Lipids Flashcards
What are the functions if white adipose tissue?
It is a complex metabolically active endochrine tissue with the following functions-
- Secretion of-
-hormones
-enzymes
-cytokines - Protection of organs
- Provides insulation
Name the different lipids that exist in the human body
Fatty Acids
Triglycerides
Phospholipids
Cholersterol
Steroid compounds (eg. oestrogen)
Sphingolipids (found in nerve cell membranes e.g. Myelin)
Glycolipids (lipids +carbohydrate) involved in cell identity
Cerebrosides (in the brain)
Fat doluble vitamins A, D, E, K
How many calories does each gram of fat provide?
9 kcal
Give 5 functions of lipids
- Energy (ATP production)
- Energy storage
- Cell membrane structure
- Thermal insulation (subcutaneous fat)
- Organ protection (visceral fat)
Define what it meant by a short chain fatty acid
One with fewer that 6 carbon atoms
Name the 3 most common SCFAs
Acetate, propionate and butyrate
Why is Butyrate particularly important for colon health
It is the primary energy source for colonocytes and supports intestinal tight junctions
It has an anti-inflammatoy effect on the colon
What is a Fatty Acid?
Hydrocarbon chains with an acid group at one end and a methyl group on the other
What are the properties of a medium chain fatty acid
-Has 6-12 carbon atoms
-Can travel directly to the liver where they can be used to create energy or ketones
-good source of energy before excercise
What are the properties of a long chain fatty acid?
-Have 14-22 carbon atoms
-Used the build cell membranes
What are the properties of Saturated fatty acids?
-Contain no CC double bonds
-All the carbons are completely saturated with hydrogen bonds
-Solid at room temperature
-Stable oil
-Best oil to cook with at high temperatures
What are the proerties of Unsaturated Fatty Acids?
-Contain 1 or more double bonds between carbons
-Liquid at room temperature
How many double bonds do Mono unsaturated fatty acids have?
One
How many bonds do Polyunsaturated Fatty Acids have and how does this affect it’s stability?
Several double bonds. This makes it more unstable as the more double bonds the less stable and the more susceptible to oxidisation it becomes.
What are trans fats and why are they to be avoided?
Unsaturated fats that are made saturated by the addition of hydrogen (hydrogenised).
To be avoided because-
-They stiffen cell membranes, making them prone to oxidation, and alters their permeability, impeding normal cell function
-They alter blood triglyceride and cholesterol levels which increases risk of CV disease, insulin resistance and cancer.
Explain the difference between a Cis fat and a trans fat?
Cis- The hydrogen atoms are on the same side as the double bond
Trans- The H atoms are on seperate sides of the double bond.
What is a Triglyceride?
Lipid mollecules made up of 1 unti of glycerol and 3 fatty acids.
They are the major form of dietary fat and the form in which fat is stored.
Why are high trglycerides considered bad?
Linked to atherosclerois.
What triggers the body to synthesise triglycerides?
Whenever caloric intake exceeds energy requirements.
Excess energy is converted to trglycerides in a process known as lipogenesis and excess ingested fat is taken up by adipose tissue
Where does Lipogenesis take place?
In adipose tissue and the liver
Define Lipogenesis?
The process through which acetyl-Co-A is converted to tryglycerides for storage in fat.
Define Lypolysis
When dietary energy is limited, the fatty acids from triglycerides are mobilised from adipocytes into circulation
What is Lipolysis stimulated by?
-Adrenaline and noradrenaline
-Adrenocorticotropic hormone (ACTH)
-Glucagon
-Growth hormone
-TSH and thyroxine
What is Lipolysis inhibited by?
Insulin
Insulin resistance=central adiposity