Cells (Chapter 3)

Developed by Dave WernerOCC BIOL-114Spring 2014

OBJECTIVES:

Outline the discoveries that led to the development of the Cell Theory. 

State the cell theory.   Describe the relationship between

cell shape & cell function.  Distinguish between prokaryotes

and eukaryotes.

3.1 History 1. In 1660, the English Scientist Robert Hooke used a

microscope to examine a thin slice of cork and described it as consisting of "a great many little boxes". Named “cells”.

2. 1673, Antony Von Leeuwenhoek – improved lenses and advanced cell biology by viewing red blood cells and sperm.

3. 1838, German Botanist Matthias Schleiden - PLANT cells

4. 1839, German Zoologist Theodor Schwann –ANIMAL cells

5. In 1855, German Physician Rudolf Virchow induced that THAT CELLS ONLY COME FROM OTHER CELLS".

6. His statement contradicted the idea that life could arise from Nonliving Matter.  "Theory of Spontaneous Generation"  The process by which life begins when ethers enter nonliving things.

CELL THEORY

A. All living things are composed of one or more cells.

B. Cells are the basic units of structure & function in an organism.

C. Cells come only from reproduction of existing cells.

How Do We “See” Cells? Compound Light

Microscope TEM SEM

So What is “A Cell”? The CELL is the smallest unit of matter

that CAN Carry on ALL the PROCESSES OF LIFE.

Both Living and Nonliving Things are composed of molecules made from chemical elements such as carbon, hydrogen, oxygen, and nitrogen. 

The organization of these molecules into Cells is one feature that distinguishes Living Things from all other matter. 

CELL SHAPE - Video Variety of Shapes SHAPE DEPENDS ON

FUNCTION – Examples? Example:Cells of Nervous

System that carry information from your toes to your brain are long and threadlike.

6.  Blood Cells are shaped like round disk that can squeeze through tiny blood vessels.

INTERNAL ORGANIZATION 1. Cells contain a variety of Internal

Structures called ORGANELLES. 2. An organelle PERFORMS SPECIFIC

FUNCTIONS FOR THE CELL. 3. The entire cell is Surrounded by A THIN

MEMBRANE, called the CELL MEMBRANE 4. A Large Organelle near the Center of

the Cell is the NUCLEUS.  IT CONTAINS THE CELL'S GENETIC INFORMATION AND CONTROLS THE ACTIVITIES OF THE CELL.

Why Aren’t Cells Bigger? Surface-to-volume

ratio

3.2 Different Cell Types Characterize Life’s Three Domains

Introducing Prokaryotic Cells

1. ORGANISMS WHOSE CELL CONTAIN A NUCLEUS AND OTHER MEMBRANE-BOUND ORGANELLES ARE CALLED EUKARYOTES.

2. ORGANISMS WHOSE CELLS NEVER CONTAIN (OR LACK) A NUCLEUS AND OTHER MEMBRANE-BOUND ORGANELLES ARE CALLED PROKARYOTES.

Examples of Each???

Differences between

UNICELLULAR ORGANISMS such as bacteria and their relatives are Prokaryotes.

Prokaryotes are placed in Two Kingdoms, Separate from Eukaryotes.

All other organisms are Eukaryotes; plants, fish, mammals, insects and humans.

4.2 Prokaryotic Cells (fig.4.3)

Believed to be the first cells to evolve.

Lack a membrane bound nucleus and organelles.

Genetic material is naked in the cytoplasm

Ribosomes are only organelle.

Http.micro.magnet.fsu.edu/cells.html

Cell Wall Rigid peptidoglycan

- polysaccharide coat that gives the cell shape and surround the cytoplasmic mem-brane. Offers protection from environment.

Http://micro.magnet.fsu.edu/cells/bacteriacell.html

Plasma Membrane Layer of phospho-

lipids and proteins that separates cytoplasm from external environment.

Regulates flow of material in and out of cell.

Http://micro.magnet.fsu.edu/cells/bacteriacell.html

Cytoplasm Also known as proto-

plasm is location of growth, metabolism, and replication. Is a gel-like matrix of water, enzymes, nutrients, wastes, and gases and contains cell structures.

Http://micro.magnet.fsu.edu/cells/bacteriacell.html

Ribosomes Translate the

genetic code into proteins.

Free-standing and dis-tributed throughout the cytoplasm.

Http://micro.magnet.fsu.edu/cells/bacteriacell.html

Nucleoid Region of the

cytoplasm where chromosomal DNA is located. Usually a singular, circular chromosome. Smaller circles of DNA called plasmids are also located in cytoplasm.

Http://micro.magnet.fsu.edu/cells/bacteriacell.html

Mesosome Infolding of cell

membrane. Possible role in cell

division. Increases surface

area. Photosynthetic

pigments or respira-tory chains here.

Http://www.med.sc.edu:85/fox/protobact.jpg

Prokaryotic vs. Eukaryotic

Http://micro.magnet.fsu.edu/cells.html

3.3 Plasma Membrane Phospholipid bi-layer

that separates the cell from its environment.

Selectively permeable to allow substances to pass into and out of the cell. (Fig. 3.10-3.11)

Http:micro.magnet.fsu.edu/cells/animal/plasmamembrane.html

Proteins (Fig 3.12)

Transport Proteins Enzymes Recognition Proteins Adhesion Proteins Receptor Proteins

3.4 Eukaryotic Organelles Divide Labor

OBJECTIVES:  Describe the structures, composition, &

function of the cell membrane.  Name the major organelles found in a

Eukaryotic cell, and describe their function. 

Describe the structure and function of the nucleus. 

Describe three structures characteristic of plant cells.

Eukaryotic Cells (Table 3.2)

“True nucleus”; contained in a mem-brane bound structure.

Membrane bound organelles.

Thought to have evolved from prokaryotic cells.

Http:micro.magnet.fsu.edu/cells/animalcell.html

CYTOPLASM EVERYTHING BETWEEN THE CELL MEMBRANE AND THE

NUCLEUS = CYTOPLASM.

Consists of TWO MAIN COMPONENTS:  CYTOSOL and ORGANELLES.

CYTOSOL = jellylike mixture that consists MOSTLY OF WATER, along with PROTEINS, CARBOHYDRATES, SALTS, MINERALS and ORGANIC MOLECULES.

Suspended in the Cytosol are tiny ORGANELLES (ORGANS).

ORGANELLES ARE STRUCTURES THAT WORK LIKE MINIATURE ORGANS, THEY CARRY OUT SPECIFIC FUNCTIONS IN THE CELL.

Any analogies???

Ribosomes Translate the genetic

code into proteins = Protein Synthesis.

Found attached to the Rough endoplasmic reticulum or free in the cytoplasm.

60% RNA and 40% protein.

Http://micro.magnet.fsu.edu/cells/animals/ribosomes.html

Ribosome

Http://cellbio.utmb.edu/cellbio/ribosome.htm

Rough Endoplasmic Reticulum

Network of continuous sacs, studded with ribosomes.

Manufactures, pro-cesses, and transports proteins for export from cell.

Continuous with nuclear envelope.

Http://micro.magnet.fsu.edu/cels/animal/endoplasmicreticulum.html

Endoplasmic Reticulum (Fig 3.15)

Http://cellbio.utmb.edu/cellbio/ribosome.htm

Smooth Endoplasmic Reticulum

Similar in appearance to rough ER, but without the ribosomes.

Involved in the production of lipids, carbohydrate metabolism, and detoxification of drugs and poisons.

Metabolizes calcium. Http://micro.magnet.fsu.edu/cells/animals/endoplasmicreticulum.html

Lysosome (Fig 3.17)

Single membrane bound structure.

Contains digestive enzymes that break down cellular waste and debris and nutrients for use by the cell.

Http://micro.magnet.fsu.edu/cells/animals/lysosome/html

Lysosome

Http://anatomy.med.unsw.edu.au/teach/phph1004/1998/WWWlect3/sld005.htm

Golgi Apparatus (Fig 3.16) Modifies proteins

and lipids made by the ER and prepares them for export from the cell.

Encloses digestive enyzymes into membranes to form lysosomes.

Http://micro.magnet.fsu.edu/cells/animals/golgiapparatus.html

Golgi Apparatus

Http://cellbio.utmb.edu/cellbio/golgi.htm

Mitochondrion = “Powerhouse” of the Cell

Membrane bound organelles that are the site of cellular respiration (ATP production)

Fig. 3.20

http://micro.magnet.fsu.edu/cells/animals/mitochondrion/html

Mitochondrion

Http://anatomy.med.unsw.edu.au/teach/phph1004/1998/WWWlect3/sld005.htm

Nucleus (Fig 3.14) Double membrane-

bound control center of cell.

Separates the genetic material from the rest of the cell.

Http://micro.magnet.fsu.edu/cells/animals/nucleus/html

Nucleus

Http://cellbio.utmb.edu/cellbio/nucleus.htm

Parts of the nucleus:

Chromatin - genetic material of cell in its non-dividing state.

Nucleolus - dark-staining structure in the nucleus that plays a role in making ribosomes

Nuclear envelope - double membrane structure that separates nucleus from cytoplasm.

Cell Wall Protects and gives

rigidity to plant cells

Formed from fibrils of cellulose molecules in a “matrix” of polysaccharides and glycoproteins.

Http://micro.magnet.fsu.edu/cells/plants/cellwall.html

PLANT CELLS

2 Additional Structures Not found in animals cells

1. CELL WALLS2. PLASTIDS

PLASTIDS MAKE OR STORE FOOD CHLOROPLAST, (figure 4-17) an organelle that

converts SUNLIGHT, CARBON DIOXIDE, AND WATER INTO SUGARS.  This process is called PHOTOSYNTHESIS

Each Chloroplast encloses a system of Flattened, Membranous Sacs called THYLAKOIDS.  It is in the Thylakoids that Photosynthesis occurs

Chloroplasts are GREEN because they contain CHLOROPHYLL, a PIGMENT that ABSORBS ENERGY IN SUNLIGHT.  THEY ARE FOUND ONLY IN ALGAE, SUCH AS SEAWEED, AND IN GREEN PLANTS.

Other PLASTIDS store reddish-orange pigments that color fruits, vegetables, flowers, and autumn leaves

Chloroplast Fig. 3.19 Site of

photosynthesis Membrane bound

structure. Contains chlorophyll

http://micro.magnet.fsu.edu/cells/plants/chloroplast.html

Chloroplast

Www.ultranet.com/~jkimball/BiologyPages/C/Chloroplasts.html

Vacuole Plants have large

central vacuoles that store water and nutrients needed by the cell.

Help support the shape of the cell.

Http://micro.magnet.fsu.edu/cells/plants/vacuole.html

Animal Vacuole

Www.puc.edu/Faculty/Bryan_Ness/vacuole_TEM.htm

Plant Cell Vacuole

Www.bio.mtu.edu/campbell/plant.htm

Animal Cell vs. Plant Cell

Http://:micro.magnet.fsu.edu/cells/html

3.5 The Cytoskeleton Supports Eukaryotic Cells

In Animal Cells, an internal framework called CYTOSKELETON maintains the Shape of the Cell (Fig. 3.23)

TWO Types of structures: MICROFILAMENTS MICROTUBULES

MICROFILAMENTS

NOT HOLLOW and have a structure that resembles ROPE made of TWO TWISTED CHAINS OF PROTEIN called ACTIN.

CONTRACT, causing movement. Muscle Cells

MICROTUBULES (Fig. 3.24) HOLLOW TUBES like plumbing pipes. They are

the Largest Strands of the Cytoskeleton. Made of a PROTEIN called TUBULIN. THREE FUNCTIONS:     A. To maintain the shape of cell.     B. To serve as tracks for organelles to move

along within the cell.     C.   When the Cell is about to divide, bundles of

Microtubules known as SPINDLE FIBERS come together and extend across the cell to assist in the movement of Chromosomes during Cell Division

Microfilaments Solid rods of

globular proteins. Important

component of cytoskeleton which offers support to cell structure.

Http://micro.magnet.fsu.edu/cells/animals/microfilaments.html

Centrioles Found only in

animal cells. Self-replicating Made of bundles

of microtubules. Help in organizing

cell division. Http://micro.magnet.fsu.edu/cells/

animals/animas/centrioles.html

How Do Cells Move? Cilia and Flagella External

appendages from the cell membrane that aid in locomotion of the cell.

Cilia also help to move substance past the membrane.

Http://micro.magnet.fsu.edu/cells/animals/ciliaandflagella.html