Biology Chapter 2 The Chemistry of Life. Draw an atom of carbon Agenda: Read Chapter 2 Lessons 2.1 and 2.2 and complete workbook pages 16- 20.

By Mrs. Shaw

Biology Chapter 2 The Chemistry of Life

Draw an atom of carbon

Agenda: Read Chapter 2 Lessons 2.1 and 2.2 and complete workbook pages 16-20

Opening Assignment Day 1

1. Draw an atom of Boron. It has an atomic # of 5 and an atomic mass of 10. Remember in a neutral atom the protons = electrons and you calculate the neutrons by subtracting the atomic number from the atomic mass.

1. Differentiate between an element and a compound.

Agenda: Finish reading lessons 2.1 and 2.2 and completing workbook pages 16-20

Opening Assignment Day 2

Opening Assignment Day 3

Copy this and fill in the blanks: ▪ An atom has a central area called a

________________where the positive ______________ and neutral _____________ are located. The electrons have a _______________ charge and are located in the ________________ _____________ which is outside the nucleus.

Chapter 2 Lesson 1 Learning Goals

Students will be able to Describe the structure of an atom

Differentiate between an element and a compound

Describe an isotope Explain how and why chemical elements bond.

MatterWHAT IS MATTER

Anything that has mass AND takes up space

Solids, Liquids, Gases, and Plasma

WHAT IS NOT MATTER

Types of energy: heat, light, sound, electrical and electromagnetic

Types of forces: gravitational and magnetic

Lesson 2.1: The Nature of Matter Review

Atoms Smallest unit of

matter that cannot be divided and still be the same element.

Each type of element has a different number of subatomic particles (protons, neutrons, and electrons)

Lesson 2.1 : The Nature of Matter

Review

Inside the Nucleus

Nucleus: center of the atom where majority of mass is.

Composed of protons (positively charged particles) and neutrons (neutral particles).

Where are the electrons?

Electrons are the negatively charged particles that reside in a cloud outside the nucleus of the cell.

VOCAB: ELECTRON CLOUD - It is a region surrounding the nucleus where one or more electrons are likely to be found

The Size of Atoms

An atom is the smallest building block of matter BUT….

An atom is made up of even smaller subatomic particles.

Protons and neutrons are about the same size and weigh 1 AMU.

Electrons are smaller and have only about 1/200 the mass of a proton or neutron.

Sooooo….you could fit 2,000 electrons into one proton!!!!

Properties of Atomic Particles…

Protons are positive, electrons are not. Neutrons have no charge so can’t be bought

DID YOU KNOW ????

If an atom were the size of a sports arena, its nucleus would be just the size of a pea.

If you compacted all the atoms in a person they would fit on the head of a needle.

Give this a try next time …

Differences in Atoms

Atomic Number- The number of protons in the nucleus of an atom of a element.

ALL ATOMS OF THE SAME ELEMENT HAVE THE SAME NUMBER OF PROTONS….

ALWAYS!!!!!!!

Every element on the periodic table

has a different atomic number thus, a different

amount of protons. Each time you add

an proton, you change the element.

Let’s practice together

Element name:

Element Symbol:

Atomic #:

Atomic Mass:

# Protons:

# Electrons:

#Neutrons:

To calculate the number of neutrons you subtract the # or protons from the Atomic Mass.

Now you try

)

1. What does the atomic number of an atom represent?

2. Copy the table and complete it:Atomic #

AtomicMassrounded

# P(+ charge)

#e(- charge)

# N(Atomic mass - #P = # of Neutrons)

F 9 19

Ar 18 40

Ti 22 48

N 7 14

Practice ANSWERS

)

1. What does the atomic number of an atom represent?

2. Complete the following table:Atomic #

AtomicMassrounded

# P(+ charge)

#e(- charge)

# N(Atomic mass - #P = # of Neutrons)

F 9 19 9 9 10

Ar 18 40 18 18 22

Ti 22 48 22 22 26

N 7 14 7 7 7

Substances

ELEMENTS

Made of a single type of atom.

All types of elements found so far are listed on the periodic table of elements.

COMPOUNDS

Made of TWO or more types of atoms (elements) chemically bonded.

Practice with types of substances: elements and compounds

Explain which of these are elements and which are compounds:

1. Hydrogen2. Water (H2O)3. Carbon4. Carbon Dioxide (CO2)

Practice with elements and compounds

Explain which of these are elements and which are compounds:

1. Hydrogen (H) ELEMENT2. Water (H2O) COMPOUND3. Carbon ( C) ELEMENT4. Carbon Dioxide (CO2) COMPOUND

What would O2 be???

Neutrons and Isotopes

Neutrons have no charge and help hold the nucleus together.

Isotopes are atoms that have extra neutrons in the nucleus.

Because neutrons have no charge adding neutrons does NOT change the charge of the atom. However, it does change the atomic mass.

Isotope…The fat atom is dope!!!!!

Radioactive Isotopes

Most isotopes are stable, however some are radioactive A

radioactive isotope is one in which the nucleus decays (breaks down) over time, giving off radiation in the form of matter and energy

Uses for Radioactive isotopes

Geologists can determine the ages of rocks and fossils by analyzing the isotopes found in them.

Radiation from certain isotopes can be used to detect and treat cancer and to kill bacteria that cause food to spoil.

Radioactive isotopes can also be used as labels or “tracers” to follow the movements of substances within organisms.

Chemical Bonds

The atoms in compounds are held together by various types of chemical bonds.

Bond formation involves the electrons that surround each atomic nucleus. The electrons in the outer energy level that are involved in chemical bonding are called VALENCE ELECTRONS.

The main types of chemical bonds are ionic bonds and covalent bonds but there is also a Hydrogen bond.

Ionic Bonds

An ionic bond is formed when one or more electrons are transferred from one atom to another.

Electrons and Ions

Remember…all atoms start out neutral with equal positive and negative charges

Protons = Electrons

However, atoms can gain or loose electrons when they form an ionic bond.

Ion- an atom that has a charge because it has gained or lost an electron

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

Covalent Bonds

Sometimes electrons are shared by atoms instead of being transferred, this type of bonding is called a covalent bond.

When the atoms share two electrons, the bond is called a single covalent bond. Sometimes the atoms share four electrons and form a double bond. In a few cases, atoms can share six electrons, forming a triple bond.

Opening Assignment Day 4

Copy and answer the following questions in your notebook.

1. Differentiate between an ionic and a covalent bond.

2. What is an ion and how are positive and negative ions different?

Molecules

A MOLECULE is two or more atoms that are bonded and act as a unit . . . .

Examples are most compounds like H2O (water) , CO2 (carbon dioxide gas), CH4 (methane gas)

Chapter 2 Lesson 2 Learning Goals

Students will be able to Describe the structure of water molecule

Explain the unique properties of water

Differentiate between an acid and a basic (alkaline) solution.

The Water Molecule

Water is a very unique substance and is essential to life here on Earth.

Water makes up over 70% of the Earth’s surface and over 70% of the human body.

It is vital for moving substances through living organisms.

Unique properties of water

High surface tension Cohesion Adhesion High Heat Capacity Lower density as a solid Universal solvent

Polarity and Water Molecules

Water is a compound made of 2 hydrogen atoms and 1 oxygen atom covalently bonded (sharing valence electrons to fill their outer shell).

Because of the angles of its chemical bonds, the oxygen atom is on one end of the molecule and the hydrogen atoms are on the other.

With 8 protons in its nucleus, an oxygen atom has a much stronger attraction for electrons than does a hydrogen atom with its single proton.

Slightly positive charge Slightly

negative charge The polarity (opposite

charges on opposite ends) of water causes the molecules to attract each other. This makes water molecules “Stick” together using hydrogen bonding.

Hydrogen Bonds

The hydrogen bonds that cause the hydrogen end of one molecule of water to attract the oxygen end of another are called hydrogen bonds.

Hydrogen bonds are weak and therefore are broken and reformed very easily.

Cohesion vs. Adhesion

COHESION

Cohesion is the attraction between molecules of the same substance.

Cohesion causes water molecules to be drawn together.

This causes surface tension which allows surface organisms to live on the top of water

ADHESION

Adhesion is an attraction between molecules of different substances.

Adhesion allows for capillary action where plant roots draw water in and up a plant to the leaves where photosynthesis occurs.

Cohesion vs. Adhesion

Heat Capacity of Water

Heat capacity is the amount of energy needed to raise the temperature of a substance.

Water has a very high heat capacity so it absorbs large amounts of heat with only a small change in the temperature.

Density of Water when Freezing

Water is a unique substance in that it expands when it freezes and the molecules move farther apart. This causes the density of water to decrease as it freezes which makes it float.

Types of Matter

SUBSTANCES: matter with a composition that is always the same.

MIXTURES: matter with a composition that can vary.

Matter can be classified into 2 things:

H2O

Hydrogen

Review of types of SubstancesELEMENTS

Made of a single type of atom.

All types of elements found so far are listed on the periodic table of elements.

COMPOUNDS

Made of TWO or more types of atoms (elements) chemically bonded.

Opening Assignment Day 5

Get your workbook out and get ready to have pages 16-20 graded. Happy Hump Day!

1. List three unique properties of water.

2. Compare and contrast the following terms

Cohesion and adhesion

Mixtures

A mixture is a material composed of two or more elements or compounds that are physically mixed together but not chemically combined.

Types of Mixtures

HOMOGENEOUS

Mixture where substances are evenly mixed.

HETEROGENEOUS

Mixture where substances are NOT evenly mixed

Solutions

Solution: Uniform mixture of two or more substances

Solvent: Substance that dissolves the other substance (and is present in a greater amount)

Solute: Substance that is dissolved (and is present in a lesser amount) When water is the solvent

it is an aqueous solution

Water is known as the universal solvent because it is able to dissolve more substances in nature than anything else

Suspensions

• Some materials do not dissolve when placed in water, but separate into pieces so small that they do not settle out. These mixtures of water and nondissolved material are known as suspensions.

• Some of the most important biological fluids are both solutions and suspensions.

• Blood is mostly water. It contains many dissolved compounds, but also cells and other undissolved particles that remain in suspension as the blood moves through the body.

Differences between Compounds and MixturesCOMPOUNDS

Have a chemical bond in which they form a NEW SUBSTANCE with different properties than the elements that made them.

Can usually only be unbound by a CHENMICAL CHANGE.

MIXTURES

DO NOT have a chemical bond to hold them together so they retain their own physical and chemical properties.

Can usually be separated by physical means: pulling apart by hand, boiling, evaporation.

Lesson 2.2 pH

Review of pH scale and physical properties of acids and bases

Property Acids Bases

Taste sour bitter

Smell Frequently burns nose Usually no smell (except NH3)

Texture Sticky Slippery

Reactivity Reacts with metals Reacts with oils and fats

Physical Properties of Acids and Bases

Acids & Bases

In aqueous solutions some water molecules break apart into ions

In pure water, about 1 water molecule in 550 million splits to form ions in this way.

Because the number of positive hydrogen ions produced is equal to the number of negative hydroxide ions produced, pure water is neutral.

Any compound that donates H+ ions to a solution is called an ACID

Any compound that removes H+ ions from a solution is called a BASE

pH Scale pH scale is used to describe how acidic or basic a

compound is based on the percentage of Hydrogen ions (H+) and Hydroxide ions (OH-)

Acidic =

H+ ions > OH-

ions

Basic = OH- ions > H+

ions

pH Neutral = H+ ions = OH- ions

Ocean Acidification Lab Opening Assignment

Describe the pH scale and explain how acids and bases are different.

The pH Scale

Each step on the pH scale represents a factor of 10. For example, a liter of a solution with a pH of 4 has 10 times as many H+ ions as a liter of a solution with a pH of 5.

For example: Coffee with a pH of 5.0 has 100x’s (10 X 10) more H+ than pure water with a pH of 7.0.

Buffers In order to maintain homeostasis the fluids within most cells in the

human body must generally be kept between 6.5 and 7.5. If it goes lower or higher, chemical reactions that take place within the cells can be affected.

One of the ways that organisms control pH is through dissolved compounds called buffers, which are weak acids or bases that can react with strong acids or bases to prevent sharp, sudden changes in pH.

pH Lab – Opening Assignment

Describe the pH scale and explain how acids and bases are different.

Be sure to turn your lab sheet in to be graded at the end of the class period today.

Students who did not complete the notes on pH assigned for homework last night MUST write -20% on their lab form.

Opening Assignment

Explain what elements carbon bonds with to make up life’s molecules.

Opening Assignment answer

Explain what elements carbon bonds with to make up life’s molecules.

Carbon can bond with many elements, including hydrogen, oxygen, phosphorous, sulfur, and nitrogen to form molecules of life.

What is a macromolecule?

The organic (organic means they contain carbon) compounds in living cells that are made of thousands or even hundreds of thousands of smaller molecules.

How are macromolecules formed?

Macromolecules are formed through a process called polymerization where large molecules are built by joinging together smaller ones.

The smaller units, monomers, are joined together to form larger ones, polymers.

Copy the chart below so we can complete it together (make it big)

Macromolecule Type

Structure Function Examples

Carbohydrates

Lipids

Nucleic Acids

Proteins

Carbohydrates

Structure: Compounds made of carbon, hydrogen, and oxygen atoms in a 1:2:1 ratio.

Function: Carbohydrates serve as the main source of energy for most living things and also for structural support.

Examples: table sugar (sucrose), bread, pasta, fruits (fructose)

Carbohydrates = ENERGY

Lipids

Structure: made of carbon and hydrogen atoms.

Function: Lipids can be used to store energy but work primarily to support structure and can provide waterproof properties.

Examples: fats and oils

Lipids = Store Energy, Support and Waterproofing

Nucleic Acids

Structure: macromolecules that contain H, N, C , and phosphorus. Made of nucleotides, monomers, that combine to form the polymers. Nucleotides include a phosphate group, a nitrogenous base, and a 5 carbon sugar.

Function: Nucleic acids store and transmit hereditary or genetic information.

Examples: DNA, RNA

Nucleic Acids = Genetic Information

Proteins

Structure: Macromolecules that contain nitrogen, carbon, hydrogen and oxygen. Proteins are polymers of molecules called amino acids.

Function: Proteins are responsible for MOST important cellular functions including, controlling rates of reactions, regulating cell processes, cellular structures, transporting substances into or out of cells, and to fight disease.

Examples: Amino Acids, all meats, beans, eggs, most animal products

Proteins: MOST Cellular Functions

Proteins make things happen

Opening Assignment

List the 4 main macromolecules and give their main function

Opening Assignment

Name the 4 main elements that make up 95% of an organism.

What is the difference between sucrose, glucose, and galactose

A glucose molecule, C6H12O6

The chemical formula for sucrose is C12H22O11

Opening Assignment

What happens to chemical bonds during chemical reactions?

Workbook pages 21-28 are due Friday

Chemical Reactions

EVERYTHING that happens in an organism – it’s growth, it’s interaction in the environment, it’s reproduction, and even it’s movement – are based on chemical reactions.

A chemical reaction (VOCAB) is a process that changes or transforms, one set of chemicals into another.

Chemical reactions in your body

An important chemical reaction in your bloodstream enables carbon dioxide to be removed from the body.

As it enters the blood, carbon dioxide (CO2) reacts with water to produce carbonic acid (H2CO3), which is highly soluble.

This chemical reaction enables the blood to carry carbon dioxide to the lungs.

In the lungs, the reaction is reversed and produces carbon dioxide gas, which you exhale.

Remember the Laws

Law of Conservation of Energy: Energy cannot be created or destroyed . . .it is transformed.

Law of Conservation of Mass: The mass of the reactants is always equal to the mass of the products in a chemical reaction.

These are NOT in your book

Review of Theories vs. Laws

Theories explain why something happens in nature.

Ex: Theory of Plate Tectonics

Laws don’t explain anything they just state what will happen.

Ex: Law of Conservation of Mass

Back to Chemical Reactions Reactants (VOCAB)

The elements or compounds that go INTO the chemical reaction

Products (VOCAB)

The elements or compounds that come OUT OF the chemical reaction

Reactants

Products

Energy in Reactions

EXOTHERMIC VS.

Chemical reactions that RELEASE energy are called Exothermic reactions. They usually react on their own or spontaneously.

They will feel warm or hot when they occur and may release light and sound..

ENDOTHERMIC

Chemical reactions that ABSORB energy are called Endothermic reactions. Require a source of energy to occur.

They will feel cool or cold when they occur.

Exothermic Reaction

An example of an energy-releasing reaction is the burning of hydrogen gas, in which hydrogen reacts with oxygen to produce water vapor.

The energy is released in the form of heat, and sometimes—when hydrogen gas explodes—light and sound.

Endothermic Reaction

The reverse reaction, in which water is changed into hydrogen and oxygen gas, absorbs so much energy that it generally doesn’t occur by itself.

2H2O + energy 2 H2 + O2

The only practical way to reverse the reaction is to pass an electrical current through water to decompose water into hydrogen gas and oxygen gas.

Thus, in one direction the reaction produces energy, and in the other direction the reaction requires energy.

Energy Sources

Every organism must have a source of energy to carry out the chemical reactions it needs to stay alive.

Plants get their energy by trapping and storing the energy from sunlight in energy-rich compounds.

Animals get their energy when they consume plants or other animals.

Humans release the energy needed to grow, breathe, think, and even dream through the chemical reactions that occur when we metabolize, or break down, digested food.

Activation Energy

Chemical reactions that release energy do not always occur spontaneously.

The energy that is needed to get a reaction started is called activation energy (VOCAB)

Activation Energy

The peak of each graph represents the energy needed for the reaction to go forward.

The difference between the required energy and the energy of the reactants is the activation energy. Activation energy is involved in chemical reactions whether or not the overall reaction releases or absorbs energy.

Energy in Reactions

http://www.youtube.com/watch?v=yvyHVA1Ww_M

What are Catalysts and Enzymes?

Catalysts (VOCAB) are substances that speed up the rate of a chemical reaction. Catalysts work by lowering a reaction’s

activation energy.

Enzymes (VOCAB) are proteins that act as biological catalysts.

How do Enzymes work?

Some chemical reactions that make life possible are too slow or have energy levels too high for practical use.

These reactions are made possible by the catalysts made by cells called enzymes.

Nature’s Catalysts

For example, the reaction in which carbon dioxide combines with water to produce carbonic acid is so slow that carbon dioxide might build up in the body faster than the bloodstream could remove it.

Your bloodstream contains an enzyme called carbonic anhydrase that speeds up the reaction by a factor of 10 million, so that the reaction takes place immediately and carbon dioxide is removed from the blood quickly.

Nature’s Catalysts

Enzymes are very specific, generally catalyzing only one chemical reaction.

Part of an enzyme’s name is usually derived from the reaction it catalyzes.

Carbonic anhydrase gets its name because it also catalyzes the reverse reaction that removes water from carbonic acid.

The Enzyme-Substrate Complex

For a chemical reaction to take place, the reactants must collide with enough energy so that existing bonds will be broken and new bonds will be formed.

If the reactants do not have enough energy, they will be unchanged after the collision.

Enzymes provide a site where reactants can be brought together to react. Such a site reduces the energy needed for reaction.

The Enzyme-Substrate Complex

The reactants (what goes in to the chemical reaction) of enzyme-catalyzed reactions are known as substrates.

For example, the enzyme carbonic anhydrase converts the substrates carbon dioxide and water into carbonic acid (H2CO3).

The Enzyme-Substrate Complex

The substrates bind to a site on the enzyme called the active site.

The active site and the substrates have complementary shapes.

The fit is so precise that the active site and substrates are often compared to a lock and key.

How are Enzyme activities regulated? Temperature, pH, and regulatory molecules are all factors

that can affect the activity of enzymes.

Enzymes produced by human cells generally work best at temperatures close to 37°C, the normal temperature of the human body.

Enzymes work best at certain pH values. For example, the stomach enzyme pepsin, which begins protein digestion, works best under acidic conditions.

The activities of most enzymes are regulated by molecules that carry chemical signals within cells, switching enzymes “on” or “off” as needed.

Opening Assignment

1. What is the purpose of an enzyme?

2. Compare and contrast endothermic and exothermic reactions

3. What 3 things can affect how an enzyme works?

Enzymes Video Lesson - Bozeman

http://www.youtube.com/watch?v=ok9esggzN18

Opening Assignment Get your workbook out and get ready to have it

graded. Remember pages 21-28 need to be completed.

Then get a laptop and login to IRCHS website. Go to staff directory, search my name and locate my website.

On my website, go to Biology, then Unit Study Notes, then Unit 3 . . . Scroll down to the Enzyme webquest link and click on it. You will use this to answer the questions for the webquest – due today .

Opening Assignment

Copy the following questions in your notebook . . this is your study guide for the quiz on Thursday.

1. Know the subunits, function, and examples of each of the 4 main macromolecules.2. Know the difference between an endothermic and exothermic reaction3. Know the definition of a reactant, product, catalyst, enzyme, activation energy, substrate4. Identify the components of an enzyme complex.5. Know the 3 things that can affect how well an enzyme works.

TOOTHPICKASE Activity

Get your calculators out.

Count out 50 toothpicks and place them in a loose pile on your desk – spread out.

I will put the timer on the board and we will start the activity

http://www.online-stopwatch.com/

Enzymes

http://www.youtube.com/watch?v=_5TaS0-VaDo

Opening Assignment

Copy the columns and match the subunit with the correct macromolecule

Lipids: ______________________

Proteins:_____________________

Carbohydrates:________________

Nucleic Acids:_________________

SubunitsMacromolecules

A. Nucleotides

B. Amino acids

C. Triglycerides

D. Monosaccharides

Let’s Review

1. Open your workbook to page 21. We will go over pages 21-28

2. Then we will go over the study guide

Study Guide for Quiz on lessons 2.3 and 2.4 tomorrow

Copy the following questions in your notebook . . this is your study guide for the quiz on Thursday.

1. Know the subunits, function, and examples of each of the 4 main macromolecules.2. Know the difference between an endothermic and exothermic reaction3. Know the definition of a reactant, product, catalyst, enzyme, activation energy, substrate4. Identify the components of an enzyme complex.5. Know the 3 things that can affect how well an enzyme works.