Exam #1 Study Guide
Exam #1 Study Guide BIO 183
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This 11 page Study Guide was uploaded by Anna Huryn on Thursday January 28, 2016. The Study Guide belongs to BIO 183 at North Carolina State University taught by Dr. Miriam Ferzli in Fall 2015. Since its upload, it has received 65 views. For similar materials see Intro to Bio Cell/ Micro in Biological Sciences at North Carolina State University.
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Date Created: 01/28/16
Anna Huryn Exam #1 Study Guide: BIO 183 Dr. Miriam Ferzli Exam #1 Study Guide Part I - Macromolecules: Monomers = the repeating units that serve as the building blocks of a polymer Polymer = a long molecule consisting of many similar or identical building blocks linked by covalent bonds Dehydration (condensation reaction) = the loss of a water molecule which covalently bonds two monomers Hydrolysis = the reverse dehydration reaction which breaks down monomers by adding water molecules There are four types of macromolecules: o Carbohydrates = sugars and polymers or sugars Monosaccharides (simplest unit, monomer) Ex. glucose Disaccharides (two monosaccharides) Ex. Maltose, lactose, sucrose Polysaccharides (polymer) Ex. Starch, glycogen, cellulose, chitin Proteins = a substance found in foods (such as meat, milk, eggs, and beans) that is an important part of the human diet and consist of amino-acid residues joined by peptide bonds Ex. Enzymes Polypeptides = the polymers of amino acids Amino acids = organic molecules possessing both carboxyl and amino groups Proteins serve to: Speed up chemical reactions Provide structural support Provide storage Help transport Aid cellular communications Aid movement 1 Anna Huryn Exam #1 Study Guide: BIO 183 Dr. Miriam Ferzli Provide defense against foreign substances Four levels of structure: primary structure: unique sequence of amino acids secondary structure: segments of polypeptide chains repeatedly coiled or folded tertiary structure: determined by interactions among various R groups quaternary structure: when two or more polypeptides join to form a protein Changes in pH, temperature, or other factors can unravel or denature a protein o Nucleic acids = Monomer = nucleotides There are two types of nucleic acids: RNA and DNA A nucleotide consists of three parts: a nitrogenous base, a pentose sugar, and a phosphate group o Lipids = compounds that have no affinity for water Ex. Waxes, fats, phospholipids, steroids Fat = constructed from two kinds of smaller molecules: glycerol and fatty acids Fatty acids = a long carbon skeleton In making a fat, three fatty acid molecules each join to glycerol by an ester linkage (a bond between a hydroxyl group and a carboxyl group) Triacylglycerol (triglyceride) = a fat containing three fatty acids linked to one glycerol molecule The major function of fats is energy storage (a gram of fat stores more than twice as much energy as a gram of a polysaccharide such as starch) Phospholipid = a lipid similar to a fat but with only two fatty acids attached to glycerol 2 Anna Huryn Exam #1 Study Guide: BIO 183 Dr. Miriam Ferzli Class Basic Unit Description Function Examples Carbohydrates monosaccharide Simple sugars Provide energy Mono and their Ex. Glucose polymers Di Ex. Lactose Poly Ex. Starch Lipids Fatty acids hydrophobic Provide energy Waxes, fats, phospholipids, steroids Proteins Amino acids complex Provide enzymes structures structural made from support, speed amino acids up chemical reactions, aid in cellular communications and movement Nucleic Acids nucleotides There are two Serve as genetic DNA, RNA types of material for the nucleic acids: cell DNA and RNA 3 Anna Huryn Exam #1 Study Guide: BIO 183 Dr. Miriam Ferzli Part II - Cells Part I: Cell Membrane Cell membrane = a selectively permeable membrane that serves as a barrier between the cell and the extracellular fluid Phospholipid bilayer = composed of a hydrophilic head and a hydrophobic tail, the head form the outer layer that is in contact with the aqueous solution while the hydrophobic tails face inwards Amphipathic molecule = a molecule with a hydrophobic and hydrophilic region The cell membrane is describe by the fluid mosaic model, “mosaic” describing the variety of proteins spread across the membrane The membrane must remain fluid to allow substances to pass back and forth Cholesterol helps keep the membrane fluid by serving as a temperature buffer Without cholesterol the membrane would slowly become solid as temperature decreases, this is because phospholipids move much quicker than slow moving proteins There are two types of membrane proteins: integral and peripheral Integral = proteins that penetrate the hydrophobic core of the lipid bilayer Peripheral = proteins that are not embedded in the lipid bilayer but are appendages loosely bound on the surface They aid transport, enzymatic activity, signal transduction, cell-to-cell recognition, and intercellular joining Nonpolar molecules (hydrophobic molecules: hydrocarbons, CO_2, and O_2) can dissolve in bilayer and cross easily The hydrophobic core prevents hydrophilic substances from crossing, they much enter through channel proteins (transport proteins) o Water passes through aquaporins (transport proteins) 4 Anna Huryn Exam #1 Study Guide: BIO 183 Dr. Miriam Ferzli Transport There are two types of transport: active and passive Passive Diffusion = spontaneous movement of ions or molecules along a concentration gradient (from high concentration to low concentration) Osmosis = the diffusion of water Facilitated diffusion = diffusion in which polar molecules cross the lipid bilayer with the aid of transport proteins o There are two types of transport proteins: channel and carrier proteins One type of channel protein is the gated channel or ion channel Gated channel = a stimulus causes them to open or close Carrier proteins = undergo shape changes to transport substances Active Active transport = transport that requires a molecule to be pumped against a concentration gradient 5 Anna Huryn Exam #1 Study Guide: BIO 183 Dr. Miriam Ferzli Electrochemical gradient = the combined forces that drive diffusion of ions across a membrane Membrane potential = the voltage across the membrane The inside of a cell is negative while the extracellular fluid is positive The membrane potential favors the passive transport of cations into the cell and anions out of the cell o There are two types of electrogenic pumps: the sodium-potassium pump and proton pump 6 Anna Huryn Exam #1 Study Guide: BIO 183 Dr. Miriam Ferzli Part III – Cells Part II: Bulk Transport Exocytosis = secretion of cellular contents to the outside of the cell by fusion of vesicles to the plasma membrane Endocytosis = uptake of extracellular material into the cell Ex. Phagocytosis, pinocytosis, receptor-mediated endocytosis Endomembrane System Cell Wall Found in plants, prokaryotes, fungi and some protists Serves multiple functions, in plants it protects the cell, maintains its shape, prevents excessive uptake of water, and supports the plant against the force of gravity Animal cells lack a cell wall but instead have an elaborate extracellular matrix 7 Anna Huryn Exam #1 Study Guide: BIO 183 Dr. Miriam Ferzli Extracellular Matrix Made up of glycoproteins the most abundant being collagen which forms strong fibers outside of the cell Embedded in a network of proteoglycans Fibronectin attaches the ECM to integrins Integrins = receptor proteins in the plasma membrane which transmit stimuli between the cell’s external and internal environment Surface Proteins & Cell Identity: Cells of the same type recognize each other o Identity is determined by surface markers (on ECM) Ex. glycolipids on the surface of red blood cells determine the A, B, O blood groups Immune system of vertebrates uses specific surface markers to distinguish “self” from “non-self” Intercellular Junctions: 8 Anna Huryn Exam #1 Study Guide: BIO 183 Dr. Miriam Ferzli o Plant cells have plasmodesmata which allow cytosol to pass between cells o Animal cells have tight junctions, anchoring junctions, and gap junctions Local signaling = direct cell-to-cell contact Long-distant signaling = uses hormones to communicate with cells not next to each other Three Stages of Signaling: 1. Receptor Activation = a chemical signal binds to a cellular protein at the cell’s surface or inside the cell. The signal molecule is a ligand, a small molecule that binds with specificity to a larger molecule (the receptor). 2. Signal Transduction = binding leads to a change in the receptor that triggers a series of changes in a series of different molecules 3. Cellular Response = the transduced signal triggers a specific cellular activity Part IV – Enzymes: Chemical Reactions: Chemical reactions can be: Exergonic = “energy outward” or releases free energy into its surroundings (spontaneous) Endergonic = “energy inward” or absorbs free energy from its surroundings (not spontaneous) Reactions always work towards being at equilibrium; in a closed system, once reactions reach equilibrium they can do no work Metabolic disequilibrium is one of the defining features of life Metabolic Pathways: Metabolic pathways = the totality of an organism’s chemical reactions is called metabolism There are two types of pathways: Catabolic = A sequence of degradative chemical reactions that break down complex molecules into smaller units, usually releasing energy in the process 9 Anna Huryn Exam #1 Study Guide: BIO 183 Dr. Miriam Ferzli Anabolic = The series of chemical reactions that constructs or synthesizes molecules from smaller units, usually requiring input of energy (ATP) in the process Cellular Work: There are three types of work: mechanical, transport, and chemical ATP powers all work Enzymes Enzymes = biological catalysts that increase the speed of a chemical reaction most enzymes are proteins enzymes function in small amounts and are reusable enzymes work by lowering the reaction’s activation energy, they form an enzyme- substrate complex (ES complex) activation energy = the energy required to break the existing bonds and begin a reaction substrate = the molecule the enzyme acts on all enzymes have one or more active sites active site = a place to fit a specific type of substrate most enzymes are highly specific, when the substrate binds to the enzyme it changes into the shape of the enzyme (induced fit) Factors Affecting Enzymes: Cofactors (coenzymes) = organic molecules that are required by certain enzymes to carry out catalysis, they bind to the active site of the enzyme and participate in catalysis but are not considered substrates of the reaction. 10 Anna Huryn Exam #1 Study Guide: BIO 183 Dr. Miriam Ferzli Inhibitors = compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination *there are two types of inhibitors: competitive and noncompetitive 11
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