1. CYTOLOGY
Regents Biology

2. Upon completion of this unit students will be able to:
OBJECTIVES
Upon completion of this unit students will be able to:
1. Recognize that improvements in microscopic techniques have allowed
for the development of the cell theory.
2. State the cell theory and the exceptions to the cell theory.
3. Discuss and compare the following relative levels of biological
organization: cell tissue organ organ system  organism
4. Describe the appearance and chief functions of the following
organelles:
nucleus
nuclear membrane
nucleolus
ribosomes
mitochondrion
Golgi apparatus
endoplasmic reticulum
cytoplasm
food vacuole
contractile vacuole
lysosome
plasma membrane
5. Describe the Fluid Mosaic Model relative to the structure and function of the
plasma membrane.
6. Discuss the function of centrioles in animal cells.
7. Discuss the function of chloroplasts and the cell wall in plant cells.
8. Differentiate plant cells and animal cells by giving 3 differences.

3. INTRODUCTION: THE SIMILARITY AMONG LIVING THINGS
Living things, whether simple or complex, are composed of small, living structural and functional units known as CELLS
Within the living cell are several sub-structures (ORGANELLES) that perform specialized functions for the cell of which they are a part.
Scientists study cell structure in the laboratory with a variety of tools and techniques, and we will be using MICROSCOPES to do just that.
Cytology is the study of CELLS; cyt(o)=CELL and logy= STUDY

4. A. THE CELL THEORY
The invention and development of the MICROSCOPE has given scientists the ability to discover cells and study their finest details.
The cell theory was developed over many years by scientists working in many parts of the world.
The major tool of early biologists was the MICROSCOPE; either in the form of the simple microscope, or in the form of the compound microscope

5. The cell THEORY provides the strongest support for the concept of UNITY (“alikeness”) of living things:
1.  ALL LIVING THINGS ARE MADE UP OF CELLS
2.  CELLS ARE THE SMALLEST UNIT OF LIFE
3. ALL CELLS COME FROM PRE-EXISTING CELLS; THIS MEANS THAT CELLS DO NOT ARISE SPONTANEOUSLY, BUT ARE PRODUCED BY THE PROCESS OF REPRODUCTION

6. HOWEVER….THERE ARE EXCEPTIONS TO THE CELL THEORY:
1.IF ALL CELLS COME FROM PRE-EXISTING CELLS, WHERE DID THE FIRST CELL COME FROM? (WE DON’T KNOW YET)
2.VIRUSES CONTAIN SIMPLE GENETIC MATERIAL AND CARRY OUT A TYPE OF REPRODUCTION, BUT ARE NOT TRUE CELLS. THEY NEED A HOST TO REPRODUCE; THEY CANNOT CARRY OUT ALL LIFE FUNCTIONS ALONE.
3.CERTAIN CELL ORGANELLES (MITOCHONDRIA AND CHLOROPLASTS) BEHAVE LIKE CELLS IN SOME RESPECTS. THEY CONTAIN THEIR OWN GENETIC MATERIAL AND PRODUCE ORGANISMS LIKE THEMSELVES UNDER CERTAIN CONDITIONS.

7. B. ORGANIZATION OF CELLS IN LIVING THINGS
Organisms are EITHER UNICELLULAR (COLONIAL), OR MULTICELLULAR
1. UNICELLULAR AND COLONIAL ORGANISMS
A cell may exist INDEPENDENTLY (UNICELLULAR) OR IN COLONIES
Unicellular organisms are able to EXIST INDEPENDENTLY (CARRY ON LIFE PROCESSES BY THEMSELVES); BACTERIA, PROTOZOA, MANY ALGAE, SOME FUNGI
The simplest level of MULTICELLULAR organization occurs in COLONIAL ORGANISMS (FEW CELLS TO THOUSANDS OF CELLS ATTACHED TOGETHER)

8. How true multicellular organisms are organized:
In true multicellular organisms, CELLS ARE FUNCTIONALLY AND STRUCTURALLY SPECIALIZED
How true multicellular organisms are organized:

9. C. TYPES OF CELLS
There are two types of cells:
1.     PROKARYOTIC
2. EUKARYOTIC
Prokaryotic cells DO NOT HAVE A MEMBRANE-
BOUND NUCLEUS
Eukaryotic cells HAVE A MEMBRANE-BOUND
NUCLEUS
 We will mainly focus on
Eukaryotic Cells,
namely PLANT
and ANIMAL cells

10. CELL STRUCTURE AND FUNCTION
The cell is extremely complex and is composed of smaller functional parts known as ORGANELLES (“little organs”).
Each of these has special work to do in the survival of a cell:
LIFE FUNCTION
ORGANELLE(S)
Respiration
MITOCHONDRIA
Regulation
NUCLEUS, CELL MEMBRANE, CONTRACTILE VACUOLE
Reproduction
NUCLEUS
Excretion
CELL MEMBRANE
Growth
Nutrition
Animal Cells
Plant Cells
CELL MEMBRANE, FOOD VACUOLE, LYSOSOME CHLOROPLASTS
Transport
CELL MEMBRANE, CYTOPLASM, ENDOPLASMIC RETICULUM (ER)
Synthesis (proteins)
NUCLEUS, RIBOSOME, ER, GOLGI APPARATUS

11. I am an ANIMAL CELL…..label me!

12. 1. NUCLEUS
The nucleus is the CONTROL CENTER OF THE CELL
It contains all of the DNA of the cell and helps to maintain HOMEOSTASIS by regulating all of the life functions of the cell (R-R-R-E-G-N-T-S)
“The Brain” of the cell also has a MEMBRANE to control what enters and
leaves the nucleus
2. NUCLEOLUS
Involved in CELL REPRODUCTION and is a dark body inside the nucleus
Primarily involved in RNA SYNTHESIS

13. 3. CYTOPLASM
Fills the cell as it is JELLY-LIKE
All ORGANELLES are located in the cytoplasm and many liquids are dissolved in it.
4. ENDOPLASMIC RETICULUM (ER)
Often referred to as the ER of the cell.
The ER is a SYSTEM OF FLUID FILLED TUBES THAT FORM A NETWORK THROUGHOUT THE CELL
There are two types of ER:
a. SMOOTH (sER) – OUTER SURFACES ARE SMOOTH
b.ROUGH (rER) –
LOOKS ROUGH
BECAUSE
RIBOSOMES
ARE ATTACHED TO
THEM

14. The tubes of the ER provide a path of TRANSPORT of materials throughout the cell.
At some spots the membrane of the ER and the CELL MEMBRANE connect, allowing for materials to pass in and out of the cell.
5. RIBOSOMES
Look at the dots on the Rough ER….those are RIBOSOMES
They are also found floating free in the CYTOPLASM
Proteins that cells
need are made by
protein synthesis
and the RIBOSOMES
HELP TO MAKE
PROTEINS

15. 6. LYSOSOMES
Contain HYDROLYTIC AND DIGESTIVE ENZYMES
In unicellular organisms, they digest food within the cell.
In multicellular organisms, they HELP DESTROY OLD ORGANELLES, FIGHT INFECTION, AND DIGEST FOREIGN MATTER
7. GOLGI APPARATUS (aka GOLGI BODY)
The Golgi Body is made up of a STACK of membranes.Its function is to PACKAGE AND STORE MATERIALS which will eventually be secreted from the cell.

16. 8. VACUOLE
Vacuoles are FLUID-FILLED organelles surrounded by a membrane.
Plant cell vacuoles are usually HUGE compared to animal cells’.
There are two types of vacuoles:
a.CONTRACTILE –
HELP TO REMOVE
EXCESS WATER
AND WASTE
b. FOOD – TAKE IN
AND STORE FOOD

17. 9. MITOCHONDRIA
The mitochondrion is often referred to as the POWERHOUSE of the cell because it provides the cell with its ENERGY through the life process of RESPIRATION
The “mighty-might” is oval in shape with two membranes surrounding it.
The inner membrane is called CRISTAE which are highly folded.
Mitochondria
CONTAIN THEIR
OWN DNA AND
CAN REPLICATE
BY THEMSELVES

18. 10. PLASMA MEMBRANE (aka CELL MEMBRANE)
The three main functions of the cell membrane are to:
1.SEPARATE THE CELL FROM ITS ENVIRONMENT
(BARRIER)
2.CONTROLS WHAT COMES IN AND OUT OF A CELL
3.MAINTAINS HOMEOSTASIS
The cell membrane is a two-layered(BILAYER) structure composed of PROTEINS, LIPIDS, AND CARBOHYDRATES
The proteins of the membrane are believed to be important in CONTROLLING THE PASSAGE OF SUBSTANCES THROUGHOUT THE MEMBRANE; PROTEIN RECEPTORS
The cell membrane is SELECTIVELY PERMEABLE
Through its selective permeability, THE CELL MEMBRANE REGULATES THE CHEMICAL COMPOSITION OF THE CELL

20. Diagram of the Fluid Mosaic Model:

21. E. THE THREE C’S
1.                 CENTRIOLES
Look like BARRELS that are usually found near the NUCLEUS
They are involved in CELL REPRODUCTION
They are ONLY FOUND IN ANIMAL CELLS
2. CELL WALL
The cell wall is a RIGID STRUCTURE made of CELLULOSE
It provides SUPPORT AND PROTECTION for the cell
They are ONLY FOUND IN PLANT CELLS
3.CHLOROPLASTS
Chloro = GREEN and plast = FORMED BODY
Chloroplasts are pigment-containing structures that aid in PHOTOSYNTHESIS
Therefore, chloroplasts are only found in PLANT CELLS

22. F. DIFFERENCES BETWEEN PLANT AND ANIMAL CELLS
ONLY PLANT CELLS HAVE CELL WALLS
2.ONLY PLANT CELLS HAVE CHLOROPLASTS
3.ONLY ANIMAL CELLS HAVE CENTRIOLES
Use the animal cell on page 7 to help with labeling the
PLANT CELL: