Lipids

Question 1

What functional group do lipids have?

Answer 1

The carboxyl group (cooh)

Question 2

Name 5 groups of lipids

Answer 2

1. Fatty acids
2. Glycerides
3. Phospholipids
4. Steroids
5. Lipoproteins

Question 3

Describe lipid properties

Answer 3

Hydrophobic/ insoluble in water
Soluble in organic solvents
Energy source
Source of cellular messengers

Question 4

Name fatty acid roles

Answer 4

Components of membranes
Modify proteins covalently
Act as energy stores and fuel molecules

Question 5

Describe the structure of fatty acids

Answer 5

Hydrocarbon chain
Carbonyl group at terminal
Even number of C atoms
Is a monocarboxylic acid

Question 6

What is a monocarboxylic acid

Answer 6

An alkylchain with a carboxyric acid group at the end- fatty acid

Question 7

How long are short, medium, long, fatty acids

Answer 7

Short: 2-4 C
Medium: 6-10 C
Long: 12 - 26 C

Question 8

What are essential fatty acids?

Answer 8

FAs that can’t be synthesized by the body

Question 9

Describe saturated FAs

Answer 9

Carbon atoms saturated with hydrogen atoms
Solid form (one bond-more rigid)
Longer chain lipids
In dairy and meat

Question 10

Describe unsaturated FAs

Answer 10

Carbons with double bonds
Liquid form (flexible double bonds )
Shorter chain lipids
Oils

Question 11

Distinguish between mono-unsaturated and poly-unsaturated FAs

Answer 11

mono-unsaturated have 1 double bond
poly-unsaturated have 2 or more double bonds

Question 12

What are cis-unsaturated FAs

Answer 12

Have hydrogen from the double bone carbon on one side of the chain

Question 13

What are trans-unsaturated FAs

Answer 13

Hydrogen on opposite sides of double bond

Question 14

What are glycerides

Answer 14

Fatty acids connected via an ester bond to glycerol

Question 15

What is the function of glycerides

Answer 15

Storage and transport
Mostly in adipose tissue

Question 16

How does saponification occur

Answer 16

Triglyceride + NaOH —> glycerine + soap

Question 17

What can dyslipidemia because by

Answer 17

Genetics
Obesity
Little exercise
Poor diet
Poor glucose control

Question 18

How to manage dyslipidema

Answer 18

To prevent acute pancreatitis
Very low fat diet
Triglyceride-lowering drug(fibrate/ nicotinic Acid)

Question 19

Structure of phospholipids

Answer 19

Fatty acid chain
Glycerol backbone
Polar head group ( phosphate and choline)

Question 20

Function of phospholipids

Answer 20

Make the plasma membrane - amphipatic phospholipid belayer

Question 21

Structure of steroids

Answer 21

Lipids with complex 4 ring structures
Vary in functional groups and double bond location

Question 22

Functions of cholesterol

Answer 22

Cell membrane component ( adds rigidity)
Precursor for bileacids, vitamin D, steroid hormones

Question 23

Features of cholesterol

Answer 23

Hydrocarbon tail and esterified fatty acid at terminals
Produced only by animals
85% produced de-novo
15% comes from diet

Question 24

Name the entry points of liver cholesterol

Answer 24

Dietary cholesterol 15%
De-novo liver synthesis 80%
Synthesis in tissues 5%

Question 25

Name the exit points of liver cholesterol

Answer 25

Secretion of HDL and LDL Cholesterol secreted in bile Conversion into bile acids/salts

Question 26

Function of lipoproteins

Answer 26

Solubilize hydrophobic lipids Contain signal molecules that regulate lipid entry/exit at specific target cells

Question 27

Explain the reverse cholesterol transport

Answer 27

LDL stores cholesterol in the blood stream HDL regulates LDL storage and promotes excretion (cleans up LDL)

Question 28

Name the risk factors of atherosclerosis

Answer 28

Age Sex Family Obesity Smoking Diabetes Hyperlipidemia Hypertension Infection/toxin

Question 29

How can cholesterol be controlled?

Answer 29

Absorption blockers- diet Satins biosynthesis ( HMG CoA reductase inhibitors) Bile acid sequestrants (using up cholesterol by making bile acid) Fibrates - lipoprotein metabolism TG reduction