amino acids proteins and dna Flashcards
state the name of the sugar molecule
2-deoxyribose
Explain how the base that you have chosen- cytosine forms a base pair with guanine
Top N–H forms hydrogen bonds to lone pair on O of guanine
The lone pair of electrons on N bonds to H–N of guanine
A lone pair of electrons on O bonds to lower H–N of guanine
Explain the origin of the interaction represented by the dotted lines in the figure
above.
Nitrogen and oxygen are very electronegative
1
Therefore, C=O and N–H are polar
1
Which results in the formation of a hydrogen bond between O and H
1
In which a lone pair of electrons on an oxygen atom is strongly attracted to the
δ+H
Aspartame has a sweet taste and is used in soft drinks and in sugar-free foods for people
with diabetes.
Hydrolysis of aspartame forms methanol initially. After a longer time the peptide link
breaks to form the free amino acids. Neither of these amino acids tastes sweet.
(a) Apart from the release of methanol, suggest why aspartame is not used to sweeten
foods that are to be cooked.
Heating speeds up (hydrolysis / breaking of peptide bonds
With reference to your answer to part (d)(i), explain why the melting point of
the amino acid X is higher than the melting point of CH3CH2CH(OH)COOH
electrostatic forces between ions in X QOL
Allow ionic bonding.
M2 (stronger than) hydrogen bonding between CH3CH2CH(OH)COOH
when writing amino acids that have 4 carbon chain, a carboxyolic acid and an amino at 2
2-aminobutanedioic acid ButanE! add the e
when drawing a dipeptide but theres a (ch2)4 group
h2n(ch2)4-c-c attach it to the nh2
when drawing a dipeptide but theres a ch2cooh on the middle carbon
draw it upwards so do ch2 and than a line up from that c and do the cooh so like this cooh [ ch2 [ c-cooh
Explain why polymer L is non-biodegradable.
non polar and the c-c or c-f or whatever bonds are strong
why is a polymer biodegradable
polar bonds, can be attacked by nucleophiles
The complex ion Q can bond to guanine in two different ways.
(i) The first way involves a hydrogen atom, from one of the ammonia ligands on
Q, bonding to an atom in a guanine molecule. State the type of bond formed to
guanine and identify an atom in guanine that could form a bond to this
hydrogen atom.
Type of bond ……………………………………………………………………………
Atom in guanine
Hydrogen bond
Oxygen (or nitrogen)
The second way involves a ligand substitution reaction in which an atom in a
guanine molecule bonds to platinum by displacing the water molecule from Q.
State the type of bond formed between guanine and platinum when a water
molecule is displaced and identify an atom in guanine that could bond to
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platinum in this way.
Type of bond ……………………………………………………………………………
Atom in guanine .
Co-ordinate
Nitrogen (or oxygen)
In terms of the intermolecular forces between the polymer chains, explain why
polyamides can be made into fibres suitable for use in sewing and weaving,
whereas polyalkenes usually produce fibres that are too weak for this purpose.
in polyamides- theres hydrogen bonding
in polyalkenes- van der waals forces
stronger forces of attraction in polyamides
Draw the structure of an isomer of G which does not react with bromine
water.
Has to be saturated, no double bonds so basically draw a alkane version of the alkene repeating unit
Describe an experiment in which you could compare the biodegradability of
these two objects a polyalkene and a polyamide
heat or reflux with aq naoh
polyalkene is inert
polyamide undergoes hydrolysis
