2.3.2 Dufan (lipids)

Molikuyuulka dufanka intiisa badani waa kaarboon iyo haaydrojiin, waana ay ku yar tahay oksijiintu. Noocyo kala duwan oo dufan ah ayaa ay muujinayaan sawirrada hoos ku yaallaa. Burcadka, xaydha, baruurta hilibka, labeenta, saliidda iyo subagga, intuba waa dufan.

Dhiska dufanka waxaa loo qaybin karaa labo: giliserool (glycerol) iyo asiidh dufaneed (fatty acid). Sidaas awgeed, halka molikuyuul ee dufanka ahi waa laba molikuyuul oo isku dabran. Dufannada kala jaadka ahi waxa ay leeyihiin asiidh dufaneedyo kala duwan.

Saddex-giliseroolle (triglyceride).

Baruur marka aan leennahay waxa aynu tilmaamaynaa waa kan, waxa uuna ka samaysan yahay hal molikuyuul oo giliserool ah oo ay ku dabran yihiin saddex (tri-) silsiladood oo asiidh dufaneedyo ah (Jaantus 2.14).

Jaantus 2.13 Noocyo kala duwan oo dufan ah. (Midig) xaydh faras, © (b) [CC BY 4.0]. (Dhex) Subag © [CC BY-SA 3.0]. (Bidix) Saliid gabbaldaye © Rasbak [CC BY-SA 3.0], all via Wikimedia Commons.
Jaantus 2.13 Noocyo kala duwan oo dufan ah. (Midig) xaydh faras, © (b) [CC BY 4.0]. (Dhex) Subag © [CC BY-SA 3.0]. (Bidix) Saliid gabbaldaye © Rasbak [CC BY-SA 3.0], all via Wikimedia Commons.

Maxaa xaydha adke ka dhigay, saliiddana dareere? Xaydhu waxa ay ka samaysan tahay asiidh dufaneedyo silsiladdoodu toosan tahay, molikuyuulladuna aad baa ay isugu cabbaysan yihiin, taas ayaana adke ka dhigta. Sababta ay u toosan yihiinna waa kaarboonka iyo haaydrojiinta oo uu isu hayo hal dabar. Halka kaarboonka iyo haaydrojiinta asiidh dufaneedka saliidaha qaarkood ay isu hayaan laba dabar. Labada dabar waxa ay qalloociyaan silsiladda, halkaana waxaa ku adkaada isku cabbayntii molikuyuullada, waxa ayna noqdaan dareere.

Jaantus 2.14 Habdhiska baruurta ama saddex-giliseroollaha. Xigashada sawirka © OpenStax College [CC BY 4.0].
Jaantus 2.14 Habdhiska baruurta ama saddex-giliseroollaha. Xigashada sawirka © OpenStax College [CC BY 4.0].

Asiidh dufaneedka halka dabar (single bond) leh waxaa lagu tilmaamaa in ay dheregsan tahay (saturated; saa-ja-raytidh) (Jaantus 2.15). Taas oo macnaheedu yahay, atam kasta oo kaarboon ah waxaa ku dheggan haaydrojiin. Halka ta meelaha qaarkood labada dabar (double bond) ku leh aysan dheregsanayn (unsaturated), oo ay awood u leedahay labadaa dabar midkood in ay atam haaydrojiin ah oo dheeraad ah kula xidhiidho. Caafimaad ahaan waxaa wanaagsan ta aan dheregsanayn oo laga helo saliid macsarada, saliidda kalluunka, saliid saytuunka,  iwm.

Jaantus 2.15 Habdhiska silsiladda dheregsan iyo ta aan dheregsanayn. Xigashada sawirka © OpenStax College [CC BY 3.0].
Jaantus 2.15 Habdhiska silsiladda dheregsan iyo ta aan dheregsanayn. Xigashada sawirka © OpenStax College [CC BY 3.0].

Molikuyuulka dufanku ma aha cirifle (polar), biyahana waa uu ka didaa oo kuma milmo. In badan waad aragtay in dufanka iyo biyuhu aysan isku darsamin. Molikuyuullada noocan ah waxaa lagu tilmaamaa in ay yihiin kuwo biyaha neceb (hydrophobic; hay-dro-foow-bik; biyo-uma-xiise). Kuwa biyaha ku milma na, sida milixda iyo sonkorta, waxaa lagu tilmaamaa in ay jecel yihiin biyaha (hydrophilic; hay-dro-fiilik; biyo-u-xiise).

Fosfowlibidh

Dhis ahaan wax yar ayaa uu kaga duwan yahay saddex-giliseroollaha, oo saddexdii asiidh dufaneed ayaa ay mid maqantahay, booskeediina waxaa qaatay koox atammo ah oo ka kooban fosforas iyo oksijiin (koox fosfayt; phosphate group). Kooxdani waa mid biyaha u xiista (hydrophilic), waana midda ka dhigta molikuyuulkan mid aad muhiim ugu ah noolaha, sida aan ku arki doonno qaybaha soo socda.

Ku noqo TUSMADA

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