Enjoy these detailed notes, directly from the Ontario Secondary School Grade 12 Curriculum, focussing on SBI4U! These extensively detailed notes should help you if you're studying for an exam or just love biology! Good luck!
Carbohydrates, Proteins, Lipids 2017-02-25
Biology Test Notes Page M1
Carbohydrates
• Store energy in all organisms
• Found in a Carbon, Hydrogen, Oxygen ratio of 1:2:1
◦ Essentially that’s (CH2O)n, where N ∈ℕ
• Types
◦ Monosaccharides (1 sugar)
◦ Oligosaccharides (2-3 monosaccharides)
◦ Polysaccharides (4 or more monosaccharides)
Monosaccharides
• Simple sugars that contain a chain of carbon atoms with two or more hydroxyl (-OH) groups
attached to the chain
• They’re distinguished using the following criteria
Number of Carbons Carbonyl Group
• n=3 →triose • Aldehyde → aldose
• n=4 →tetrose • Ketone → ketose
• n=5 →pentose In rings, ketoses have an
• n=6 →hexose additional carbon attached to
• n=7 →heptose the anomeric one. Illustration 1: Ribose
is an aldopentose.
The formula is (carbonyl group)+(# of carbons)+(ose)
• In water, the above chains actually form rings, using nucleophillic (-OH group) attacks
◦ A tetrose in water forms a furanose, with oxygen at the top of the ring
◦ A pentose in water forms a pyranose, with oxygen on the right of the ring
◦ If an aldehyde group was present, it’s now called a cyclic hemiacetal
◦ If a ketone group was present, it’s now called a cyclic hemiketal
◦ The carbon on the right hand side of the ring is the anomeric carbon,
which is a stereoisomer. It’ll allow the ring to change between α and β anomeres
▪ In an α isomer, hydrogen up, hydroxide down
▪ In aβ isomer, hydrogen down, hydroxide up “downright uplefting”
Illustration 2: An example of alpha and beta
isomers (a furanose excluding hydrogen)
, Carbohydrates, Proteins, Lipids 2017-02-25
Biology Test Notes Page M2
Oligosaccharides
• Contain 2 or 3 simple sugars that are attached using covalent bonds involving oxygen called
glycosidic linkages (which are essentially condensation reactions)
◦ The special name for two connected sugars is a disaccharide, and the following examples of
oligosaccharides are all disaccharides
• Maltose: product of the digestion of starch→ contains 2 α glucoses :α 1,4 glycosidic linkages
Reducing vs Non-Reducing Sugars
• Reducing sugars have a free OH group on the anomeric carbon, which allows the sugar to act as
a reducing agent when the carbonyl group (which is now an OH) becomes an carboxyl group
◦ Examples: Glucose and lactose
• Non-reducing sugars do not have this luxury, as the OH group is attached or linked elsewhere
◦ Example: Sucrose
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller hassanalibhai. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $9.99. You're not tied to anything after your purchase.
