5. Lipids Flashcards
Which side of lipids are hydrophobic and hydrophilic?
hydrophobic fatty acid tails, hydrophilic heads
Know micelle, liposome and phospholipid bilayer
Know them structures. Micelles make soap bubbles
Saturated fatty acid vs unsaturated fatty acid. Which one is better for membrane fluidity?
made up of single bonds vs made up of double bonds –> kinks –> hard for them to stack and solidify; better for membrane fluidity
How are lipids’ solubility and melting temp determined?
longer chain –> higher melting temp and lower solubility; more double bonds –> lower melting temp
What are glycerophospholipids? How are they named?
phospholipids with glycerol backbone with ester linkages to 2 fatty acids and phosphodiester linkage to 1 highly polar head group. They’re named according to their head group (ex: phosphatidyl-“head group”)
What are sphingolipids? What are the 4 subclasses?
phospholipids with SPHINGOID backbone with long nonpolar fatty acid tails and polar head groups; they’re used in ABO blood typing system. Ceramide (has H has head group and only has actual spingosine backbone), sphingomyelins (has phosphodiester bond => phospholipid), glycosphingolipids (has no phosphodiester bond, has glycosidic bond => not a phospholipid), gangliosides (has no phosphodiester bond, has glycosidic bond => not a phospholipid)
What are waxes made up of?
esters of long fatty acid chains with long chain alcohols
Know the structure of triglycerides. Know their purpose and what type of bond and type of rxn bond makes. Know chylomicron
3 fatty acid chains + glycerol (a 3 C alc)
dehydration –> 3 water molec released
ester bond
Purpose: storage lipids
Chylomicron = lipoproteins consisting of triglycerides, phospholipids, proteins and cholesterol
Know the basic structure of steroids. Know basic description of steroid hormones
3 cyclohexane rings and 1 cyclopentane ring. Produced in endocrine glands, travel in bloodstream to high-affinity receptor in nucleus
What are fatty acids made up of? How are they bonded?
CA + long hydrocarbon (C-H) chain via ester bond
What type of rxn is making a phosphodiester bond? What’s the difference b/w alpha vs beta glycosidic bonds?
dehydration
both groups = same side vs both groups = opposite sides
What is the only FA humans can synthesize? Where is it formed?
Palmitic acid made of 16 carbons. Produced in cytoplasm from 8 acetyl CoA that’s been transported out of mitochondria, 7 ATP, and 14 NADPH
How does keto genesis occur?
Prolonged starvation, excess acetyl CoA in liver, beta [O] occurs in mito matrix
Terpenes
Class of lipids built by isoprene, monoterpene = 2 isoprene units; precursor to steroids, cholesterol and ear wax; can create terpenoids like vit A
Big thing about cholesterol?
Found in cell membrane and is responsible for fluidity: prevents from solidifying at low temps and prevents too much permeability at high temps; they’re amphipathic; they’re steroid hormone precursors. They have the four ring steroid structure. They help make bile in liver
What are prostaglandins? What can prevent their production?
Unsaturated CAs derived from arachidonic acid that act as autocrine and paracrine signal molecs; they help regulate synthesis of cAMP; also help with inflammation, pain and smooth muscle function. NSAIDS like aspirin
How are vitamins synthesized, name 2 categories and list examples of fat soluble vitamins
Can’t synthesize them, get them thru diet; water soluble that can be excreted thru urine and fat soluble that can be stored in fat; A, D, E and K
Vitamins A vs D vs E vs K
Carotene; vision, growth, immunity; retinal = most important vit A metabolite, stored as retinol which can be oxidized to retinoic acid to regulate epithelial development vs cholecalciferol from UV light, can be converted to calcitriol in liver and kidneys; lack of D results in rickets: long curved bones and impede growth vs tocopherols and tocotrienols; antioxidants vs phylloquinone and menaquinone; post translational modification of prothrombin, coagulation
Saponification
Ester hydrolysis of triacylglycerols using a strong base
Why is more energy stored as fats than glycogen?
Fats are more reduced and carry more weight —> more energy
Can fats be converted to glucose during starvation? What about glucose converted to fats?
No, humans don’t have the enzymes to do so. Yes, in the liver: glu = converted to FAs, which are converted to triacylglycerides
