TKheory Section: [Total 16 Marks]

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It is composed of two types of polypeptide, known as α and β globin. (a) Explain how a globular protein differs from a fibrous protein, such as collagen. Dedicated to Mohammad Irtaza aider Zain. 1.

1 Bloomfield all School Test (Unit 2) Name :... Paper: Biolog y Date :... lass: A1&2 Time Allowed: 40Minutes Maximum Marks: 2 TKheory Section: [Total 16 Marks] 1 aemoglobin is a globular protein that shows quaternary structure. It is composed of two types of polypeptide, known as α and β globin. (a) Explain how a globular protein differs from a fibrous protein, such as collagen. Dedicated to Mohammad Irtaza aider Zain. 1...[2] Fig.1.1 shows part of the base sequence of the mrna that codes for the first ten amino acids of β globin. Table 6.1 shows some of the codons and the amino acids for which they code. GUG A UG AU U GAG GAG AAG UU G (b) Fig.1.1 Table 1.1 amino acid abbreviation codons alanine ala GA G GG GU glutamic acid glu GAA GAG histidine his A AU leucine leu UUA UUG UA U UG UU lysine lys AAA AAG proline pro A G U serine ser UA U UG UU AG AGU threonine thr AA A AG AU valine val GUA GU GUG GUU Use the information in Table 1.1 to complete the sequence of amino acids at the beginning of β globin using the first three letters of each amino acid. Some of them have been done for you. val his glu ala [2]

2 (c) 2 β globin has a tertiary structure that consists of eight helices arranged to give a precise three-dimensional shape. Describe how the precise three-dimensional shape of a polypeptide is maintained....[4] [Total: 8] 2 Fig. 2.1 shows a β glucose molecule Fig. 2.1 (a) State how α glucose differs from β glucose as shown in Fig [1] 1 (b) Fig. 2.2 shows a molecule of β glucose that is about to be added to the end of a growing chain of a polysaccharide. (i) Name the bond E. E Fig [1] Dedicated to Mohammad Irtaza aider Zain.

3 (ii) 3 Use the diagram below to show how the β glucose molecule will attach to the end of the growing chain of the polysaccharide. You may annotate the diagram if you wish. (c) (iii) Name a polysaccharide that is formed entirely from β glucose molecules in the way shown in Fig [1] A solution of starch was poured into six separate test-tubes, labelled F to K. The testtubes were kept at 3 for minutes and then treated as shown in Table 2.1. After a further 30 minutes the contents of the test-tubes were tested for the presence of reducing sugar. Table 2.1 [2] presence or absence of test-tubes substances added after minutes reducing sugar after 30 minutes F distilled water absent G amylase + boiled maltase present amylase + distilled water present I boiled amylase + maltase absent J amylase + maltase present K maltase + distilled water absent Explain the results shown in Table 2.1. Dedicated to Mohammad Irtaza aider Zain.

4 [3] [Total : 8] MQ SETIN: [Total 9 Marks] Which level of protein structure maintains the globular shapes of enzymes? A primary tertiary B secondary D quaternary The diagram shows a molecule that is found in cell surface membranes. Y X Z What is present at X, Y, and Z? X Y Z A phosphate double-bond carbon chain protein B phosphate single-bond carbon chain double-bond carbon chain protein glucose single-bond carbon chain D protein phosphate glucose 3 Which molecular bonds will be broken by hydrolysis when a molecule of glycogen is converted to glucose? bonds 1,2 1,4 1,6 A B D Dedicated to Mohammad Irtaza aider Zain.

5 4 Which levels of protein structure are demonstrated by a haemoglobin molecule? primary secondary tertiary quaternary A B D 6 Which type of reaction takes place when starch molecules are converted into reducing sugars? A condensation polymerisation B hydrolysis D synthesis A solution of starch is mixed with a solution of amylase. Which reagent should be used to confirm that a reaction had taken place and what would be the appearance of the mixture when the reaction was complete? reagent the appearance of the mixture A Benedict s solution brick-red B biuret solution blue ethanol cloudy D iodine in potassium iodide solution blue-black 7 Which describes the structure of amylopectin? A B a branched chain with 1,2 and 1,4 glycosidic bonds a branched chain with 1,4 and 1,6 glycosidic bonds an unbranched chain with only 1,4 glycosidic bonds 8 D an unbranched chain with 1,4 and 1,6 glycosidic bonds When hydrolysed, which molecules have products containing a carboxyl group? 1 phospholipids 2 polysaccharides 3 proteins A 1 and 2 B 1 and 3 2 and 3 D 3 only Dedicated to Mohammad Irtaza aider Zain.

6 6 9 Which molecule is found in glycogen? A B 2 D MQ Answer Sheet 1 A B D 6 A B D 2 A B D 7 A B D 3 A B D 8 A B D 4 A B D 9 A B D A B D Dedicated to Mohammad Irtaza aider Zain.

AMERICAN NATIONAL SCHOOL General Certificate of Education Advanced Subsidiary Level and Advanced Level

AMERICAN NATIONAL SCHOOL General Certificate of Education Advanced Subsidiary Level and Advanced Level AMERIAN NATINAL SL General ertificate of Education Advanced Subsidiary Level and Advanced Level BILGY 9700/01 Paper 2 Structured Questions AS December 2009 lass A1 1 hour 15 minutes andidates answer on