Biological Molecules - Carbohydrates Flashcards
Carbohydrates (23 cards)
Name of the sequences of carbon chains.
‘Backbone’ - allows atoms to attach to it.
Describe what monosaccharides are and give the 3 examples.
- Monomers are soluble substances
* Glucose, Fructose and Galactose
What 2 glucose molecules are there and which one has a -OH group on the top right?
- Alpha and beta glucose
* Beta glucose has a -OH on the top right and a -H on the bottom
Which reaction and what bond is made when monosaccharides join?
- Condensation reaction
* Glycosidic bond
What molecules form Maltose?
Glucose and Glucose.
What molecules form Sucrose?
Glucose and Fructose.
What molecules form Lactose?
Glucose and Galactose.
What’s the product of the condensation reaction of Alpha Glucose?
Starch and Glycogen (helix).
What’s the product of the condensation reaction of Beta Glucose?
Cellulose (not helix).
What’s a condensation reaction?
Two molecules join to form chemical bond and water.
What’s a hydrolysis reaction?
Breaks the chemical bond between monomers using water.
What is a reducing sugar?
A sugar that can donate electrons to another chemical.
Is Benedict’s reagent alkaline or acid and what colour is it before and after its reduced?
- Alkaline solution of Copper(II) Sulfate
* Blue when its Copper(II) and Red when its Copper(I)
How do you carry out reducing sugar Benedict’s test?
- Add test sample (liquid) and Benedict’s reagent
- Heat mixture
- Positive result is a orange-brown colour.
When testing for non-reducing sugars, what form do they have to be in?
These have to be monosaccharides, if they are disaccharides break them down into monosaccharides.
How do you carry out non-reducing sugar Benedict’s test?
- Add test sample and dilute HCL
- Heat mixture
- Add sodium hydrogencarbonate to neutralise HCL
- Add Benedict’s reagent
- Heat mixture again
- Positive result is Brick-red precipitate
How do you test for starch?
- Add potassium iodide to test sample
* Positive result is a colour change from browny-orange to blue-black.
What is starch made up of?
Alpha glucose and glycosidic bonds.
What is good about unbranched starch molecules?
They can be tightly coiled making the molecule compact and good for storage.
Reasons for why starch is a energy storing molecule.
- INSOLUBLE - doesn’t affect water potential so water isn’t drawn in through osmosis
- COMPACT - lots can be stored in a small space
- BRANCHED - branched starch has many ends allowing for enzymes to simultaneously breaking it down quickly
Reasons for why glycogen is a energy storing molecule.
- INSOLUBLE - doesn’t affect water potential so water isn’t drawn in through osmosis
- COMPACT - lots can be stored in a small space
- BRANCHED - glycogen is more branched so it has many ends allowing for enzymes to simultaneously breaking it down quickly
What is cellulose made from?
Beta glucose where the next monomer is turned upside-down.
Explain the structure of Cellulose that makes it strong.
- Cellulose has long unbranched parallel chains of Beta glucose
- Cross-links of Hydrogen bonds which add to collective strength
- Group of molecules form microfibrils which are fibres that add to strength
