1. Cytology

2. Cytology Cytology ~ the study of cells History of Cytology:
Robert Hooke ~ English scientist that started the study of cells 300 years ago. He was able to see the cell walls of cork cells with his compound microscope. The rows of “boxes” reminded him of prison cells, so he named them cells. (1665)
Anton van Leeuwenhoek ~ first person to observe living organisms under a microscope (1674)

3. History of Cytology:
Robert Brown ~ set apart the nucleus as a special structure found in all cells (1833)

4. History of Cytology:
Matthias Schleiden ~ stated that all plants are composed of cells (1838)
Theodore Schwann ~ stated that all animals are composed of cells (1839)

5. History of Cytology:
Rudolf Virchow ~ proposed cells arise only from preexisting cells (1855)
*The work of these men led to the formation of the Cell Theory.

6. Cell Theory The Cell Theory ~ formulated in the late 1800’s
Has three parts:
1. Cells are the units that make up all living things
2. Cells are the units that carry on the functions of all living things
3. Cells come from preexisting cells.

7. Cell Theory 1. Cells are the basic units of living things:
*Size of organisms does not indicate the size of its cells, but the number of its cells. An elephant and a mouse have about the same size cells!
*Not all of the organism is made of cells. Parts of organisms are made of materials that cells manufacture.
Example: Exoskeletons and most bone material

8. Cell Theory 2. Cells carry on the functions of living things:
* Cells are responsible for all the functions of any living thing
*Not all cells perform all functions. Cells are specialized for particular function (Cellular division of labor)
* Cells must carry on all life functions in unicellular and colonial organisms.

9. Cellular Functions Absorption Digestion Synthesis Respiration Movement
Sensing
Excretion
Egestion
Secretion
Homeostasis
Reproduction

10. Cell Theory 3. Cells come from other preexisting cells:
biosynthesis of materials in cells results in maintenance and growth of cells.
Mitosis and meiosis are two important processes that produce new cells in living things

11. Why do cells have to be small?
What is surface area?
What is volume?
What is a ratio?
Cells need a high surface area to volume ratio.
That means a lot of surface area per unit of volume
They need a high surface area to volume ratio so they can bring nutrients, materials, and reactants into the cell and get rid of waste
Larger cells have a lower surface area to volume ratio than small cells
Larger cells must do one of the following
Slow down metabolism
Change shape- flat, long, surface folds
Divide

13. Two Types of Cells: 1. Eukaryotic ~ has a true nucleus with a set of membranes around it and have specialized structures called cytoplasmic organelles. Cytoplasmic organelles ~ specialized structures in the cytoplasm that carry on the specific functions of the cell. Membrane-bound organelles ~ have a membrane around them Non-membrane-bound organelles ~ do not have a membrane around them 2. Prokaryotic ~ cell lack a true nucleus and have only non-membrane-bound organelles.

14. Types of organisms based on cellular organization:
1. Unicellular ~ organisms that consist of only one cell.
EX: Bacteria, protozoans, algae, fungi
2. Multicellular ~ organisms made of many cells
EX: Some algae and fungi, all plants and animals
3. Colonial ~ collection of similar cells living together, and except for certain specialized reproductive cell, any of the cells could carry on the processes of the organism.
EX: can be a “clump of cells”

16. Cellular
Organelle
Molecular
Atomic
Subatomic

17. Organism Organ System Organ Tissue Pronghorn Antelope Nervous System
Brain
Nervous Tissue
Tissue

18. Biosphere Ecosystem Community Population Earth’s surface Air Snake
Soil
Ecosystem
Pronghorns
Bushes
Water
Hawk
Grass
Hawk
Community
Snake
Pronghorns
Population
Herd of Pronghorns

19. Levels of Organization of Multicellular Organisms
1. Cells ~ the basic unit of structure and function of living organisms
2. Tissues ~ similar cells that are grouped together to perform a similar function
3. Organs ~ tissues grouped together to perform a specific function
4. Organ Systems ~ Groups of organs working together to accomplish life functions.