Chapters 1 and 2

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Chapters 1 and 2 The Science of Biology and the
Chemistry of Life
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I. What is Science?

1. The Goal of Science to investigate and
   understand nature, to explain events in nature,
   and to use those explanations to make predictions

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• Science is
• 1. Uncertain
• a. Evidence is NOT proof
• b. From evidence, we form a
  hypothesis (possible
  explanation/answer)
• 2. Always changing
• a. Scientific ideas are not absolute
  fact
• b. From new evidence we can change
  or reject original hypothesis

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• 3. Collaborative
• a. Scientific ideas are open to
  interpretation
• b. As a result, scientists work
  together to share and review their
  research

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II. The Scientific Method

• Observe and Question
• - focus on things that can be tested
• Form a hypothesis
• - educated guess based upon observations

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• Design an Experiment
• 1. Variable factor that can influence the
  outcome of the experiment
• 2. Controlled experiment tests the effect
  of a single variable by changing it while
  keeping all other variables the same
• some investigations called field
  studies examine organisms in their
  natural environmentas a result, it is
  virtually impossible to control all
  variables

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• Collect Data
• Conclusion
• 1. Was the hypothesis correct?
• 2. What can you conclude?
• Theory vs. Law
• 1. Theory a hypothesis that has been
  tested supported by a great amount of
  evidence over a long period of time
• 2. Law statement describing (but not
  explaining) a natural event or phenomenon

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III. Studying Life

• Characteristics of Living Things
• 1. Made up of one or more cells
• a. Cell smallest unit of life
• b. Unicellular 1 celled organism
• c. Multicellular many celled organism

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• 2. Reproduction
• a. Asexual 1 parent
• b. Sexual 2 parents
• 3. Based on a Genetic Code
• - DNA determines the inherited traits of
  almost every living organism on Earth

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• 4. Growth and Development
• a. Growth change in size
• b. Development change in form
• 5. Need for materials and energy
• a. Metabolism building up or breaking
  down materials to carry out life
  processes
• b. Source of energy for
  most life on Earth SUN

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• - plants use sun to make energy autotrophs
  (auto self, troph feeder)
• - animals must eat organisms to gain energy
  heterotrophs (hetero other)

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• 6. Response to environment
• a. Environment is constantly changing
• b. Stimulus causes response
• 7. Maintain internal balance
• - homeostasis process by which organisms
  keep their internal conditions stable

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• 8. Adaptation to change
• a. When the environment changes,
  organisms have 3 choices
• 1. Adaptation inherited trait that
  helps organisms survive in a particular
  environment
• 2. Migration move to another area
• 3. Extinction die out

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• b. Evolution slow, gradual change in a
  species over time

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• Organization Levels smallest to largest
• 1. Molecule
• 2. Cell
• 3. Tissue group of cells that perform a
  specific function
• 4. Organ ex. heart,
  lung, liver

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• 5. Organ system ex. respiratory,
  circulatory, nervous
• 6. Organism individual living thing
• 7. Population group of one species in an
  area

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• 8. Community all populations in an area
• 9. Ecosystem community nonliving factors
• 10. Biome
• 11. Biosphere all biomes on Earth

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IV. Tools Procedures in Science

• Metric system
• 1. Length meters
• 2. Mass grams
• 3. Volume liters
• 4. Temperature ºC
• Tables and Graphs
• - used to analyze data

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• Microscopes instruments which use lenses to
  produce an enlarged, focused image of a specimen
• - Types of microscopes
• a. Light microscope
• 1. Uses beams of light passing
  through lenses to magnify an object
• 2. Can magnify objects about 1000
  times
• 3. Stain used to increase contrast

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• b. Electron microscope
• 1. Uses a beam of electrons focused by
  magnetic lenses
• 2. Advantages
• - greater magnification (up to 100
  times greater)
• 3. Disadvantages
• - no color
• - cannot study living organisms

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Picture of a radiolarian using an electron
microscope
Electron Microscope
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• 4. Types
• a. Transmission electron microscope
  (TEM)
• - used to study thin slices
• b. Scanning electron microscope (SEM)
• - used to study surface of a specimen

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• Laboratory Techniques
• 1. Cell cultures
• - used to grow large amounts of a single
  type of cell
• 2. Cell fractionation
• - used to separate cell parts
• 3. Electrophoresis
• - molecules are separated according to
  shape, size, or electrical charge

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• 4. Chromatography
• - used to separate components of a liquid
  or gas mixture

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V. The Nature of Matter

• Atom the basic unit of matter

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• Element substance that consists entirely of one
  type of atom
• 1. Represented by a chemical symbol
  (example C Carbon, H Hydrogen)
• 2. Most common elements in living things
  C, H, N, O, P, S
• Compound 2 or more elements linked in definite
  proportions

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VI. pH Scale

• Used to measure concentration of Hydrogen ions
  (H)
• 1. More H than water acid (pH 1-6)
• 2. Less H than water base (pH 8-14)
• 3. Equal H to water neutral (pH 7)

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• pH Scale
• acids get stronger as numbers get smaller
• bases get stronger as numbers get bigger

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• Each number on the scale is a factor of 10
• example
• pH 5 is 10 times more acidic than pH 6
• pH 4 is 100 times more acidic than pH 6
• pH 3 is 1000 times more acidic than pH 6

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VII. Carbon Compounds

• 4 major groups of organic compounds
• 1. Carbohydrates
• 2. Lipids
• 3. Nucleic acids
• 4. Proteins

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• Carbohydrates
• 1. Main source of energy for living things,
  some structural purposes
• 2. Monosaccharides (1 sugar unit)
• - examples glucose, fructose
• 3. Disaccharides (2 sugar units)
• - examples sucrose (table sugar)
• lactose (milk sugar)
• maltose (malt sugar)

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• 4. Polysaccharides (many sugar units)
• -examples
• a. Glycogen stored in muscles and
  liver of animals
• b. Starch stored in plants
• c. Cellulose plant cell walls
• d. Chitin exoskeletons of arthropods

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• Lipids
• Fats used for energy storage and insulation

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• Phospholipids make up cell membranes

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• Steroids cholesterol, vitamin D, some hormones
• Waxes used for waterproofing (leaves, fruit,
  bird feathers)

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• Nucleic acids 2 kinds
• Deoxyribonucleic acid (DNA)
• - stores hereditary info
• - codes for instructions on how to
  make proteins
• Ribonucleic acid (RNA)
• - carries out protein making instructions in
  DNA

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• Proteins
• 1. Made up of amino acids
• 2. Functions of proteins
• a. Structural make up fibers of bones,
  muscles, tendons, ligaments, cartilage,
  hair, horns, skin, feathers
• b. Movement enable muscles to
  contract

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• c. Transport hemoglobin carries oxygen
• d. Storage casein in milk stores amino acids
• e. Defense antibodies fight foreign cells
• f. Regulation many hormones are proteins
• - ex insulin
• g. Biochemical control enzymes are proteins

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VIII. Enzymes

1. Catalyst a substance that speeds up the rate of
   a chemical reaction by lowering the activation
   energy (energy needed to start a reaction)
2. Enzyme protein that acts as a catalyst
3. Substrate molecule upon which an enzyme acts

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• How do enzymes work?
• - Lock and Key Hypothesis
• 1. Enzyme attaches to substrate at a place
  called an active site
• 2. Enzymes are specific they speed up only
  1 kind of reaction (only 1 kind of key fits a
  lock)
• 3. Enzyme-substrate complex causes bonds to
  be broken (or formed)
• 4. Once the reaction is complete, products
  are released and enzyme moves on to another
  substrate

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