Met 1: Lipids Overview

Question 1

Define saturated and unsaturated fatty acids

Answer 1

Saturated fatty acids: no double bonds (every carbon is saturated with hydrogens)

Unsaturated fatty acids: double bonds

Question 2

Do unsaturated fatty acids have cis or trans bonds?

Answer 2

Unsaturated fatty acids naturally have cis double bonds

Trans fats are fatty acids that have been chemically modified to introduce trans double bonds

Question 3

Compare the melting point of saturated and unsaturated fatty acids

Answer 3

Saturated fatty acids have a higher melting point.

This means that saturated fats (such as butter) are solid at room temperature, while unsaturated fats (such as olive oil) are liquid at room temp

Question 4

What makes up a triglyceride?

Is it polar?

Answer 4

Glycerol backbone + 3 fatty acids

The fatty acids were amphoteric, but esterification with glycerol makes triglycerides entirely nonpolar

Question 5

Describe the structure of an omega-3 fatty acid

Answer 5

Fatty acid with double bond 3 carbons from the end

Question 6

What makes up a phospholipid?

Answer 6

Glycerol + fatty acids + polar head group (eg. phosphate)

Question 7

What are phospholipids used for?

Answer 7

Signaling and structures (eg. membrane)

Question 8

What is the structure of a free cholesterol?

What about a cholesterol ester?

Answer 8

Free cholesterol: 4 rings of carbon with a hydroxyl

Cholesterol ester: 4 rings of carbon with something esterified where the hydroxyl was

Question 9

Compare the polarity of triglycerides, free cholesterol, phospholipids, cholesterol ester, and fatty acids.

Answer 9

From most polar to least polar:

1. Fatty acid (amphoteric)
2. Phospholipid
3. Free cholesterol
4. Tryglyceride
5. Cholesterol ester

Question 10

How are the more polar lipids moved throughout the body?

Answer 10

Lipoproteins! (too lipophilic to be dissolved in blood)