2.3 Carbon-Based Molecules KEY CONCEPT Carbon-based molecules (proteins, lipids, carbohydrates and nucleic acids) are found in all organisms. These molecules

2.3 Carbon-Based Molecules

KEY CONCEPTCarbon-based molecules (proteins, lipids, carbohydrates and nucleic acids) are found in all organisms. These molecules form all the structures and carry out the functions of all life.


• Carbon atoms are considered the building blocks of life Carbon atoms are considered the building blocks of life because they :because they :

1. They form most of the structures in living things1. They form most of the structures in living things

(Structure)(Structure)

2. Carry out most processes that keep organisms alive 2. Carry out most processes that keep organisms alive

(Function) (Function)

Each molecules structure is unique and is specific to its job Each molecules structure is unique and is specific to its job or function in living things.or function in living things.

..


Why is Carbon so special?

• Carbon has Carbon has fourfour valence electrons. valence electrons.

• It It sharesshares these electrons with other atoms these electrons with other atoms to form molecules that are held together by to form molecules that are held together by strong strong covalentcovalent bonds. bonds.

.


Molecules that contain carbon are called

Organic compounds.

Exceptions are CO(Carbon monoxide) and

CO2 (Carbon dioxide)

There are over 2 million known organic compounds. They are made and found only in living things.


There are 3 basic shapes of carbon-based compounds depending on how the carbon atoms are bonded together:

• straight chainstraight chain• branched chainbranched chain• ringring


Monomers

and

Polymers


• Large carbon-based molecules are made of many Large carbon-based molecules are made of many repeating small subunits that are bonded together.repeating small subunits that are bonded together.

Smaller individual molecular subunits are called Smaller individual molecular subunits are called MonomersMonomers

Ex. GlucoseEx. Glucose

CC66HH1212OO66


Larger molecules made when monomers Larger molecules made when monomers bond are called bond are called PolymersPolymers..





=MONOMER – one train car

=POLYMER – the whole train


The reaction that joins monomers to form polymers is called Dehydration Synthesis.

• Animation

Dehydration synthesis means “to make by removing water.” (Dehydration – remove water Synthesis – to make)


Dehydration Synthesis


• Polymers can be broken down into the monomers that made them through Hydrolysis

• Hydrolysis means “to break by adding water”


Four major groups of organic compounds in living things:

• Carbohydrates

• Lipids

• Proteins

• Nucleic Acids

Quick Check for Understanding –

What atom do all these molecules contain?


Four major groups of organic compounds in living things:

• Carbohydrates

• Lipids

• Proteins

• Nucleic Acids







CARBON


Where do we get these molecules?

(Click for video)

FROM OUR FOOD!!


CARBOHYDRATES


Carbohydrate molecules are made of Carbon (C), Hydrogen (H), and Oxygen (O) atoms


• Food that contain primarily carbohydrate molecules are called Sugars (simple carbohydrates) and Starches (complex carbohydrates).


Uses in Living Things

• 1. “Quick” Energy

• 2. Builds body structures


3 Categories of Carbohydrates based on Size:

1.Monosaccharides (smallest)

2.Disaccharides

3. Polysaccharides (largest)


1. 1. Monosaccharide: one single molecule

• 11. Glucose – made in photosynthesis;– made in photosynthesis; blood sugar

2. Galactose - Component of milk sugar

3. 3. Fructose - - fruit sugar

4. 4. Deoxyribose and Ribose – – in nucleic acids

glucoseglucose


2. Disaccharide – 2 monosaccharides joined together

1. Sucrose – table sugar (glucose + fructose)

2. Lactose – milk sugar (glucose + galactose))

fructosefructoseglucoseglucose


3.3. Polysaccharides - Polysaccharides - manymany monosaccharides joined monosaccharides joined togethertogether

11. . Starch Starch – glucose storage in plants (bread, taters)– glucose storage in plants (bread, taters)

2. 2. GlycogenGlycogen – glucose storage in animals – glucose storage in animals

3. 3. CelluloseCellulose – forms plant cell walls – forms plant cell walls

4. 4. ChitinChitin – forms insect exoskeletons and – forms insect exoskeletons and

fungus cell wallsfungus cell walls

glucoseglucoseglucoseglucose




cellulosecellulose


Carbohydrate molecules can have the same monomers but they are joined together differently

.

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


Chitin (C8H13O5N) used to form Insect bodies

• Monomer

Polymer


• REMEMBER A UNIFYING THEME:

• The structure of a molecule affects its function


LIPIDS Fats, Oils, Waxes)


•Types of Atoms: C, H, O


• Uses of Lipids in Living Things:

1.Stores large amounts of chemical energy

2.Provide warmth and insulation

3. #1 component of cell membranes

4. Makes hormones the body’s chemical

messengers


Common Features of Lipids

1. Nonpolar molecules – no charge on atoms

2. Hydrophobic – Don’t dissolve in water

3. No specific monomer found in all lipids.

Many lipids do contain fatty acid molecules.


• The 100’s of different types of fatty acid molecules have the same basic structure


3 Categories of Fatty Acids

No double bonds

between Carbon atoms

No kinks

One or more double bonds between carbon atoms

Molecule has kinks and bends


If the Fatty Acid molecules have :

•Single bonds between C atoms –

Saturated Fats (Bad fats in diet)

•Double bonds between C atoms –

Unsaturated Fats (Good fats in diet)

(Copy what’s underlined below into notes)

•LDL - Lousy for you Want # to be LOW

•HDL - Happy for you Want # to be HIGH


• Dangers of Saturated Fats (Video)


Get in the habit of checking food labels for fat content


Cell Membrane


Has negative charge Molecules have no charge


Types of Atoms in Protein Molecules:

C, H, O, N, S


•Uses of Proteins in Living Things:

•Make chemical reactions go faster (Enzymes)

•Move molecules in/out of cells

•Help cells move

•Receptors on cell surfaces


Monomers of Proteins: Amino Acids

• 20 different amino acids molecules linked by a special bond called a peptide bond.

• 9 amino acids are Essential – Can only be obtained by eating food


Don’t forget: Proteins are BIG molecules Don’t forget: Proteins are BIG molecules

made by joining SMALL amino acid moleculesmade by joining SMALL amino acid molecules

.

Protein – Polymer

Amino Acids - Monomers


Basic structure of all known 20 amino acids

Amine group Carboxylic acid group

Variable group


• .Amino acids are joined by peptide bonds .Amino acids are joined by peptide bonds which form between them through which form between them through dehydration synthesisdehydration synthesis

.

OH + H

OH + H


Examples of Protein Molecules in Living things:

• 1. Albumin – protein in egg white

• 2. Amylase – breaks apart starch to glucose through hydrolysis. Enzyme found in your saliva

• 3. Keratin – protein in hair, feathers and nails

• 4. Hemoglobin – in red blood cells, oxygen attaches to it to be carried throughout the body and delivered to all cells


NUCLEIC ACIDS DNA and RNA


Types of Atoms in N.A.:

C, H, O, N, P


Two Types of Nucleic Acid Molecules:

1. Deoxyribonucleic Acid - DNA

2. Ribonucleic Acid – RNA

Uses of Nucleic Acids:

1. Stores hereditary information

2. Helps to make protein molecules


• Monomers of Nucleic acids are nucleotides.

• 1000’s of nucleotides join together to make a nucleic acid.


3 Molecules Join Together to form a Nucleotide

1. Sugar

2. Phosphate group

3. Nitrogen containing base (5 kinds).

A phosphate group nitrogen-containing molecule,called a base

deoxyribose (sugar)


Types of Nitrogen Containing Bases in:

DNA•Adenine A

•Thymine T

•Guanine G

•Cytosine C

RNA• Adenine A

• Uracil U

• Guanine G

• Cytosine C

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2.3 Carbon-Based Molecules KEY CONCEPT Carbon-based molecules (proteins, lipids, carbohydrates and nucleic acids) are found in all organisms. These molecules