AQA Year 1 Unit 1: biomolecules Exam
Questions With 100% Verified Answers
What is a monomer - answer✔A monomer is a small unit that can join together repetitively to
form a larger molecule / polymer.
what is a polymer - answer✔large number of monomer units joined together
What is the monomer of carbohydrates called? - answer✔monosaccharides
What is the monomer of protein called? - answer✔amino acids
What is the monomer of nucleic acids called? - answer✔nucleotide
what happens in the condensation of two monosaccharides? - answer✔glycosidic bond is
formed, water is released
what happens in the condensation of two amino acids? - answer✔peptide bond forms between
the carbon of the carboxyl group of one amino acid and the nitrogen of the amine group. Water is
released.
what happens in the hydrolysis of a triglyceride to its component parts? - answer✔Water is used
to break 3 ester bonds. This forms 3 fatty acids and one glycerol molecule and uses up 3
molecules of water.
name 3 monosaccharides - answer✔glucose, galactose and fructose
what is sucrose made from - answer✔glucose and fructose
what is maltose made from - answer✔two alpha glucose molecules
what is lactose made from - answer✔glucose and galactose
what is the difference between alpha and beta glucose - answer✔alpha glucose has the H above
the plane on carbon one, and beta glucose has the H below the plane on carbon 1.
how is glycogen made - answer✔many alpha glucose join by 1,4 glycosidic bonds to make a
coiled chain, with 1,6 glycosidic bonds forming branches.
how is starch made - answer✔amylose is coiled chains of alpha glucose joined by 1,4 glycosidic
bonds formed in a condensation reaction.
amylopectin is branched chains of beta glucose joined by 1,6 glycosidic bonds formed in a
condensation reaction.
how is cellulose made - answer✔every other beta glucose molecule is flipped as they join
together via 1,4 glycosidic bonds. Many long straight chains of cellulose attract to each other via
hydrogen bonds able to be formed due to the closeness of each strand and that each strand
contains every other glucose rotated.
structure and function of glycogen - answer✔Glycogen is a carbohydrate made from many alpha
glucose joined together by 1,4 and 1,6 glycosidic bonds. It has a coiled and compact structure
making it excellent for storing a lot of glucose molecules in a small space. It has many branches
so many ends /large surface area for action by enzymes to hydrolyse glycosidic bonds and
release glucose molecules quickly for respiration. It is an insoluble polysaccharide that can be
stored in cells without affecting water potential and so not cause osmosis. Glycogen is a energy
storage molecule.
structure and function of starch - answer✔Starch is a polysaccharide made from many Alpha
glucose joined together. Two types of polymer make up starch, amylose which is coiled and
compact to store a lot of glucose in a small space. Amylopectin which is branched for many ends
to increase rate of hydrolysis to release glucose. Both polymers are insoluble and can be stored
without affecting water potential.
structure and function of cellulose - answer✔Cellulose is a polysaccharide beta glucose.
Glycosidic bonds form between monomers, every other monomer if flipped 180 degrees. This
causes straight chains to form which can form hydrogen bonds between chains to form micro
fibrils. This gives cellulose strength for structural support in cell walls.
reducing sugar test - answer✔Add excess benedicts solution which is blue to the sugar solution
and heat to 80 degrees. If the solution forms a brick red precipitate which can be filtered off and
removed. The remaining solution is blue, the darker the solution is the lower the concentration of
sugar.
non reducing sugar test - answer✔Add benedicts, heat to 80 no brick red precipitate forms. Then
add acid, boil, and then add alkali to neutralise acid. Then add benedicts, heat to 80, this time if
brick red precipitate forms, it is a non reducing sugar.
iodine test - answer✔Test for starch, add a few drops, should turn from orange brown to
blue/black solution.
name two groups of lipid - answer✔triglycerides and phospholipids
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