review-material-for-mid-term-exam.docx

DRAFT-BIOLOGY REVIEW FOR MIDTERM EXAM1. Introduction to Biology: Exploring Life1) Levels of organization of lifeBiosphere(earth) Living thingsEcosystem EnvironmentsCommunity(living things in an area)Population(all members of a species in area) Organism Organ system Organs Tissues Cells Atoms2) Scientific methodsDiscovery and hypothesis-based science.3) Eukaryotic cells (with nucleus)Prokaryotic cells (before nucleus)4) 5 kingdomsMonera (bacteria) prokaryote (no nucleus)Protista (single cell organisms)Fungi (multicell saprobes) eukaryote (with nucleus)Plantae (multicell producer/autotroph) plantsAnimals (multicell heterotrophy animals5) Levels of organizationKingdom Phylum Class Order Family Genus Species6) 4 elements make up most living matterCarbon Hydrogen Oxygen Nitrogen7) Darwin: Evaluation-change over time.Natural selected: Organisms most suited to environment will have most2. The Chemical Basis of Life1) Atom: an atom is made up of protons and neutrons located in a central nucleusThe nucleus is surrounded by electrons arranged in electron shellsAtoms of each element are distinguished by a specific number of protonsChemical elements combine in fixed rations to form compoundsThe number of neutrons in an atom may vary variant forms of an element are called isotopes. Some isotopes are radioactive2) Electrons in an atom are arranged in shells, which may contain different numbers of electrons3) Atoms whose shells are not full tend to interact with other atoms and gain, lose, or share electrons. These interactions form chemical bonds.4) An electrical attraction between ions with opposite charges results in an ionic bond.Covalent bonds join atoms into molecules through electron sharingIn a polar covalent bond, electrons are shared unequally between atoms, creating a polar molecule.A molecule is non-polar when its covalently bonded atoms share electrons equally.The charged regions on water molecules are attracted to the oppositely charged regions on nearby molecules. This attraction forms weak bonds called hydrogen bonds.5) Hydrophobic water hatingHydrophilic water loving6) In a chemical reaction, reactants interact, atoms rearrange, and products result3. The Molecules of Cells1) 4 groups of biological macromolecules and functions of each.a. Proteins A protein is a polymer constructed from amino acid monomers.Proteins are involved in almost all of a cells activities.As enzymes, they regulate chemical reactions.A proteins specific shape determines its function and a proteins shape depends on four levels of structure, which are primary structure, secondary structure, tertiary structure and quaternary structure. (denaturation change in shape of protein, heat, acid, etc) Monosaccharide - glucose Disaccharides sucrose (table sugar) b. Carbohydrates storage: starch (plants) Polysaccharides glycogen (animals) structure: celluloseFats - are significant components of cell membranes and are a major form of stored energy.c. Lipids Phospholipids are the major component of cell membranes.Steroids (hydrophobic calorie)d. Nucleic acid: DNA & RNA4. A Tour of the Cell1) Prokaryotic cells are small, relatively simple cells and do not have a membrane-bound nucleus.Eukaryotic cells are distinguished by the presence of a true nucleus 2) Plant cell - chloroplast - cell wall - central vacuoles - nucleus Animal cell - lysosome3) Organelles: organs of the cellNucleus: DNA genetic information of the cellSmooth ER(endoplasmic reticulum): make lipidsRough ER: + ribosome (make proteins)Golgi apparatus: shipment of cellular productsLysosomes: packets of digestive enzymesplant central vacuole (storage) Vacuoles H2O + carbohydrate animal contractile vacuoleChloroplast: plant cells, some protista Photosynthesize make chemical energy from solar energyMitochondria: power plant of the cell(make energy) ATPCytoskeleton Locomotion, movementCilia and flagella5. The Working Cell1) Energy is the capacity to perform workPotential energy is stored energy and can be converted to kinetic energyThe First Law of Thermodynamics: energy can be changed from one form to another. Energy cannot be created or destroyed.The Second Law of Thermodynamics: transformations increase disorder or entropy, and some energy is lost as heat.2) Activation energy(EA): energy necessary to start a reactionEnzymes(biological catalyst): speeds up chemical reactions(catalytic proteins)Temperature, salt concentration(salinity), and pH influence enzyme activity.3) ATP shuttles chemical energy and drives cellular work.Make a bond store energy (endergonic)Break a bond release energy (exergonic)4) Plasma membrane phospholipid bilayer first level: hydrophilic second level: hydrophobic5) Passive transport(requires energy): high concentration to areas of low concentrationa. Osmosis water moves across a membrane to equalize concentration of a salt or sugar (put more water into a cell turgor pressure)b. Diffusion chemical movesActive transport(consumes energy): need ATP, energy 6) Exocytosis: a vesicle may fuse with the membrane and expel its contents.Endocytosis: membranes mat fold inward enclosing material from the outside6. How Cells Harvest Chemical Energy and Photosyntheses Using Light to Make Food1) Photosynthesis and cellular respiration provide energy for life:a. Cellular respiration makes ATP and consumes O2 during the oxidation of glucose to CO2 and H2Ob. Photosynthesis uses solar energy to produce glucose and O2 from CO2 and H2O REDUCTIONCO2 + H2O glucose(C6H12O6) +O2 OXIDATION2) Depending on whether the degradation involves oxygen, catabolic processes can be divided into two basic types: fermentation, where ox