Tuesday, June 28, 2011

biochemistry- Carbohydrates

Assalamualaikum :)

Today we'll learn about carbohydrates, a essential polymer that needs by our body as well as the other organisms too. Ok, let's start! (ecehh,,poyo kot..haha)



First thing first, let's do a little briefing about carbohydrates. Carbohydrates is consists of element C,H and O, which include:

  1. Monosaccharides
  2. Disaccharides/oligosaccharides
  3. Polysaccharides
just proceed to the components of carbohydrates...


MONOSACCHARIDES

  • the simple sugars of (CHnO)n, where n=3,4,5,6,7. (more than 7 is not a monosaccharide)
  • the simplest form of sugar, cannot be hydrolysed anymore.
  • Divided into two types, aldose and ketose.
  • Each monosaccharide MUST have one hydroxyl (-OH) and one carbonyl (=O) group
  • Structure of monosaccharide can be represented in THREE ways,
  1. straight chain (Fischer Projection)
  2. cyclic/ring form (Haworth Projection)
  3. chair/boat form.

Fischer projection

Haworth Projection

Chair Form

*Glucose can form over 16 isomers. Yet, the most important types (that you must remember) are:
  1. D and L isomerism
  2. Epimers
  3. Aldose-ketose isomerism
  4. Pyranose and furanose ring strutures
  5. Alpha and beta anomers

D and L isomerism

The position of H and OH in carbon number 5 (C5) determines whether the sugar belongs to D or the L series.
If -OH on the right, the sugar is the D isomer
If -OH on the left, the sugar is the L isomer. *Note: L=LEFT

   

Epimers

Isomers that differs due to the variation of H and OH position on C2, C3 and C4 of the glucose:
At C2 and C4, if -OH on the right, the sugar is glucose
At C2, If -OH on the left, the sugar is mannose
At C4, if -OH on the left, the sugar is galactose 
*the carbon where the rotation occurs is called the anomeric carbon 

Aldose-Ketose Isomerism

Depends on the position of the carbonyl group. If, the carbonyl in C1, the sugar is aldose. If the carbonyl group is in C2, it is a ketose. In this chapter, we use glucose as aldehyde while fructose as ketones.

Pyranose and Furanose Ring

Those with 5 membered ring structure (furan) are called furanoses, while one with 6 membered rings (pyran) are called pyranose.
(in Haworth projection -ring form)


     
FURANOSE (5) PYRANOSE (6)








p/s: how the ring can be formed. The H on the fifth carbon (C5) combine with O at the first carbon. The remaining O (kan asalnya OH) become the connector.



Ok, masuk pulak pada jenis2 monosaccharide mengikut bilangan CARBON ATOM
Yang kitorang belajar ade triose(3), pentose (5), hexose (6).

PENTOSE

  • Molcular formula : C5H10O5
  • Example: Ribose and Deoxyribose
  • D-Ribose found in coenzymes, ATP and RNA

IN FISCHER PROJECTION


IN HAWORTH FORM


*beza deoxyribose dengan ribose ialah komponen pada C ke 2 dalam ring form. Ribose: OH, Deoxyribose:H


Hexose

Molcular formula : C6H10O6
Example (the most common): glucose, galactose, fructose------>strukur2 dy dah dibezakan masa kat atas tadi
*All the three hexoses share the same molecular formula but ARRANGEMENT OF THE ATOMS are DIFFERENT (structural isomers)






galactose







bersambung kemudian...bnyaaaaak lagi ni.>!! yada2~


Ingatlah hadith nabi: Rasulullah s.a.w bersabda, maksudnya:

"Siapa yang keluar untuk menuntut ilmu maka ia berjuang fisabilillah hingga ia kembali".

Sekian :)

Saturday, June 25, 2011

friend

Sometimes you think you'll be fine by yourself
'Cause a dream is a wish that you make all alone
It's easy to feel like you don't need help
But it's harder to walk on your own

You'll change inside when you realize

The world comes to life and everything's bright
From beginning to end when you have a friend by your side
That helps you to find the beauty you are
When you open your heart and believe in the gift of a friend
The gift of a friend

Someone who knows when you're lost and you're scared
And there through the highs and the lows
Someone you can count on, someone who cares
Beside you wherever you'll go

You'll change inside when you realize

The world comes to life and everything's bright
From beginning to end when you have a friend by your side
That helps you to find the beauty you are
When you open your heart and believe in the gift of a friend

And when your hope crashes down
Shattering to the ground you, you feel all alone
When you don't know which way to go
And there's no signs leading you home, you're not alone

The world comes to life and everything's bright
From beginning to end when you have a friend by your side
That helps you to find the beauty you are
When you open your heart and believe in
When you believe in, when believe in the gift of a friend



[dedikasi untuk semua kawan2, especially to fath yg banyak bantu ak dalam perjalanan yang sukar ni..to shak, hajar n ckin too. the gift of a friend ]