Characteristics of Life & The Scientific Method Vocabulary 1) Biology = study of life 2) Cell = basic unit of structure and function of all living things 3) Science = A body of evidence-based knowledge gained through observation and experimentation related to the natural world and technology. 4) Homeostasis = the regulation of an organism’s internal environment to maintain conditions that allow it to live 5) Hypothesis = testable explanation; written in “ IF… THEN ” format 6) Theory = is an explanation based on many observations (hypothesis is repeatedly verified over time and through may separate experiments) 7) Principle (scientific) = A concept based on scientific laws and axioms (rules assumed to be present, true, and valid) where general agreement is present. 8) Law = describes relationships under certain conditions in nature; Describes but does not explain a natural event 9) Agriculture = The artificial cultivation of food, fiber, and other goods by the systematic growing and harvesting of various organisms. 10) Embryology = The branch of zoology studying the early development of living things. 11) System = A set of interacting or interdependent components, real or abstract, that form an integrated whole. An open system is able to interact with its environment. A closed system is isolated from its environment. 12) Mechanism (scientific) = The combination of components and processes that serve a common function. Classification Vocabulary: 1) Eukaryotic cells = have membrane-bound nucleus and organelles; usually more complex than prokaryotic cell 2) Prokaryotic cells = does NOT have a nucleus or other membrane-bound organelles 1 Chemistry of Life Vocabulary: 1) Atom = Smallest particle of an element that has the characteristics of that element 2) Nucleus = Center of atom; contains protons & neutrons 3) Molecule = a group of covalently bonded atoms with no charge 4) pH = how acidic or basic a substance is 5) Freezing Point = The temperature at which a liquid changes state to a solid. 6) Macromolecules = extremely large compounds made of smaller ones. 7) Carbohydrates = Compounds used for storage and release of energy ; Made of C, H, O atoms; Ratio is 2 Hydrogen atoms : 1 Oxygen atom 8) Lipids = Commonly called fats & oils; Contain more C-H bonds and less O atoms than carbohydrates; Basic building blocks: 3 fatty acids + 1 glycerol o Functions of lipids in our body: a) Long term energy storage (used when carbohydrates are NOT available) b) Insulation c) Protect body tissue (cushioning) 9) Proteins = Large complex polymer composed of C, H, O, N, & sometimes S; Basic building blocks: Amino acids o Functions of proteins in our body: 1. Muscle contraction 2. Transport oxygen in the bloodstream 3. Provide immunity (antibodies) 4. Carry out chemical reactions 46) Peptide bond = a covalent bond that joins amino acids to each other 47) Adhesion = The intermolecular attraction between unlike molecules. Capillary action results from the adhesive properties of water and the molecules that make up plant cells 48) Specific heat = The measure of the heat energy required to increase the temperature of a unit quantity of a substance by a certain temperature interval. 49) Temperature = A measure of the average kinetic energy (energy of motion) of particles in a sample of matter. This physical property can determine the rate and extent to which chemical reactions can occur within living systems. It is commonly measured in degrees Celsius or Fahrenheit. 50) Enzymes = A specialized type of protein ; acts like a catalyst = substance that speeds up the rate of a chemical reaction but it is not used up in the reaction. 51) Nucleic acids = Complex polymer that stores information in cells in the form of a code; Monomer: nucleotides, which consist of C, H, O, N, P • 2 types of nucleic acids: 2 1. DNA (deoxyribonucleic acid) contains all the instructions for an organisms development…..AKA genetic information 2. RNA (ribonucleic acid) forms a copy of DNA and is used for protein synthesis (production) Cell Vocabulary: 1) Tissue = a group of cells functioning together to perform and activity 2) Organs = groups of two or more tissues that function together 3) Eukaryotic cell = cells that contain a nucleus and other membrane-bound organelles 4) Prokaryotic cell = cells that lacks a nucleus and other membrane-bound organelles 5) Organelles = carries out specific functions in a cell 6) Nucleus = Control center of the cell 7) Ribosomes = produces proteins 8) Intracellular = Located inside a cell. 9) Golgi body = Temporary storage, secretion and packaging of proteins and fats 10) Mitochondria = Powerhouse of the cell (energy production →ATP) 11) Lysosomes = Contains digestive enzymes that break down molecules; ONLY in animal cells 12) Pumps (ion or molecular) = Any of several molecular mechanisms in which ions or molecules are transported across a cellular membrane requiring the use of an energy source (e.g., glucose, sodium [NA+], Calcium [CA+], and potassium [K+]). 13) Centrioles = Moves chromosomes during cell division; ONLY in animal cells 14) Cell wall = supports and protects; ONLY in plant cell; outside the plasma membrane 15) Chloroplast = site of photosynthesis; ONLY in plant cells 16) Passive Transport = movement of molecules across the membrane by using the molecules kinetic energy. The cell exerts NO energy! 17) Diffusion = the net movement of particles from an area of HIGHER concentration of particles to an area of LOWER concentration of particles. 18) Osmosis = the diffusion of water molecules from an area of HIGH water concentration to an area of LOW water concentration 19) Facilitated Diffusion = type of passive transport that increases the rate of diffusion with the use of carrier proteins 20) Active Transport = transport of materials against the concentration gradient and requires cellular energy 21) Endocytosis = type of active transport by which a cell surrounds and takes in material from its environment 22) Exocytosis = type of active transport that expels materials out of the cell, reverse of endocytosis 23) Homeostatic Mechanism = A regulatory mechanism that contributes to maintaining a state of equilibrium (e.g., thermoregulation, water regulation, and oxygen regulation) 24) Impermeable = Not permitting passage of a substance or substances. 3 Cellular Division & Mitosis Vocabulary: 1) Chromosomes = made of protein & a long, single, tightly coiled DNA molecule visible only when the cell divides 2) Interphase = longest part of a cell's life cycle; DNA is replicated, more cytoplasm and organelles are being made in preparation of diving Photosynthesis & Cellular Respiration Vocabulary: 1) ATP = (adenosine triphosphate); energy storing molecule 2) Photosynthesis = the process that provides energy for almost all life DNA & Protein Synthesis Vocabulary: 1) DNA = blueprint of life (has the instructions for making an organism) 2) Chromosome = coiled DNA 3) Gene = a segment of DNA that codes for a protein, which in turn codes for a trait (skin tone, eye color, etc); a gene is a stretch of DN 4) Semiconservative replication = parental strands of DNA separate, serve as a template, and produce DNA molecules that have one strand of parental DNA and one strand of new DNA. 5) Transcription = is the process through which DNA transfers the code to mRNA 6) Translation = is the process through which mRNA is decoded and forms a protein 7) Ribosomes = tiny organelles where proteins are assembled 8) Protein = a polymer made up of amino acids 4 Meiosis Vocabulary: 1) Gamete = sex cell 2) Crossing over = when nonsister chromatids of homologous chromosomes exchange genetic information, results in a new combination of gene 3) Meiosis = a two stage type of cell division that results in gametes with half the number of chromosome number as the body cells 4) Endosymbiosis = A theorized process in which eukaryotic cells were formed from simpler prokaryotes. Mendelian Genetics Vocabulary: 1) Genetics = study of heredity 2) Alleles = two forms of a gene (dominant & recessive) 3) Dominant = stronger of two genes expressed in the hybrid; represented by a capital letter (R) 4) Recessive = gene that shows up less often in a cross; represented by a lowercase letter (r) 5) Genotype = gene combination for a trait (ex: RR, Rr, rr) 6) Phenotype = the physical feature resulting from a genotype (e.g. tall, short) 7) Gene expression = The process in which a nucleotide sequence of a gene is used to make a functional product such as protein or RNA. 8) Sex-linked traits = traits that occur more frequently in one sex than the other because the genes are on the sex chromosomes 9) Allele Frequency = The measure of the relative frequency of an allele at a genetic locus in a population; expressed as a proportion or percentage. Patterns of Heredity Vocabulary: 5 1) Incomplete dominance = neither allele for a gene dominates ° Notation: • Alleles are all capital letters because NEITHER one dominates the other. So one of the alleles has a prime ( ‘ ) on it to represent an alternate expression of the gene. 2) Codominance = both alleles are expressed equally ° Notation: • 2 different alleles (capital letters) are used 3) Multiple alleles = more than 2 alleles for a single gene can control a trait; example = blood types 4) Polygenic inheritance = traits are determined by many genes 5) Sex-linked crosses = traits are carried on the sex chromosomes ° Notation: • The alleles for these traits are written as superscripts on the X chromosome ONLY. • No alleles are written on the Y chromosome!