MACROMOLECULES SBI 3C: SEPTEMBER 2012. MACROMOLECULES Macromolecules: Very large molecules...

MACROMOLECULES

SBI 3C: SEPTEMBER 2012

MACROMOLECULES Macromolecules:

Very large molecules containing many carbon atoms

4 major groups of macromolecules:1. Carbohydrates2. Lipids3. Proteins4. Nucleic acids

WHAT IS A CARBOHYDRATE? Molecules that contain carbon, hydrogen, and

oxygen Used mainly by living organisms for energy Produced by plants by photosynthesis

WHAT DOES A SIMPLE CARBOHYDRATE LOOK LIKE? Glucose:

Formula: C6H12O6

Hydroxyl group (OH)

WHAT DOES A SIMPLE CARBOHYDRATE LOOK LIKE? Fructose

Formula: C6H12O6

Hydroxyl group (OH)

MONOSACCHARIDES: Also known as simple sugars What are they?

Carbohydrates that contain 6 carbon atoms and hydroxyl groups

Examples and Information: Glucose (C6H12O6) Fructose (C6H12O6) Both are water soluble

DISACCHARIDES Also known as double

sugars What are they?

2 monosaccharides linked together

Examples and information: Sucrose is glucose +

fructose Formed by bonding two

sugars together Occurs when hydroxyl

groups react with each other Sucrose is water soluble

MAKING SUCROSE

+

H2O

POLYSACCHARIDES Also known as complex carbohydrates What are they?

Sugars attached together in a chain Examples and information:

Insoluble in water Polymer:

Molecule composed of many linked subunits Monomer:

Individual subunits of a polymer

EXAMPLES OF POLYSACCHARIDES Starch (polymer of glucose)

Used by plants for energy Glycogen (polymer of glucose)

Used by animals for energy Cellulose (polymer of glucose)

Makes up plant cell walls Humans cannot digest

Chitin (polymer of type of glucose) Hard exterior of insects, fungi

and crustaceans

MACROMOLECULES - LIPIDS What is a lipid?

A molecule made up of carbon, hydrogen, and oxygen

Used by animals as energy storage molecules Soluble (dissolves) in oils and other non-polar

solvents Insoluble (does not dissolve) in H2O

TRIGLYCERIDES Also known as oils and fats What are they?

Lipids consisting of 4 parts (glycerol and 3 fatty acids)

Examples and Information Butter, oil

glycerol 3 fatty acids

TRIGLYCERIDE STRUCTURE Glycerol is a 3 carbon molecule with a hydroxyl

group attached to each carbon atom

Fatty acid is a long chain of carbon and hydrogen atoms with a carboxyl group at the end

Hydroxyl groups (OH)

Carboxyl group (COOH)

TYPES OF LIPIDS Waxes:

Used by plants and some animals as waterproof-coating

Steroids Composed of 4 carbon rings Ex. Testosterone and

cholesterol Phospholipids

Similar to triglyceride with additional phosphate group

Found in cell membrane

SATURATED FATTY ACIDS Saturated Triglycerides:

Single bonds between the carbon atoms Animal fats Causes clogging of arteries

UNSATURATED FATTY ACIDS Unsaturated Triglycerides:

Double bonds between some carbon atoms more than one double bond = polyunsaturated Low melting points, liquids at room temperature

Ex. Plant oils – olive oil, canola oil

MACROMOLECULES: PROTEINS What is a protein?

Unbranched chain of amino acids Most diverse and important molecule in living

organisms Produced by protein synthesis

AMINO ACIDS: How many are there?

20 Common examples:

Leucine, serine, cytsteine, phenylalanine Other facts:

Small molecules that contain a central carbon atom attached to an amino group, a carboxyl group, a hydrogen, and a side chain (R group)

R groups distinguish the amino acid 20 amino acids are in food we eat, 8 are essential

because our body cannot make them

POLYPEPTIDE What is it?

Chain of amino acids Formed by a reaction

between the amino group and carboxyl group on adjacent amino acids

Forms bond called peptide bond

Polypeptides can fold up into different shapes. For example: fold into a

sheet or wrap into coils

DENATURING What is it?

When proteins lose their shape due to high temperatures, high salt or pH

What happens? Changes the 3D shape of the protein

What happens to a protein if it is done? Can’t carry out its function Will return to normal if no bonds are broken Examples:

Fever can denature enzymes in the brain Curing meats with salt denatures enzymes, preserving

meat Heat denatures protein in the hair making it straight

MACROMOLECULES: NUCLEIC ACIDS What is a nucleic acid?

Where organisms store information about the structures of their proteins

Polymers of nucleotides Each nucleotide is made up of:

A five-carbon sugar (ribose in RNA; deoxyribose in DNA) A phosphate group An nitrogen containing component (nitrogenous base)

DNA Stands for:

Deoxyribonucleic acid Looks like:

Double helix Helix held together by

hydrogen bonds Contains which base pairs?

A – T C – G A – adenine, T – thymine C – cytosine, G – guanine

RNA Stands for:

Ribonucleic acid Looks like:

Single stand Contains which base pairs?

A – U (uracil) C – G

Types of RNA… mRNA – carries info to ribosomes tRNA – transfers amino acid to mRNA

DIFFERENCES BETWEEN DNA AND RNA

RNA DNA

Single stranded Double stranded

Has uracil Has thymine

Decodes hereditary info Stores hereditary info

Sugar is a ribose Sugar is deoxyribose

DNA DETAILS What does the code in DNA specify?

The order of amino acids in proteins What is a gene?

Instructions to code a protein How many genes are in the human genome?

30,000 – 35,000 How many base pairs are in the human

genome? 3 billion