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Thorough Biology 102 Exam Review Chapters 1-4

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BIOL 102
Wayne Snedden

Chapter 1: An Introduction to Biology Principles of Life: Distinguish living things from non-living things 1. Cells are the simplest units of life/organization. Organisms maintain internal order (homeostasis) different from the environment. Cell theory: all organisms are composed of cells; cells are the smallest units of life; new cells form via cell diffusion from old cells 2. Living organisms use energy: they must acquire energy from environment to maintain eternal order 3. Interaction with environment: respond to environmental changes 4. Homeostasis: the degree varies from organism to organism but all regulate cellular metabolism 5. Growth/development/reproduction: series of changes in state of cells, tissue or organism eventually resulting in organisms with defined set of characteristics; all have finite lifespan – reproduction 6. DNA (genetic material): transmitted from parent to offspring via reproduction. Used dynamically to fit needs of organization 7. Evolution: heritable change in DNA for population of organisms 8. Related by Evolutionary History: all organisms on Earth share a common ancestry 9. Structure determines function: follow rules of chemistry and physics plus shape plays a function of biology Levels of Organization 1. Atom: smallest component of an element with all chemical properties 2. Molecules and macromolecules: atoms bond to form molecules, molecules then form macromolecules. This includes carbohydrates, proteins, DNA, RNA etc 3. Cells: associate with one another to from organelles which are enclosed by a cell membrane 4. Tissues: many cells of the same type associate with each other (ex. muscle tissue) 5. Organs: composed of two or more types of tissue 6. Organ systems: work together to accomplish larger functions 7. Organism: distinct unit of life 8. Species: related group (genetics); distinct form + set of attributes 9. Population: organisms of same species occupying a continuous space 10. Community: assemblage of populations of different species 11. Ecosystem: interactions of community with physical non-living environment 12. Biosphere: all of living earth: air, water, land Evolution In evolution, structure is often modified for new purpose. Two types of changes through evolution: vertical descent with mutation and horizontal gene transfer. Vertical descent: changes in a series of changes through series of ancestors (lineage). Called vertical descent because of how it’s usually depicted. Become a species by mutation (inheritable change in genetic material). Increase chance of survival or reproduction. Natural selection: neutral changes occur too. Horizontal gene transfer: genetic exchanges occurring between different species, especially bacteria. Taxonomy Sub discipline of biology in attempt to determine relatedness. Three main domains: Bacteria, Archaea, Eukarya Bacteria and Archaea are prokaryotic microorganisms that still show differences in lipid organization, packaging of heretic material, regulation of production of mRNA. Eukarya are eukaryotic with larger cells with genetic material with membrane. Eight different subgroups. Binomial nomenclature: used to provide each species with unique scientific name (in latin). Order: Domain Kingdom Phylum Class Order Family Genus Species Genome The genetic material of an organism, compiled of collection of DNA. This acts as stable information unit +encodes information of organism function. It stores encoded info to make located + modify all organisms proteins  proteome: collection of proteins being made in a cell under particular conditions. Also, provides continuity from generation to generation (via reproduction). Helps evolutionary change via mutation. Used for genomic analysis in research. Reading of blueprint is influenced by the environment; RNAs read genome differently. Biology as a science Follows a scientific method via predictions that can be experimentally/observationally tested. Discovery based science is collection and analysis without need for preconceived hypothesis. This includes hypothesis (proposed explanation for a natural phenomenon), theory (based explanation of some aspect of natural world). Hypothesis testing is the scientific method, observations  hypothesis, experimentation, data, acceptance/rejection Chapter 2: The Chemical Basis of Life I; Atoms, Molecules and Water Electrons Energy shells are where orbitals (area of where probability is high in finding electrons are found). Orbitals can only have two electrons. First level is 2s. Second level is 2s + 2p which is 6 electrons. Energy shells closest to the nucleus have the lowest energy and they fill up first. In orbitals with one or more than one section, each compartment fills up evenly. Valence electrons are located in outmost energy cell and are available to combine with other atoms. Cations: ions with new positive charge. Anions: ions with net negative charge. Free radical: molecule containing single unpaired electron in outer shell, and this can be harmful. Brownian motion: heat energy causes atoms to vibrate and move. Catalysts: substance that speeds up chemical reaction without itself being affected. For example, a biomolecule catalyst such as RNA or protein. A feature of chemical reactions in living things occur in water environments. Molecular flexibility is of great importance, as is shape. Chemical forces Van der Waals: chemical forces that occur intermolecularity between different regions of large molecules. Electrostatic interactions between molecules of opposite charges. The strength is determined by degree of charges and distance between molecules. Weaker than covalent and ionic. Ion-dipole: occur between ions + dipoles, for example ionic molecules in water (most important type) Dipole-dipole: there are many different types, with the most important one being hydrogen of one polar molecule and oxygen, nitrogen or fluorine. Hydrogen bonds: stronger than other dipole-dipole because all three relevant atoms and H-O and H-N bonds are very polar. H is very positive and other are very negative. Single H bond is weak bu makes a huge difference. For example, it makes DNA stable. The closer the molecules are, the stronger the van der waal force is Heat of vaporization: heat required to bring 1 mole of any substance to boiling point under standard pressure. Heat of fusion: when substance goes from liquid to slid (fusion) = amount of energy released. Specific heat: amount of heat required per unit of mass to raise mass one degree Celsius. Water has a high specific heat because of hydrogen bonds. Solutes are substances dissolved in solvent to form a solution. Concentration is the amount of solid dissolved in unit volume of solution. Colligative properties depend strictly on concentration of dissolved solute particles. Anti-freeze found in some organisms. Micelles: what long amphipathic molecules from spheres can form when mixed with water. Hydrophilic have polar regions on surface, hydrophobic regions are non-polar parts that face the center. Chapter 3: Chemical Basis of Life II; Organic Molecules Organic molecules Hydrocarbons: mainly hydrogen and carbon. Hydrophobic because H-C bonds are non-polar and insoluble. But when C makes polar covalent bonds with oxygen or nitrogen, it is polar and soluble. They can then serve different functions. Bonds are stable at different temperatures associated with life. Short bonds because small molecules. Functional groups Groups of atoms with special chemical features that contribute to molecular properties. Isomers: two structures with identical molecular formula but different structures and characteristics. Structural isomers: same atoms in different bonding relationships. Stereoisomers: identical bonding relationships but different spatial positioning. Geometric isomers (another stereoisomer): cis and trans bonding. Erantiomers (stereoisomer): mirror images, identical properties but different orientation = different bonding. Condensation reaction: Two or more molecules combine (lose water molecule) Dehydration reaction: types of water condensation, catalyzed by enzymes (opposite of hydrolysis) Triglycerides/triacylglycerol: glycerol bonded to three fatty acids (C and H with carboxyl at end). Ester bond found between the glycerol carboxyl group of fatty acid (covalent). Essential fatty acids: needed for good health, organisms (eg. humans) who cannot be made in the body but must be obtained Most unsaturated fats have H in cis position, trans fats are trans positions. Unsaturated or trans are more solid. Hydrolysis of triglycerides release fatty acids from glycerol (fatty acid metabolised). The energy for the C-H bond is greater than C-OH bond. 1g of fats = 2x energy as 1g carbohydrates. In phospholipids, third hydroxyl is linked to phosphate group instead of fatty acid. Steroids have four fused carbon rings where steroids with hydroxyl groups = sterols. Not water soluble. Factors that determine protein structures 1. Hydrogen bonds: strong force that promotes protein folding and stability (second, third, fourth degree) 2. Ionic/polar: some amino acid chains = positive/negative which promotes folding stability (second, third, fourth degree) 3. Hydrophobic effect: non-polar avoid water and are the centre of the protein (third, fourth degree) 4. Van der waals force
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