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Published byCuthbert Gregory Modified over 9 years ago
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Safety review
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CHAPTER 1 THE SCIENCE OF LIFE
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Lets play a game… Am I alive? How can you tell?
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Characteristics of Life? Organization Response to stimuli Homeostasis metabolism Growth and Development Reproduction Change through time
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Organization High degree of order between internal and external parts Interactions with the living world Examples?
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Response to stimuli Ability to respond to changing environment
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Homeostasis ability to maintain a stable internal condition. No matter the changes in environment.
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Metabolism Use of energy to power life processes
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Growth and Development Growth? increase in amount of living material Development? process ending in adulhood Ie. Frog
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Reproduction Production of Offspring Coded information is passed on to the offspring Like Produces Like
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Change through time evolution
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Science as a process Scientific method Organized approach to learn how the natural world works
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Scientific method 1. Observation / question: 2. Hypothesis: tries to answer question; proposed explanation 3. Prediction: guesses what will happen 4. Experiment: tests hypothesis 5. Collect and analyze data 6. Supports or disputes hypothesis
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Scientific theory When a set of confirmed hypotheses is confirmed to be true many times Examples?
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Tools of the trade Microscopes 1. Compound light microscope Uses light through a specimen Electron microscpes use a stream of electrons to visualize a specimen 2. Scanning (SEM) electron microscope 3-D surface view 3. Transmission (TEM) electron microscope 2-D internal view
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Compound Light Microscope
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Scanning Electron Microscope SEM
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Transmission Electron Microscope TEM
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Light vs. Electron
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SEM or TEM SEM TEM TEMSEM
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SEM or TEM SEM TEM TEM SEM
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More SEM
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The Metric System Common Metric Units Length (meters)Mass (grams) 1 meter (m) = 100 centimeters (cm) 1 meter = 1000 millimeters (mm) 1000 meters = 1 kilometer 1 kilogram (kg) = 1000 grams (g) 1 gram = 1000 milligram (mg) 1000 kilograms = 1 metric ton (t) Volume (liters)Temperature (Celcius) 1 liter (L) = 1000 milliliters (mL) 1 liter = 1000 cubic centimeters (cm 3 ) 0 o Celsius (C) = freezing point of water 100 o C = boiling point of water System of measuremnt in science. Based on multiples of ten = easy conversion
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Ch 1 Vocab quiz next class 1. Biology 2. Compound light microscope 3. Electron microscope 4. Gene 5. Hypothesis 1. Metabolism 2. Metric system 3. Organization 4. Scientific method 5. Theory
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CH 2 CHEMISTRY OF LIFE
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Matter Everything is made of matter (?) Has mass and occupies space
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Elements and atoms Element: substances that cannot be broken down into simpler substances Atoms: smallest particle of an element that retains the properties of that element
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Atomic structure Nucleus makes up most of mass of an atom Consists of protons (positive) and neutrons (no charge) Number of protons = atomic number Number of protons + neutrons = mass number
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Atomic structure Electrons: negatively charged particles Balance out with positive charge of protons Very small mass Move around the nucleus in orbitals
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Isotopes Atoms of same element have equal number of protons but not necessarily neutrons Isotopes: atoms of the same element that have a different number of neutrons
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Compounds Made of atoms of two or more elements H 2 O CO 2 CH 4
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A Covalent Bond occurs when atoms share electrons Covalent Bonds
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Ionic Bonds Example: Sodium Chloride Oppositely charged atoms, attracted to each other Note: they do not share electrons
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Energy and Matter Energy: ability to do work Many types of energy Electrical Radiant (light) Thermal (heat) Chemical mechanical
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Chemical reactions One or more substances change to produce one or more different substances Reactants: on the left side of the equation
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Chemical reactions One or more substances change to produce one or more different substances Products: on the right side of equation
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Activation energy Energy needed to start a reaction Catalysts reduce activation energy Example: enzymes
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Water and solutions Properties of water are necessary for life Many of water’s functions come from it’s chemical structure Polarity: uneven distribution of charges Water is polar Polar nature allows water to dissolve polar substances
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Hydrogen bonding Polar nature allows water to be attracted to one another + region of one moleculue attracted to the – region on another
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Cohesion and adhesion Cohesion: attractive force between molecules of a single substance Water attracted to water Adhesion: attractive force between molecules of different substances Water attracted to other stuff
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Quick cohesion and adhesion lab HOW MANY DROPS OF WATER CAN I PUT ON LINCOLN’S HEAD? Get in lab groups. Send one member up to the front to get a penny and a cup Count the number of drops that you can put on the head of a penny
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Temperature moderation Water has a high heat capacity Water can absorb or release large amounts of energy with only a slight change in temperature This allows water to absorb heat during the summer to keep air cool w/o increasing the temp. And at night, water cools and warms the air
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Density Is ice more or less dense than water? Discuss with your partner and write your ideas down in your notes
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Solutions Solution: mixture of two or more substances Solute: substance that dissolves in a solvent Solvent: substance in which the solute is dissolved
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Acids and bases pH scale is used to measure acidity or alkalinity Scale from 0 14 0 6.9: acid 7 neutral (water) 7.1 14: base Buffers: chemical substances that neutralize small amounts of acids or base added to a solution They keep the pH from changing greatly
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