Biological molecules Flashcards
to learn it (25 cards)
What are the 4 hexose monosaccharides
(monomers of carbohydrates)
Alpha glucose (H on top of OH)
Beta glucose (H on bottom cuz its beta w OH on top)
Galactose (OH on top both sides)
Fructose (4c)
Disaccharides
Glucose + Glucose = ?
Maltose
Disaccharides
Glucose + Galactose = ?
Lactose
Disaccharides
Glucose + Fructose = ?
Sucrose
How are Disaccharides formed and broken?
They are formed via condensation = -H2) for covalent bond.
They are broken via hydrolysis using H2O
If a polysaccharides only contained Beta 1-4 glyosidic bonds what would the chain be like?
A straight and unbranched chain
If a polysaccharides only contained Alpha 1-4 glyosidic bonds what would the chain be like?
A Coiled chain
If a polysaccharides contained Alpha 1-4 and 1-6 glyosidic bonds what would the chain be like?
Coiled and branched chain
Why are starch and glucose good storage molecules:(3)
1) As they consist of only 1-3 and 1-6 glyosidic bonds they are compact with a coiled stricture
2) Unable to cross cell membrane due to big size
3) Insoluble so cant affect water potential
Groups of cellulose are called microfibrils and groups of that are macrofibrils. What is the bond and its structure for all of these
Only Beta 1-4 glyosidic that are long straight and unbranched
How do you test if something is reducing sugar (E.g all monosaccharides?(3)
Benedict’s test:
1) Grind sample w water
2) Add equal volumes of Benedict’s
3)Heat
- Positive result = Blue to orange
How do you test that something is a non-reducing sugar carbohydrate?
1) Negative Benedicts test
2)Grind w water and add acid
3)Boil to break down carbohydrates into reducing sugars
4)Cool + Alkali to neutralise
5) + Benedicks reagent + Heat
- If now orange then u had a non-reducing sugar
What does the IODINE test test for and how is it done?(2) -Shakira
- starch
1)+ sample to test tube
2)+ 2 drops of iodine solution + shake
positive result = blue-black
Whats the formula for a fatty acid
RCOOH
What reaction and bond makes Glycerol and 3 fatty acids into triglycerides
A condensation reaction forms ester bonds
What do phospholipids contain
1 glycerol
2 fatty acids
1 phosphate group
What 3 structures do phospholipids from in water?
Micelle
Monolayer
Bilayer
What test is used to find the presence of lipids and how is it performed?
The Emulsion test:
1) + 2cm3 of food sample
2) + 5cm3 of alcohol to dissolve the lipid and shake
3) + 5cm3 of water and shake
positive result = milky white colour due to emulsion of micelles
What’s the formula for an amino acid?
NH2CRHCOOH
How many natural amino acids are there?
20 all with varying R groups
What reaction takes place to form what bond between amino acids?
A condensation reaction (-H20) gives a peptide bond
What are the 4 levels of structure to a protein (smallest to largest) and what are they?
Primary - Sequence of amino acids in a polypeptide chain
Secondary - The folding of a polypeptide chain into alpha helix or beta pleated sheets
Tertiary - 3D folding of the whole polypeptide chain via ionic and hydrogen bonds + disufide bridges
Quaternary - When 2 or more polypeptides join together
What are 3 properties and an example of a globular protein?
Compact and round/spherical
Soluble in water
functional (enzymes hormones)
E.g Insulin
What are 3 properties and an example of a fibrous protein?
Elongated and thread like
Insoluble in water
Structural/provides strength for support and protection
E.g Elastin, collagen, keratin
