Chap3 Biological Molecules Flashcards
What is a monomer?
Small unit from which larger molecules are made
What molecules are made from monomers;
amino acids
nucleotide
glucose
proteins
DNA
carbohydrates
Give three examples of monosaccharides
glucose
fructose
galactose
What is the name of monosaccharide containing 5 carbon atoms? Give example
Pentose monosaccharide
Ribose
Name a property of monosaccharides
Why is this?
Soluble in water
Large number of hydroxyl groups form hydrogen bonds.
Hydrophillic molecules.
Give chemical formula of glucose
C6 H12 O6
Describe test for sugar
- Benedicts reagent
- Hot water bath
- Positive result = brick red colour
Why does benedicts reagent turn brick red?
Electrons gained in solution.
Precipitate produced
Give chemical formula for sucrose (disaccharide)
C12 H22 O11
Sucrose:
Lactose:
Maltose:
glucose + fructose
glucose + galactose
glucose + glucose
Name bonds that are present in maltose
Glycosidic bonds (1, 4)
What is the reaction for maltose called?
Condensation reaction
What is the reverse of condensation reaction?
Hydrolysis reaction
(water added back in)
What are all monosaccharides?
reducing sugars
What does acid do to disaccharide?
Neutralises it
In test for non-reducing sugars, how would we check if not added too much sodium hydrogen carbonate?
Litmus paper
Describe test for non-reducing sugars
- Complete test for reducing sugars
- If solution does not change colour dispose of liquid
- Add 1cm uknown solution and 1cm HCl into boiling tube
- Add sodium hydrogen carbonate
- Retest with benedicts solution
- If now positive result, this means you started off with non-reducing sugar (orange/brown)
What monomer is starch?
What bonds does it consist of?
Alpha glucose
(1, 4) glycosidic bonds for amylose
(1, 6) glycosidic bond for amylopectin due to branching
What monomer is glycogen?
What bonds does it consist of?
Alpha glucose
(1, 4) and (1, 6) glycosidic bonds
What monomer is cellulose?
What bonds does it consist of?
Beta glucose
Hydrogen bonds
What is the main role of starch in the plant?
Energy storage
How is starch suited for its role?
(amylose) Insoluble. Does not effect osmotic balance.
Compact molecule due to helical shape
What is the main role of glycogen in animals?
Provides quick energy when needed
How is glycogen suited for its role?
Many branches allow rapid hydrolysis to provide high glucose level
(meaning more respiration to maintain metabolic needs)
What is the main role of cellulose in the plant cell wall?
Structural support
How is cellulose suited for its role?
Strong support structure and arranged parallel to each other
Why are hydroxyl groups polar?
Small negative charge on oxygen atom and small positive charge on hydrogen atom
What are the two polymers starch consists of?
Amylose and amylopectin
(amylose is a polysaccharide containing hundreds of alpha glucose molecules)