Chapter 5 - Lipid Structure And Funciton Flashcards Preview

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Four major subclasses of sphingolipids

1) Ceramide: single H atom as its head group

2) sphingomyelins:
- also phospholipids
- have either phosphatidylcholine or phosphatiylethanolamine as head group
- head groups have no net charge
- found in plasma membranes of cells producing myelin

3) glycosphingolipids:
- cerebrosides: single sugar
- globosides: two or more

4) gangliosides:
- glycolipids that have a polar head groups w one or more N-acetylneuraminic acid (NANA)
- negative charge



Esters of long chain fatty acids with long chain alcohols



Metabolic precursors to steroids and other lipid signaling molecules

- built from isoprene (C5H8)
- strong smells



Derivatives of terpenes that have undergone oxygenation or rearrangement of the carbon skeleton



20 carbon molecules are unsaturated carboxylic acids derived from arachidonic acid
- contain one five-carbon ring
- paracrine and autocrine signalling

*regulate synthesis of cAMP

Downstream effects:
- smooth muscle function
- influence over the sleep-wake cycle
- elevation of body temp (fever and pain)

* NSAIDS inhibit cyclooxygenase (COX)
- aids in production of prostaglandins


What are fat soluble vitamins?
List 4

Vitamin: essential nutrient that can’t be adequately synthesized by the body

lipid Soluble: accumulate in stored fat

Vitamin A, D, E, K


Tell me about Vitamin A

- unsaturated hydrocarbon
- vision, growth, development, immune function


Vitamin D


Can be consumed or formed in a UV light driven reaction in the skin

Liver and Kidneys: D is converted to calcitriol
- increases calcium and phosphater uptake in intestines
- this promotes bone production

* deficiency results in ‘rickets’:
- in children, underdevelopment, curved long bones and impeded growth


Vitamin E

Tocophérols and tocotrienols

- antioxidants
- their aromatic ring reactions with free radicals and destroys them

- prevents oxidative damage (contributes to cancer and aging )


Vitamin K

Phylloquinone (k1), menaquinones (K2)

- posttranslational modifications required to form prothrombin (clotting factor)

- also required to introduce calcium-binding sites on several calcium dependant proteins


Why are lipids good for energy storage?

1) carbon atoms of fatty acids are more reduced than those of sugars (which have numerous alcohol groups)
- ox of triaglycerols yields 2x amount of energy per gram as carbohydrates
- much more energy dense!

2) they are hydrophobic
- don’t draw in water and don’t require hydration for stability
- this decreases their weight

3) also a perk for vertebrates is the lipid layers are great for insulation