Transcript Chapter 2

Chapter 2
The Chemistry of Life
What We are Learning Today
Section 1: The Nature of Matter
Review atoms and element structure
Identify the different ways chemicals bond
Define Key Terms
Atoms
• The smallest unit of matter that cannot be
broken down by chemical means
– Very small and always changing
• 3 particles make up an atom
– Electrons (-)
– Protons (+)
– Neutrons (neutral)
Attract each
other…
*Therefore atom
itself has no
charge (negative
electron cancels
out positive
proton)
Atomic Structure
• Electron Cloud
made of electrons,
which have (-)
charge so Electron
Cloud = (-)
• Nucleus made up
of protons and
neutrons, protons
have (+) charge and
neutrons have
neutral (no) charge
so nucleus has a (+)
charge
Elements
• An element is a pure substance made of only one
kind of atom
– Represented by chemical symbols (C, N, H)
– Elements differ in the # of protons (C=6, O=8)
• Equal to the atomic number
– Number of protons usually = number neutrons
• Are exceptions…
Differences in Elements
• Atomic Number all atoms of a
particular element have the same number of
protons which is called the atomic number.
– Ex: Helium = 2
b/c it has 2 protons
Chemical Bonding
• Atoms can join together to form a stable substance
– The force that joins atoms together is called a chemical
bond
• A compound is a mixture of the atoms of 2+ different
elements joined together in a chemical bond
• 3 Types
– Covalent
– Hydrogen
– Ionic
Covalent bond
• When 2+ atoms share electrons to form a
molecule.
• Arrangement of electrons determine how atoms
bond together
– Electron levels
• Closest to nucleus = 2 electrons
• Second level = 8 electrons…
– Atom becomes stable when the outer electron level is full
– If it is not full it will react with atoms that can provide the
electrons needed.
Energy Levels
Carbon Energy Levels
Carbon = 6 electrons
3
4
2
1
6
5
Atomic # = number of protons = # electrons
A Water Molecule has a POLAR Covalent Bond
• Water is made of
Hydrogen and
Oxygen
• Hydrogen =H
– 1 electron in its
outer most level
• Oxygen =O
– 6 electrons in its
outer most level
They react to fill
each ones outer
most level
22 2
3
1
6
4
5
Hydrogen bonds
• Electrons in a water
molecule are shared by
oxygen and hydrogen atoms
– Electrons more strongly
attracted to the oxygen
nucleus than by the
hydrogen’s
– This unequal distribution of
electrical charge are called
polar molecules
Which pole
attracts which
pole?
Polar Molecule
(Water)
Ionic Bonding
• Sometimes atoms or molecules gain or loose
and electron
– “Ion”
– Electric charge b/c they contain an unequal
number of electrons and protons
Gaining/Losing an Electron
• Gaining Makes the atom more negative
– Adds a (-) charge onto the atom… electrons are (-)
• Losing Makes the atom more positive
– Adds a (+) charge onto the atom… negative charges
were lost
Ionic Bond Example
Na LOST an
e- so it
became
more
positive
Cl GAINED
an e- so it
became
more
negative
Closure
• Do you remember anything about atoms?
– Make an atom of carbon using playdough
– Include the #
• protons,
• neutrons
• and electrons!
6
Carbon
What did we learn today?
• Word Association
– Come to the board and write down any word you remember from
today’s lesson!
QUIZ
• FRIDAY 
– quiz on Chapter 2 section 1 & 2
– Period 12 Quiz THURSDAY
Exit Ticket
• Draw a carbon atom (Atomic number = 6)
– Label all the parts and correctly show the
number of electrons in the right levels
• Write 3 things you learned today
• Begin 2.1 Section Review
– Page 30
– Questions 1-4
– Finish for HW
Chapter 2
Section 2: Water & Solutions
• Water in Living Things
– Storage of heat
– Cohesion/ adhesion
• Aqueous Solutions
– Polarity
– Acids and Bases
Chapter 2
Section 2
Water and Solutions
Notes
Water in Living Things
• 70% of your body is made of water
• Water helps move nutrients into and out of your
cells
• Certain properties of water make it such an
important substance for life
– Storage of heat
– Cohesion & Adhesion
Storage of Heat
• Water heats more slowly and retains heat
longer than many other substances
• Many organisms release heat through
water evaporation
– Sweating
• Helps maintain homeostasis
Cohesion &
Adhesion
• Cohesion
– Attraction between substances of the same kind
– Surface tension prevents water from breaking easily
– The hydrogen bonds between water molecules cause the
cohesion of liquid water
• Adhesion
– Attraction between substances of a different kind
• Substances get wet
• Capillary action water molecules move up through a
narrow tube (stem of plant)
• Because of these water can move up the stems of
leaves
Aqueous Solutions
• Many substances dissolve in water
• Solution: a mixture in which one or more substances are evenly
distributed in another substance
– Salt water
– Gatorade
• Because certain substances can dissolve in water they
can more easily move throughout the body
Polarity
• Enables many substances to dissolve in water
– When ionic compounds are dissolved in water,
• ions become surrounded by polar water molecules
• Ions and molecules become evenly distributed in the water
• Non polar molecules do not dissolve in water well (oils)
Acids and Bases
• Pure water always has a low concentration of hydrogen
ions (H+) and hydroxide ions (OH-)
– Compounds that form hydrogen ions when dissolved in water
are acids
– Compounds that reduce the concentration of hydrogen ions
in water are called bases
• lower the concentration of hydrogen ions because hydroxide ions
react with hydrogen ions to form water
(H+) + (OH-)  WATER
pH Scale
SECTION REVIEW QUESTIONS
• Chapter 2.2 Section Review Questions!
On your note sheets…
• Write at least 1 example of a
– Carbohydrate
– Lipid (fats)
– Protein
– Nucleic acid
– What do you think they all have in common?
Question #1
Which of the following is NOT an organic
molecule?
Carbohydrate
Ice
Lipid
Nucleic Acid
Question #2
Write down 3 types of carbohydrates
AND
give examples of each
(how many sugars in each)
Monosaccharide- 1 sugar
Disaccharide – 2 sugar
Polysaccharide- 3 sugar (starch, cellulose,
glycogen)
Index Card #3
• Are lipids polar or non polar?
– Non polar
• Do they dissolve in water?
– no
• Give 3 examples of Lipids
– Steroids, fats, waxes
Card#4
• What are the building blocks of proteins?
– Amino Acids
• Give 2 examples of proteins and where they are
located in the body.
– Keratin- hair
– Hemoglobin- blood
Card 5
What is a fatty acid and which bio-molecule
does it belong to?
it is a lipid attached to a glycerol backbone
It is a lipid
Card 6
Give 2 examples of carbohydrates produced
by plants
starch, cellulose
Give 1 example of carbohydrates
produced by animals.
glycogen
Card 7
• What are three characteristics of saturated
fats?
– Solid at room temp
– Made from animal fats
– Straight chain
Card 8
What are 3 characteristics of unsaturated
fats
liquids at room temperature
from plants
structure is kinked because of the
double carbon bond
Card 9
• What are 2 examples of nucleic acids?
– DNA and RNA
10
• What is the function of nucleic acids?
11
• What is the function of lipids?
12
• Which type of fat has a kink in the
structure?
13
• All organic compounds contain what
element?
2.3 Chemistry of Cells
• Most matter in your body that isn’t water
IS an organic molecule
– Organic = Carbon based
• 4 classes of organic molecules in your
body (can’t function w/o them)
Structure
– Carbohydrates
Where its found
– Lipids
Examples
– Proteins
Function
– Nucleic Acids
Other
Carbohydrates
Structure
Where its found
Examples
Function
Other
• Organic molecules made of carbon, hydrogen and
oxygen
• Major source of energy for the body
• Found in most foods (fruits, veggies, grain) in the
form of sugars
– 3 types of sugars
• Monosaccharide (simple sugars; glucose & fructose)
• Disaccharide (double sugars; sucrose)
• Polysaccharide (3+monosaccharides; starch, glycogen)
Examples of Sugars (Carbs)
• Polysaccharides
storehouses for energy
• starch, glycogen, cellulose
– Starch – made by plants
– Glycogen- made by
animals
• Both made from linked
glucose molecules (pg 34)
– Cellulose- made by
plants (for structure)
Structure
Where its found
Examples
Function
Other
Lipids
•
•
•
•
Non-polar molecules… soluble or non-soluble?
Fats, phospholipids, steroids and waxes
Steroids (cholesterol, estrogen, testosterone)
Important for structure and function of
cell membranes
– Found in animal cell membranes & pigments
• Lipids store energy
Structure
Where its found
Examples
Function
Other
Write this in OTHER!
Structure
Where its found
Examples
Function
Other
Structure of Lipids
• 3 fatty acids bonded to a glycerol molecule
backbone
– Fatty acid is long chain of carbon atoms with
hydrogen bonded to them
• Strong bonds between carbon and hydrogen
 can store lots of energy
Structure
Where its found
Examples
Function
Other
Saturated and Unsaturated
Saturated
Unsaturated
• All carbons have single • Some carbons linked by
bonds to hydrogen
a double covalent bond
– Causes kinks in chain
• Most animal fats
• Plant oils, olive oil, fish
– Butter, lard, grease
oils
• Usually solids at room
temperature
• Liquids at room
temperature
Structure
Where its found
Examples
Function
Other
Unsaturated Fats
Vocabulary!
• Complete Chapter 2.3 Vocabulary!
– HW if not finished!
What did we talk about yesterday?
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What is the name of compounds that contain carbon?
What are the 3 types of carbohydrate “sugars?”
What organism makes cellulose?
What organism makes glycogen?
Are lipids polar or non-polar?
What are some examples of lipids?
What is the difference between saturated and unsaturated
fats?
Proteins
• Structure:
Structure
Where its found
Examples
Function
Other
– Large molecules formed by linked smaller molecules
called amino acids (AA)
• Function:
– AA are building blocks of proteins
• Only 20 AA
– Cause various shapes of proteins
– Some proteins are enzymes (help chemical reactions)
– Others used for structure
• Skin, ligaments, bone (Collagen)
• Hair & nails (keratin)
• Blood (hemoglobin)
Nucleic Acids
• Where Found
– All cells contain nucleic acids
• Structure
Structure
Where its found
Examples
Function
Other
Long chain of smaller molecules ( called nucleotides)
– 3 parts
• Sugar
• Base
• Phosphate group (P& O)
• Function:
– Store genetic info
• Examples:
– 2 types of nuclei acids
• DNA- deoxyribonucleic acid
• RNA- ribonucleic acid
Chapter 2.4
Energy & Chemical Reactions
• Energy
– ability to move or change matter
• Many forms
– light, heat, chemical energy, mechanical energy, electrical energy
• Can be stored or released
– by chemical reactions (build/break bonds)
• Metabolism all of the chemical reactions that occur
within an organism
Enzymes and Activation Energy
• Activation energy
– amount of energy needed to start a
reaction
– Can take a long time for reaction to occur
• Heat the substance? NO!
• Add a catalyst!! YES
– ENZYMES!
» Lower the amount of energy needed to start
the reaction without changing the original
reactants
Enzymes
• Shape specific
• Enzyme holds the reactant
• Fits like puzzle piece
– Active site
• Each enzyme has its own specific substrate
(reactant)
• pH, Temperature, environment can affect
Section Review Questions
• 2.4 pg42
– #1-4 Write the Questions & Answer
• Complete 2.3 Directed Reading
Worksheet
• Finish 2.4 Vocabulary Terms
• Complete 2.4 Directed Reading Sheet