BIO 121 1nd Edition Final Exam Study Guide Lectures 1 24 Chapter 1 There are new properties emerge at each level in the biological hierarchy o The hierarchy of life is biosphere ecosystem community population organism organ system organ tissue cell organelle molecule atom o In reductionism complex systems are broken down into simpler more manageable components o In systems biology the behavior of a whole biological system rather than the parts of a biological system looking at the big picture Organisms interact with other organisms and the physical environment Life requires energy transfer and transformation o Energy flows through an ecosystem Structure and function are correlated at all levels of biological organization The cell is an organisms basic unit of structure and function o Cells are either prokaryotic or eukaryotic o Prokaryotic cells lack membrane enclosed organelles o Eukaryotic cells contain membrane enclosed organelles The continuity or life is based on heritable information in the form of DNA Feedback mechanisms regulate biological systems o Negative feedback accumulation of end products slow down the process that is making the products o Positive feedback the end product stimulates the production of more products Evolution accounts for the unity and the diversity of life and also the match of organisms to their environments o Including the 3 Domains Bacteria Archaea and Eukarya o Natural selection was developed by Charles Darwin and it suggests that the natural environment selects for certain traits in a species o There are three requirements for evolution to occur variation in a population desired trait necessary for survival a way for the variation to be inherited must be able to reproduce if only two have the desired trait needed both can t be female or male one must be female and the other must be a male Differential effect of the environment on the variation Reasoning o Inductive reasoning derives generalizations after collecting and analyzing observations o Deductive reasoning used after the hypothesis has been made and instead of a general conclusion we conclude more specifically Chapter 2 Matter is made up of elements a substance that cannot be broken down into any other substances by chemical reactions unlike a compound which is composed of two or more elements combined in a fixed ratio o There are four elements that make up the majority of organisms Carbon Hydrogen Nitrogen and Oxygen An elements properties depend on the structure of its atoms o The atom is the smallest unit of an element and it is composed of a nucleus protons neutrons 0 and electrons o The atomic number is determined by the number of protons in an element o The atomic mass is determined by the number of protons and neutrons o An element may have isotopes the same element with different number of neutrons changing the atomic mass o Electrons occupy specific electron shells of each shell the electron has a characteristic energy level and that determines the chemical behavior of an atom The outer most shell is called the valence shell The farther away from the nucleus the higher the energy level As you move toward the nucleus energy is released The closer to the nucleus the lower the energy level As you move away from the nucleus energy is absorbed Chemical bonds form when atoms interact and complete their valence shells o Covalent bonding is the sharing of electrons Polar covalent bonding Non polar covalent bonding o Ionic bonding is the attraction of oppositely charge electrons one atom lost electron making it positively charged and one atom gained electrons making it negatively charged o Hydrogen an attraction between a hydrogen atom that is carrying a partial positive charge and an electronegative atom o Van der Waals interactions occur between transiently positive and negative regions of molecules Chapter 3 Polar covalent bonds in water molecules result in hydrogen bonding o A hydrogen bond forms when the slightly negatively charged oxygen of one water molecule is attracted to the slightly positively charged hydrogen of a nearby water molecule o Hydrogen bonding between water molecules is the basis for water s properties There are four emergent properties of water o Cohesion hydrogen bonding allows water molecules to stick together collectively related to cohesion is surface tension o Adhesion hydrogen bonding allows water to cling to other substances o Moderation of Temperature water moderates air temperature by absorbing heat from warmer air and releasing stored heat to cooler air Water resists temperature change Water is able to release and absorb a lot of heat without changing its own temperature water has a high specific heat o Expansion upon freezing water is less dense because it expands as a solid than as a liquid allowing ice to float on water At temperatures above 4 C water behaves like other liquids expanding as it warms and contracting as it cools At temperatures below 4 C water begins to freeze and becomes about 10 less dense than in its liquid state Water makes a good solvent because of its polarity o Polar bonds are hydrophilic water loving o Non polar bonds are hydrophobic water fearing Molarity is the number of moles of solute per liter of solution A mole is a certain number of molecules of a substance Acid vs Base o Acids donate their extra H in aqueous solution pH is 7 o Bases accept the H in aqueous solution pH is 7 o Hydronium ions are acidic because of their extra H i e H or H3O o Hydroxide ions are basic because they are lacking an H i e OH pH affects many things such as shape and function of molecules rates of chemical reactions molecules ability to bind together and ions ability to dissolve in water o pH log H concentration o increasing hydrogen increases acidity o increasing hydroxide increases basicity Buffers are weak acids or weak bases that help solutions resist the pH Chapter 4 Organic chemistry is the study of carbon compounds Carbon atoms can form diverse molecules by bonding with four other atoms o Carbon has a valence of 4 allowing it to bond with four other atoms such as Hydrogen Nitrogen and Oxygen o The simplest carbon molecules is a hydrocarbon strictly hydrogen and carbon o Can form non polar molecules poorly water soluble as well as polar molecules more water soluble Isomers same chemical formula but different arrangement o Structural isomers same molecular form but different structural arrangement such as branching o Geometric isomers
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