2.3 Carbon-Based Molecules

KEY CONCEPTOrganic molecules are the foundation of life.

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2.3 Carbon-Based Molecules

Objectives

• Identify what makes an organic molecule “organic”• Identify/Recognize carbon skeletons & functional groups

in organic molecules• Relate monomers to polymers• Describe the processes of building and breaking

polymers (2 reactions involved)• Describe the basic structure and function of

carbohydrates, lipids, proteins, and nucleic acids

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2.3 Carbon-Based Molecules

Introduction to Organic Introduction to Organic Biomolecules!!!!Biomolecules!!!!

Directions: While you watch this video, please answer the questions on the worksheet.

• Biological Molecules - You Are What You Eat: Crash Course Biology #3 - YouTube

2.3 Carbon-Based Molecules

Organic Molecules

• Organic Molecules – Carbon-based molecules– Carbon forms covalent bonds with up to four other

atoms, including other carbon atoms as it tries to fill its outermost energy level.

• Hydrocarbons– Organic molecules made of only carbons and

hydrogens (example CH4)

• Inorganic Molecules– Non-carbon based molecules– Examples: H20, NH3, O2

2.3 Carbon-Based Molecules

Carbon atoms have unique bonding properties.

• Carbon-based molecules have three general types of structures.

1. straight chain

2. branched chain

3. ring

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2.3 Carbon-Based Molecules

Functional Groups on Organic molecules

Functional Group – group of atoms within a molecule that interact in predicable ways with other molecules.

2.3 Carbon-Based Molecules

Polymers vs Monomers• Many carbon-based molecules are made of many small

subunits/peices bonded together.

– Monomers are the individual subunits/pieces– Polymers are made of many monomers.

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2.3 Carbon-Based Molecules

Monomers bond together to build Polymers

• Each time a monomer is added to a chain a water molecule is released (dehydration reaction)

• Each time a monomer is broken from a chain a water molecule is added (hydrolysis reaction)

Dehydration Rxn Hydrolysis Rxn

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2.3 Carbon-Based Molecules

Dehydration Reaction (Lose Water) when adding monomers to the polymer

2.3 Carbon-Based Molecules

Hydrolysis Reaction (add water) when breaking polymers

2.3 Carbon-Based Molecules

Four main types of organic molecules are found in living things

1. Carbohydrates (5.2)

2. Lipids (5.3)

3. Proteins (5.4 & 5.5)

4. Nucleic Acids

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2.3 Carbon-Based Molecules

Carbohydrates • Carbohydrates are made of carbon, hydrogen, and

oxygen (Ratio= 1C:2H:1O)• Are made up of monomers of simple sugar molecules• The building blocks (simple sugar monomers) of

carbohydrates are ring-shaped.

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2.3 Carbon-Based Molecules

Three Types of Carbohydrates

Disaccharide

Monosaccharide

Polysaccharides

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2.3 Carbon-Based Molecules

– Carbohydrates include

1.Sugars

2.starches.

– Monosaccharides are simple sugars. (ex: glucose)

– Disaccharides are made up of two monosaccharides (ex: sucrose)

– Polysaccharides include starches, cellulose, and glycogen. (ex: found in pasta & potatoes)

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2.3 Carbon-Based Molecules

1. Carbohydrates can be broken down to provide energy for cells ( this requires water: Hydrolysis Rxn)

2. Some carbohydrates are part of cell structure (provide support)

Polymer (starch)Starch is a polymer of glucose monomers that often has a branched structure.

Polymer (cellulose)Cellulose is a polymer of glucose monomers that has a straight, rigid structure

monomer

Functions of Carbohydrates:

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2.3 Carbon-Based Molecules

Warm-Up

1. What are the monomers of Carbohydrates?

2. List the 3 different types of carbohydrates and give an example of each.

3. Which carbohydrate is found in plant cells?

2.3 Carbon-Based Molecules

– Lipids are Hydrophobic molecules “water fearing”– Example (oil and water don’t mix)

– Many contain carbon chains called fatty acids.

– Fats and oils contain:– fatty acids bonded to glycerol.

Lipids are nonpolar molecules that include fats, oils, and cholesterol.

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2.3 Carbon-Based Molecules

Lipids

Structure Close-Up:

- Glycerol

- fatty acid chains

2.3 Carbon-Based Molecules

• Fats and oils have different types of fatty acids.

– saturated fatty acids (bad for you)– unsaturated fatty acids

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2.3 Carbon-Based Molecules

• Lipids have several different functions.

– broken down as a source of energy – make up cell membranes (phospholipids)– used to make hormones

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2.3 Carbon-Based Molecules

• Phospholipids make up all cell membranes.

– Polar phosphate “head”– Nonpolar fatty acid “tails”

Phospholipid

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HydrophobicHydrophillic

2.3 Carbon-Based Molecules

A closer look at phospholipid orientation in cell membranes:

2.3 Carbon-Based Molecules

Steroids

• Steroids are lipid molecules that form 4-Ring structures• Function: Act as chemical signals in our bodies

– Example: Testosterone & Estrogen sex hormones– Example: Cholesterol (in cell membranes)

2.3 Carbon-Based Molecules

Warm - Up

Lipids are hydrophobic and nonpolar. What do those words mean?

• What is the name of the lipids that make up cell membranes?

• What is the general structure of steroids?

Hydrophobic = fear of waterNonpolar = no charged areas

phospholipids

4 connected Closed-Rings

2.3 Carbon-Based Molecules

• Proteins are polymers of amino acid monomers.

– Twenty different amino acids are used to build proteins in organisms.

Parts of an amino acid:

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2.3 Carbon-Based Molecules

– Amino acids differ in side groups, or R groups.

• Proteins are polymers of amino acid monomers.

– Twenty different amino acids are used to build proteins in organisms.

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2.3 Carbon-Based Molecules

Building a Protein Polymer

• How would you put these amino acid monomers together to form a protein polymer?

2.3 Carbon-Based Molecules

– Amino acids are linked by peptide bonds.

• Proteins are polymers of amino acid monomers.

– Amino acids differ in side groups, or R groups.

– Twenty different amino acids are used to build proteins in organisms.

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2.3 Carbon-Based Molecules

Polypeptides

• Polypeptides are the result of joining many amino acid monomers

2.3 Carbon-Based Molecules

• Proteins differ in the number and order of amino acids.

– Amino acids interact to give a protein its shape.

– Incorrect amino acids change a protein’s structure and function.

– Denaturation – proteins loose their shape in unfavorable conditions (temperature or pH)

hydrogen bond

Hemoglobin

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2.3 Carbon-Based Molecules

Warm-Up: Organic Molecules Review

• List the 4 types of organic molecules

• Monomers of carbohydrates?

• Two main functions of carbohydrates?

• Examples of Carbohydrates?

• Lipid that makes up cell membranes?

• Two types of Fatty Acids in lipids?

2.3 Carbon-Based Molecules

Warm-Up

• What are the building blocks of Proteins?

• What are the 4 main parts of an amino acid?

• What part of an amino acid give it it’s identity?

• What reaction puts amino acids together? What happens during that reaction?

• What special type of bond links amino acids?

2.3 Carbon-Based Molecules

Enzymes

• Many chemical reactions occur inside cells

Reactants products

• Enzymes are protein catalysts that speed up reactions by lowering the activation energy needed to start a reaction.

• Activation Energy -The energy needed to start up a reaction

• Catalyst – any compound that speeds up a reaction by lowering the activation energy

2.3 Carbon-Based Molecules

Enzymes are never ‘used up’

• Enzymes are reaction specific• Substrate – reactant• Active site – groove area where substrates attach to

enzyme• Enzymes always pick up another substrate when the

active site is unoccupied!!

• Enzyme Animation - YouTube

2.3 Carbon-Based Molecules

Enzymes Speed Up Chemical Reactions

• They are able to do this by LOWERING the activation energy of a reaction.

2.3 Carbon-Based Molecules

A reaction utilizing an enzyme = catalytic reaction

Activation Energy is lowered!

2.3 Carbon-Based Molecules

• Nucleic acids are polymers of monomers called nucleotides.

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2.3 Carbon-Based Molecules

– Nucleotides are made of a:- sugar- phosphate group- nitrogen base

A phosphate group nitrogen-containing molecule,called a base

deoxyribose (sugar)

• Nucleic acids are polymers of monomers called nucleotides.

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2.3 Carbon-Based Molecules

– DNA stores genetic information.

• Nucleic acids are polymers of monomers called nucleotides.

– Nucleotides are made of a sugar, phosphate group, and a nitrogen base.

– RNA builds proteins.

DNA

RNA

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