Chapter 6: The Chemistry of Life

Georgia Standards: The learner will identify the structure & function of the four major macromolecules (i.e., carbohydrates, proteins, lipids, nucleic acids).

Essential Questions: How does the structure of a carbohydrate influence its function? What are the roles of carbohydrates in living things?

Why is Chemistry important to Biology?

• Life depends on chemistry. • The first job of a biologist is to understand the chemistry of life.

Carbon Compounds & Organic Chemistry

• What is organic chemistry?

• Organic chemistry is the study of all compounds that contain bonds between carbon atoms.

Properties of Carbon Compounds

1.Carbon atoms have four valence electrons to make 4 bonds. 3. Carbon atoms can bond to other carbon atoms 2. Carbon can bond with many elements including hydrogen, oxygen, phosphorus, sulfur, and nitrogen 4. Chains of carbon atoms can even close upon themselves to form rings

What is a Macromolecule?

• Many of the molecules in living cells are so large that they are known as macromolecules (large molecules) • Monomers + Monomers = polymers Polymerization to form polymers.

Types of Macromolecules in Living Systems

• Four groups of organic compounds

found in living things are

– Carbohydrates – Lipids – Nucleic acids – Proteins

What are Carbohydrates?

• Carbohydrates compounds made up of carbon, hydrogen, and oxygen atoms, usually in a ratio of 1 : 2 : 1. are • Living things use

carbohydrates as their main source of energy.

• Plants and some

animals also use carbohydrates for structural purposes.

Carbohydrates

• Starches and

sugars are examples of carbohydrates that are used by living things as a source of energy.

• Single sugar =

monosaccharides (simple sugar)

– Glucose – Galactose – Fructose

Carbohydrates

• Polysaccharides (complex sugar) – Forms when monosaccharides link together • Animals store excess sugar as glycogen.

• Plants store excess sugar as starch .

– Cellulose

Go to Section: Starch Glucose

Molecular Model Building

• Use the molecular model kit to build glucose – Carbon = black – Oxygen = blue – Hydrogen = white – Electron bond = white plastic tube

#6 question to WS

• The structural arrangement of C, H, and O in glucose, fructose, and galactose differs. This helps explain why different model shapes are used for each monosaccharide.

• Molucules of monosaccharides may have the same molecular formula but differ in the 3D structure. This is called isomerism. Using the three models and structural formulas, describe isomerism in your own words.

Ticket out the Door

Frayer Model on Carbohydrates

Warm-up:

1. What properties of carbon explain carbon’s ability to form many different macromolecules? 2. Why do living things need carbohydrates?

Lipid Function:

• Lipids can be used

to

– store energy – Form biological

membranes

– Form waterproof

coverings

– Steroid Hormones – Pigments • Examples: – Body Fats – Oils – Waxes – Steroids – Testosterone – Chlorophyll – Cell

Lipid Structure:

• Lipids are made mostly from: – Carbon, hydrogen, & oxygen atoms – Monomers of

fatty acids & Glycerol

• Many lipids are formed when a called

fatty acids .

glycerol

molecule combines with compounds

Lipid Structure

• Saturated

Types of Lipids

• Unsaturated – Carbon-carbon single bonds – All carbons are completely surrounded by hydrogen – Solid at room temp • Lard – Carbon-carbon double or triple bonds – All carbons are not completely surrounded by hydrogen.

– Liquid at room temp • Olive oil

Fats in Foods Lab

• See Handout

Nucleic Acids

• Contain hydrogen, oxygen, nitrogen, carbon, and phosphorus. • Nucleic acids store

and transmit hereditary, or genetic, information.

• Monomers of

nucleotides

– 5-carbon sugar – Phosphate group – Base • Ribonucleic acid

( ( RNA DNA )

• Deoxyribonucleic acid ).

Nucleic Acid

Strawberry DNA Extraction Lab

• See Handout

Proteins

• Made of carbon, hydrogen, nitrogen, and oxygen. • Monomers =

amino acids

– 20 different amino

acids

• Transport substances

into or out of cells

Amino Acids

Amino group Carboxyl group Go to Section: General structure Alanine Serine

Amino Acids (monomers) are linked by peptide bonds form proteins (polymers).

to

Levels of Proteins

• Proteins can have up to four levels of organization. • Primary level chain. is the sequence of amino acids in a protein • Secondary level or folded. is the amino acids within a chain can be twisted • Tertiary level is when the chain itself is folded. • Quaternary level folded chains interact.

is when two or more

Examples:

• Structural: – Collagen, Keratin,

myosin,

• Functional: – enzymes

Go to Section: Amino acids

Figure 2-17 A Protein

Concept Map

Go to Section: Carbohydrates Monomers of Sugars and starches which contain Carbon, hydrogen, oxygen Lipids Monomers of Fats and oils which contain Carbon, hydrogen, oxygen Carbon Compounds include Nucleic acids Monomers of Nucleotides which contain Carbon,hydrogen, oxygen, nitrogen, phosphorus Proteins Monomers of Amino Acids which contain Carbon, hydrogen,oxygen, nitrogen,

Checkpoint!!!

1. Name four groups of organic compounds found in living things. 2. Describe at least one function of each group of organic compounds. 3. What properties of carbon explain carbon’s ability to form many different macromolecules? 4. Explain why proteins are polymers but lipids are not.

Chapter 6: The Chemistry of Life

Georgia Standards: •Explain how enzymes (functional proteins)

function as biological catalysts.

Essential Questions:

• How does the enzyme-substrate complex work? •Why are enzymes important to living things?

Chemical Reactions & Enzymes

• A chemical reaction is a process that changes one set of chemicals into another set of chemicals. • Chemical reactions always involve the breaking of bonds in reactants and the formation of new bonds in products.

Chapter 6 Chemistry in Biology 6.2 Chemical Reactions

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.

Chapter 6 Chemistry in Biology 6.2 Chemical Reactions

 Glucose and oxygen react to form carbon dioxide and water.

Chapter 6 Chemistry in Biology 6.2 Chemical Reactions

Balanced Equations  The law of conservation of mass states matter cannot be created or destroyed.

 The number of atoms of each element on the reactant side must equal the number of atoms of the same element on the product side.

Chapter 6 Chemistry in Biology 6.2 Chemical Reactions

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

Chapter 6 Chemistry in Biology 6.2 Chemical Reactions

 This reaction is

exothermic

and

released heat energy

.

 The energy of the product is lower than the energy of the reactants.

Chapter 6 Chemistry in Biology 6.2 Chemical Reactions

 This reaction is

endothermic and absorbed heat energy

.

 The energy of the products is higher than the energy of the reactants.

Energy in Reactions

• Chemical reactions that release energy often occur spontaneously – Exothermic – Feels warm to the touch • Chemical reactions that absorb energy will not occur without a source of energy.

– Endothermic – Feels cools to the touch

Enzymes

• Enzymes are proteins as biological catalysts that act – Functional protein • Cells use enzymes to speed up chemical reactions that take place in cells, by energy reaction) lowering the activation (energy needed to start a

Chapter 6 Chemistry in Biology 6.2 Chemical Reactions

Enzymes  A catalyst is a substance that lowers the activation energy needed to start a chemical reaction.

 It does not increase how much product is made and it does not get used up in the reaction.

Go to Section:

Section 2-4 Effect of Enzymes

Reaction pathway without enzyme Activation energy without enzyme Reactants Reaction pathway with enzyme Activation energy with enzyme Products

Chapter 6 Chemistry in Biology 6.2 Chemical Reactions

 The reactants that bind to the enzyme are called substrates .

 The specific location where a substrate binds on an enzyme is called the active site .

Chapter 6 Chemistry in Biology 6.2 Chemical Reactions

 The active site changes shape and forms the enzyme-substrate complex, which helps chemical bonds in the reactants to be broken and new bonds to form.

 Factors such as pH, temperature, and other substances affect enzyme activity.

Enzyme Action: How do enzymes do their job?

• Enzymes are very specific.

• Enzymes have an active site where the substrate ( reactant ) will bind.

• Enzymes must collide with enough energy so that old bonds can be broken and new bonds can be formed.

• Activation energy reduced is

Go to Section:

Section 2-4 Enzyme Action

Enzyme (hexokinase) Products ADP Glucose-6 phosphate Products are released Active site Enzyme-substrate complex Substrates are converted into products Glucose Substrates ATP Substrates bind to enzyme

Chapter 6 Chemistry in Biology

Classwork: Complete the Regulation of Enzyme Handout • pH • Temperature • Other proteins turn enzymes “on” and “off”

Checkpoint!!!

1. What happens to chemical bonds during chemical reactions? 2. Describe the role of energy in chemical reactions. 3. What are enzymes, and how are they important to living things? 4. Describe how enzymes work, including the role of the enzyme-substrate complex. 5. A change in pH can change the shape of a protein. How might a change in pH affect the function of an enzyme such as hexokinase?

Enzyme Lab

• See Handout