Lecture notes
Lecture Notes
- Module
- Metabolic Pathways
- Institution
- Queen Mary, University Of London (QMUL)
Lecture notes of 12 pages for the course Metabolic Pathways at QMUL
[Show more]
1 review
By: betulalm • 3 year ago
Content preview
Fatty acid oxidationLearning objectives:
1. Importance of triacylglycerol (TAGS or TGS)
2. Overview of fatty acid metabolism
3. Mobilisation of fatty acids
4. Metabolism glycerol
5. Describe 3 stages of fatty acid metabolism (with reference to the committed steps of the process)
6. Strategy for metabolism of odd chain and unsaturated fatty acids
7. Ketone body formation
8. Role in normal physiology and diseases
CTP IS AN ENERGY SOURCE FOUND IN LIPID METABOLISM
Fatty acid: what are they & biological roles?
What is a fatty acid?
- Molecules that contain a long linear (unbranched) hydrocarbon chain and a terminal carboxylate group.
4 major biological roles of fatty acids
1. Building block form phospholipids & glycolipids: important components of biological membranes
2. Covalent attachment to proteins- targets them to membrane locations (prenylation)
3. Fuel molecules: stored as triacylglycerol (also called triglycerides) uncharged ester of fatty acids with glycerol
4. Derivatives serve as hormones & intracellular messengers
Caloric value of fats and carbohydrates
Why store fuel as a fatty acid?
- High concentrated food supply (as completely reduced and anhydrous i.e. no water attached)
- Complete oxidation fats = 9Kcal/g
- Complete oxidation carbohydrates/protein =4kcal/g
- As non-polar are not hydrated
- Unlike carbohydrates - 1g glycogen binds 2g water
- Hydrated carbohydrate 1.3kcal/g
- Thus can store more energy in less weight
Fuel reserves and energy needs
An average human has the following fuel reserves:
- Approx. 1600 kcal of glycogen in liver and muscle
- Approx. 24,00 kcal as protein
- Approx. 13,000 kcal as fat
Typically humans need about 2000-2500 kcal/day
- Fat reserve will last for ~ 2 months
- Average body weight is ~160 Ib (equivalent to 72 Kg)
- Fat weight is ~ 20% (32Ib equivalent to 14 kg)
- Same amount of energy stored as hydrated glycogen would weigh ~220 Ib (equivalent to 99 kg)
Fats provide energy during fasting & starvation
Fasting
- The first source of energy is stored glycogen
Starvation
- Glycogen stores depleted within 24 hours
Brain need glucose as fuel and gets it from 2 sources
1. Protein →AA → glucose
, 2. Triglycerides → glycerol → glucose
- No glucose from FA
Prolonged starvation:
- Proteins preserved for muscle activity
- Fatty acid converted to ketone bodies
- Brain fuel shifted to ketone bodies
Fatty acids (FA)
Long chain linear hydrocarbons carboxylic acids
- usually even number of C atoms ~ 12 to 20
- The C are numbered starting from carboxylic C
They are amphillic
- Have a polar end
- Rest of the molecule is nonpolar
FA may be saturated (no double bonds) or unsaturated (1 or more double bonds)
All naturally occurring double bonds have a cis-configuration longer chain and saturation increases melting point
of FA and FA are ionised at physiological pH
How to get FA?
FA Are the direct source of energy from lipids
FA are oxidised by a process called β-oxidation
When excess fats or calories are consumed in the diet they are condensed into triglycerides
TG are stored in specialised fat-storage called adipocytes
These special cells allow triglycerides to coalesce to form large globules that take up most of cells
Adipose tissue accumulates subcutaneously and in different body cavities of obese people
Liposuction removes this adipose tissue
Sources of fatty acids
1. Dietary lipids processed by the intestinal cells
2. Newly synthesised lipids, mostly by the liver
3. Lipids mobilised from adipocyte stores
LO1. IMPORTANCE OF TRIAGLYCEROLS (TAGS OR TGS)
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller fatima-attia. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £2.99. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
67866 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy revision notes and other study material for 14 years now