Plasma Membrane- The plasma membrane keeps things inside the cell, as well as outside. It is semi-permeable, which means that certaing things can go in and out of the cell while others cannot. It allows waste products to leave the cell and oxygen, water, and carbon dioxide are all small enough to penetrate the membrane. Cytoplasm- Cytoplasm is a jelly-like material, made up of mostly water, that fills the cell. It surrounds the nuclear envelope and cytoplasmic organelles in the plasma membrane. Cytoplasm contains proteins and important molecules that the cell needs. Proteins, lipids, carbohydrates, salts, sugars, amino acids, and nucleotides make up the fluid part of the cytoplasm. This organelle contains dissolved products that help to dissolve waste. The cytoplasm also helps things to move around throughout the cell.
Nuclear membrane- similar to plasma membrane. Pores in the membrane allow the internal nuclear environment to communicate with the cytoplasm of the cell.
Organelles- Little Organs
Cisternae- spaces within the folds of the ER
Flagella- long, hairlike organelles that extend from the cell permitting it to move. In prokaryotic cells, such as bacteria, the flagella rotate like the propeller of a moterboat. In eukaryotic cells, such as certain protozoa and sperm cells, the flagella whip about and propel the cell. Cillia- shorter and more numerous than flagella. Paramecium is a well known ciliated protozoan. They are also found on surface of several types of cells, such as those that line human respiratory tract.
similar to the lipid bilayer in that it helps provide the interior structure of the cell the way the lipid bilayer provides the structure of the cell membrane. The cytoskeleton also allows the cell to adapt. Often, a cell will reorganize its intracellular components, leading to a change in its shape. The cytoskeleton is responsible for mediating these changes. By providing &quot;tracks&quot; with its protein filaments, the cytoskeleton allows organelles to move around within the cell. In addition to facilitating intracellular organelle movement, by moving itself the cytoskeleton can move the entire cells in multi-cellular organisms. In this way, the cytoskeleton is involved in intercellular communication.
The Cell “ Everything you'll ever need to know is within you; the secrets of the universe are imprinted on the cells of your body.” Dan Millman
History of the Cell <ul><li>Robert Hooke- in mid 1600s, he used the newly invented microscope to examine a thin slice of cork . He was impressed by the microscopic compartments in the cork and they reminded him of rooms in a monastery, which are known as cells. He therefore referred to these units as cells. </li></ul><ul><li>Anton Van Leeuwenhoek- Dutch merchant who made further observations of the cells of plants, animals and microorganisms . </li></ul>
History of Cell Continued <ul><li>Matthias Schleiden- in 1838, this German Botanist proposed that all plants are composed of cells. </li></ul><ul><li>Theodore Schwann- a year later, this anatomist concluded that all animals are composed of cells. </li></ul><ul><li>Rudolf Virchow- In 1858, he proposed all living things are made of cells </li></ul>
Cell theory <ul><li>The theory states that all organisms are composed of similar units of organization, called cells. </li></ul>
Aspects of the Cell Theory <ul><li> 1. all known living things are made up of cells. </li></ul><ul><li> 2. the cell is structural & functional unit of all living things. </li></ul><ul><li> 3. all cells come from pre-existing cells by division. (Spontaneous Generation does not occur). </li></ul><ul><li> 4. cells contains hereditary information which is passed from cell to cell during cell division. </li></ul><ul><li> 5. All cells are basically the same in chemical composition . </li></ul><ul><li> 6. all energy flow (metabolism & biochemistry) of life occurs within cells. * </li></ul>
<ul><li>A Eukaryote cell is much more complex, as suggested by this generalized diagram showing its makeup </li></ul>
Prokaryotic vs. Eukaryotic <ul><li>Simpler than eukaryotes </li></ul><ul><li>Lack a Nucleus </li></ul><ul><li>Lack internal structural bodies (organelles) </li></ul><ul><li>Bacteria and cyanobacteria </li></ul><ul><li>More complex </li></ul><ul><li>Have a nucleus </li></ul><ul><li>Have internal structural bodies </li></ul><ul><li>Protozoa, fungi, plants, and animals. </li></ul>
Structure of the Cell <ul><li>Cytoplasm- gel like substance in which the cell is composed </li></ul><ul><li>Plasma membrane- outermost surface of the cell which separates the cell from the external environment. </li></ul>
The Nucleus <ul><li>The nucleus has the following functions: to store genes, to produce messages that code for proteins, to produce ribosomes in the nucleolus, and to organize genes into chromosomes to use for cell division. The nucleolus produces ribsomes that are then sent out onto the rough endoplasmic reticulum where they are used in protein synthesizing. ( information storing area of the cell). </li></ul>
Cytoplasm and Organelles <ul><li>Cytoplasm- essentially, it is the gel like material enclosed by the plasma membrane. Within the cytoplasm are a number of microscopic bodies called organelles. Various functions go on within these organelles. </li></ul>
Organelles: Endoplasmic reticulum or ER <ul><li>Site of Protein production (synthesis) of the cell. </li></ul><ul><ul><li>Rough ER- studded with submicroscopic bodies called ribosomes </li></ul></ul><ul><ul><li>Smooth ER- no ribosomes </li></ul></ul>
Ribosomes <ul><li>Ribosomes have the responsibility of assembling the proteins within a cell structure . They are found in two places, attached to the endoplasmic reticulum or in the cytosol. </li></ul>
Golgi Apparatus (Golgi Body) <ul><li>sometimes considered the shipping department for the cell's chemical products . It modifies proteins and lipids that have been created in the endoplasmic reticulum and prepares them for export outside of the cell or for transport to other locations in the cell. Proteins and lipids built in the smooth and rough endoplasmic reticulum leave in tiny vesicles that move through the cytoplasm until they reach the Golgi apparatus. The vesicles combine with the Golgi membranes and distribute their internally stored molecules into the organelle. The compounds are further processed by the Golgi apparatus. The final product is taken from the Golgi Apparatus in a vesicle and directed to its final destination inside or outside the cell. ( Where proteins are modified and then shipped to specific location ) </li></ul>
Lysosomes <ul><li>Lysosomes are membranes full of enzymes. They are made by the endoplasmic reticulum and Golgi apparatus. Lysosomes are believed to be formed by budding from the Golgi complex. They are involved in recycling the organic material in the cell and in the digestion of macromolecules . Lysosomes are also involved in cell death . </li></ul><ul><li>Break down particles of food taken into the cell and make them available for use </li></ul><ul><li>Also known as “ Suicide Sacs” </li></ul>
Mitochondria <ul><li>Mitochondria are rice-shaped structures that play a big role in breaking down sugar to release energy for the cell to use. A mitochondria also contains small amounts of DNA that are used to direct the manufacture of proteins. Mutations in the mitochondria's protein coding are the result of human diseases. </li></ul><ul><li>Energy released is used to form ATP . </li></ul><ul><li>“ Powerhouse of the Cell ” </li></ul>
Cell Wall <ul><li>Provide support and help cell resist mechanical pressure </li></ul><ul><li>Not as selective as plasma membrane </li></ul><ul><li>Many prokaryotes and eukaryotes contain this structure </li></ul><ul><li>Almost all bacteria have cell wall </li></ul><ul><li>Among eukaryotes, the fungi and plants have cell walls. </li></ul>
Cytoskeleton <ul><li>An interconnected system of fibers, threads, and interwoven molecules that give structure to the cell. </li></ul><ul><li>Main components of cytoskeleton are the microtubules, microfilaments, and intermediate filaments . </li></ul><ul><li>Another organelle called the centriole is a cylinderlike structure that occurs in pairs. It functions in cell division </li></ul>