Macromolecules

Life: Small Picture to Big Picture
Macromolecules

What are Macromolecules?
• Cells and their organelles are made up of smaller building blocks called macromolecules .
• There are 4 basic types of macromolecules. They are:
– Lipids
– Proteins
– Carbohydrates
– Nucleic Acids

Monomers & Polymers
• Macromolecules are actually made up of even smaller subunits. Each subunit of a macromolecule is called a monomer .
• The macromolecules themselves are called polymers , because they are made up of many of these subunits.
Monomer : one basic unit or subunit
Polymer : a chain of many basic units

What you need to know:
• Names of the 4 macromolecules
• Structure - monomers and polymers of each
• Function - what are they used for?
• Food sources - what foods will you find these in?
• Indicator Tests - what tests do we use to find out if a food contains them?

Lipids

Lipids: Structure
• Lipids are made up of…
– Monomer (basic unit): fatty acids
– Polymer (chain of units): lipids
• Specific examples: triglycerides, phospholipids

Lipids: Structure*
Properties of Lipids caused by:
• Saturated vs.
Unsaturated fatty acids
• Polar head and nonpolar tail regions
– Hydrophilic and hydrophobic regions

Lipids: Function
• Make up the cell membrane, providing cell structure
• Provide insulation (fat keeps body warm)
• Long-term energy storage

Lipids: Food Sources
• As you might have guessed, fatty foods contain lipids.
• Lipids are found in meat and fish, oils, avocados, eggs & nuts .

Lipids: Indicator Test
• Paper Bag Test :
– Smear substance onto paper bag
– If see-thru, it contains lipids

Proteins

Proteins: Structure
• Proteins are made up of…
– Monomer (basic unit): amino acids
• 20 different kinds!*
– Polymer (chain of units): protein
• More specificallypolypeptides dipeptide
Amino acids linked by peptide bonds

Proteins: Structure*
20 Amino
Acids:
Some of these are polar & hydrophilic, others are nonpolar and hydrophobic.
Proteins can contain both kinds.

Proteins: Structure
• Proteins have complex structures. The shape of a protein determines its function!
• The levels of protein structure are:
– Primary structure: polypeptide chain
– Secondary structure: polypeptides in coils or sheets
– Tertiary structure: coils or sheets form a tangle
– Quaternary structure: more than one tangle combine to make a very complex protein!

Proteins: Function
• Build and repair muscle and tissues
– “ No pain, no gain!
”
• Enzymes- proteins that speed up chemical reactions

Proteins: Food Sources
• Proteins are found in meat, fish, legumes, nuts, milk, eggs, grains and soy products .
• There are 6 amino acids that our bodies cannot make- we can only get these from food.

Proteins: Indicator Test
• Biuret ’ s Solution :
– Turns from blue to purple if protein is present

Carbohydrates

Carbohydrates: Structure
• Carbohydrates are made up of…
– Monomer (basic unit): simple sugars (or monosaccharides )
• Ex.: glucose
– Polymer (chain of units): complex carbohydrates (or polysaccharides )
• Ex.: starch, cellulose, chitin, glycogen
Disaccharide:
2 simple sugars bonded together

Carbohydrates: Function
• Provide body with energy!
– What should you eat before playing the big game?
Candy bar or pasta?
• Candy bar: contains simple sugars, provides a short burst of energy
• Pasta: contains starch which takes longer to break down, provides longer-lasting energy
– *We can ’ t digest celluloseit is used as fiber, or roughage instead.
• Ex. : corn
Complex carb (ex. Starch)
Broken down to disaccharides
Broken down further
Simple sugars (ex. Glucose)

Carbohydrates: Food Sources
• Simple carbs (simple sugars) are found in most candy and sweet drinks, fruit, vegetables, and milk.
They are quickly digested and give a short burst of energy.
• Complex carbs (like starches) are found in pasta, bread, potatoes, legumes & corn. They take longer to digest, and provide energy longer.

Carbohydrates: Indicator Tests
• Simple Sugars:
– Benedict ’ s solution
– Blue solution turns orange/green/brown
• Complex Carbs:
– Lugol ’ s solution/Iodine
– Turns from orangered-brown to blackpurple

Nucleic Acids

Nucleic Acids: Structure
• Nucleic Acids are made up of…
– Monomers (basic unit): nucleotides
– Polymers (chain of units): DNA or RNA

Nucleic Acids: Function
• Stores and carries genetic information

Nucleic Acids: Food Sources
• We get nucleic acid components from vitamins and minerals in our diet.
These in turn, come from fruits, vegetables, grains, meats, & almost anything else you can think of with some nutritional value (no junk food!).

Nucleic Acids: Indicator Test
• You will not be using an indicator test for these but in case you ’ re wondering…
• Dische diphenylamine test
– Turns from clear-light blue to dark blue if nucleic acids are present

Digestion & Reconstruction
• When macromolecules are eaten, they are digested and broken down into their subunits (monomers).
– Analogy: taking apart an old brick building
• Inside the cells, these subunits are reconstructed into the macromolecules we need.
– Analogy: using bricks to build a new building

Digestion Products
Macromolecule eaten:
Broken down in stomach to:
Carbohydrates Simple sugars (i.e. glucose)
Lipids
Proteins
Fatty acids & glycerol
(glycerol further broken down to glucose)
Amino acids
Nucleic Acids Nucleotides