Docsity
Docsity
Prepare for your exams
Prepare for your exams

Study with the several resources on Docsity

Earn points to download
Earn points to download

Earn points by helping other students or get them with a premium plan

Guidelines and tips
Guidelines and tips
Sell on Docsity
Sell on Docsity
Docsity AI
Docsity AI
Log inSign up

Prepare for your exams

Study with the several resources on Docsity

Find documents

Prepare for your exams with the study notes shared by other students like you on Docsity

Search for your university

Find the specific documents for your university's exams

Docsity AINEW

Summarize your documents, ask them questions, convert them into quizzes and concept maps

Explore questions

Clear up your doubts by reading the answers to questions asked by your fellow students

Earn points to download

Earn points by helping other students or get them with a premium plan

Share documents
download point icon20 Points

For each uploaded document

Answer questions
download point icon5 Points

For each given answer (max 1 per day)

All the ways to get free points
Get points immediately

Choose a premium plan with all the points you need

Study Opportunities

Choose your next study program

Get in touch with the best universities in the world. Search through thousands of universities and official partners

Community

Ask the community

Ask the community for help and clear up your study doubts

Free resources

Our save-the-student-ebooks!

Download our free guides on studying techniques, anxiety management strategies, and thesis advice from Docsity tutors

lipids biochemistry notes, Study notes of Medical Biochemistry

University of Lahore (UL)Medical Biochemistry

easy to study and to pass exam

Typology: Study notes

2016/2017

Uploaded on 12/31/2017

sana-javed-janjua
sana-javed-janjua 🇵🇰

4.4

(5)

6 documents

1 / 20

Toggle sidebar

This page cannot be seen from the preview

Don't miss anything!

bg1
1
1
2
Learning Objectives
•Food Quality
-Flavor, aroma, texture, mouth feel
- Safety
•Nutritional
-energy source
- cell structures
- essential fatty acids
•Biological
-vitamins A, D, E, & K (fat soluble)
- cell membrane characteristics
- cholesterol for Vit. D3, corticosteroids, bile acids
- signaling molecules, e.g. eicosanoids
PDF Creator - PDF4Free v2.0 http://www.pdf4free.com
pf3
pf4
pf5
pf8
pf9
pfa
pfd
pfe
pff
pf12
pf13
pf14

Partial preview of the text

Download lipids biochemistry notes and more Study notes Medical Biochemistry in PDF only on Docsity!

1

2

Learning Objectives

  • Food Quality
    • Flavor, aroma, texture, mouth feel
    • Safety
  • Nutritional
    • energy source
    • cell structures
    • essential fatty acids
  • Biological
    • vitamins A, D, E, & K (fat soluble)
    • cell membrane characteristics
    • cholesterol for Vit. D3, corticosteroids, bile acids
    • signaling molecules, e.g. eicosanoids

PDF Creator - PDF4Free v2.0 http://www.pdf4free.com

3

Background

n Lipids (fats) include a diverse range of compounds that have nonpolar groups that make them relatively insoluble in water (hydrophobic)

n Three major classes:

n Simple lipids – FA, TG, Waxes n Compound lipids – Phospholipids, glycolipids, lipoproteins n Derived lipids - Sterols

4

18.1 Lipids

18.2 Fatty Acids

Chapter 18 Lipids

PDF Creator - PDF4Free v2.0 http://www.pdf4free.com

7

Diversity in structure leads to a diversity in biological function

n Non-polar lipids (fats) are the principal molecules for energy storage n Polar lipids (nitrogen and phosphorus containing) are components of biological membranes n The steroid class of lipids (cholesterol) is found in biological membranes and used as a precursor for many hormones n Miscellaneous lipids present only in minor quantities in the cell are involved as light-absorbing pigments (â-carotene, retinal), enzyme cofactors (vitamin K), signal molecules (prostaglandins), and electron carries (ubiquinone)

8

Classes of Lipids

PDF Creator - PDF4Free v2.0 http://www.pdf4free.com

9

Fatty acids are:

  • Long carbon chains that contain a methyl group (CH3) at one end and a carboxyl group (COOH) at the other (usually 12-18) of carbon atoms.

n Insoluble in water. n Saturated or unsaturated.

  • Location and orientation of these bonds (non-conjugated, conjugated; cis , trans )

Fatty Acids

10

Fatty Acid Formulas

n The formulas for fatty acids are written as condensed and line-bond formulas. For example caprylic acid with 8 carbon atoms can be written as: CH 3 —(CH 2 ) 6 —COOH CH 3 —CH 2 —CH 2 —CH 2 —CH 2 —CH 2 —CH 2 —COOH O || CH 3 —CH 2 —CH 2 —CH 2 —CH 2 —CH 2 —CH 2 —C—OH

OH

O

PDF Creator - PDF4Free v2.0 http://www.pdf4free.com

13

General nomenclature

n The carbon atoms of an acid are numbered (or lettered with Greek lettering system, such as á, â, ã) either from the carboxyl group or from the carbon farthest removed from the carboxyl group (n or omega numbering system) n CH 3 -CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -COOH n 10 9 8 7 6 5 4 3 2 1 n 1 2 3 4 5 6 7 8 9 10 n ù ä ã â á

14

Saturated – single bonds

Nomenclature and Structure

Unsaturated – double bonds

R1 C C C C C R

R1 C C C C C R

PDF Creator - PDF4Free v2.0 http://www.pdf4free.com

15

Cis-fatty Acids

n A cis configuration means that adjacent

hydrogen atoms are on the same side of the

double bond. The rigidity of the double

bond freezes its conformation.

16

Trans-fatty Acids

n A trans configuration, by contrast, means that the next two hydrogen atoms are bound to opposite sides of the double bond. n Animal fats and foods with partially hydrogenated vegetable oils can contain trans-fatty acids

n Increased consumption of partially hydrogenated vegetable oils is associated with increased risk of heart disease

PDF Creator - PDF4Free v2.0 http://www.pdf4free.com

19

Saturated Fatty Acids

Saturated fatty acids have single C–C bonds.

20

Systematic names

Components Common name Systematic name 1 formic methanoic 2:0 acetic ethanoic 3:0 propionic propanoic 4:0 butyric butanoic 5:0 valeric pentanoic 6:0 caproic hexanoic 8:0 caprylic octanoic 10:0 capric decanoic 12:0 lauric dodecanoic 14:0 mystiric tetradecanoic

PDF Creator - PDF4Free v2.0 http://www.pdf4free.com

21

Systematic names (continue)

Components Common name Systematic name 16:0 palmitic hexadecanoic 16:1 (9) palmitoleic cis-9-hexadecenoic 18:0 stearic octadecanoic 18:1 (9) oleic cis-9-octadecenoic 18:1 (11) vaccenic cis-1-octadecenoic 18:2 (9,12) linoleic all cis-9,12- octadecadienoic 18:3 (9,12,15) linolenic all cis-9,12,15- octadecatrienoic 20:0 arachidic eicosanoic 20:4 (5,8,11,14) arachidonic all cis-5,8,11,14- eicosatetraenoic

22

Saturated fatty acids have: n Molecules that fit closely together in a regular pattern. n Strong attractions between fatty acid chains. n High melting points that makes them solids at room temperature.

Saturated Fatty Acids

PDF Creator - PDF4Free v2.0 http://www.pdf4free.com

25

Unsaturated fatty acids: n Have nonlinear chains that do not allow molecules to pack closely. n Have low melting points. n Are liquids at room temperature.

Unsaturated Fatty Acids

26

linoleic acid cis -9, trans -11 CLA trans -11 18:

Double bonds: cis vs. trans

PDF Creator - PDF4Free v2.0 http://www.pdf4free.com

27

linoleic acid cis -9, trans -11 CLA trans -11 18:

Double bond pairs: non-conjugated vs. conjugated

28

21

Hydrogenation of Oils

The hydrogenation of oils

  • adds hydrogen (H 2 ) to the carbon atoms of double bonds.
  • converts double bonds to single bonds.
  • increases the melting point.
  • produces solids such as margarine and shortening.

PDF Creator - PDF4Free v2.0 http://www.pdf4free.com

31

Essential FA

n Humans are unable to synthesize fatty acids that have double bonds in the omega-3 or omega-6 positions

n Omega-3 EFAs n Eicosapentaenoic acid (EPA): coldwater fish n Docosahexaenoic acid (DHA): coldwater fish n Alpha-linolenic acid (ALA): flax, walnut, soybean oils

n Omega-6 EFAs n Linolenic acid (LA): animal fats, sunflower oil n Gamma-linolenic acid (GLA): sunflower oil

32

Omega-6 and Omega-

Fatty Acids

The first double bond: n In vegetable oils is at carbon 6 (omega-6). n In fish oils is at carbon 3 (omega-3).

PDF Creator - PDF4Free v2.0 http://www.pdf4free.com

33

Essential fatty acids

n Mammals cannot synthesize the two main types of polyunsaturated fatty acids: the linoleic (omega-6) and linolenic (omega-3) n Essential fatty acid deficiency is characterized by dermatitis and poor wound healing n Most prostaglandins are synthesized from arachidonic acid (a linoleic acid derivative) n Lack of these prostaglandins causes some aspects of the essential fatty acid deficiency syndrome n A small daily intake of linolenic acid is recommended (this may be especially important when the nervous system is developing) n Docosahexaenoic acid (22:6n-3) – omega-3 fatty acid is needed for maximum development of the visual and central nervous systems during the neonatal period (it is present in large amounts in the retina and parts of the brain; it enhances the visual response and the function of certain domains in neural membranes)

34

Prostaglandins

Prostaglandins have: n 20 carbon atoms in their fatty acid chains. n An OH on carbon 11 and 15. n A trans double bond at carbon 13.

PDF Creator - PDF4Free v2.0 http://www.pdf4free.com

37

LDL

  • Too much LDL can circulate in the blood
  • Build up in arteries; lead to heart attack

38

HDL

  • Another lipoprotein that converts cholesterol into a lipoprotein that returns to the liver ; Removes cholesterol out of the bloodstream;
  • believed to prevent heart attacks

PDF Creator - PDF4Free v2.0 http://www.pdf4free.com

39

Ratio of LDL to HDL

  • LDL cholesterol of less than 100 mg/dL is the optimal level. Less than 130 mg/dL is near optimal for most people.
  • A high LDL level (more than 160 mg/dL or 130 mg/dL or above if you have two or more risk factors for cardiovascular disease) reflects an increased risk of heart disease
  • Low HDL cholesterol levels [less than 40 mg/dL] is thought to increase the risk for heart disease.

40

Other eicosanoids

n When a cell responds to a stimulus, bioactive mediators (prostaglandins, thromboxanes, leukotrienes, and others) often are formed from the lipids contained in its membranes. n Thromboxanes regulate blood coagulation. n Leukotrienes play a role in allergic and inflammation responses. They were isolated from leukocytes (white blood cells).

PDF Creator - PDF4Free v2.0 http://www.pdf4free.com