Chapter 2

Chemistry in Chemistry in BiologyBiology

Elements in the Human Elements in the Human BodyBody(CHON 96%)(CHON 96%)

We’ve got chemistry…We’ve got chemistry…(which is the study of (which is the study of matter)matter)

The The atomatom is the basic unit of is the basic unit of matter.matter.

(building block of matter)(building block of matter) Atoms consist of Atoms consist of subatomicsubatomic

particlesparticles

Protons (+ charge)Protons (+ charge)

Neutrons ( no charge)Neutrons ( no charge)

Electrons (- charge)Electrons (- charge)

Protons & neutronsProtons & neutrons are found in are found in the nucleus.the nucleus.

Electrons Electrons orbitorbit the the nucleusnucleus.. Protons & neutrons have about Protons & neutrons have about

the same the same massmass, and electrons , and electrons are much less (are much less (1/18401/1840 the mass the mass of p & n)of p & n)

Using the Periodic Table Using the Periodic Table to calculate:to calculate:

Protons = atomic numberProtons = atomic number Electrons = atomic number (neutral atom, Electrons = atomic number (neutral atom,

not in an ion)not in an ion) Remember Protons are positive and Remember Protons are positive and

Electrons are negative so they are equal!Electrons are negative so they are equal! Neutrons = atomic MASS – atomic Neutrons = atomic MASS – atomic

numbernumber

ELEMENT: pure substance, ELEMENT: pure substance, consisting of only 1 type of consisting of only 1 type of atom.atom.

COMPOUND: substance COMPOUND: substance formed from the chemical formed from the chemical combination of 2 or more combination of 2 or more elements inelements in

definite proportions.definite proportions.

HH22O - water contains H and O - water contains H and O in a definite proportion O in a definite proportion (2 to 1) This is the (2 to 1) This is the formula for water.formula for water.

What is the formula for What is the formula for table salt?table salt?

Examples of Compounds:Examples of Compounds:

IsotopesIsotopes

atoms of the same atoms of the same element with different element with different numbers of numbers of neutronsneutrons

Brainpop Brainpop video:http://glencoe.mcgraw-hill.com/sites/dl/free/0078695104/164155/00038306.html

Isotopes of CarbonIsotopes of Carbon

Carbon-12 Carbon-13 Carbon-14

Radioactive Isotopes

When a nucleus breaks apart, it gives off radiation that can be detected and used for many applications.

Chemical BondsChemical Bonds

Involve valence Involve valence (outermost) electrons.(outermost) electrons.

There are 2 types.There are 2 types.

1) Ionic Bonds1) Ionic Bonds

Involves a Involves a transfertransfer of electrons. of electrons. Produces Produces ionsions ( (charged atoms charged atoms

that have gained or lost that have gained or lost electrons)electrons)

MetalMetal + + NonmetalNonmetal

2) Covalent Bonds2) Covalent Bonds

Electrons are Electrons are sharedshared between between atoms.atoms.

Smallest unit of this type of Smallest unit of this type of compound is called a compound is called a moleculemolecule..

NonmetalNonmetal + + NonmetalNonmetal or or diatomic molecules have this diatomic molecules have this type of bond.type of bond.

Chemical Reactions Chemical reaction - process by

which atoms or groups of atoms in substances are reorganized into different substances.

Clues that a chemical reaction has taken place: 1) heat or light

2) see bubbles 3) something new

Chemical Equations Chemical formulas describe the

substances in the reaction and arrows indicate the process of change.

Reactants are the starting substances, on the left side of the arrow.

Products are the substances formed during the reaction, on the right side of the arrow.

Glucose and oxygen react to form carbon dioxide and water.

Energy of Reactions

The activation energy is the minimum amount of energy needed for reactants to form products in a chemical reaction.

What is an enzyme?What is an enzyme?

An enzyme is a special type of protein called a catalyst

Catalyst: substance that speeds up a reaction because it lowers the activation energy

Cells use enzymes to speed up reactions Very specific: usually only catalyzes one

item called the SUBSTRATE

How do enzymes work?How do enzymes work?

Enzyme comes in contact with substrate at certain spot called ACTIVE SITE

Fits together like a “lock & key” Bonding at active site weakens the bonds in the

substrate

Makes it easier to change substrate

What are enzymes used for? What are enzymes used for? What regulates them? What regulates them?

Used for digestion, photosynthesis, & DNA reproduction

Regulated by changes in pH, temperature, other proteins, and chemicals

Enzyme Lab!Enzyme Lab!

Warm up - Warm up -

Make a Venn Diagram for Ionic and Make a Venn Diagram for Ionic and Covalent Bonds.Covalent Bonds.

Copy the following: 1) What is this Copy the following: 1) What is this called? Label the reactant(s) and the called? Label the reactant(s) and the product(s)product(s)

HH22OO22 2H 2H22O + OO + O22

Water is soooo Water is soooo special!special!

Most abundant compound in Most abundant compound in living thingsliving things..

LiquidLiquid at temperatures found at temperatures found over much of earth.over much of earth.

ExpandsExpands when freezes, which when freezes, which causes causes density less than liquid density less than liquid water. (unusual for a liquid)water. (unusual for a liquid)

What is polarity???What is polarity??? Polarity is the Polarity is the

uneven uneven distribution of distribution of electrons electrons between atoms in between atoms in a covalent bond.a covalent bond.

In water, the In water, the oxygenoxygen is slightly is slightly negativenegative because because the electrons are the electrons are attracted more to attracted more to it than Hydrogen.it than Hydrogen.

The hydrogen The hydrogen atoms in atoms in water have a water have a slight slight positivepositive charge charge because they because they are missing are missing the the electronselectrons attracted attracted more to more to oxygen.oxygen.

Because of polarity, the water Because of polarity, the water molecules molecules attractattract each other. each other. This is called This is called cohesioncohesion..

Water is also Water is also attractedattracted to to molecules of molecules of differentdifferent substances. This is called substances. This is called adhesionadhesion..

Example of Example of adhesion: adhesion: water on the water on the sides of a sides of a graduated graduated cylinder.cylinder.

Capillary Capillary actionaction is is caused by caused by this.this.

Water Lab!!!!Water Lab!!!!

Warm up Warm up Enzymes p. 159Enzymes p. 159

1.1. What is the function of an enzyme?What is the function of an enzyme?

2.2. What type of organic compounds are What type of organic compounds are enzymes?enzymes?

3.3. What substance takes part in an What substance takes part in an enzymatic reaction, but is enzymatic reaction, but is unchangedunchanged by the reaction?by the reaction?

4.4. Draw Figure 6.18 and label it. (p. 160)Draw Figure 6.18 and label it. (p. 160)

MixturesMixtures Two or more elements or Two or more elements or

compounds that are compounds that are physically mixed physically mixed together, but not together, but not chemically combined. chemically combined. They can be separated They can be separated Physically!Physically!

Solutions vs. Solutions vs. Suspensions Suspensions

Can be made with Can be made with waterwater…the …the universaluniversal solvent. solvent.

Solution = Solution = solvent + solutesolvent + solute solution = solution = homogeneous homogeneous

mixturemixture

Water can dissolve Water can dissolve ionic ionic compoundscompounds and other and other polarpolar moleculesmolecules…it is …it is known as the greatest known as the greatest solventsolvent on earth! on earth!

Universal solvent!Universal solvent!

Water and non-Water and non-dissolved material dissolved material with small particles with small particles that are suspended that are suspended in the water.in the water.

SuspensionSuspension

Acids & BasesAcids & Bases

pH scale: pH scale: indicates the indicates the concentration of H+ ions in a concentration of H+ ions in a solution.solution.

Below 7 = Below 7 = acid,acid, the the lowerlower the number, the the number, the moremore acidic. acidic.

Above 7 = Above 7 = BaseBase, the , the higherhigher the the moremore basic basic

BuffersBuffers

Weak acid/bases that Weak acid/bases that can react with strong can react with strong acids or bases to acids or bases to prevent sharp sudden prevent sharp sudden changes in pH.changes in pH.

Carbon Carbon CompoundsCompounds

C6

carbon12.011

What is organic What is organic chemistry?chemistry? The study of all compounds containing the element CARBONNatural elements: make up 96% of the mass of a human: CARBON, HYDROGEN, OXYGEN, NITROGEN (CHON)

Trace elements: only needed in small amounts, called “minerals”:

What is a What is a macromolecule?macromolecule?

A giant molecule made up of 100’s or 1000’s of smaller units called MONOMERS

Monomers link together to form large POLYMERS

formed by polymerization

The types of The types of macromolecules:macromolecules:

CARBOHYDRATES

LIPIDS

NUCLEIC ACIDS

PROTEINS

CarbohydratesCarbohydrates Made of Carbon, Hydrogen Made of Carbon, Hydrogen

& Oxygen atoms& Oxygen atoms Main source of energy for Main source of energy for

living thingsliving things Plants & some animals use Plants & some animals use

for structural purposesfor structural purposes Examples: monosaccharide, Examples: monosaccharide,

disaccharide, disaccharide, polysaccharide (sugars & polysaccharide (sugars & starches)starches)

Simple sugars are monosaccharide.Simple sugars are monosaccharide. Two monosaccharides join together to Two monosaccharides join together to

form a disaccharideform a disaccharide Longer carbohydrate molecules are Longer carbohydrate molecules are

called polysaccharides (starches).called polysaccharides (starches).

Starch

Glucose

Section 2-3

Figure 2-13 A Starch

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Lipids (Fats, Oils & Waxes)Lipids (Fats, Oils & Waxes)

Made mostly from carbon & hydrogenMade mostly from carbon & hydrogen Used to store energy & waterproof Used to store energy & waterproof

coveringscoverings Olive oil, peanut oilOlive oil, peanut oil

A triglyceride is a fat if it is solid at room A triglyceride is a fat if it is solid at room temperature and an oil if it is liquid at temperature and an oil if it is liquid at room temperature.room temperature.

Nucleic AcidsNucleic Acids Made of hydrogen, oxygen, Made of hydrogen, oxygen,

nitrogen, carbon, & nitrogen, carbon, & phosphorusphosphorus

Made of monomers called Made of monomers called nucleotidesnucleotides

Nucleotides consist of Nucleotides consist of 1) a 5 carbon sugar1) a 5 carbon sugar 2) a phosphate group2) a phosphate group 3) a nitrogenous base3) a nitrogenous baseStore and transmit genetic Store and transmit genetic

information.information.

ProteinsProteins Made of nitrogen, carbon, Made of nitrogen, carbon,

hydrogen, & oxygenhydrogen, & oxygen Polymers of amino acidsPolymers of amino acids Some control the rate of Some control the rate of

reactions and regulate reactions and regulate cell processescell processes

Some used to form bones Some used to form bones & muscles& muscles

Others transport Others transport substances into or out of substances into or out of cells or help fight diseasecells or help fight disease