Lipids (CH 3.5) Flashcards
What is a Lipid?
- Loosely defined group of molecules that are INSOLUABLE in water
- Have very high proportion of nonpolar C-H bonds= cluster together when placed in an aqueous environment
What is the structure of a Lipid?
-Glycerol molecule that has 3 fatty acids, one to each Carbon molecule of the glycerol backbone
What are Fatty acids?
-Long Carbon Hydrogen chains with carboxylic acid on one end
What is Glycerol?
-3 carbon polyalcohol (3 -OH group)
What is a Triglyceride?
- A fat molecule bc it has 3 of the C-H chains attached to glycerol
- Very dense form of energy storage for plants & animals
- They’re HIGHLY reduced (have hella H’s) & energy can be released via oxidation
- Have a lot of energy for its mass (9 Kcal)
What ar the 3 types of Lipids?
- Triglycerides (small polymers)
- Phospholipids (small polymers)
- Steroids
What is the structure of a Triglyceride?
- Have 3 fatty acids= carboxylic acids/w long chains of methyl & methylene groups covalently bonded to glycerol
- 30 H groups covalently bonded to carboxylic acid in fatty acids
What are Phospholipids & what is their structure?
- Small polymers that are Polar & Nonpolar
- Have 2 fatty acids & a phosphate covalently bonded to glycerol
- Connected by ester bonds
- Completely nonpolar bc O’s are small part of the molecule & buried inside
What makes Phospholipids different from Triglycerides?
-Phospholipids REPLACE 1 nonpolar fatty acid w/ polar phosphate
What is the function of Phospholipids?
-Major component of the biological membrane
What are Steroids?
- Has backbone of 4 interconnected carbon rings which allows it to be configured in many different ways (cholesterol & lipid hormones)
- Completely nonpolar & are lipids that aren’t polymers
What is the structure of steroids?
- 4 rings of C & H atoms w/ attachments
- Different attachments have different functions (hormones, vitamin D, membrane components)
What does it mean when Membranes are Aggregate?
- They have an irregular noncovalent association w/ molecules
- These molecules are mostly phospholipids & steroids & proteins
- The not covalent polymers allow them to move more
- The nonpolar parts of these components associate by hydrophobic effect
What are the 2 types of fatty acids?
- Saturated
- Unsaturated
What are the characteristics of Saturated fats?
- Are less healthy than unsaturated fats
- Excess consumption can increase heart disease, & risk of diabetes
- Pack well together= easily forms a solid (chicken fat, lard, bacon fat)
What are the 2 kinds of Unsaturated fats?
- Cis
- Trans
What are Cis Unsaturated fats?
- Super healthy
- Naturally occuring
- Lead to more muscle mass & less ab/ viceral (organ) fat
What are Trans Unsaturated fats?
- The worst out of all 3 types of fatty acids
- Artifical food additives made by partial hydrogenation of the cis fats
- It its completely hydrogenated then it turns into a saturated fat
How does partial hydrogenation affect Cis unsaturated fats?
- It leaves the double bonds & turns some of the natural Cis double bonds into Trans
- This causes things not to spoil fast (twinkies)= we can’t break then down & neither can bacteria
What do Cis fatty acids look like?
C-C=C-C
-Goes up, straight at the double bond, then goes back down
What do Saturated fatty acids look like?
C-C-C-C
-Straight & only single bonds
What do Trans fatty acids look like?
C-C=C-C
-Goes up, straight at double bond, then goes up again
What does the overall saturation of a triglyceride determine?
-Determine if the fat is liquid or solid at room temperature
What are the characteristics of Unsaturated fats?
- Don’t pack well together bc they have kinks (double bonds)
- They stay as a liquid (canola oil, olive oil, corn oil)
What do Phospholipids look like?
- 2 of Fatty acid chains connected to glycerol
- Glycerol is connected to phosphate to form a polar head
- Have Polar Hydrophobic heads & Nonpolar hydrophobic tails
What are the characteristics of Phospholipid layers?
- Are part nonpolar & polar
- Polar heads are facing on the exterior of bilayer
- Nonpolar tails will interact with eachother in the interior of bilayer
- In between both tails= methyl group
- Properties are modified by other membrane components which allow polar molecules (UREA) to cross the membrane
How are Phospolipid layers made?
-By phospholipids when they interact w/ water
What is the function of the Phospholipid bilayer?
- They’re major components of biological membranes
- They create barrier that SEPARATES COMPARTMENTS in the cell
