BREAKING
Mole Day revealed to be a lie, chemists demand refund★Student titrates to pale pink, class gives standing ovation★Bunsen left on yellow flame, teacher sighs for 3rd week★
  1. Home
  2. A Level
  3. Chemistry
  4. OCR
  5. Amino acids

OCR A Level Chemistry

Topic questions Bonding, structure and the properties of matter Amino acids

Amino acids

5 questions · 67 marks · about 1.5 hours

Amino acids questions

TopicAmino acids

OCR H432 Amino acids 5 questions

Synthesis and analytical techniques June 2023, Question 21 9 marks

This question is about maths symbol-amino acids.

(a)

The general formula of an maths symbol-amino acid is RCH(NH2)COOH.

Most maths symbol-amino acids show optical isomerism.

Explain the term optical isomerism.

[1]
Reveal mark scheme Mark scheme for question 21(a)
(b)

The maths symbol-amino acid valine has the R group of –CH(CH3)2.

(b)(i)

What is the systematic name of valine?

[1]
Reveal mark scheme Mark scheme for question 21(b)(i)
(b)(ii)

Draw diagrams to show 3D structures of the optical isomers of valine.

Figure for question 21
[2]
Reveal mark scheme Mark scheme for question 21(b)(ii)
(c)
Figure for question 21
(c)(i)

How many optical isomers are possible for compound E ?

[1]
Reveal mark scheme Mark scheme for question 21(c)(i)
(c)(ii)

A student hydrolyses compound E with dilute hydrochloric acid, HC l (aq).

Draw the structures of the organic products formed by this hydrolysis.

[4]
Reveal mark scheme Mark scheme for question 21(c)(ii)

Synthesis and analytical techniques June 2022, Question 19 22 marks

This question is about compounds that contain the carboxylic acid functional group.

(a)

Carboxylic acids react with alkalis, metals and carbonates to form salts.

Write full equations for the following three reactions. Show structures for organic compounds.

• the reaction of propanoic acid with aqueous potassium hydroxide:

• the reaction of aqueous methanoic acid with magnesium:

• the reaction of the maths symbol–amino acid, aspartic acid (R=CH2COOH), with an excess of aqueous sodium carbonate, Na2CO3:

[4]
Reveal mark scheme Mark scheme for question 19(a)
(b)
Figure for question 19
[4]
Reveal mark scheme Mark scheme for question 19(b)
(c)

This part is about polymers derived from carboxylic acid monomers.

(c)(i)

Poly(pent-3-enoic acid) is an addition polymer.

Draw the structure of pent-3-enoic acid and two repeat units of this polymer.

Figure for question 19
[2]
Reveal mark scheme Mark scheme for question 19(c)(i)
(c)(ii)

Butanedicarboxylic acid and 1,4-dihydroxy-2-methylbenzene react to form a condensation polymer.

Draw one repeat unit of this condensation polymer.

[2]
Reveal mark scheme Mark scheme for question 19(c)(ii)
(c)(iii)

Three repeat units of a condensation polymer are shown below.

Figure for question 19

Draw the structure of the monomer required to form this polymer.

[1]
Reveal mark scheme Mark scheme for question 19(c)(iii)
(d)

A polymer is formed from 400 molecules of 2-aminopropanoic acid.

(d)(i)

Draw one repeat unit of this polymer.

[1]
Reveal mark scheme Mark scheme for question 19(d)(i)
(d)(ii)

What is the relative molecular mass, Mr, of the polymer?

[2]
Reveal mark scheme Mark scheme for question 19(d)(ii)
(e)
Figure for question 19
[6]
Reveal mark scheme Mark scheme for question 19(e)

Synthesis and analytical techniques November 2021, Question 18 18 marks

This question is about organic acids.

(a)

Table 18.1 shows the R groups in four amino acids.

Figure for question 18

Most amino acids show optical isomerism.

(a)(i)

Explain the term optical isomerism.

[1]
Reveal mark scheme Mark scheme for question 18(a)(i)
(a)(ii)

Draw 3-D diagrams to show the optical isomers of alanine.

[2]
Reveal mark scheme Mark scheme for question 18(a)(ii)
(a)(iii)

How many optical isomers does threonine have?

[1]
Reveal mark scheme Mark scheme for question 18(a)(iii)
(b)
Figure for question 18
[7]
Reveal mark scheme Mark scheme for question 18(b)
(c)

Ibuprofen, shown below, is used as a painkiller.

Figure for question 18
(c)(i)

What is the molecular formula of ibuprofen?

[1]
Reveal mark scheme Mark scheme for question 18(c)(i)
(c)(ii)

One ibuprofen tablet contains 400 mg of ibuprofen.

Calculate the number of ibuprofen molecules in one ibuprofen tablet.

Give your answer to 3 significant figures.

[3]
Reveal mark scheme Mark scheme for question 18(c)(ii)
(d)

Tablets based on ibuprofen and lysine are now available from pharmacies.

These tablets are claimed to act faster than ibuprofen by being absorbed into the body more quickly than ibuprofen alone.

One type of these tablets contains a salt of ibuprofen and the amino acid lysine (R = –(CH2)4NH2) in a 1:1 molar proportion.

(d)(i)
Figure for question 18
[2]
Reveal mark scheme Mark scheme for question 18(d)(i)
(d)(ii)

Suggest why tablets based on a salt of ibuprofen should act faster in the body than ibuprofen.

[1]
Reveal mark scheme Mark scheme for question 18(d)(ii)

Synthesis and analytical techniques June 2019, Question 17 11 marks

This question is about maths symbol-amino acids, RCH(NH2)COOH.

(a)

Table 17.1 shows the R groups in four amino acids.

Figure for question 17
(a)(i)

In the boxes, draw the organic products for the reactions of serine shown below.

Figure for question 17
[4]
Reveal mark scheme Mark scheme for question 17(a)(i)
(a)(ii)
Figure for question 17
[4]
Reveal mark scheme Mark scheme for question 17(a)(ii)
(b)
Figure for question 17
(b)(i)

What is the Rf value of serine (ser) in solvent W?

[1]
Reveal mark scheme Mark scheme for question 17(b)(i)
(b)(ii)

Analyse the chromatograms to identify the unknown amino acid.

Explain your reasoning.

Name of unknown amino acid........

Explanation........

[2]
Reveal mark scheme Mark scheme for question 17(b)(ii)

Synthesis and analytical techniques June 2018, Question 17 7 marks

The general formula of an maths symbol-amino acid is RCH(NH2)COOH.

(a)

The maths symbol-amino acid cysteine (R = CH2SH) shows optical isomerism.

Draw 3-D diagrams to show the optical isomers of cysteine.

[2]
Reveal mark scheme Mark scheme for question 17(a)
(b)

The maths symbol-amino acid lysine (R = (CH2)4NH2) reacts with an excess of dilute hydrochloric acid to form a salt.

Draw the structure of the salt formed in this reaction.

[2]
Reveal mark scheme Mark scheme for question 17(b)
(c)

maths symbol-Amino acids can react to form proteins.

A short section of a protein chain is shown below.

Figure for question 17

A student hydrolyses the protein with hot NaOH(aq).

Draw the structures of the organic products formed from this section of the protein.

[3]
Reveal mark scheme Mark scheme for question 17(c)

Report a problem with a question on this page
What is wrong?

Goes to whoever maintains the question split. No account needed and nothing is published on this page.

Memes

Certified Chemistry memes. Peer-reviewed by nobody.

Laugh now. Cry in the exam hall later. Then come back and do a past paper.

Do the mole calculation
Write ‘exothermic’ and pray
Me on the 6-marker about electrolysis
Knowing water is H₂O
Balancing an equation first try
Getting two concordant titres
Realising nobody actually knows what a mole is
Chemistry enlightenment, ranked

Mum 💖

how's chemistry going love?? 🥰

we're doing bonding rn

aww that's lovely 💕

📱 Screen time this week · TikTok6h 2m

Zero bonds were formed

Chemistry starter pack

Goggles that fog instantlyBunsen on the orange flameBurette that's always leakingThis website
Goggles on, collect all four