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Biology. The study of Life. Scientific Method. Observation Question Hypothesis- educated guess that can be tested Experiment-needs to be controlled only manipulating one variable Record and analyze-be accurate and use graphs - PowerPoint PPT Presentation
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THE STUDY OF LIFEBiology
Scientific Method Observation Question Hypothesis- educated guess that can be
tested Experiment-needs to be controlled only
manipulating one variable Record and analyze-be accurate and use
graphs Conclusion-you gain evidence to support
hypothesis or disprove hypothesis
Biology “study of life” Where did life come from?
A mixture of logic and magicBiosphere
○ The part of the earth in which organisms live○ Land, water, and air
Aristotle (300 BC) and etherSpontaneous Generation
Spontaneous Generation
“Recipes”Bees Dead Bull in ShedFlies Rotting MeatMiceDiscarded RagesGeese Mudding River BanksSalamanders Wood & Fire
Francesco Redi’s Experiment 1668 in Italy Used cloth cover jars that would not
allow maggots to get to meat Proved flies don’t come from rotting
meat After hundreds of years of debate,
biogenesis theory replaced spontaneous generation ideas
Biogenesis- “life comes from life”
Five Properties of Life1. Organization2. Energy (metabolism)3. Growth & Development4. Reproduction5. Response & Adaptation
OrganizationAtoms
MoleculesCellsTissueOrgansOrgan system Individual PopulationCommunitiesEcosystem
BIOCHEMISTRY
Matter, Mass, and Weight
1. Matter: An object occupies space and has mass.
2. Mass: The quantity of matter an object has.
3. Weight: The pull of gravity on an object’s total mass.
Atomic Theory All elements are composed of tiny, indivisible
particles that we call atoms. Atoms of the same element are identical while
atoms of different elements are different. Atoms can combine together in whole number
ratios. Atoms can be rearranged into different chemical
compounds by chemical reactions. Atoms of one element can NOT be changed into
atoms of different elements.
Atoms
Atom: The smallest unit into which an element can be divided and retain its characteristic properties.
One unit of an element.
Elements
Element:A substance composed only of atoms of the same atomic number.
One of more than 100 distinct types of matter that, singly or in combination, compose all materials of the universe.
Atoms: Basic structure
Made up of:
Protons (+)Neutrons
( )(Nucleus)Electrons (-)Electrically Neutral
if…Protons = Electrons
Atomic Number, Symbol, Mass
Atomic Number: The number of protons found in an atom.
Symbol: The abbreviation for an element.
Atomic Mass: Weight of an atom; approx. the sum of its protons
and neutrons.
Periodic Table of the Elements
Beryllium
Atomic Number: 4Symbol: BeNameAtomic Mass:
9.0112
4
BeBeryllium
9.0112
.
Periodic Table of the Elements
4
BeBeryllium
9.0112
Be94
Mass = Protons + Neutrons
What’s wrong with this picture?
Elements are arranged:Vertically into Groups
Horizontally Into Periods
If you looked at one atom of every element in a group you would see…
The group 2 atoms all have 2 electrons in their outer shells
Be (Beryllium) Atom
Mg (Magnesium) Atom
The number of outer or “valence” electrons in an atom effects the way an atom bonds.
The way an atom bonds determines many properties of the element.
This is why elements within a group usually have similar properties.
If you looked at an atom from each element in a period
you would see…
Each atom has the same number of electron holding shells.
An example…
The period 4 atoms each have 4 electron containing shells
K (Potassium) Atom Fe (Iron)
Atom
Kr (Krypton) Atom
4th Shell
Isotopes
1. Neutrons do not equal protons.2. More neutrons than protons.3. Unstable nucleus.4. Radioactive Isotope: Isotopes that give off
energy because neutrons peel off their unstable nucleus.
Ions
Protons do not equal electrons.
More protons than electrons = a positive charge.
More electrons than protons = a negative charge.
Na+
Compounds
Definition: Two or more elements in definite
proportions that are joined together by a chemical bond.
Two Types of Bonds:○ Ionic○ Covalent
Ionic Bonds Why do they form?
Octet Rule (Rule of Eight):Atoms tend to establish completely full outer energy levels. (K fills with 2, L and M generally fill with 8.)
Ionic Bonds: an example
Chlorine has 17 electrons.Orbital K takes the first 2.Orbital L takes the next 8.Orbital M takes 7.
Sodium has 11 electrons.Orbital K takes the first 2.Orbital L takes the next 8.Orbital M takes 1.
Ionic Bonds: an example
Chlorine needs one more electron to fill its outer shell with 8 electrons. (Octet Rule)
If sodium gives up one electron it will have eight in its outer level.
Ionic Bonds: an exampleChlorine:17 protons18 electronsWhat’s its charge?-1 (negative ion)Sodium:11 protons10 electronsWhat’s its charge?
+1 (positive ion)
What do you think happens next?
Ionic Bonds: opposites attract
The sodium atom and the chloride atoms are attracted toward one another because of their opposite electrical charges.
The combination makes sodium-chloride,
abbreviated NaCl,commonly known as salt.
Ionic Bonds Definition:
An attraction between ions of opposite charge.
These bonds are relatively weak and will easily dissolve in water.
Covalent Bonds Definition:
A chemical bond formed by the sharing of one or more pairs of electrons.
These bonds can be very strong. Most of the structures in the body are
made using these types of bonds.
Molecules
Definition:A group of elements held together by covalent bonds.
Example:WaterTwo hydrogens and one oxygen share two pairs of electrons.
Covalent Bonds, cont.
Why do hydrogen and oxygen want to share?
Answer:Each wants to fill its outer shell with electrons.
Hydrogen fills with 2.Oxygen fills with 8.
Covalent BondsMany types of covalent bonds
Single covalent:shares one pair.
Double covalent:share two pairs.
Triple covalent:share three pairs.
Chemical Reactions Equation:
A formula that describes what happens during a chemical reaction.
H2
+ O2
H2O + O• Balanced Equation:
The elements on the left side of the equation are the same as those on the right.Notice! States of matter (liquid, solid,
gas) may change during a reaction.
Chemical Reactions: Terms
Activation Energy (Energy of Activation):The energy needed to make a reaction occur.
• Reactant- The chemicals before reaction
• Product- The chemicals after reaction
BIOLOGY
WATER,ACIDS, AND BASES
Water
The Cradle of Life:1. The Universal Solvent.2. The Polarity of Water.
Solutions
Solution:A homogeneous mixture of the molecules of two or more
substances.
Ex. Water and glucose mixture.
Solvent
Solvent: Medium in which a substance is dissolved (water).
Water is known as the universal solventbecause most of the chemical reactionsnecessary for life take place in water (i.e.water is the solvent).
Solutes
Solutes: A compound dissolved in some solution.
Ex. The glucose in the waterglucose mixture.
Polarity
For example:
In a water molecule, one oxygen atom shares electrons with two hydrogen atoms.
Do they share equally?
Polarity, cont.
Oxygen and Hydrogen do not share electrons equally.
Oxygen is more electronegative (it attracts electrons more heavily) than hydrogen.
Polarity, cont.
The result is that the electrons shared by oxygen and hydrogen actually spend more of their time nearer the oxygen atom. This gives the oxygen a slightly negative charge and leaves hydrogen with a slightly positive charge.
+-
Note: The charges are only partial. (i.e. not as large as a full proton or electron would be.
The Polarity of Water
1. Water bonds (hydrogen bonds) to itself.
2. Water bonds to other molecules.3. Water will group non-polar molecules.4. Water is a powerful solvent.
Hydrogen Bonds1. The positive or negative end of water will be
attracted to other polar molecules.2. Weak bonds3. Usually last only 1/100,000,000,000 sec.,
but their cumulative effect can be great.
Water Clings
Cohesion: Water attracted to water.
Adhesion: Water attracted to other polar molecules.
Capillary Action – water will “climb” by adhering to a surfaces electrical charges.
Adhesion
Hydrophobic: Water-fearingWater tends to form hydrogen bonds. When it mixes with non-polar molecules, it tends to shun them and instead cling to other water molecules.
Hydrophilic: Water-loving.Polar compounds will form hydrogen bonds with water. This breaks ionic bonds, dissolving the compound.
WATER
It’s reactions…
Acids and Bases
pH
1. A measure of the relative concentration of hydrogen ions in a solution.
2. Values range from 0 to 14.3. Less than 7 is an acid.4. More than 7 is a base.
Acids
1. A substance that causes an increase in the concentration of H+ ions.
2. Tastes sour.3. Tingles the skin.
Bases
1. A substance that causes a decrease in the relative concentration of H+ ions.
2. Also called alkaline.3. Tastes bitter.4. Sometimes slippery or slick feeling.
Chemical Reactions
Catalyst-substance that speed up chemical reaction
Enzyme-is a protein that acts as a biological catalyst
Elements important for life. Oxygen (65% of body by weight) Carbon (18%) Hydrogen (10%) Nitrogen (3%)
(N.O.C.H.)
Elements in Human Body
Oxygen (65%) Carbon (18%) Hydrogen (10%) Nitrogen (3%) Calcium (2%) Phosphorus
(1%)
Other 1% Potassium Silicon Aluminum Iron Sodium Chlorine more...
Organic Compounds
1. Pertaining to living things.
2. The chemistry of compounds containing carbon.
Building Macromolecules Monomer-smaller unit of large
compounds Polymers-monomer that join together to
form macromolecules
Organic Compounds or Macromolecules
4 Types of Organic Compounds:1. Carbohydrates2. Lipids3. Proteins4. Nucleic Acids.
Carbohydrates
Three types:1. Monosaccharides2. Disaccharides3. Polysaccharides
Monosaccharides
One sugar molecule.
Carbon Backbone: Carbon atoms line up near the center of the molecule and other atoms attach to them.
Formula for Simple Sugars: C6H12O6
Monosaccharides
Three basic types:1. Glucose (general sugar)2. Fructose (fruits)3. Galactose (milk)
Isomer: Alternative forms of a molecule that
have the same formula.
Polysaccharides
Many monosaccharides bonded together.(Storage sugars.)
Three types:1. Starches (plants – potato!).2. Cellulose (structure – plant cell walls).3. Glycogen (animal storage).
Functions of Carbohydrates
1. Energy source (glucose).2. Long-term energy storage (starch,
glycogen).3. Structure (cellulose).
Organic Compounds
4 Types of Organic Compounds:1. Carbohydrates2. Lipids3. Proteins4. Nucleic Acids.
Lipids
Five types:1. Fats2. Oils3. Waxes4. Phospholipids5. Steroids
Lipids
Functions: Long-term energy storage (fats, oils). Insulation (fat). Protection (waxes waterproof or keep in
water). Cell membrane structure (phospholipids). Control of body functions (steroids).
Organic Compounds
4 Types of Organic Compounds:1. Carbohydrates2. Lipids3. Proteins4. Nucleic Acids.
Proteins
Types:1. Amino acids.2. Dipeptides.3. Polypeptides.
Proteins
Amino Acids: Building blocks for all proteins. 20 total. Link together to form “peptide” bonds.
Proteins
Functions: Movement Structure Regulation (catalysts, enzymes) Transport Nutrition Defense
Proteins(catalysts and enzymes)
Catalyst:Substances used in small amounts which speed up chemical reactions without themselves being affected by the reaction.
Enzyme:Proteins that function as catalysts.(overhead)
Organic Compounds
4 Types of Organic Compounds: Carbohydrates Lipids Proteins Nucleic Acids.
Nucleic Acids
Types: DNA (deoxyribonucleic acid)
RNA (ribonucleic acid)
Functions of Nucleic Acids
Information storage (DNA)
Information transfer (RNA carries genetic information from DNA to ribosomes)