unit #2: biomolecules notes.4: intro to biomolecules & lipids
TRANSCRIPT
Unit #2: Biomolecules
NOTES.4: INTRO TO BIOMOLECULES & LIPIDS
Do Now:Here is the structural formula of phospholipid an
important structural that makes up parts of the cell membrane. Identify the hydrophobic (hates water) end and the hydrophilic end of this molecule and explain
why using the Claims, Evidence, and Reasoning Format.
PART I:All molecules are made of atoms.
Atoms are building blocks.Where do you get your building
blocks?
You Are What You Ate!Food is a mixture of biomolecules:
• Carbohydrates (sugars & starches)
• Proteins• Lipids (fats, oils, & cholesterol)• Nucleic Acids (DNA & RNA)• Vitamins• Minerals (Calcium, sodium, iron,
etc.)• Water
Your body breaks down food items and rearranges them to give you:
ENERGY and BUILDING BLOCKS
Biomolecules are ORGANIC molecules, because they contain the building block of CARBON.
Why is carbon so important?
Carbon atoms have four valence electrons.
Carbon atoms can make up to four bonds with other atoms.
Carbon atoms can make single, double, and triple covalent bonds.
Carbon atoms can easily bond with itself as well as other common elements, such as H, N, and O.
Carbon skeletons can:o vary in lengtho brancho make rings
In addition to carbon, the top four biomolecules also include the building blocks of…
Element
Carbohydrates
Lipids Proteins Nucleic Acids
C ✔ ✔ ✔ ✔
H ✔ ✔ ✔ ✔
O ✔ ✔ ✔ ✔
N ✔ ✔
P ✔* ✔
S ✔**
* Phospholipids ** Some proteins
Functional GroupsAll biomolecules have functional groups.
Functional groups are groups of atoms that give similar properties onto otherwise dissimilar molecules.
For example:(1) Alcohols are characterized by a hydroxyl group. This group makes the compound polar and hydrophilic. Therefore, alcohols dissolve in water easily. An example is ethanol.
(2) Carboxylic acids are characterized by a carboxyl group. These compounds are water soluble weak acids that are often aromatic. An example is acetic acid (vinegar).
Polarity is important! Functional groups of molecules helps us understanding interactions
between molecules!
Let’s investigate polarity:1. Part I & II: How does a Soap Molecule Work?
2. Part III: Hello Kitty Shaving Art Contest with Shaving Cream!
Part II:How does our body put these
building blocks together and take them apart in order to make and
break biomolecules?
How does the body build biomolecules?Biomolecules are examples of MACROMOLECULES, which are giant molecules in living things that are made from 1000’s of smaller molecules.
All macromolecules are made by the process of polymerization, which is simply making large molecules from smaller molecules.Monomers: single-subunits of a macromolecule
Ex. Glucose
Polymers: large molecules formed from repeating subunits of a smaller molecule
Ex. Starch
Monomers / subunitsCarbohydrate: Monosaccharide Protein: Amino Acid
Lipid: Fatty Acid Nucleic Acid: Nucleotide
Carbohydrate: Polysaccharide Protein: Polypeptide
Lipid: Triglyceride (specific example)
Nucleic Acid: DNA (specific example)
Polymers / macromolecules
Another View: Putting It All Together in Nature…
Amino Acid PolypeptideIntermediate Filament
Nucleotide DNA strandChromosome
Another View: Putting It All Together in Nature…Monosaccharide Polysaccharide
Starch grains in a chloroplast
Fatty Acid TriglycerideAdipose cells with fat droplets
A closer look at polymerization…
Polymerization occurs through the chemical reaction of dehydration synthesis:
Two molecules covalently bond by a removing water molecule.
One molecule loses a –OH, the other molecule loses a –H
Two monosaccharides bonding together to make a disaccharide:
Try it yourself:
Draw out dehydration synthesis of these two amino acids.
+
How does the body break down biomolecules?Biomolecules are broken down through the process of de-polymerization, which is simply breaking large molecules to form smaller molecules.
De-polymerization occurs through the chemical reaction of hydrolysis.
A water molecule is added to disrupt the bond linking monomers together.
One molecule gains –OH, the other molecule gains –H.
A disaccharide breaking apart into two monosaccharides:
Part III:What are the four main
biomolecules? How is each biomolecule structured? What are their roles in life? Where do
we find them in our body?
1. Lipids Large & Varied Group!
Fats, Oils, & Waxes
Do not dissolve in water!
Composed of: mostly C and H atoms
Functions: Energy storage Waterproofing Structure Hormones
What is a saturated vs. unsaturated fat?
Fatty acids that contain one or more double bonds between two carbon atoms are said to beUNSATURATED.
Fatty acids with only single covalent bonds between carbon atoms are said to beSATURATED.
Monounsaturated = 1 double bond
Polyunsaturated = 2 or more double bonds
Saturated fats are bad for you, because they are linear in shape. They easily stack upon one another to clog up blood vessels.
Monounsaturated Fats
Unsaturated FatsPolyunsaturated Fats
Only ONE double bond
TWO or MORE double bonds
http://www.youtube.com/watch?v=5aukVvYC-WA
Two Types of Unsaturated Fats
Cis-Unsaturated Fats• Occur naturally• Hydrogen atoms are on the SAME side of the double bond • the GOOD fats•Ex: Olive Oil
Trans-Unsaturated Fats•Do NOT occur naturally•Hydrogen atoms are on OPPOSITE sides of the double bond•The REALLY BAD fats•Ex: Crisco
Another look… Trans fats occur when H atoms are on opposite sides of the double bond, thus creating symmetry. As a result the fatty acid is linear, so it behaves like a saturated fat in your body.
Cis fats occur when H atoms are on the same side of the double bond, thus creating asymmetry. As a result, the fatty acid is bent in shape.
Let’s Watch A Video!
http://www.youtube.com/watch?v=EJa3E_zXrCo
Where do you find fats in your diet?
TriglycerideBody fat functions to:
Cushion organs Insulation Long-term energy storage
Composed of: Glycerol + 3 fatty acids
PhospholipidPhospholipids are the building blocks of a cellular membrane.
Phospholipids have a:
Polar head that is hydrophilic (“water-loving”).
Nonpolar tails that are hydrophobic (“water-fearing”).
SteroidsCarbon skeleton has:
Four interconnected rings Different functional groups attached
Group of lipids derived from cholesterolIncludes a variety of hormones:
sex hormones glucocorticoids, which regulate glucose metabolism mineralocorticoids, which regulate water and electrolyte levels in
blood