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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
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