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
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)
What molecule is water?
Covalent molecule
Surface tension
Allowed movement on water surface
Strong cohesion
Holds water molecules together
Adhesion
Allows water molecules to stick to Eg) xylem vessel walls
What is capillary action?
Water moving up the vessel
What makes water a good solvent?
Polar molecules allow for water molecules to bind to solute molecules
Why is high specific heat capacity important?
Allows organisms to live in environment with small changes in temperature
Why does water have large latent heat of vaporisation?
Efficient as coolant
How is water a useful metabolite?
Hydrolysis and condensation reactions
Aquatic habitat
Light penetrates through transparency of water
Ice habitats
Breeding areas for animals because ice floats
Ice insulates water below
What does R group do in amino acids?
Determines chemical property
What joins amino acids together?
Peptide bonds
What is a chain of amino acids called
Polypeptide
Primary structure of protein
DNA determines sequence
Peptide bonds
Carboxyl and amine amino acids
Secondary structure
Coils and folds. Alpha helix and beta pleated sheet.
Hydrogen bonds
Carboxyl and amine amino acids
Tertiary structure
3D shape (further coiling of secondary structure)
R group interactions
Hydrogen bonds
Ionic bonds
Disulphide bonds
Hydrophobic /phillic interactions
Quaternary structure
Two or more polypeptide chains in protein. Insulin, haemoglobin.
Fibrous protein Eg) collagen
Staggered cross links between molecules
Form tendons and ligaments
Globular protein Eg) Elastin and keratin
Insoluble and strong
Chains form H bonds
Globular proteins Eg) haemoglobin
Cool up due to hydrophobic/phillic groups
Soluble
Specific shape
How do you identify amino acids?
Chromatography
How to test for proteins
Equal volume sodium hydroxide to solution
Add few drops of dilute sulphate solution and mix gently
Protein present if purple shows (peptide bonds)
Saturated fatty acid
One single C-C bond
Unsaturated fatty acid
At least one double C-C bond
Characteristics of lipids
Hydrophobic
Non-polar molecules
Fatty acid and glycerol -> triglyceride
Do not form polymers
Functions of triglyceride
Energy source and Heat insulation
What bond is found in triglyceride?
Ester bond
What is the function of sterol cholesterol
Regulates fluidity of membrane
Testing for lipids
Mix sample with ethanol
Mix with water and shake
White emulsion = lipids present
Which biological molecule contain only C H and O?
Carbohydrates and lipids
What biological molecule contains nitrogen and sulphur?
Proteins
Eg) insulin
Which processes involve formation of ester bonds?
Synthesis of polynucleotides
Synthesis of triglycerides
