UNIT 3 - CELLS

[Pages:30]UNIT 3 - CELLS

CELL page 1

At the successful completion of this unit, the student should be able to:

1. Compare prokaryotic and eukaryotic cells and eukaryotic plant and animal cells 2. Identify the following cellular parts: cell membrane, nucleus, nucleolus,

centriole, ribosome, endoplasmic (smooth and rough), Golgi body, mitochondrion, flagella, cilia and describe the major function of each 3. Describe the difference between diffusion and active transport using various solutions where differences in concentrations affect the direction of movement 4. Diagram and label the double phospholipid structure of the cell membrane 5. Describe the structure of a water molecule and relate this to hydrogen bonds 6. Compare polar versus non-polar molecules 7. Diagram the structure of double phospholipid membrane and explain how the membrane acts as a barrier to ions and large molecules 8. Describe how active transport occurs at the cell membrane level 9. Describe the other roles played by proteins in the cell membrane 10. Understand the process of cell division in prokaryotic and eukaryotic cells 11. Describe the major events that occur during G1, G2, S, mitosis and cytokinesis 12. Compare mitosis and meiosis

CELL page 2

LESSON 1. CELL STRUCTURE

Section A

I. Cell Theory A. The idea that the cell was the unit of living organisms, started with Robert Hooke, who observed a slice of cork under a microscope. He noted that the whole tissue was composed rectangular boxes. He named these boxes cells, because they reminded him of a monk's cell in an abbey. B. In 1828, Schwann and Schleiden proposed the cell theory that all living organisms were composed of cells. C. All plants, animals and microscopic organisms are composed of cells as are all tissues bone, skin, wood, roots, fruit, seeds, etc. D. The cell is the structural unit of all living organisms. E. Later the idea that all cells came from pre-existing cells was added to the cell theory. Cells or living organisms did not spontaneously arise from non-living materials. F. Reproduction involves a cellular process: the union of two cells. G. The developmental process involves cell growth by cell division and cell specialization by interaction and differentiation. H. Finally, came the proof that all physiological processes are based on cellular processes. All physiological processes could be explained as chemical reactions such as digestion, muscle contraction, and nerve transmission.

Section A - Review

1. Describe three major points to the cell theory.

Structural unit:___The cell is the structural unit of life. _____________________________

Functional unit: ___The cell is the functional unit of life.____________________________

Preexisting (Developmental) unit: __Cells must come from pre-existing cells.___________

2. What two German men are credited for the Cell Theory?

a.__Schleiden___ and b.____Schwann__

3. Write a statement describing the Cell Theory:

____(any thing that included the three statements from question 1, is okay.)____________ Cells are the basic unit of structure and function and all living things consist of cells. Cells must come from pre-existing cells. ____________________________________________

Section B. Major kinds of Cells

CELL page 3

I. Comparison of prokaryotes and eukaryotes A. There are two fundamental types of cells: prokaryotes and eukaryotes. B. Prokaryotes means that the cell lacks a distinct nucleus. DNA occurs in the cell but as circular loop connected to the cell wall and contains no protein associated with it. C. Prokarotic cells are also small in size and lack any membraneous organelles. D. Examples of prokaryotes include bacteria and cyanobacteria sometimes called blue-green algae. E. Eukaryotes means that the cell has a distinct nucleus, one with a nuclear membrane. F. Eukaryotes contain membrane organelles such as chloroplasts, mitochondria, endoplasmic reticulum and golgi apparatus. G. Examples of eukaryotes are plants, animals, algae and protozoa.

2. Prokaryotes A. There are archebacteria and eubacteria. A. Archebacteria are smaller, less complex and live in more extreme environments such as hot springs and waters with high salt concentrations than eubacteria. B. Structure of the ribosomes is different in archebacteria than in eubacteria. C. They typically have unique chemical processing systems such as utilizing sulfur or methane as source of energy. D. In eubacteria, there is no nuclear membrane and the DNA forms a loop and is attached to the cell wall. E. Eubacteria are what we normally associate with bacteria. They are found nearly everywhere and they perform photosynthesis, aerobic and anareobic respiration, decay dead organisms and some cause disease.

3. Eukaryotes A. Eukaryotes can be divided into several groups, depending whether they are single-celled organisms or multicellular organisms. B. Examples of unicellular eukaryotes are various forms of protozoa and algae. C. Examples of multicelllular eukaryotes include most plants and animals that we come into contact with. D. Fungi such as yeast or molds are sometimes unicellular or multicellular, and always eukaryotes. E. Another division among eukaryotes is division between plant and animal cells. F. Plant cells have a cell wall, chloroplasts and a large vacuole; animal cells do not. H. Plant and animal eukaryotic cells have: nucleus, golgi apparatus, mitochondria, endoplasmic reticulum, centrioles.

CELL page 4

Section B - Review

1. Describe the major differences between prokaryote cells and eukaryote cells (single and multicellular).

Cell Size Nucleus

PROKARYOTE

Smallest (1-10 micrometer)

No

EUKARYOTE (single cell)

Larger (10-100 micrometes)

Yes

EUKARYOTE (multicellular cell)

Larger (10-100 micrometers)

Yes

Organelles

Give 2 Examples

Yes, but not Yes, membrane bound Yes, membrane bound membrane bound

Ribosomes

Mitochondria, Endoplasmic Reticulum, Gogi Body

Same as single cell

2. Describe major differences between eukaryotic plant and animal cell.

Plant cells have a. _Cell Wall___ b. _Large Central Vacuole_ c. __Chloroplasts___ but animal cells do not.

Both plant and: a. __Cell membrane__ b. _Ribosomes_ c. _Endoplasmic Reticulum_

animal cells have

these organelles d. Nucleus

e. _Mitochondria f. Golgi Body

Section C. Cell Organelles

CELL page 5

1. Internal cell structure ? organelles. A. Nucleus ? stores genetic information as DNA and RNA and controls cell's activities. B. Nuclear membrane ? keeps DNA molecules and chromosomes from entering the cytoplasm. C. Mitochondrion ? membrane organelle that is involved in cell respiration and produces ATP. D. Endoplasmic reticulum ? system of internal membranes that move substances such as proteins throughout the cell. E. Ribosome ? site of protein synthesis. F. Rough endoplasmic reticulum ? has ribosomes attached and protein synthesis is occurring. G. Smooth endoplasmic reticulum ? does not have ribosomes attached and involved in lipid synthesis. H. Vesicles ? small, membrane-bound sac that contain various substances. I. Golgi appratus ? a stacked membrane structure that is involved in chemical synthesis and packaging the chemicals in vesicles. J. Cilia ? small hair-like structures on the surface of the cell and responsible for movement. K. Flagella ? long whip-like structure responsible for movement particularly in sperm cells. L. Lysosome ? sacs that contain digestive enzymes that clean up debris in cytoplasm. M. Cytoskeleton ? a system of microscopic fibers within the cell and provides support for the cell. N. Chloroplast ? site of photosynthesis in plant cells. O. Cell wall ? structure outside cell membrane that provides support for cell. P. Centrioles ? microtubule structures that replicate and form spindles at opposite ends of dividing cell. They assist in separation of chromosomes.

2. Coordination of protein synthesis within the cell A. Nucleus has the genetic information that codes for the sequence of amino acids in the protein. This is stored in the base sequence in the DNA molecule. B. Ribosome are where the RNA molecules and amino acids are joined together to form a protein. C. Rough endoplasmic reticulum (RER) has the ribosome attached so that the produced protein is released into the ER and the ER transports the synthesized protein to the Golgi apparatus. D. Golgi apparatus is where the protein may be altered and combined with lipids or carbohydrates to form new molecules and these molecules are packaged into membrane sacs called vesicles. E. Vesicles store the synthesized molecules until needed. F. The vesicles are transported along microtubules usually to the cell membrane where exocytosis causes the release of the vesicle contents.

Cell Membrane

Centrioles Nucleolus Lysosome Mitochondria Ribosome

Golgi Body(apparatus)

Cell ? page 6

Vesicle

Mitochondria

Nucleus

Endoplasmic Reticulum ? Rough or

Cell ? page 7

Section C - Review

1. Describe the main function of the following organelles: a. Nucleus: Main Office of cell ? controls the actions of the cell and contains the information on how to make everything in the cell, including export proteins out of the cell.

b. Cell membrane: Fence or gate of cell ? regulates what comes into the cell and goes out of the cell.

c. Ribosome: Workers of the cell ? These subunits come together around mRNA and make proteins ? they are the site of protein synthesis.

d. Rough endoplasmic reticulum: Assembly Line on the factory floor ? this is the location of protein production for the cell to export out of the cell.

e. Smooth endoplasmic reticulum: Assembly Line on the factory floor ? this is the location of lipid processing (lipid synthesis) f. Golgi apparatus : Packaging and Shipping Department of the cell ? This is where the cell processes proteins, adding hydrogen bonds to give them their shape.

g. Vesicle: Trucks of the cell ? These structures bring in raw materials and export out finished product. h. Large vacuole: Water Tower of the cell ? Storage unit of the cell ? stores water usually and typically is found in the plant cell. i. Lysosomes: Recycling Center of the cell ? "digests" cell debris and nutrients j. Centrioles: Microtubule Organizing Center - produces new cytoskeletal structures k. Cilia: Used for movement ? these structures move in synchrony to move the cell l. Flagella: Used for movement ? usually a single long structure using either a propeller movement or a whips back and forth. m. Cell wall: ____________________________________________________________ n. Mitochondrion : _______________________________________________________ o. Chloroplast: __________________________________________________________ p. Nucleolus ____________________________________________________________

LABEL THE DIAGRAM OF THE ANIMAL CELL

Cell ? page 8

Use the following terms to label the diagram below.

Cell membrane, nucleus, nucleolus, nuclear membrane, cytoplasm, mitochondrion, golgi apparatus, ribosome, rough endoplasmic reticulum, smooth endoplasmic reticulum, vesicle, centrioles, cilia.

Microvilli (cilia)

Cytoplasm Golgi Body(apparatus)

Mitochondria

Vesicle Cell Membrane Centrioles Ribosome Nucleolus

Nucleus

Endoplasmic Reticulum ? Rough

Nuclear membrane

Endoplasmic Reticulum ? Smooth

LABEL THE DIAGRAM OF THE PLANT CELL

Use the following terms to label the diagram below.

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