Biology 1020 Notes.docx

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Department
Biological Sciences
Course
BIOL 1030
Professor
Online
Semester
Fall

Description
Biology 1020 Cell Theory: The principle stating that all organisms of one or more cells, which are the smallest living things and that all cells come from preexisting cells. Cell is the smallest unit of life. (Some organisms are single celled) Tissue is a group of similar cells that perform a function. Organs are several tissues joined together. An organ system is various organs that work together. Complex organisms are a collection of organ systems. Genes allow cells and organisms to reproduce. DNA contains the hereditary information that directs cell structure of the cell and its metabolism. Biodiversity encompasses the total number of species, the variability of their genes and the ecosystems they live in. Classification: Domain Archea: Capable of living in extreme locations. Aquatic environments that lack oxygen or are too salty, too hot or too acidic for most other organisms. (Unicellular Prokaryotes.) Domain Bacteria: Found almost everywhere. Found in water, air, soil, atmosphere along with our skin and digestive tracts. (Unicellular Prokaryotes.) Domain Eukarya: 1. Protista: Complex single cellular and sometimes multicellular. Absorb, photosynthesize or ingest food. (Protozoan, algae, water molds, slime molds.) 2. Fungi: Some unicellular, most multicellular filamentous forms with specialized complex cells. Absorb food. (Molds, yeasts and mushrooms.) 3. Plantae: Multicellular form with specialized cells. Photosynthesize foods. (Mosses, ferns, non-woody and woody flowering plants.) 4. Anamalia: Multicellular form with specialized complex cells. Ingest food. (Invertebrates, fishes, reptiles, amphibians, birds and mammals.) Cell Anatomy Plasma Membrane: Semi permeable membrane that consists of phospholipid bilayer in which some protein molecules are imbedded. Regulates the entrance and exit of molecules into and out of the cytoplasm. Cytoplasm: Jelly like fluid (semi fluid medium) inside the cell that holds the cell’s organelles within the cell in place. Prokaryotic Cells Cell Wall: Located outside of the plasma membrane, contains peptidoglycan, a complex molecule that is unique to bacteria and composed of chains of disaccharides joined by peptide chains. Protects the bacteria. Capsule/Slime Layer: Surrounds the cell wall. Flagella: Rotating filament, which pushes the cell forward. Fimbrae: Hair like bristles that allow adhesion to surfaces. Nucleoid: A single chromosome located within a region of cytoplasm. It is not bound by any sort of membrane. Plasmid: Small accessory rings of DNA. Ribsomes: Used in the synthesis of proteins. Thykaloids: Photosynthetic cyanobacteria have light-sensitive pigments usually within the membranes, which resemble flattened disks. Eukaryotic Cells Cell Walls: Permeable but protective cell wall, in addition to a plasma membrane. Plant cells often have a primary and secondary cell wall. Cellulose molecules make up the cell wall. Secondary cell wall, which forms within the first cell wall, consists of lignin. Often cell walls could consist of chitin. Nucleus: Prominent structure. Stores genetic material such as DNA, which governs the characteristics and metabolic information for the cell. Chromatin: DNA and associated proteins. Appears grainy material but is threadlike in structure and undergoes coiling to form chromosomes. Chromatin is immersed in a semi fluid medium known as the nucleoplasm. Nucleolus: RNA is stored here, called rRNA (ribosomal RNA. Nuclear Envelope: A membrane surrounding the nucleus that separates the nucleus from the cytoplasm. Nuclear Pores: Small pores that allow proteins to pass through into the nucleus and allows the ribosomal units to pass out. Ribosomes: Composed of two types of units, small and large. rRNA and protein molecules which comprise ribosomes can be found individually in ribosome form in the cytoplasm. They can also be found in groups called polyribosomes. Ribosomes are often found attached to endoplasmic reticulum. Proteins synthesized and attached to the endoplasmic reticulum have different destinations than those floating freely in the cytoplasm. Endoplasmic Reticulum: Complicated system of membranous channels and saccules. Continuous with the outer membrane of the nuclear envelope. Rough ER is studded with ribosomes on the side of the membrane that faces the cytoplasm. Proteins are synthesized here and enter the ER interior where modification and processing begin, without the protein in the proper place the cell is unable to regulate itself resulting in various symptoms of diseases. Smooth ER is continuous off the rough ER does not have ribosomes. Smooth ER synthesizes the phospholipids that occur in membranes and performs various other functions depending on the particular cell. ER also forms vesicles which products are transported to the Golgi Apparatus. Golgi Apparatus: Named for Camillo Golgi who discovered it in 1898. The Golgi consists of 3 – 20 stacked slightly curved saccules. This organelle is used for the collecting, sorting and distributing proteins and lipids within the cell. The Golgi receives proteins and lipid filled vesicles from the ER and then passes through the Golgi Apparatus and the proteins and lipids are modified before they are repackaged into vesicles. Repackaging occurs in the form of secretory vesicles, which travel to the plasma membrane where they discharge their contents. Lysosomes: Membrane bound vesicles produced by the Golgi Apparatus, they contain hydrolytic digestive enzymes. Vacuole: A large membranous sac. Larger than a vesicles, very prominent in plant cells which stores substances. Often they contain pigments, which is responsible for the coloring of the plant, or they contents could be toxic substances which help protect the plant from herbivorous animals. Peroxisomes: Are similar to Lysosomes in regards to being a membrane- bounded vesicle with enclosed enzymes. However, the enzymes in peroxisomes are synthesized by the cytoplasmic ribsomes and transported to the peroxisome by carrier proteins. Peroxisomes enzyme actions often result in hydrogen peroxide. Hydrogen Peroxide is immediately broken down to water and oxygen peroxisomal enzyme called catalase. However, the enzyme present in the peroxisome depends on the function of the cell. Chloroplasts: Specialize in converting energy to a form the (plant) cell can use. Bounded by two membranes that enclose a fluid filled place known as the stroma. The membrane inside the stroma is organized into interconnected flattened sacs called thykaloids. The thykaloids are stacked up in structures called grana, often there are hundreds of grana inside of the cell. Chloroplasts are used to synthesize carbohydrates, which are then broken down in the mitochondria. Mitochondria: Bounded by a double membrane. The inner fluid filled area is called the matrix, it contains DNA, ribosomes and enzymes that break down carbohydrate products releasing energy to be used for ATP production. The inner membrane opens to form cristae which increases surface area to accommodate the protein complexes and other participants that produce ATP. Cytoskeleton: The protein components of the cytoskeleton are interconnected and extend from the nucleus to the plasma membrane. The cytoskeleton contains actin filaments, intermediate filaments and microtubules which maintain the shape of the cell and allows the organelles and the cell to move. Actin Filament: long extremely thin yet flexible fibers that occur in bundles or meshlike networks. Play a structural role when they form a dense complex web just under the plasma membrane; they are anchored here by special proteins. They are also seen as Microvilli that project from intestinal cells. Intermediate Filaments: Intermediate in size between actin filaments and microtubules, they perform a structural role in the cell. They are a ropelike assembly of fibrous polypeptides. Intermediate filaments support the nuclear envelope while others support the plasma membrane. Microtubules: Small hollow cylinders, made up of the globular protein tubulin. They have 13 rows of tubulin dimmers, surrounding what appears to be an empty core. The microtubule-organizing centre is in the centrosome of most cells, which lies near the nucleus. They radiate from the centrosome helping maintain the shape of the cell and acting as tracks along which organelles can move. Before the cell divides microtubules disassemble and reassemble into the structure called the spindle that distributes the chromosomes in an orderly manner, at the end of cell division the spindle disassembles and the reassembles into microtubules. Centrioles: Short cylinders with a 9+0 patter in microtubule triplets. (A ring has nine sets of triplets with none in the middle) In animal cells centrosomes contain 2 centrioles lying at right angles to one another. The centrosome is the major microtubule-organizing centre for the cell. During division centrosomes function to organize and function to organize the meiotic spindle. Plant cells have the equivalent of a centrosome but it does not contain centrioles since they are not necessary to the assembly of cytoplasmic microtubules. Cilia/Flagella: Hair like projections that can move either in an undulating fashion like a whip or stiffly like an oar. Cells, which have these organelles, are capable of movement. Both cilia and flagella are membrane bound cylinders enclosing a matrix area. In the matrix there are 9 microtubules surrounding 2 central microtubules. Cilia and Flagella move when the microtubule doublets slide past one another. Labs Lab 1 Workplace Hazardous Material Information System (WHMIS) Material Safety Data Sheet (MSDS) Lab 3 1. What are the chemical constitutions of the plasma membrane and how are they arranged? The chemical composition of the Plasma membrane is: Proteins Lipids Carbohydrates Enzymes Water It is composed of a phospholipid bilayer with the hydrophilic/polar heads of the of the phospholipids facing outward and the hydrophobic/nonpolar tails facing inward. There is an array of amphipathic proteins used in cell to cell recognition,transport via passive or active transport, etc.There are glycoproteins mainly facing the extracelluar matrix and some cholestrol molecules to maintain the membranes fluidity. 2. Give three functions of the plasma membran
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