Carbohydrates, Lipids and Proteins Flashcards
Carbohydrates are polymers, what is a polymer?
Large complex molecules made of long chains of joined monomers.
Name the elements carbohydrate contains.
Carbon, Hydrogen, Oxygen.
What kind of monomers are carbohydrates made from?
Monosaccharides.
List the monosaccharides.
Glucose, Fructose, Galactose.
Glucose is a hexose sugar, what does this mean?
It is a monosaccharide with 6C in each molecule.
What is the difference between alpha and beta glucose?
Alpha - H at top, OH at bottom.
Beta - OH at top, H at bottom.
How are monosaccharides joined, and what bond holds them together?
Joined in condensation reactions. Joined by glycosidic bonds.
What is a disaccharide?
Two joined monosaccharides.
Name the disaccharides.
Sucrose (glucose and fructose)
Lactose (glucose and galactose)
How are polymers broken down?
In hydrolysis reactions, water breaks the bonds between monomers.
What does the Benedict’s Test test for?
Reducing or non-reducing sugars.
How do you test for reducing sugars?
Add Benedict’s reagent to sample and heat it in a water bath that has been brought to the boil. If positive it will form a coloured precipitate: green, yellow, orange, red.
How do you test for non-reducing sugar?
Take test solution, add dilute hydrochloric acid and heat in wage bath. Neutralise it with sodium hydrocarbonate and carry the test out as usual (add Benedict’s and heat). If positive for non-reducing a coloured precipitate will be formed.
What is starch made up of?
Amylose - long unbranched chain of alpha glucose.
Amylopectin - long branched chain of alpha glucose.
Structure of amylose and amylopectin related to function.
Amylose - coiled making it compact and good for storage.
Amylopectin - branches make glycosidic bonds easily accessible to enzymes, meaning quick release of energy.
Why is starch good for storage?
Insolvable in water so doesn’t affect water potential, so no osmosis or swelling.
How would you test for starch?
Add iodine dissolved in potassium iodide solution to sample. It will turn black/brown if starch is present.
How do animals store excess glucose?
As glycogen - polysaccharide of alpha glucose.
Structure of glycogen.
Similar to amylopectin but more branched for fast energy release and compact so good for storage.
Describe cellulose.
Long unbranched chains of beta glucose, chains held by hydrogen bonds to form microfibrils - strong structural support.
Triglycerides are a type of lipid, what are they made of?
Glycerol molecule and three fatty acids.
Describe a fatty acid structure.
Hydrocarbon tail that is hydrophobic (making them insoluable) and a hydrophilic head.
How is a triglyceride created?
A fatty acid joins a glycerol molecule in a condensation reaction forming an ester bond. Three fatty acids must join to create a triglyceride.
How can you tell if a fatty acid is saturated?
By their hydrocarbon tails(R group), no double bonds between carbons means saturated.
