Biomolecules Flashcards
What is the biological test for starch?
- Add a few drops of iodine solution
2. Record any colour change
What is the colour change for the biological starch test?
Yellow to Dark Blue/ Black (for a positive result)
What is the biological test for reducing sugars?
- Add 2cm’ of Benedict’s reagent to the solution
- Place in a 90° - 100° water bath for 5 mins.
- Record any colour change
What is the colour change for the biological test for reducing sugar?
Blue to Red (for a positive result)
What is the biological test for non-reducing sugars?
- Add 1cm’ of 1M of hydrochloric acid to solution
- Place in a 90°-100° water bath for 2 mins
- Neutralise with sodium hydrogen carbonate
- Add 2cm’ of Benedict’s reagent
- Place in a 90°- 100° water bath for 5 mins
- Record any colour change
What is the colour change for the biological test for non-reducing sugar?
Blue to Red (for a positive result)
What is the biological test for a protein?
- Add 2cm’ of 0.4M sodium hydroxide to solution
- Add 0.4M copper (II) sulphate drop by drop
- Shake gently and record results
What is the colour change for the biological for a protein?
Blue to Purple (for a positive result)
What is the biological test for a lipid?
- Shake solution with absolute ethanol for 1 min
- Add 2cm’ of water and shake well
- Record observations
What is the colour change for the biological for a lipid?
Clear to a milky solution (for a positive result)
What are the three types of carbohydrates?
- Monosaccharides
- Disaccharides
- Polysaccharides
Which two carbohydrates for crystals, are soluble, and ?
Monosaccharides and Disaccharides
What are the 4 functions of carbohydrates? (In humans and plants)
- Instant energy source
- Transportable form of energy
- Stored as glucose
- Structural material ( in plants)
What is the formula for Glucose?
C6H12O6
What is the definition of a disaccharide?
Two monomers joined together by a condensation reaction
What is the definition of a condensation reaction?
A reaction between two hydroxyl groups where water is lost and a glycosidic bond is formed.
What type of bond is C-O-C?
A glycosidic bond
What is made from Glucose + Glucose?
Maltose
What is made from Glucose + Galactose?
Lactose
What is made from Glucose + Fructose?
Sucrose
What is the definition of a hydrolysis reaction?
Splitting a glycosidic bond using a molecule of water
What is the general formula of a monosaccharide?
C(H2O)n
What is a ring with 6 carbon atoms called?
A Hexose
Why is glucose a suitable sugar? (4 reasons)
- Its very soluble so its easily transported in plasma
- A polar molecule (uneven charge within the molecule)
- Small so easily crosses membranes
- Major respiratory substrate is readily broken down in respiration and energy release to make ATP
Why is chitin good for animal/insects’ exoskeleten?
- Its waterproof which prevents water loss
- Its strong for support
- Its light weight for flight
What is the structure of Glycogen? (3 points)
.Alpha glucose
.More Branched
.1-4 and 1-6 glycosidic bonds
What is the function of starch?
Storage in plants
What are the two types of starch?
Amylose and Amylopectin
What is the structure of amylose?
Straight chain
What is the structure of amylopectin?
Curved/ Coiled chain
What is the structure of starch?
.Alpha molecules joined in a straight chain with similar bonds
. 1-4 glycosidic bonds
. Either amylose or amylopectin
Why does amylopectin form a coil?
Amylopectin forms a coil structure for a more stable structure of molecules, iodine molecules slot between the coil to cause the colour change in the iodine test.
What is the function of cellulose?
Used for structure in plants
What bonds join the linear chains in cellulose?
Hydrogen bonds
In cellulose 60-70 chains make what?
Microfibril
In cellulose several microfibrils make what?
A macrofibre
What is the structure of cellulose?
. Beta glucose
. B-Glycosidic bonds
. Every other B-Glucose is flipped 180°
Chitin is a polysaccharide made of what?
Beta Glucose
Why do polysaccharides store glucose in its insoluble form?
To prevent an osmotic effect
What is the structure of chitin?
Same structure as cellulose but has nitrogen, creating a Acetyl amide side groups.
What elements do lipids contain?
Carbon, Hydrogen, and oxygen. (Phosphate lipids also contain phosphate)
Are lipids polar or non-polar ? Do they dissolve?
Non-polar so do not dissolve (but do dissolve in non-polar substances like organic solvents)
What are the 5 functions of lipids?
- Energy source and storage: 1g of lipid= X2 of carbs
- Protection: protecting organs from physical damage
- Thermal insulation
- Oxidation: of triglycerides to produce metabolic water
- Phospholipids: are a component of cell membranes and electrical insulation of nerves.
- Waxes and Oils: waterproofing
What are three types lipid chains?
- Unsaturated
- Saturated
- Polyunsaturated
What is the definition for a saturated chain?
A chain where all the carbon atoms are joined by single hydrogen bonds.
What is the definition for a unsaturated chain?
A chain with carbon to carbon bonds
What is the structure of a saturated chain?
Straight chain