Molecular Cell Biology PDF

# Molecular Cell Biology ## Life Begins with Cells ### ORDER OF CELLS - Order - Evolutionary Adaptions - Regulation - Response to Homeostasis - Energy Processing - Reproduction - Growth & Development ## Cells - Small membrane-bounded compartments filled with concentrated aqueous solutions of chem...

# Molecular Cell Biology ## Life Begins with Cells ### ORDER OF CELLS - Order - Evolutionary Adaptions - Regulation - Response to Homeostasis - Energy Processing - Reproduction - Growth & Development ## Cells - Small membrane-bounded compartments filled with concentrated aqueous solutions of chemicals. - Simplest form of life are solitary cells that reproduce by dividing in two. - Higher organisms (humans) -> cellular cities where groups of cells perform specialized functions. - Cells are a "sac" surrounded by the membrane with gates (proteins & lipids). - Lipids are fatty acids composed of Carbon, hydrogen & Carbon dioxide. - Lipids contain little amounts of oxygen in the "head". - Proteins -> composed of amino acids used for structural support. ## Modern Cell Theory - Cells are the structural & functional unit of all living things. - Come from pre-existing cells by division. - Contains DNA passed from cell to cell during division. - Composed of 6 elements → C, H, O, N, P, S. - Energy flow (metabolism) of life occurs. - Plasma membrane : permeable to specific molecules that a cell needs. - Transport proteins in cell membrane allow selective passage of molecules. - Each transport protein is specific to a certain molecule. ## Major Components of a Cell - 70% H₂O → most abundant molecule, inorganic ions, & carbon-containing. - Nucleic acids: deoxyribonucleic (DNA) & ribonucleic acid (RNA). - Proteins, Simple & Complex Carbohydrates, Lipids & Organelles. - Digest quick & spike blood sugar faster (Eg. white bread) - Digest slower & release glucose into blood stream slower (Eg. whole-grain bread) ## Organelles - Orderly arrangements of molecules → Produce Energy - Eg. Mitochondrian - Animals & Chloroplasts - Plants ## Different Types of Cells - **Prokaryotic** - DNA not separated from the cytoplasm. - Bacteria & archea (single cells). - Some are free living single celled & some are part of multicellular organisms. - **Eukaryotes** - DNA is partitioned off in its own membrane - nucleus. - Similarities -> Chromosomes, DNA as genetic material, Ribosomes, Cytoplasm, Plasma Membrane, Vacuoles. ## Types of Microorganisms - Bacteria, Fungi, Virus, Prions, Parasites, Protozoans ## The Evolution of the Cell - Natural selection involves 2 processes. 1. Random variation is passed from an individual to its descendant. 2. Selection in favor of genetic info helps to survive & propagate. ### From Molecules to the first cells - Organic molecules in cells : amino acids, sugars, purines & pyrimidines to make nucleotides. - DNA, RNA, Proteins are made of: H, C, N, O, S, P. - Amino Acids & Nucleotides associate to form: Polimers → Polypeptides (protein), polynucleotides (DNA, RNA), polysaccharides (carb). - Polyneucleotides: direct their own synthesis. - Self-replicating molecules: undergo Natural Selection. - RNA can catalyze biochemical reactions. - Flow of genetic material: polynucleotide → DNA → polypeptide. - DNA = hereditary material. - Friedrich Wohler (1800-1882) synthesis of urea. - Proteins: 20 types of amino acid. - Phospholipids : fundamental building blocks of ALL cell membranes. - oil-water interface> hydrophillic head & lipophilic tail (head in water, tail in all). - Polypeptides: Proteins, Polynucleotides: DNA/RNA, Polysaccharides: Carbohydrates. - Nucleus is covered by: outer & inner nuclear membranes (ONM & INM) & surrounded by cytoplasm where organelles float. ### How are cells studied - Microscopes: Electron microscopes -> higer magnification, higher resolution, more detail compared to light microscopes. - R.Hook: discovered new world in cells using microscopes. ## Classifications of Living things: Domains of Life - **3 Domains** - Bacteria: domain & kingdom - Eukaryota: Kingdoms: Fungi, Plants, Animals, Protists (single-celled) - Archea: Domain & Kingdom ### Prokaryotic Cell Structure - Appendages: Pilli, Flagella, Axial Filaments. - Cell Envelope: Capsule (glycocalyx), Outer membrane -> inner layer: phospholipids, outter layer: lipopolysaccharides = bilayer. - Cell Wall: Peptidoglycan. - Periplasm: space between cell membrane & peptidodycan cell wall. - Plasma/Cell Membrane: encloses cytoplasm, composed of membrane lipids & proteins & contains cholestorol. - DNA in nucleoid: NoTenclosed in membrane. - Cytoplasm. - Bacteria cells: 0.1-5.0 µm diameter much smaller than eukaryotic cell. - E.coli weighs 25×10⁹ - Bacteria in human body weighs 1-1.5kg. - # of bacteria on earth is 5x10³⁰ weighs 10²kg. ### Eukaryotes Cell Structure - Appendenges: Cilia, Flagella. - Cell Walls: Composed of Cellulose, Chitin (only in plants) Animal cells = No cell walls. - Plasma/Cell Membrane: encloses cytoplasm, composed of membrane lipids & proteins & contains cholestorol. - Glycocalyx - Cytoplasm, Nucleus, Ribosomes, Membrane-bound organelles. - 10-100 μm much larger than bacteria. ### Archea - Bacteria - Halophiles: "salt loving" need high conc. of salts to survive chemoheterotrophic. - Thermacidophiles : "heat & acid loving" (80C Sulfur, pH<2). - Methanogens: "methane producers", live in oxygen free enviro → autotrophs. ### Single-celled Organisms Produce - Sexually mating by Meiosis. - Asexually: budding by Mitosis. ## Viruses - Ultimate parasites, infect a host cell to grow & reproduce + transport genetic material. - Much smaller than cells: 100 nm. - Composed of a protein coat : encloses genetic material. - Protein coat provides: Protection from enviro, Allows virus to enter host cell. - Eg Bacteriophage: virus attacks bacteria. ## We Develope From A Single Cell: Zygote - 200 micrometer (Mm). - Zygote: union of an egg & sperm : houses instructions for building the human body containing 60-100 trillion (10¹²) cells. - Embryonic Stem Cells (ES): cells with the capability to give rise to an entire body of the organism. - Totipotent stem cells: can differenciate into all type of cells. - Pluripotent stem cells: can differenciate into many types of cells. - Organization of cell: from simple to complex form. - atoms simple molecules -> chain molecules molecular structures cells organs organisms -> population, ecosystem. - Reductionism: Knowledge about what genes are & how they work. - Ecosystem Dynamics: Cycling of nutrients, Flow of energy. ## Energy Conversion - Work requires a source of energy. - Energy can be stored in diff forms: light, chemical, Kinetic & thermal. - Energy exchange involves energy transformations. - Energy flows through an ecosystem -> enters as light & exits as heat. - Calorie: amount of heat needed to raise the temp. - Joule: amount of energy required to apply a 1 newton force over a distance of 1 metre. ### Primary Sources of energy in Organisms - Organotraph: feed on other living things or organic chemicals (Animals, fungi, gut bacteria) - Consumers. - Inorganotroph: teed on non-living things - Autotrophs - Producers. 1. Phototrophs: feeding on sunlight (plants, algae). 2. Chemoautotrophic: feeding on chemical rocks - Lithotrophic. - Decomposer: decompose dead organisms. - We obtain energy from metabolic fuels (Foods): Sugars, Proteins, Lipids, Vitamins, Minerals. - Mitochondria: power plants. ## Small Molecules of Cell & their Functions - Water: Interacts with water & biomolecules. 1. Most abundant biological medium. 2. Small, fast molecule. 3. Polar, dipolar allows formation of H-bonds. 4. Cohesive: surface tension. 5. Ability to moderate temp. 6. Expands when frozen. 7. Versatile solvent. - Small molecules: carry energy: ATP; transmit signals: using hormones & neurotransmitters; linked into macromolecules: covalantly. - macromolecules: molecules with same bonds (IVOT lipids). - Proteins: give cell structure & perform most cellular tasks. - Composed of 20 diff amino acids = 1 protein. - Carbohydrates: used as fuel, strengthens plant cell walls, stores glucose for energy. - Composed of monosaccharides (Eg. Glucose). - Lipids: important energy source, comp. of cell membranes. - Composed of long fatty chains. - Nucleic acids : DNA/RNA → stores hereditary info, carries protein coding from DNA to protein synthesizing machinery. - Composed of a sugar & phosphate group joined together by covalent & non-covalent bonds. - The Genome: set of DNA, packaged into chromosomes & replicated during cell division - linear. - Mutation can be good or bad. - come in various forms swap of 1 nucleotide for another, deletion, insertion, inversion or translocation of a strand of DINA from 1 chromosome to another. - * Nucleotide > nucleosome > chromatin > chromosome > genome. - Monomers (small molecules) join to form polymers -> by repitition of a single type of chemical-linkage reaction. - cells produce 3 types of large polymers called macromolecules: polysaccharides, proteins, nucleic acids. - proteins & nucleic acids: exhibit greater into complexity. - Protein Structure: primary, secondary, teritiary & quarternary. ## What cells can do - Seperated from external enviro by plasma/cell membrane. - Produce energy: ATP. - Produce their own external enviro: Extracellular matrix proteins, gap junctions. - Change shape & move: Cytoskelaton fillaments. - Send & Sense info: External & Internal signals transmitted, Receptors. - Grow & Divide: Mitosis & Meiosis. - Die: Apoptosis (programmed death).