Lipids

Question 1

What are the structural characteristics of lipids?

Answer 1

Question 2

What are the functional characteristics of lipids?

Answer 2

Active:
-Pigments
-Hormones

Question 3

What are fatty acids?

Answer 3

Question 4

What is the nomenclature for fatty acids?

Answer 4

Question 5

Describe fatty acid structure

Answer 5

Question 6

What fatty acids are of nutritional importance?

Answer 6

Question 7

What is triacylglycerol?

Answer 7

Question 8

Why are fats key molecules for long term energy storage?

Answer 8

Question 9

What is saponification?

Answer 9

Question 10

What are waxes and their function?

Answer 10

Question 11

Explain structural lipids in membranes

Answer 11

Question 12

What are glycerophospholipids?

Answer 12

Question 13

Draw the structure of Phosphatidylinositol and what is its function?

Answer 13

involved in intracellular signal transduction

Question 14

What are galactolipids and sulpholipids?

Answer 14

Question 15

What are sphingolipids?

Answer 15

Question 16

Describe archaebacteria (extremophiles)

Answer 16

Question 17

What are sterols?

Answer 17

Question 18

What is cholesterol?

Answer 18

Question 19

Draw the structure of DAG and IP3

Answer 19

Question 20

How does Phophatidylinositol Act as an intracellular signal?

Answer 20

Question 21

What are steroid hormones?

Answer 21

-Hydrohpobic oxidized sterol derivaties
-carried through bloodstream by carrier proteins
-pass through plasma membrane to bind receptors in the nucleus
-alter patters of gene expression and metabolism
-precurson to hormones (signalling)

Question 22

What are characteristics of vitamins A,D,E,K

Answer 22

-All contain rings and long, aliphatic side chains
-All are highly hydrophobic
-differ widely in their functions

Question 23

Describe vitamin D

Answer 23

-Regulates Ca2+ uptake and deposition
-Can be obtained from the diet or produced endogenously
-Endogenous production occurs in a series of reactions, one of which requires UV light
-Insufficient vitamin D is associated with skeletal defects (rickets)
-Excessive vitamin D can cause calcification of soft tissues

Question 24

describe vitamin A

Answer 24

-Obtained from liver, egg yolks, and milk products
-Some animals have sufficient vitamin A in their livers to present a danger to humans if they were to consume them
-vitamin A exists in 3 forms: Alcoho (retinol), aldehyde and retinoic acid
-Retinal (aldehyde) is a light-sensitive compound with a role in vision. Deficiency causes night blindness
-“red eye” in photos results from retinal

Question 25

Describe vitamin E (a-tocopherol)

Answer 25

-A reducing reagent that scavenges oxygen free radicals
-may prevent damage to fatty acids in membranes
-Often used as an additive in cosmetics
-deficiency causes scaly skin, muscular weakness and sterility

Question 26

What are the common carbon chain lengths of fatty acids in plants and animals?

Answer 26

16-18 (most common)
20-22 (nutrients such as omegas)

Question 27

What does unsaturated fatty acid mean?

Answer 27

1 or more double bonds

Question 28

What are delta vs omega nomenclatures of unsaturated fatty acids?

Answer 28

Delta: COOH end
Omega: CH3 end

Question 29

Are C=C double bonds commonly in cis or trans configuration? Why is it important?

Answer 29

Cis: Makes a structural kink change

Question 30

Why do animal fat and plant oil look and feel so different while they are all tracylglycerols?

Answer 30

Cis double bonds found it plant oil make kinks that don’t allow for tight packing that makes the gel like structure in animal fats

Question 31

Why are omega-3 fatty acids such as DHA branded as nutrional supplements?

Answer 31

-The body cannot make omega 3 or 6 fatty acids, must come from food
-Abundant in brain and spinal chord

Question 32

To form micelles, do we need a polar group in addition to the hydrophobic tail?

Answer 32

Yes, need hydrophilic head to maintain structure of biological membranes

Question 33

Which one has higher energy stored in one gram: sugar or fat, and why?

Answer 33

Fat, has a low oxidation state that burns more efficiently and a low hydration state that limit water interaction and are a more compact, dehydrated energy storage form

Question 34

In biological membranes, how many long hydrophobic tails does a membrane-forming lipid molecule have?

Answer 34

Two hydrophobic tails per one hydrophilic head

Question 35

How many backbones are commonly found in lipids? what are they?

Answer 35

Glycerol:
-Triacylglycerols
-Glycerophospholipids
-Galactolipids (sulfolipids)

Sphingosine:
-Sphingolipids

Question 36

How many types of polar head groups are commonly found in lipids? What are they?

Answer 36

Phospho and glyco (sugars)

Question 37

Which type of lipids are richest in oligosaccharide varieties?

Answer 37

Glycosphingolipids

Question 38

Which type of lipids determines blood type?

Answer 38

Glycosphingolipids

Question 39

Are biological membranes typically bi-layered or mono-layered? What organisms are the exception?

Answer 39

Typically bilayered, Archaebacteria (extremophiles) are the exception because they live under conditions of high temp, pH and ionic strength

Question 40

Which type of lipid is often found to modulate the fluidity of biological membrane?

Answer 40

cholesterols

Question 41

How does PIP2 processed to produce two signaling molecules? What are they?

Answer 41

Activation of PLC in response to extracellular signal triggers cleavage of PIP2 to produce IP3 which increases Ca2+ in which Ca and DAG activate specific intracellular pathways and processes
-IP3 and DAG

Question 42

What type of compounds are sex hormones?

Answer 42

Steroid hormones (hydrophobic oxidized sterol derivatives)