BIOL 111 1st Edition Exam 1 Study Guide Lectures 7 13 Lecture 7 February 6 Cells Prokaryotic Cell before the nucleus The DNA is not contained in a membrane enclosed region instead it is concentrated in an area called the nucleoid Cell Wall maintains structure and protects from outside damage Fimbriae attaches the surface of prokaryotes to other prokaryotes Capsule jellylike outer coating Flagella or Cilia used for locomotion Eukaryotic Cell true nucleus The DNA is contained in a membrane enclosed nucleus These cells are generally much larger than Prokaryotic cells and size relates to function Endoplasmic Reticulum smooth ER does not have ribosomes rough ER has ribosomes Golgi Apparatus sorts and transports proteins Mitochondria makes ATP by cellular respiration Peroxisomes convert hydrogen into hydrogen peroxide and then to water Cytoskeleton reinforces cell s shape and movement Unique to animals cells not in plant cells Lysosomes Centrosomes Flagella Lysosomes digestive organelle where macromolecules are hydrolyzed Centrosomes occurs in triplets and made of centrioles and microtubules Flagellum or cilia used for locomotion Unique to plant cells not in animal cells Chloroplasts Central Vacuole Cell Wall and Plasmodesmata Chloroplasts where photosynthesis conversion of light to energy occurs Cell Wall maintains cell shape and protects from mechanical damage Plasmodesmata channels that connects cytoplasms of adjacent cells Central Vacuole in older plants that use it for storage and waste breakdown Both Prokaryotic and Eukaryotic Cells Plasma Membrane functions as a selective barrier that allows passage of oxygen and nutrients into the cell and waste out of the cell Cytosol a semifluid jellylike substance in which subcellular components are suspended All cells contain ribosomes to make proteins and chromosomes to carry genes in the form of DNA Endosymbiont Theory This theory states that an early ancestor of eukaryotic cells engulfed a prokaryotic cell forming a relationship with the host cell in which it was engulfed becoming an endosymbiont a cell living within another cell When they split up into single organisms one eukaryotic cell had a mitochondria and the other eukaryotic cell that took with it the photosynthetic prokaryote cell had chloroplasts Mitochondria and Chloroplasts display similarities with bacteria Like prokaryotes mitochondria and chloroplasts have double membranes they contain ribosomes and circular DNA attached to the inner membrane and finally they are autonomous semi independent organelles that grow and reproduce within the cell Lecture 8 February 11 Cytoskeleton It reinforces cell shape functions in cell movement components are made of protein Microtubules the thickest hollow tubes of the three types of cytoskeleton fibers it is made up of tubulin a dimer molecule made up of two subunits Functions maintain cell shape and support the cell serve as motility as cilia or flagella where the microtubules are arranged in a 9 2 9 doublets forming a ring and 2 single microtubules at the center guide secretory vesicles from Golgi apparatus to the plasma membrane separation of chromosomes during cell division they grow out of centrosomes and within the centrosome is centrioles composed of nine sets of triplet microtubules arranged in a ring before an animal cell divides the centrioles replicate Microfilaments These are the thinnest of the three cytoskeleton fibers It is composed of actin in a twisted double chain Functions Maintains and changes cell shape responsible for muscle contractions myosin and actin sliding past one anther cytoplasmic streaming circular flow of cytoplasm within cells cell motility pseudopodia cellular extensions and cell division cleavage furrow formation Intermediate Filaments Larger than microfilaments smaller than microtubules hence intermediate Composed of Keratin that are supercoiled into thick cables Functions Maintain cell shape tension bearing elements anchorage of nucleus and other certain organelles and formation of nuclear lamina lines the interior of the nuclear envelope Membrane Structure and Function The plasma membrane exhibits selective permeability allowing some substances to cross more easily than others Nonpolar molecules i e gases CO2 N2 O2 are hydrophobic and dissolve easily and cross membranes easily without any help Polar molecules i e glucose and Ions i e Na K Cl do not pass the membrane easily and therefore require help of transport proteins They are made up of phospholipids lipids and proteins bilayer two layers that are amphipathetic have a hydrophobic and a hydrophilic region Membranes are made up of a mosaic of proteins the two major ones are Integral proteins intrinsic are embedded in the membrane Most are transmembrane proteins that span the membrane using alpha helices And serve a variety of functions including transport enzymatic activity signal transduction cellcell recognition intercellular joining and attachment to the cytoskeleton and extracellular matrix ECM Peripheral proteins extrinsic loosely associated with the membrane or integral proteins Lecture 9 February 13 Transporting across a Membrane Passive Transport is diffusion of a substance across a membrane with no energy investment go with the flow of concentration gradient Diffusion is the tendency of molecules to spread out evenly into the available space in the absence of other forces a substance will diffuse from where it is more concentrated to where it is less concentrated Facilitated Diffusion transport proteins speed up the passive movement of molecules across the plasma membrane Osmosis is the diffusion of water across a membrane Tonicity is the ability of a solution to cause a cell to gain or lose water Hypotonic solution the solute concentration is lower outside the cell than on the inside therefore a substance will flow to the inside of the cell turgid ideal for plants which are protected from bursting like an animal cell would by the cell wall Isotonic solution the solute concentrations are equal flaccid ideal for animal cells Hypertonic solution the solute concentration is higher outside the cell than inside the cell plasmolyzed shriveled up the substance will rush out of the cell Active Transport moves substances against their concentration gradient requiring energy usually in the form of ATP Metabolism The totality of an organisms chemical reactions Metabolic pathway begins with a specific molecule and ends with a product Catabolic