BSCI105 Exam Study Guide 22 multiple choice questions Exam I Ch 1 5 Themes of Life 1 Theme New properties emerge at each level in the biological hierarchy Biosphere Ecosystems Communities Populations Organisms Organisms Organs Organ systems Tissues Cells Organelles Molecules Biology The chemistry of life Life has order evolutionary adaptation response to the environment reproduction growth and development energy processing and regulation Themes that connect the concepts of biology Biology consists of more than memorizing facts Themes help to organize biological information Organisms interact with other organisms and the physical environment Life requires energy transfer and transformation Structure and function are correlated at all levels of biological The cell is an organism s basic unit of structure and function The continuity of life is based on heritable information in the other form organization of DNA Feedback mechanisms regulate biological systems The Core Theme Evolution accounts for the unity and diversity of life Evolution the Overarching theme of biology Evolution makes sense of everything Theme Organisms Interact with Other Organisms and the Physical Environment Theme Life Requires Energy Transfer and Transformation All living organisms use energy to do life s activities Energy in an ecosystem enters as light and exits as heat Theme Structure and Function Are Correlated at All Levels of Biological Organization Example A bird s wing shape is adapted for flight Theme The Cell Is an Organism s Basic Unit of Structure and Function Cell lowest level of organization that can perform all activities required All cells are enclosed by a membrane and use DNA for genetic for life information 2 Eukaryotic Cell multicellular contain various membrane bound organelles nucleus with DNA Prokaryotic Cell bacteria archaea simple single celled no membrane bound organelles no nucleus contains unbound DNA Theme The Continuity of Life Is Based on Heritable Information in the Form of DNA Chromosomes contain a cell s genetic material DNA Genes units of inheritance from parents to offspring Cells divide for reproduction growth and repair Theme Feedback Mechanisms Regulate Biological Systems Feedback mechanisms allow biological processes to self regulate Negative feedback As more product accumulates the process Positive Feedback As more product accumulates the process slows down and less is produced speeds up and more is produced Chemistry Elements cannot be broken down chemically to other substances Trace elements required in small quantities SiMgFeAlCa A compound contains two or more elements O C H N cover 96 of living matter An atom is the smallest unit of an element has the following components subatomic particles Protons Neutrons Electrons Electrons that are closer to the nucleus have less energy Nucleus contains protons and neutrons Spontaneous reactions Exothermic releases heat Endothermic gains heat Atomic of Protons Mass number of protons neutrons Isotopes two atoms of an element that differ in neutron number Will form the same chemical bonds have same number of protons but different number of neutrons Isomers same molecular formula but different carbon skeletons different double bond positions have different chemical properties and different biological activity Know electron shells orbitals 3D Water The solvent of life Properties of water 3 Valence shell outermost shell Number of unpaired electrons here determines bonding and the number of covalent bonds Know hydrogen bonds Van der Waals interactions Covalent bonds share a pair of electrons two nonmetals Ionic bonds attraction of oppositely charged atoms metal and a Hydrogen bond H bonded to 2 electronegative atoms usually O or nonmetal weak bond ex transfer from sodium to chlorine N weak bond When they break heat is absorbed When they form heat is released Van der Waals interactions between two nonpolar molecules that are close together weaker than hydrogen bonds Cohesive behavior holds molecules together helps transport water against gravity in plants ex water traveling up a tree Related to surface tension how hard it is to break the surface of a liquid Ability to moderate temperature Expansion upon freezing Versatility as a solvent b c it can hydrogen bonds and form hydration shells around ions Dissociation transfer of Hydrogen atom from one water molecule to another H2O H2O H30 OH Hydrophobic substance that does not have an affinity for water Has nonpolar side chains CH groups or rings on the ends Hydrophilic substance that has an affinity for water Has polar side chains have OH groups pH log H Acid pH 7 increases H concentration Base pH 7 increases OH concentration Water pH 7 Buffers minimizes changes in the concentration of H and OH H2CO3 carbonic acid is a buffer in human blood Ocean Acidification CO2 dissolves in seawater it reacts with water and forms carbonic acid and lowers the oceans pH 4 Reduces carbonate concentration which is required for calcification in coral reefs etc which are habitats for marine life Acid Precipitation rain snow fog with a pH lower than 5 2 Biological Molecules Carbohydrates and Lipids 4 classes of biological molecules 1 Carbohydrates sugars and polymers of sugars long molecule of monomers has chemical formula with multiples of CH2O Sugars Monosaccharides ex Glucose simplest carbs single sugars classified by spatial arrangement of atoms carbonyl and hydroxyl groups Serve as fuel Disaccharides Joined by Glycosidic linkage Polysaccharides polymers of sugars 2 primary roles Storage roles starch plants and glycogen animals Structural roles cellulose plants and chitin animals 2 Lipids hydrophobic molecules not soluble in water consist of hydrocarbons do NOT form polymers major function is energy storage constructed from Phospholipids Fats glycerol 3 C alcohol and fatty acids long C chain phosphate hydrophilic head attached to a glycerol fused rings Steroids Cholesterol lipids with a carbon skeleton of 4 two fatty acids hydrophobic tails and a 3 Proteins for structural support storage transport cellular communications movement and defense against foreign substances polypeptide polymers of amino acids D STRCHES mnemonic Defensive proteins Antibodies i e White blood cells protection against disease Structural proteins Keratin hair support Transport proteins Hemoglobin red blood cells Receptor proteins Signaling molecules response of transport of substances cell to stimuli 5 Contractile and motor