Lipids (CH 3.5)

Question 1

What is a Lipid?

Answer 1

• 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

Question 2

What is the structure of a Lipid?

Answer 2

-Glycerol molecule that has 3 fatty acids, one to each Carbon molecule of the glycerol backbone

Question 3

What are Fatty acids?

Answer 3

-Long Carbon Hydrogen chains with carboxylic acid on one end

Question 4

What is Glycerol?

Answer 4

-3 carbon polyalcohol (3 -OH group)

Question 5

What is a Triglyceride?

Answer 5

• 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)

Question 6

What ar the 3 types of Lipids?

Answer 6

• Triglycerides (small polymers)
• Phospholipids (small polymers)
• Steroids

Question 7

What is the structure of a Triglyceride?

Answer 7

• 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

Question 8

What are Phospholipids & what is their structure?

Answer 8

• 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

Question 9

What makes Phospholipids different from Triglycerides?

Answer 9

-Phospholipids REPLACE 1 nonpolar fatty acid w/ polar phosphate

Question 10

What is the function of Phospholipids?

Answer 10

-Major component of the biological membrane

Question 11

What are Steroids?

Answer 11

• 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

Question 12

What is the structure of steroids?

Answer 12

• 4 rings of C & H atoms w/ attachments

- Different attachments have different functions (hormones, vitamin D, membrane components)

Question 13

What does it mean when Membranes are Aggregate?

Answer 13

• 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

Question 14

What are the 2 types of fatty acids?

Answer 14

• Saturated

- Unsaturated

Question 15

What are the characteristics of Saturated fats?

Answer 15

• 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)

Question 16

What are the 2 kinds of Unsaturated fats?

Answer 16

• Cis

- Trans

Question 17

What are Cis Unsaturated fats?

Answer 17

• Super healthy
• Naturally occuring
• Lead to more muscle mass & less ab/ viceral (organ) fat

Question 18

What are Trans Unsaturated fats?

Answer 18

• 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

Question 19

How does partial hydrogenation affect Cis unsaturated fats?

Answer 19

• 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

Question 20

What do Cis fatty acids look like?

Answer 20

C-C=C-C

-Goes up, straight at the double bond, then goes back down

Question 21

What do Saturated fatty acids look like?

Answer 21

C-C-C-C

-Straight & only single bonds

Question 22

What do Trans fatty acids look like?

Answer 22

C-C=C-C

-Goes up, straight at double bond, then goes up again

Question 23

What does the overall saturation of a triglyceride determine?

Answer 23

-Determine if the fat is liquid or solid at room temperature

Question 24

What are the characteristics of Unsaturated fats?

Answer 24

• Don’t pack well together bc they have kinks (double bonds)

- They stay as a liquid (canola oil, olive oil, corn oil)

Question 25

What do Phospholipids look like?

Answer 25

• 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

Question 26

What are the characteristics of Phospholipid layers?

Answer 26

• 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

Question 27

How are Phospolipid layers made?

Answer 27

-By phospholipids when they interact w/ water

Question 28

What is the function of the Phospholipid bilayer?

Answer 28

• They’re major components of biological membranes

- They create barrier that SEPARATES COMPARTMENTS in the cell