BS 161 Final Examination Notes ● Chapter 1.1 ○ Scientific Inquiry ■ Observation - the act of viewing the world around us ■ Experimentation - a disciplined and controlled way of asking and answering questions about the world in an unbiased manner ■ Hypothesis - Questions that arise from observations and proposing tentative explanations ■ Exploration > Investigation > Communication (This is known as Scientific Inquiry) ■ Variable - a researcher deliberately introduces something different ■ Test Group - a theory that results change based on variable ■ Control Group - Expectation is that no effect will occur in this group ■ A theory is a general explanation of natural phenomena supported by many experiments and observations. ● Chapter 1.2 ○ Chemical and Physical Principles ■ The living and nonliving worlds follow the same chemical rules and obey the same physical laws ■ First Law of Thermodynamics - Energy can neither be created nor destroyed ■ Second Law of Thermodynamics - the degree of disorder (number of possible positions and molecules) in the universe tends to increase ■ The Entropy is considered the disorder of a system ■ Scientific inquiry shows that living organisms come from other living organisms (For example, microbial bacteria communities occur from letting live meat rot) ● Chapter 1.3 ○ The Cell ■ Cell - simplest entity that can exist as an independent unit of life ■ Nucleic acids store and transmit information needed for growth, function, and reproduction■ In all organisms, the information archive is a remarkable molecule known as deoxyribonucleic acid (DNA) ■ DNA is a double stranded helix with each strand made up of varying sequences of four different kinds of molecules connected end to end ■ The information encoded in DNA directs the formation of proteins ■ Proteins - the key structural and functional molecules that do the work of the cell ■ Existing proteins create a copy of the DNA’s information in the form of a closely related molecule known as ribonucleic acid (RNA) ■ Transcription - the synthesis of RNA from a DNA template ■ Translation - Specialized molecular structures within the cell then “read” the RNA molecule to determine which building blocks to use to create a protein ■ The pathway from DNA to RNA (mRNA) to protein is known as the central dogma of molecular biology. ■ DNA (Transcription) > RNA (Translation) > Protein ■ DNA can be replicated allowing genetic information to be passed from cell to cell or from an organism to its progeny. ■ Mutations - Errors in DNA can and do occur during the process of replication and environmental insults can damage the DNA sequence ■ Membranes define cells and spaces within cells ■ Plasma Membrane - Separates the living material within the cell from the nonliving environment around it ■ The membrane selects certain molecules to enter/exit the nucleus ■ Nucleus - houses the cell’s DNA ■ Cytoplasm - a discrete space within the cell, seperate from the space outside the nucleus. ■ Prokaryotic - Cells with NO nucleus ■ Eukaryotic - Cells WITH a nucleus ■ Three domains of life - Bacteria, Archaea, and Eukarya\ ■ Metabolism converts energy from the environment into a form that can be used by cells ■ Metabolism - describes chemical reactions by which cells convert energy from one form to another and build and break down molecules. ■ ATP - All organisms use chemical reactions to break down molecules, in the process of releasing energy that is stored in a chemical form ■ A virus is genetic material that requires a cell to carry out its functions■ A virus infects a cell by binding to the cell’s surface, inserting its genetic material in the cell, and in most cases using the cellular machinery to produce more of itself ● Chapter 2.1 ○ Properties of Atoms ■ Elements - Materials of nature that are made up of a small number of fundamental substances combined in various ways (Think Carbon, Hydrogen, and Oxygen) ■ Atoms consist of protons (+), neutrons (o), and electrons (-). ■ Atomic mass - Determined by protons and neutrons added together ■ Isotopes - atoms of the same element that have differing numbers of neutrons ■ Ions - Electrically charged atoms ■ Electrons occupy regions of space called orbitals ■ Orbital - where an electron is present most of the time ■ Elements have recurring, or periodic, chemical properties ● Chapter 2.2 ○ Molecules and Chemical Bonds ■ Atoms combine with other atoms to form molecules ■ A chemical bond holds the two atoms together by force of attraction ■ A covalent bond occurs when two atoms share electrons ■ Valence Electrons - outermost electrons with the highest energy level ■ The orbitals of the two atoms merge causing a molecular orbital ■ Double Bond - when two adjacent atoms share two pairs of electrons ■ A polar covalent bond is characterized by unequal sharing of electrons ■ Electronegativity - The unequal sharing of electrons results from a difference in ability of the atoms to attract electrons ■ Electronegativity increases across a row ■ Nonpolar Covalent Bond - A covalent bond between atoms that have the same, or nearly the same, electronegativity ■ An ionic bond forms between oppositely charged ions. ■ A chemical reaction involves breaking and forming chemical bonds. ■ Reactants - Atoms or molecules independent ■ Products - the result of the molecules or atoms being chemicallyrearranged ● Chapter 2.3 ○ Water ■ Water is a polar molecule ■ Polar attracts Polar <> Nonpolar attracts Nonpolar ■ Hydrophilic - Water loving or water attracting ■ Hydrophobic - Water Fearing or Water Repelling ■ Water is a reliable solvent that can dissolve many substances when it is polar ■ Water is repelled in Nonpolar environments ■ A hydrogen bond is an interaction between a hydrogen atom and an electronegative atom (H,N,O, or F) ■ Hydrogen bonds give water many unusual properties ■ Cohesion - Hydrogen bonds give water molecules a property known as Cohesion that cause them to stick together ■ pH is a measure of the concentration of protons in a solution ■ pH = 7 = Neutral ■ pH lower than 7 = Acidic ■ pH greater than 7 = Basic (Base) ● Chapter 2.4 ○ Carbon ■ Organic Molecules - Any