anton von LeeuwenhoekLeeuwenhoek - 1st - 1st person to observe & person to observe & describe describe microorganisms & microorganisms & living cells. living cells.

1st person to construct a microscope to view microorganisms

Robert HookeRobert Hooke

Robert HookeRobert Hooke 1600s 1600s observed dead plant observed dead plant cells from cork. cells from cork.

In fact, it was Hooke In fact, it was Hooke who coined the term who coined the term "cells": the box-like "cells": the box-like cells of cork cells of cork reminded him of the reminded him of the cells of a monasterycells of a monastery.

1833 Robert Brown1833 Robert Brown

Observed that Observed that many cells to many cells to have a dark have a dark structure near structure near the center of a the center of a cell. We now call cell. We now call this structure a this structure a nucleusnucleus

1838 Matthias Scheleiden1838 Matthias Scheleiden

German German botanistbotanist

Studied plants Studied plants & concluded & concluded that all plants that all plants are made of are made of cellscells.

1839 Theodor Schwann1839 Theodor Schwann

a German a German cytologist and cytologist and physiologistphysiologist

Concluded that Concluded that all animals are all animals are made up of cells.made up of cells.

1855 Rudolf Virchow1855 Rudolf Virchow

Researched and Researched and concluded that all concluded that all cells arise from cells arise from preexisting cellspreexisting cells

example: skin example: skin cells develop into cells develop into new skin cells.new skin cells.

Cell TheoryCell Theory The combined work of The combined work of

these scientists these scientists developed what we know developed what we know today as the Cell Theory.today as the Cell Theory.

The cell theory states: The cell theory states: 1.1. all living things are all living things are

composed of cells.composed of cells.

2.2. cells are the basic unit of cells are the basic unit of structure and function in structure and function in living thingsliving things

3.3. all cells come from all cells come from preexisting cellspreexisting cells.

1970 Lynn Margulis1970 Lynn Margulis Proposed the idea Proposed the idea

that certain that certain organelles were once organelles were once free-living cells free-living cells themselves.themselves.

Ex: Chloroplasts were Ex: Chloroplasts were once free-living once free-living photosynthetic photosynthetic bacteria that were bacteria that were incorporated into incorporated into plant cells and formed plant cells and formed a symbiotic a symbiotic relationship.relationship.