3 Approaches to studying biology Emergent Properties Reductionism Systems Biology 2 approaches to the study of life Biology Levels of biological study of life 7 Activities Required for life Homeostasis Organization Metabolism Growth Adaptation Response to stimuli Reproduction Cells Prokaryotic Cells Eukaryotic cells Chromosomes CHAPTER 1 Emergent Properties Reductionism Systems Biology Result from the arrangement and interaction of parts within a system Example a bicycle functions due to all the parts working together The reduction of complex systems to simpler components that are more manageable to study Example molecular structure of DNA Constructs models for the dynamic behavior of whole biological systems Example How does a drug for blood pressure affect other organs Discovery Science observe and describe some aspect of the world and use inductive reasoning to draw general conclusions Hypothesis Based Science based on observations scientists propose hypothesis that lead to predictions Biosphere Ecosystem Community Population Organism Organ system Organ Tissue Cell Organelle Molecule Atom Homeostasis Organization Metabolism Growth Adaptation Response to stimuli Reproduction Regulation of the internal environment to maintain a constant state Being structurally composed of one or more cells Transformation of energy by converting chemicals and energy into cellular components anabolism and decomposing organic matter catabolism Maintenance of a higher rate of anabolism than catabolism A growing organism increases in size in all of its parts rather than simply accumulating matter Ability to change over a period of time in response to the environment Fundamental to the process of evolution Can take many forms from contraction of a unicellular organism to external chemicals to complex reactions involving all the senses of multicellular organisms The ability to produce new individual organisms asexually from a single parent organism or sexually from two parent organisms Basic units of structure and function lowest level of organization that can perform all 7 activities required for life Enclosed by membrane use DNA as genetic info ability to divide is the basis of reproduction growth and repair Simpler and smaller than eukaryotic cells no nucleus or membrane enclosed organelles Bacteria and Archaea are prokaryotic Have membrane enclosed organelles and nucleus Plants animals fungi and all other forms of life are eukaryotic Contain most of a cells genetic material in the form of DNA each chromosome has one long DNA molecules with thousands of genes DNA Atom Genes Matter Genome Elements Compounds Trace elements Subatomic particles CHAPTER 2 Is the substance of genes inherited by offspring from parents controls the development and maintenance of organisms made up of 2 long chains arranged in double helix each link in DNA chain is one of four different nucleotides Units of inheritance that transmit info from parent to offspring control protein production indirectly because DNA is transcribed into RNA then translated into a protein An organisms entire set of genetic info Anything that takes up space and has mass consists of chemical elements in pure form and in combinations called compounds Organisms are composed of matter Substance that can t be broken down to other substances by chemical reaction properties depend on structure of its atoms each element has unique atoms A substance consisting of two or more elements in a fixed ratio Has characteristics different from those of its elements Essential Elements of Life 25 of the 92 elements are essential to life Carbon Hydrogen Oxygen and Nitrogen make 96 of living matter The majority of the remaining 4 is calcium phosphorus potassium and sulfur Elements required by an organism in minute quantities Smallest unit of matter that still retains the properties of an element composed of subatomic particles Neutrons no electrical charge in atomic nucleus Protons positive charge in atomic nucleus Electrons negative charge in electron cloud around the nucleus Sum of proton and neutron masses which are equal measured in Daltons Atomic mass atom s total mass can be approximated by the mass The number of protons in its nucleus Two atoms of an element that differ in number of neutrons Decay spontaneously giving off particles and energy Applications Dating fossils Tracing atoms through metabolic processes Diagnosing medical disorders Capacity to cause change Energy that matter has because of its location or structure Electrons of an atom differ in their amounts of potential energy Also known as electron shell is an electron s state of potential energy Determined by the distribution of electrons in the electron shells particularly valence outer most shell Elements with a full valence shell are chemically inert The periodic table shows the electron distribution for each element The three dimensional space where an electron is found 90 of the time Each electron shell consists of a specific number of orbitals The sharing of a pair of valence electrons by two atoms the shared electrons count as part of each atom s valence shell Can form between atoms of the same element or atoms of different elements An atom s attraction for the electrons in a covalent bond The more electronegative an atom the more strongly it pulls shared electrons toward itself Polar and nonpolar bonds Nonpolar covalent bond atoms share the electrons equally Polar covalent bond one atom is more electronegative and the atoms do not share the electron equally Unequal sharing of electrons causes a partial positive or negative charge for each atom or molecule Bonds where one atom strips the electrons from its bonding partner results in both Mass Atomic Isotopes Atomic Mass or Element s Chemical behavior of an Radioactive Isotopes Electronegativity Potential Energy Electron Orbital Covalent Bonds Energy level Ionic Bonds Energy atom atoms having a charge Attraction between Cation and Anion Compounds formed by ionic bonds are called ionic compounds or salts A charged atom Cations are positively charged and anions are negatively charged Ionic and hydrogen are both weak chemical bonds they reinforce shapes of large molecules and help molecules adhere to each other form when a hydrogen atom covalently bonded to one electronegative atom is also attracted to another electronegative atom In living cells the electronegative partners are usually oxygen or nitrogen atoms Attractions between molecules that
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