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144 Cards in this Set
- Front
- Back
The Goal of Science
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investigate and understand the natural world, to explain events in the natural world, and to use those explanations to make useful predictions.
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Science
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organized way of using evidence to learn about the natural world; also, the body of knowledge that scientists have built up after years of using this process
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Observation
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use of one or more of the senses—sight, hearing, touch, smell, and sometimes taste—to gather information
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Hypothesis
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possible explanation for a set of observations or possible answer to a scientific question
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Controlled Experiment
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a test of the effect of a single variable by changing it while keeping all other variables the same
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Theory
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well-tested explanation that unifies a broad range of observations
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Characteristics of Living Things
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made up of cells; reproduce; based on universal genetic code; grow and develop; obtain and use material and energy; respond to environment; stable internal environment; change over time as a group
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Metabolism
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set of chemical reactions through which an organism builds up or breaks down materials as it carries out its life processes
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Stimulus
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a signal to which an organism responds
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Homeostasis
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process by which organisms maintain a relatively stable internal environment
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Evolution
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change in a kind of organism over time; process by which modern organisms have descended from ancient organisms
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Levels of Organization
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Molecules, cells, group of cells, organisms, population, community, ecosystem, biosphere
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Atom
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basic unit of matter
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Isotope
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atom of an element that has a number of neutrons different from that of other atoms of the same element; Because they have the same number of electrons, all isotopes of an element have the same chemical properties
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Ionic Bond
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bond formed when one or more electrons are transferred from one atom to another
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Ion
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atom that has a positive or negative charge
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Covalent Bond
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bond formed by the sharing of electrons between atoms
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Molecule
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smallest unit of most compounds
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van der Waals forces
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a slight attraction that develops between the oppositely charged regions of nearby molecules
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Why water is polar
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A water molecule is polar because there is an uneven distribution of electrons between the oxygen and hydrogen atoms
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Cohesion
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attraction between molecules of the same substance
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Adhesion
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attraction between molecules of different substances; in plants, attraction between unlike molecules
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Capillary Action
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one of the forces that draw water out of the roots of a plant and up into its stems and leaves
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pH scale
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measurement system used to indicate the concentration of hydrogen ions (H+) in solution; ranges from 0 to 14
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Acidic Solutions
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contain higher concentrations of H+ ions than pure water and have pH values below 7
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Acid
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compound that forms hydrogen ions (H+) in solution
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Base
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compound that produces hydroxide ions (OH+) in solution
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Basic Solutions
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alkaline, solutions contain lower concentrations of H+ ions than pure water and have pH values above 7
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Buffer
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weak acid or base that can react with strong acids or bases to help prevent sharp, sudden changes in pH
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Four groups of organic compounds found in living things
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carbohydrates, lipids, nucleic acids, and proteins
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Carbohydrate
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compound made up of carbon, hydrogen, and oxygen atoms; major source of energy for the human body
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monosaccharide
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single sugar molecule
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polysaccharide
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large macromolecule formed from monosaccharides
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Lipids
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macromolecule made mainly from carbon and hydrogen atoms; includes fats, oils, and waxes
can be used to store energy |
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Building block of lipids
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fatty acids
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Nucleic Acid
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macromolecule containing hydrogen, oxygen, nitrogen, carbon, and phosphorus
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Nucleotide
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monomer of nucleic acids made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base
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ribonucleic acid (RNA)
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single-stranded nucleic acid that contains the sugar ribose
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deoxyribonucleic acid (DNA)
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nucleic acid that contains the sugar deoxyribose
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Protein
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macromolecule that contains carbon, hydrogen, oxygen, and nitrogen; needed by the body for growth and repair and to make up enzymes
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Amino Acid
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compound with an amino group (−NH2) on one end and a carboxyl group (−COOH) on the other end, building blocks of protein
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Chemical Reactions
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always involve the breaking of bonds in reactants and the formation of new bonds in products.
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Energy in Reactions
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Chemical reactions that release energy often occur spontaneously. Chemical reactions that absorb energy will not occur without a source of energy.
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Activation Energy
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energy needed to get a reaction started
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Catalyst
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substance that speeds up the rate of a chemical reaction
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enzyme
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protein that acts as a biological catalyst
speed up chemical reactions that take place in cells |
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Substrate
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reactant of an enzyme-catalyzed reaction
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Cell Theory
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idea that all living things are composed of cells, cells are the basic units of structure and function in living things, and new cells are produced from existing cells
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electron microscopes
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capable of revealing details as much as 1000 times smaller than those visible in light microscopes because the wavelengths of electrons are much shorter than those of light
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Transmission electron microscopes (TEMs)
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make it possible to explore cell structures and large protein molecules.
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scanning electron microscopes (SEMs)
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pencillike beam of electrons is scanned over the surface of a specimen produces stunning three-dimensional images of cells
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scanning probe microscopes
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produce images by tracing the surfaces of samples with a fine probe
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Cytoplasm
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material inside the cell membrane—not including the nucleus
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Nuclear Envelope
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layer of two membranes that surrounds the nucleus of a cell
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Chromatin
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granular material visible within the nucleus; consists of DNA tightly coiled around proteins
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Chromosome
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threadlike structure within the nucleus containing the genetic information that is passed from one generation of cells to the next
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Ribsome
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small particle in the cell on which proteins are assembled; made of RNA and protein
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Endoplasmic Reticulum
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internal membrane system in cells in which lipid components of the cell membrane are assembled and some proteins are modified
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Golgi Apparatus
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stack of membranes in the cell that modifies, sorts, and packages proteins from the endoplasmic reticulum
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Lysosome
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cell organelle filled with enzymes needed to break down certain materials in the cell
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Vacuole
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cell organelle that stores materials such as water, salts, proteins, and carbohydrates
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Mitochondria
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cell organelle that converts the chemical energy stored in food into compounds that are more convenient for the cell to use
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Chloroplasts
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organelle found in cells of plants and some other organisms that captures the energy from sunlight and converts it into chemical energy
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Cytoskeleton
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network of protein filaments within some cells that helps the cell maintain its shape and is involved in many forms of cell movement
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Centrioles
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one of two tiny structures located in the cytoplasm of animal cells near the nuclear envelope
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Lipid Bilayer
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double-layered sheet that forms the core of nearly all cell membranes
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Diffusion
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process by which molecules tend to move from an area where they are more concentrated to an area where they are less concentrated
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Equillibrium
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when the concentration of a solute is the same throughout a solution
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Osmosis
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diffusion of water through a selectively permeable membrane
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Isotonic
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when the concentration of two solutions is the same
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Hypertonic
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when comparing two solutions, the solution with the greater concentration of solutes
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Hypotonic
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when comparing two solutions, the solution with the lesser concentration of solutes
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Facilitated Diffusion
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movement of specific molecules across cell membranes through protein channels
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Active Transport
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energy-requiring process that moves material across a cell membrane against a concentration difference
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endocytosis
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process by which a cell takes material into the cell by infolding of the cell membrane
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phagocytosis
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process in which extensions of cytoplasm surround and engulf large particles and take them into the cell
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pinocytosis
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process by which a cell takes in liquid from the surrounding environment
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exocytosis
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process by which a cell releases large amounts of material
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Cell Specialization
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the process in which cells develop in different ways to perform different tasks
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Tissue
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group of similar cells that perform a particular function
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Organ
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group of tissues that work together to perform closely related functions
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Organ System
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group of organs that work together to perform a specific function
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Autotrophs
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organism that can capture energy from sunlight or chemicals and use it to produce its own food from inorganic compounds; also called a producer
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Heterotrophs
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organism that obtains energy from the foods it consumes; also called a consumer
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adenosine triphosphate (ATP) |
one of the principal chemical compounds that living things use to store and release energy; Energy is released when the bonds that hold the phosphate groups together are broken
Provides immediate energy for the cell. The removal of a phosphate group from ATP produces adenosine diphosphate or ADP |
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Photosynthesis
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process by which plants and some other organisms use light energy to convert water and carbon dioxide into oxygen and high-energy carbohydrates such as sugars and starches
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Helmont, Priestley, and Ingenhousz Experiments
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discovered that in the presence of light, plants transform carbon dioxide and water into carbohydrates, and they also release oxygen
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Photosynthesis Chemical Equation
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Carbon dioxide + water -glucose + oxygen + energy
or 6CO2 + 6H2O C6H12O6 + 6O2 |
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Pigment
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light-absorbing molecule
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chlorophyll
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principal pigment of plants and other photosynthetic organisms; captures light energy
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Thylakoid
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saclike photosynthetic membrane found in chloroplasts
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Photosystems
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light-collecting units of the chloroplast; located in thylakoid membrane
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Stroma
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region outside the thylakoid membranes in chloroplasts, where the Calvin Cycle takes place
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NADP+ (nicotinamide adenine dinucleotide phosphate)
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one of the carrier molecules that transfers high-energy electrons from chlorophyll to other molecules
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Light-Dependent Reactions
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produce oxygen gas and convert ADP and NADP+ into the energy carriers ATP and NADPH; takes place in the thylakoid membrane
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ATP synthase
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large protein that uses energy from H+ ions to bind ADP and a phosphate group together to produce ATP
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Calvin Cycle
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reactions of photosynthesis in which energy from ATP and NADPH is used to build high-energy compounds such as sugars; takes place in the stroma
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Factors Affecting Photosynthesis
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amount of water, temperature, and light intensity
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Calorie
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amount of energy needed to raise the temperature of 1 gram of water 1 degree Celsius
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Glycolysis
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first step in releasing the energy of glucose, in which a molecule of glucose is broken into two molecules of pyruvic acid
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Cellular Respiration
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process that releases energy by breaking down glucose and other food molecules in the presence of oxygen
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NAD+ (nicotinamide adenine dinucleotide)
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electron carrier involved in glycolysis
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Fermentation
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process by which cells release energy in the absence of oxygen
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Anaerobic
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process that does not require oxygen
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2 Types of Fermentaion
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Alcoholic Fermentation and Lactic Acid Fermentation
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Aerobic
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process that requires oxygen
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Krebs Cycle
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second stage of cellular respiration, in which pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions
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Electron Chain Transport
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a series of proteins in which the high-energy electrons from the Krebs cycle are used to convert ADP into ATP
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Chromatid
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one of two identical “sister” parts of a duplicated chromosome
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Centromere
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area where the chromatids of a chromosome are attached
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Interphase
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period of the cell cycle between cell divisions
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Cell Cycle
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series of events that cells go through as they grow and divide
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Prophase
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first and longest phase of mitosis, during which the chromosomes become visible and the centrioles separate and take up positions on the opposite sides of the nucleus
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Spindle
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fanlike microtubule structure that helps separate the chromosomes during mitosis
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Metaphase
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second phase of mitosis, during which the chromosomes line up across the center of the cell
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Anaphase
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the third phase of mitosis, during which the chromosome pairs separate and move toward opposite poles
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Telophase
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fourth and final phase of mitosis, during which the chromosomes begin to disperse into a tangle of dense material
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Cyclin
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one of a family of closely related proteins that regulate the cell cycle in eukaryotic cells
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Cancer
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disorder in which some of the body's own cells lose the ability to control growth
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Homologous
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term used to refer to chromosomes that each have a corresponding chromosome from the opposite-sex parent
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Meiosis
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process by which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell
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Diploid
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term used to refer to a cell that contains both sets of homologous chromosomes
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Haploid
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term used to refer to a cell that contains only a single set of chromosomes and therefore only a single set of genes
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Transformation
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process in which one strain of bacteria is changed by a gene or genes from another strain of bacteria
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bacteriophage
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virus that infects bacteria
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Base Pairing
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principle that bonds in DNA can form only between adenine and thymine and between guanine and cytosine
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Atomic Number
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Number of protons/electrons
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Atomic Mass
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Protons + Neutrons
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Hydrogen Bonds
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Between oxygen and hydrogen or oxugen and nitrogen
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Phospholipids
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one of the fatty acid is replaced with phosphate which causes it to have a polar head in the
phospholipids bilayer |
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Richard Hooke
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called the cells of a slice of cord "cells" because they reminded him of tiny rooms
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Melvin Calvin
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Discovered the Kelvin Cycle
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The four nitrogenous bases in DNA
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Adenine Thymine Guanine Cytosine
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The four nitrogenous bases in RNA
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Adenine, Guanine, Cytosine, Uracil
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The Hydrogen Bonds of DNA
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A--T; G---C
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DNA polymerase
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enzyme involved in DNA replication that joins individual nucleotides to produce a DNA molecule
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NADPH
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electron carrier in photosynthesis
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carotenoids
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• The pigments that produce yellow and orange fall leaf colors, as well as the colors of many fruits, vegetables, and flowers
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Totals
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Glycolysis: 4 ATP (net gain 2)
Cellualar Resp. : 36 ATP, 18 each turn of the cycle |
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Equation for Lactic Acid Fermentation
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pyruvic acid + NADH ➝ lactic acid + NAD+
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Equation for Alchoholic Fermentation
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pyruvic acid + NADH ➝ alcohol + CO2 + NAD+.
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acetyl-CoA
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made from two carbon atoms from pyruvic acid are joined to a compound called coenzyme A; starts the Krebs cycle
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Electron acceptors in Cellular Resp.
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NAD+ and FAD
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electron carriers in Cellular Resp.
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NADH and FADH2
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