Opening Assignment

• What are the 4 main elements that make up 95% of the human body?

• Draw an atom of Carbon including the protons, neutrons, and electron shells. (Hint: Carbon has an atomic number of 6)

Opening Assignment

• What are the 4 main elements that make up 95% of the human body?

• Draw an atom of Carbon including the protons, neutrons, and electron shells. (Hint: Carbon has an atomic number of 6)

Anatomy and Physiology Honors Chapter 2 The Chemical Basis of Life

By Mrs. Shaw

Resources Hole’s Essentials of Anatomy and Physiology 9th Edition

Learning Goals for Lessons 2.1 and 2.2

Students will be able to:– Explain how the study of living things depends on the

study of chemistry.– Discuss how atomic structure determines how atoms

interact.– Describe the relationship between atoms and molecules.– Explain how molecular and structural formulas symbolize

the composition of compounds.– Describe the three types of chemical reactions.– Define pH.

Chemistry is . . . .

• Chemistry is the branch of science that considers the composition of matter and how this composition changes.

• This is essential to the study of anatomy and physiology because body structures and functions result from chemical changes within cells.

What’s the Matter?

• Matter is anything that has mass and takes up space.

• This includes all the solids, liquids, and gases in our surroundings and in our bodies.

Elements

• ELEMENT – single type of atom. As of 2010 there are 118 known elements (98 occur naturally on Earth)

Living organisms require about 20 elements. Oxygen, Carbon, Hydrogen, and Nitrogen make up more than 95% of the human body.

Atoms• ATOM-the smallest complete unit of elements

that maintain the characteristics of that element.

– Nucleus- The center of the atom, contains protons and neutrons

– Electron Cloud –Region surrounding the nucleus containing the electrons

The NucleusProton-A positively charged sub-atomic particle

(+). Atomic Mass = 1 amuThe number of protons is the same as the atomic

number

Li3

7 The atomic massThe atomic mass

The Atomic Symbol

The Nucleus

Neutrons –A sub-atomic particle in the nucleus--Has a mass equal to 1 atomic mass unit

--Neutron do not have a charge (0)To calculate the number of neutrons in an element…

Li3

7

The atomic number

The atomic massThe atomic mass

The atomic mass- The atomic number The number of neutrons

Li3

7

The atomic number

The atomic massThe atomic mass

7 (Atomic Mass)- 3 protons(Atomic #) 4 neutrons

WRITING RESPONSE

How many protons does Mg have?

How many neutrons does Mg Have?

WRITING RESPONSE

How many protons does Mg have?12

How many neutrons does Mg Have? 12

The Electron Cloud

• Electrons-• The number of electrons equals the number of protons• Sub-atomic particle with a negative charge (-)• Electrons behave as if in a 3-D orbit

• Valence Electrons– The outer most electrons– Valence electrons are responsible for bonding

WRITING RESPONSE

How many protons?

How many neutrons?

How many electrons?

WRITING RESPONSE

How many protons? 3

How many neutrons? 4

How many electrons? 3

Bohr Model• The first shell can have

2 electrons• The second shell can

have 8 electrons

Shells and the Electron Cloud

Let’s look at a few elements…

Hydrogen 1= Proton 1= electron

Let’s look at a few elements…

Helium 2=protons 2=neutrons2=electrons

Let’s look at a few elements…

Lithium 3=protons 4=neutrons3=electrons

Let’s look at a few elements…

Fluorine9=protons 10=neutrons

9=electrons

Let’s look at a few elements…

Argon18=protons 22=neutrons

18=electrons

IONSCharged particles that occur when an atom gains or loses an electron during chemical bonding.

• If the atom gains an electron- Negative charge• Ex: Cl-

• Most non-metals form negative Ions

• If the atom loses an electron- Positive Charge• Ex: Na+

• Most metals form Positive Ions

Losing an Electron = Positive ion Na+ has 11 protons but only 10 electrons

Gaining an Electron = Negative ion Cl- has 17 protons but has 18 electrons

Which shows a negative ion? Explain

Which shows a neutral atom? Explain

Which shows a positive atom? Explain

A

B

C

What would the charge be on an atom that lost an electron? Gained two electrons?

ISOTOPES

Atoms that have the same # of protons but have neutrons that have been added, resulting in a different atomic mass.

Electrons and bonding• Think about having two magnets. The closer they are to each

other the stronger the attraction is. There is a similar attraction between the negatively charged electrons and the positively charged nucleus.

• The outermost electrons (valence electrons) can be attracted to the nucleus of other atoms. This attraction is what causes a chemical bond.

Valence electrons 1

• The outer most electrons (valence electrons) are the only electrons involved in chemical bonding.

• Valence electrons have the most energy out of all the electrons in an atom.

• The number of valence electrons in each atom of an element can help determine the type and the number of bonds It can form.

Chemical bonding • Chemical bonding is the joining of atoms to

form new substances. A chemical bond is an interaction that holds two atoms together.

• Most atoms form bonds by gaining, losing, or sharing valence electrons until they fill their outer shell to become “happy” or stable.

Types of Chemical Bonds

• There are three types of chemical bonds we will discuss: ionic bonds, covalent bonds, and hydrogen bonds.

Covalent Bonds

• Covalent bonds happen when atoms share electrons.

• For example: Chlorine needs one electron to have a full outer shell so it can share 2 electrons with another Chlorine atom and become stable.

Covalent Bonds

• Another very important covalent bond is

Ionic Bonds

• Ionic bonds happen when electrons are transferred from one atom to another, causing the atom to become either positively charged or negatively charged.

• Na + Cl = Na Cl Table Salt

Ionic Bond

Losing an Electron = Positive ion Na+ has 11 protons but only 10 electrons

Gaining an Electron = Negative ion Cl- has 17 protons but has 18 electrons

This is the formation of a new substance through an Ionic Bond

Polarity and Hydrogen BondsDifferent types of chemical bonds share electrons to different degrees.

An ionic bond gains or loses electrons.

A covalent bond shares electrons.

A molecule formed when electrons are not shared equally. This results in the formation of a polar molecule hydrogen bond

Hydrogen Bonds

• The attraction of the positive hydrogen end of a polar molecule to the negative nitrogen or oxygen end of another polar molecule is called a hydrogen bond.

Hydrogen bonds• Hydrogen bonds are

important in protein and nucleic acid structure. In these cases, hydrogen bonds occur between polar regions within different parts of a single, very large molecule.

Molecules and Compounds

• When two or more atoms bond, they form a MOLECULE. They can be the same type of atom (Element)

• When atoms of two different types of elements bond, they form molecules called COMPOUNDS.

Formulas• A molecular formula presents the numbers

and types of atoms in a molecule.• Hydrogen Peroxide

• A structural formula shows the bonds that happen within a molecule

Elements, Compounds, and Mixtures

• http://www.bing.com/videos/search?q=mr%20lee%20elements%20compounds%20mixtures&qs=n&form=QBVR&pq=mr%20lee%20elements%20compounds%20mixtures&sc=0-28&sp=-1&sk=#view=detail&mid=20E281F99AE7071776D120E281F99AE7071776D1

Opening Assignment

1. Draw an atom of Nitrogen.2. How many bonds can an atom of Nitrogen

make?3. Differentiate from the 3 types of chemical

bonds: ionic, covalent, hydrogen.

Chemical Reactions

• Chemical reactions form or break bonds between atoms, ions, or molecules generating new chemical combinations.

Synthesis

• When two or more atoms bond to form a more complex structure the reaction is called synthesis. Synthesis requires energy!

Decomposition

• When the bonds within a molecule break so that simpler molecules, atoms or ions form, the reaction is called decomposition.

Exchange Reaction

• A third type of chemical reaction is an exchange reaction. In this reaction two different types of molecules trade positions.

Reversible Reactions

• Many chemical reactions are reversible. They are shown with a double arrow.

Carbonic Acid

Acids and Bases

• Some compounds release ions when they dissolve in water or react with water molecules.

• Since the resulting solution contains electrically charged particles it will conduct an electric current. Substances that release ions in water are called electrolytes.

Acids

• Acids are electrolytes that release hydrogen ions in water.

Bases• Electrolytes that release

ions that bond with hydrogen ions are called bases.

• For example sodium hydroxide releases hydroxide ions when placed in water. These hydroxide ions can bond with hydrogen ions to form water. This makes them a base.

ACIDS BASES

• All compounds can be classified in 2 broad categories:

• Organic compounds- Contain carbon and hydrogen atoms

• Inorganic compounds- Can have one or the other, but do not contain both carbon and hydrogen atoms

Organic Compounds• Most of your body’s molecules are organic

compounds.•

– Macromolecules are built from small organic compounds the same way a railroad train is built, by linking a lot of smaller units together into long chains.

•

Monomers and Polymers• Large carbon compounds are built up from smaller simpler

molecules called monomers (mono = one )• Monomers can bind to one another to form complex molecules

known as polymers (poly = many)• A polymer consists of repeated, linked units, which can also bind

forming large polymers called Macromolecules. (macro = large )

Dehydration Synthesis• Monomers link to form polymers through a chemical

reaction called condensation reaction or dehydration synthesis. During the formation of polymers, Water (H2O), is released or is by-product of the reaction.

Hydrolysis or DecompositionThe breakdown of some complex molecules, such as polymers, occurs through a process known as hydrolysis. (decomposition)

Hydrolysis is the reverse of a condensation reaction. The addition of water, to some polymers can break the bonds that hold them together

4 Main Macromolecules• There are four main types of macromolecules

found in living organisms: • Carbohydrates• Lipids • Proteins• Nucleic Acids

Carbohydrates– Carbohydrates

• Composed of carbon, hydrogen, and oxygen atoms in the proportion of 1 : 2 : 1

– General formula: (CH2O)n where n is the number of carbon atoms.

» Example: The sugar glucose is a small carbohydrate; its n equals 6. Therefore its chemical formula is C6H12O6.

• The building blocks (or monomers) of carbohydrates are monosaccharides.

Carbohydrates• Monosaccharides are simple sugars (saccharide = sugar). Examples:

– Glucose: commonly found in blood of animals– Galactose: a simple sugar found in milk – Fructose: commonly found in fruit

» Glucose and Fructose both have the formula C6H12O6, Sometimes compounds may have the same formula, however they have different structures/ arrangements. In such cases, those compounds are called isomers.

Carbohydrates• Disaccharides contain 2 monosaccharides joined by

dehydration synthesis. Examples: –Lactose: commonly found in milk, made up of

Galactose + Glucose–Sucrose: “table sugar”, transported in plants, made

up of Fructose + Glucose

Carbohydrates• Polysaccharides are carbohydrates formed from linking individual sugars into long chains. Examples:

– Starch: a common storage form of glucose in plants (breads, pasta, potatoes)

– Cellulose: a polysaccharide contained in the cell walls of plants; gives strength and rigidity to plant cells.

– Glycogen: a common storage form of glucose in animals (stored in the muscles and liver to be used as quick energy)

•

Lipids– Lipids (include fats, oils, waxes, etc.)

• Class of macromolecules that do not dissolve in water

• Lipids usually serve one of three functions: – Energy storage– structural support in cell membranes

(phospholipids)– serve as reactants ( starting materials) for

metabolic reactions

• Fatty acids are the building blocks (or monomers) that make up most lipids.

• Fatty acids are classified as either saturated or unsaturated.

Lipids– The classification depends on the proportion of hydrogen atoms

to carbon - carbon bonds in the molecule:– Saturated fatty acids have the maximum number of bonds

possible, they are full.» Saturated fats are usually solid at room temperature, and

most come from animal products.– Unsaturated fatty acids have double bond(s) in the carbon

chain and are not full.» Most unsaturated fats are liquid at room temperature, and

are usually referred to as oils.– Saturated animal fats are associated with circulatory disorders;

plant oils can be substituted for animal fats in the diet.

Lipids• A common lipid that contains fatty acids is a

triglyceride. Triglycerides (referred to as neutral fats) are glycerol linked to three fatty acids (in the shape of an “E”) by condensation reaction.

Proteins• Proteins are organic compounds composed mainly of

carbon, hydrogen, and nitrogen atoms.• Proteins are the construction materials for body

parts such as hair, skin, nails, and blood.

Proteins• Amino acids are the

building blocks (or monomers) that make up most proteins

– There are 20 different kinds of amino acids that humans use.

• One important group of proteins - enzymes - help control chemical reactions by acting as catalysts. Catalysts speed up reactions by lowering activation energy.

•

Nucleic Acids• Nucleic Acids are complex

organic molecules that store genetic information in the cell.

• Nucleotides are the building blocks (or monomers) that make up most nucleic acids.

–Nucleotides consist of a sugar (pentose) + base (nitrogenous) + phosphate.

•

Nucleic Acids• Three main types of nucleic acids

– DNA = Deoxyribonucleic acid» Is the genetic information inside the nucleus of cells

– RNA = Ribonucleic acid» Instructions which code for protein synthesis

– ATP = Adenosine triphosphate = has a slightly different structure than DNA and RNA. It contains a base + sugar + three phosphates

» ATP is used as energy for the cell

Macromolecules• http://

www.bing.com/videos/search?q=macromolecules+amoeba+sisters&FORM=VIRE1#view=detail&mid=28E79698F384F31B45C528E79698F384F31B45C5 (Amoeba Sisters – Review of Function)

• http://www.bing.com/videos/search?q=Macromolecules+Animation&FORM=RESTAB#view=detail&mid=3E26F3D92D4C97E606FB3E26F3D92D4C97E606FB (Review of structure)