Biology, Week 1 Notes
Biology, Week 1 Notes Biology 101
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This 5 page Class Notes was uploaded by Bailey Wilhoit on Thursday September 8, 2016. The Class Notes belongs to Biology 101 at University of South Carolina - Columbia taught by Dr. Czako in Fall 2016. Since its upload, it has received 42 views. For similar materials see Biological Principles I in Science at University of South Carolina - Columbia.
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Date Created: 09/08/16
Biology Lecture Notes Chapter 1, Week 1 1.1 Themes of Biology ● Life is recognized by what living things do and characteristics of cells ○ Characteristics of all Living things: ■ Order complex organized structure based on Carbon ■ Reproduction passing down traits ■ Growth and Development ■ Energy Processingtake in materials from environment and convert them to other things ■ Regulation maintain homeostasis (internal temperature, blood pressure, etc) ■ Response to environment ■ Evolutionary adaptations surviving change ● Cell Theory: all living things are composed of cells, and all existing cells came from preexisting cells ● Organization ○ Levels of Organization (From biggest to smallest) ■ Biosphere Earth ■ Ecosystems all living/nonliving things in a particular area ● Ex: arctic tundra, desert, deciduous forest ■ Communities organisms inhabiting a particular ecosystem ● Ex: in a forest, all the types of trees and animals form communities ● Each form of life is known as a different species ■ Populations all individuals of a particular species ● Ex: all of the deer living in a particular forest ■ Organisms each individual living thing is called an organism ■ Organs and Organ Systems each organ in an organism has a function, and makes up a larger organ system to help the organism survive ● Ex: lungs in an animal are an organ. Lungs, combined with the trachea, capillaries, bronchi, etc make up the Respiratory system that allow the animal to breathe. ■ Tissues group of cells that work together to perform a specific function ● Ex: The skin tissue of the epidermis allow for waterproofing of the entire body ■ Cells performs all the functions of life; building blocks of life ■ Organelles functional components of cells ● Ex: mitochondria ■ Moleculeschemical structure of two or more atoms ● Information ● Energy and Matter ● Interactions ● Evolution Emergent Properties ● Result from arrangement and interaction of parts in an ecosystem Reductionism: ● Breaking down complex systems into simpler parts that are easier to understand and study Structure and Function: ● The lowest level of organization that can perform activities necessary for life is the cell ● Cells are enclosed in a membrane that allows materials to pass through from the environment ○ Two types of cells: ■ Prokaryotic: simple, no nucleus ■ Eukaryotic: complex, nucleus, organelles Expression and Transmission of Genetic Information ● Cells contain chromosomes that contain genetic material (DNA) ● Genes encode information for building molecules ● DNA controls development and maintenance of organism ○ Two long strands in a double helix ● Each chain of DNA is made up of 4 kinds of chemical building blocks (called nucleotides A, G, T, C) ● DNA is transcribed into RNA that is then turned into protein ● Gene expression: converting information from gene to cellular product ● Genes are units of inheritance Genomics: large scale analysis of DNA sequence ● An organism’s genome is it’s entire set of genetic instructions ● Genomics is the study of certain sets of genomes within species ● Proteomics is the study of whole sets of genome proteins Life requires Transfer and Transformation of Energy and Matter ● Energy from the sun and its transformation make all life possible ● When organisms use energy to perform work, some of it is lost as heat ● Energy usually enter ecosystem as light and leaves as heat Interactions are Important ● Organisms interact continuously with environment and the environment is thereby affected by these interactions ● Molecules ○ Interactions between lower level organization groups are crucial for smooth operations ○ Cells coordinate various chemical pathways through a mechanism called feedback ■ In feedback regulation the product of the process regulates the process ● Most commonly, it is negative the product reduces the initial stimuli ● Positive feedback: end product speeds up its own production ○ Ex: blood clotting. When platelets begin clotting to heal a wound, the positive feedback calls for increased production of platelets Evolution (Core theme of Biology) ● Scientific explanation for unity and diversity ● Grouping Species ○ Taxonomy: names and classifies species into groups ○ Three Domains of Life ■ Archaea (prokaryotes) ■ Bacteria (prokaryotes) ■ Eukarya (eukaryotes) ● Three molecular kingdoms ○ Plants autotrophic (produce their own food) ○ Fungi absorb nutrients ○ Animals ingest food ● Charles Darwin and Natural Selection ○ Two main points: ■ Species show evidence of “descendants with modification” ■ “Natural Selection” ○ On the Galapagos Darwin observed: ■ Individuals in a population can have many traits, many inheritable ■ More offspring are produced than survive, which shows competition for resources ■ Over time the organisms with undesirable traits will die out because they don't reproduce or they are easily preyed upon ■ Eventually the dominant trait will become the only trait ○ Darwin proposed that Natural Selection can produce multiple descendant species from one ancestral species Scientists make observations and form hypothesis ● Inquiry: search for information or explanations of natural phenomena ● Inductive reasoning: repeating specific observations that lead to generalizations ● Deductive reasoning: uses general premises to make predictions ● Hypotheses must be testable and falsifiable ● Theory: broader in scope that hypothesis; general; can lead to new hypotheses; supported by large body of evidence Biology Lecture and Textbook Notes Chapter 2, Week 1 Matter Consists of Chemical Elements and in Combination called Compounds ● Matter: anything that has mass and takes up space ● Element: substance that cannot be broken down ○ About 2025% of 92 elements are essential to life ○ Carbon, Nitrogen, Oxygen, and hydrogen compose 96% of all living matter ○ Trace elements are elements required for life in minute quantities (Iodine) ● Compound: substance that can be broken down into simpler materials Element’s Properties Depend on Its Atomic Structure ● Atoms are the smallest unit of matter ● Subatomic particles ○ Electrons (negative charge) ○ Protons (positive charge) ○ Neutrons (no charge) ● Protons and neutrons account for an element’s atomic mass and their masses are almost identical ● Electrons form a cloud around the nucleus (called the electron cloud) ● Atomic number= number of protons ● Mass number= protons + neutrons ● Atomic mass= atom’s total mass Isotopes ● Atoms that have the same element but different numbers of neutrons ● Radioactive isotopes decay, giving off energy ○ Used as diagnostic tools in medicine ● Radioactive dating ○ “Parent” isotope decays to “daughter” at a fixed rate (half life) ○ Scientists measure how many half lives pass Energy Levels of Electrons ● Energy is the capacity to change ● Potential energy: energy an object has based on location and structure ○ Electrons state of potential energy mostly determined by electrons in electron shell ● Valence electrons are in the outermost shell ○ These are what determine the behavior of the atom ● Orbitals are spaces where electrons are found Formation and Function of Molecules Depend on Chemical Bonding ● Atoms with incomplete valence shells can share electrons with other atoms ● These interactions usually lead to chemical bonds ● When atoms share valence electrons it is called a covalent bond ● A molecule is two or more atoms held by covalent bonds ○ Single bond: sharing of one pair of valence electrons ○ Double bond: sharing of two pairs of valence electrons ○ Structural formula: ○ Molecular formulas: 2 ○ Valence is also known as bonding capacity ● Electronegativity is the atom’s attraction for electrons in covalent bonds ○ The more electronegative an atom is, the more force is has to pull electrons closer ● Nonpolar covalent bonds are when atoms share electrons equally ● Polar covalent bonds are when when atom is more electronegative, therefore they share the electrons unequally ● Ionic Bonds ○ Ions are atoms that gain/lose electrons, and are therefore charged ○ Cations are positively charged and anions are negatively charged ○ Ionic bonds are electrostatic attractions between anions and cations ○ Compounds formed by ionic bonds are called ionic compounds or salts ● Weak Chemical Bonds ○ Easily reversible ○ Hydrogen bonds (when hydrogen atom covalently bonded to an electronegative atom is also attracted to another electronegative atom) ○ Van der Waals interactions: attractions between molecules that are close together because of charge ○ Coordinate bonds: both electrons come from same atom ○ Hydrophilic: water loving ○ Hydrophobic: water fearing ● Molecular Shape and Function ○ Shape is determined by positions of atoms in orbitals and is important to function ○ Determines how biological molecules specifically recognize and respond to one another Chemical Reactions Make and Break Chemical Bonds ● Reactants are the starting molecules of reactions ● Products are the ending molecules ● All chemical reactions are reversible ● Chemical equilibrium: reached when forward and reverse reactions occur simultaneously
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