Biological molecules Flashcards
Monomer
the smaller units of which larger units are made
Polymer
Molecules made from a large number of molecules joined together
Examples of monomers
monsaccharides ,amino acids,nucleotides
Polymer examples
polysaccharides,polypeptide/proteins, DNA
Condensation reaction
A condensation reaction joins two molecules together with the formation of a chemical bond and involves the elimination of a molecule of water.
Hydrolysis reaction
A hydrolysis reaction breaks a chemical bond between two molecules and involves the use of a water molecule. (adding water)
Monosaccharides
Monosaccharides are the monomers from which larger carbohydrates are made.
common monosaccharides
Glucose,fructose and galactose.
What forms during a condensation reaction between two monosaccharides?
A glycosidic bond.
How are disaccharides formed?
By the condensation of two monosaccharides
what disaccharide does the condensation of two glucose molecules form?
maltose
what disaccharide does the condensation of one glucose and one fructose molecules form?
sucrose
what disaccharide does the condensation of one glucose and one galactose molecules form?
lactose
what is an isomer?
Molecules with the same molecular formula but a different structure.
what are the isomers of glucose?
Alpha and beta
The difference between reducing and non-reducing sugars
Reducing sugars can donate electrons
what are the two groups of lipid?
triglycerides and phospholipids
how are triglycerides formed?
The condensation of 1 glycerol molecule and 3 fatty acid molecule.
how are phospholipids formed?
The condesnation of 1 glycerol molecule,2 fatty acid molecule and 1 phosphate-containing group molecule.
A condensation reaction between glycerol and a fatty acid (RCOOH) forms an _______ bond.
A condensation reaction between glycerol and a fatty acid (RCOOH) forms an ESTER bond.
the R-group of a fatty acid may be __________ or un__________.
the R-group of a fatty acid may be SATURATED or UNSATURATED.
The difference between unsaturated fatty acids and saturated.
unsaturated contain at least one double bond between carbons in the fatty chain. (saturated= single bonds only)
Properties of lipids?
-contain hydrogen,carbon and oxygen.
-proportion of carbon to oxygen and hydrogen much less than in carbohydrates.
-Insoluble in water
-soluble in organic solvents such as alcohols and acetone.
roles of lipids?
-contribute to flexibility of cell membranes
-source of energy
-waterproofing
-insulation
-protection
properties of triglycerides
-excellent source of energy because of high ratio of energy-storing carbon-hydrogen bonds
-good storage, low mass to energy ratio, lots of energy stored in a small volume.
-large non-polar molecules, so are insoluble in water so storage doesn’t affect osmosis or water potential of cells.
-high ratio of hydrogen to oxygen atoms means water released when oxidised, important source of water especially for animals in the desert.
structure of a phsopholipid
-charge hydrophilic head (phosphate molecules) attract water
-non-polar hydrophobic tails (fatty acid molecule repel water).
phospholipids are the main components of cell __________.
phosopholipids are the main components of CELL MEMBRANES.
Phospholipids are amphipathic (contain hydrophilic and hyrophobic parts) so form __________.
Bilayers