<p><strong>231/3</strong></p>
<p><strong>BIOLOGY</strong></p>
<p><strong>PAPER 3</strong></p>
<p><strong>KASSU </strong></p>
<p><strong>TIME: 2 HOURS</strong></p>
<p><strong><em>Kenya Certificate of Secondary Education (K.C.S.E.)</em></strong></p>
<p><strong><u>REQUIREMENTS FOR EACH CANDIDATE</u></strong></p>
<ul>
<li>Solution P- starch</li>
<li>Solution Q- egg white</li>
<li>Solution Z- water</li>
<li>Solution R- Diastase</li>
<li>Benedict’s solution</li>
<li>Iodine solution</li>
<li>Visking tubing &#8211; 8cm</li>
<li>Thread</li>
<li>100ml beaker</li>
<li>5 test tubes</li>
<li>5 labels</li>
</ul>
<ul>
<li>D1-Blackjack</li>
<li>D2-Sonchus</li>
<li>D3-Jacaranda</li>
<li>D4-Mango</li>
</ul>
<hr />
<p><strong>Name………………………………………………… Adm no. ……………Class…….</strong></p>
<p><strong>School ………………………………………………&#8230; </strong></p>
<p><strong>231/3</strong></p>
<p><strong>BIOLOGY</strong></p>
<p><strong>PAPER 3 (PRACTICAL)</strong></p>
<p><strong>Time: 1 ¾ HOURS</strong></p>
<p><strong><em>KASSU JET EXAMINATION &#8211;</em></strong></p>
<p><strong>231/3</strong></p>
<p><strong>BIOLOGY PAPER 3 (PRACTICAL</strong>)</p>
<p><strong>Time: 1 ¾ HOURS</strong></p>
<p><strong><u>INSTRUCTIONS TO CANDIDATES</u></strong></p>
<ul>
<li>Answer ALL the questions.</li>
<li>You are required to spend the first 15 minutes of 1 ¾ hours allowed for this paper reading the whole paper carefully before commencing your work.</li>
<li>Answers must be written in the spaces provided in the question paper.</li>
<li>Additional pages must not be inserted.</li>
</ul>
<p><strong><u>FOR EXAMINERS USE ONLY</u></strong></p>
<table width="774">
<tbody>
<tr>
<td width="249"><strong>Question</strong></td>
<td width="255"><strong>Maximum score</strong></td>
<td width="270"><strong>Candidate’s score</strong></td>
</tr>
<tr>
<td width="249"><strong>1</strong></td>
<td width="255"><strong>12</strong></p>
<p><strong> </strong></td>
<td width="270"><strong> </strong></td>
</tr>
<tr>
<td width="249"><strong>2</strong></td>
<td width="255"><strong>14</strong></p>
<p><strong> </strong></td>
<td width="270"><strong> </strong></td>
</tr>
<tr>
<td width="249"><strong>3</strong></td>
<td width="255"><strong>14</strong></p>
<p><strong> </strong></td>
<td width="270"><strong> </strong></td>
</tr>
<tr>
<td width="249"><strong>Total Score</strong></td>
<td width="255"><strong><em>40</em></strong></p>
<p><strong><em>Marks</em></strong></td>
<td width="270"><strong> </strong></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p><em>This paper consists of 5 printed pages.Candidates should check the question paper to ensure that all pages are printed as indicatedand no questions are missing</em></p>
<ol>
<li>You are provided with the photomicrograph of an onion outer epidermis as seen under light microscope</li>
<li>a) On the photograph, name parts labelled A, C, and D <strong>(3mark)</strong> A ……………………………………………………………</li>
</ol>
<p>C ……………………………………………………………</p>
<p>D ……………………………………………………………</p>
<ol>
<li>Explain how the part <strong>labelled B</strong> is adapted to its function <strong>(2marks)</strong></li>
</ol>
<p>………………………………………………………………………………………………………………………………………………………………………………………………</p>
<ol>
<li>Calculate the actual size of the cell <strong>marked K</strong>, give your answer in micrometres</li>
</ol>
<p><strong>(2marks)</strong></p>
<p><strong> </strong></p>
<ol>
<li>The differences between the cells in the photograph and those obtained from an animal epithelial cells <strong>(3marks)</strong></li>
</ol>
<table width="815">
<tbody>
<tr>
<td width="418">Onion epidermal cells</td>
<td width="397">Animal epithelial cells</td>
</tr>
<tr>
<td width="418"> ;</td>
<td width="397"> ;</td>
</tr>
<tr>
<td width="418"> ;</td>
<td width="397"> ;</td>
</tr>
<tr>
<td width="418"> ;</td>
<td width="397"> ;</td>
</tr>
</tbody>
</table>
<p> ;</p>
<ol>
<li>State the process that make the structures in the cell above appear more distinct</li>
</ol>
<p><strong>(1mark)</strong></p>
<p>………………………………………………………………………………………..</p>
<ol>
<li>In microscopic procedure in 1 (d) above name what was used to achieve the process</li>
</ol>
<p><strong>(1mark)</strong></p>
<p>……………………………………………………………………………………………</p>
<p> ;</p>
<ol start="2">
<li>The photographs below represent specimen labeled A, B, C and D</li>
</ol>
<p> ;</p>
<table>
<tbody>
<tr>
<td width="374"><strong>SPECIMEN A</strong></td>
<td width="367"><strong>SPECIMEN B</strong></td>
</tr>
<tr>
<td width="374"></td>
<td width="367"></td>
</tr>
<tr>
<td width="374"><strong>SPECIMEN C</strong></td>
<td width="367"><strong>SPECIMEN D</strong></td>
</tr>
<tr>
<td width="374"> ;</td>
<td width="367"></td>
</tr>
</tbody>
</table>
<ol>
<li>Name the type of placentation shown in specimen A and B <strong>(2marks)</strong></li>
</ol>
<p><strong>A</strong>…………………………………………………………………………&#8230;……</p>
<p><strong>B</strong>…………………………………………………………..………………….…</p>
<ol>
<li>Identify the type of sections from which specimen <strong>C</strong> and D was obtained?</li>
</ol>
<p><strong>(2 marks)</strong></p>
<p><strong>C</strong>……………………………………………………………………………&#8230;…</p>
<p><strong>D</strong>…………………………………………………………..………………….…</p>
<ul>
<li>Classify the above specimen labeled D <strong> (1mark)</strong></li>
</ul>
<p>………………………………………………………………………………</p>
<ol start="4">
<li>You are provided with specimen labeled <strong>D1, D2, D3</strong> and<strong> D4</strong>. Examine them</li>
</ol>
<p>Draw and label specimen labeled<strong> D2</strong> <strong>(3marks)</strong></p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</p>
<ol>
<li>Giving a reason and state the agent of dispersal of the specimen <strong>(6marks)</strong></li>
</ol>
<table width="789">
<tbody>
<tr>
<td width="100"><strong>Specimen </strong></td>
<td width="181"><strong>Agent of dispersal </strong></td>
<td width="508"><strong>Reason </strong></td>
</tr>
<tr>
<td width="100">D1</td>
<td width="181"> ;</p>
<p> ;</p>
<p> ;</td>
<td width="508"> ;</p>
<p> ;</td>
</tr>
<tr>
<td width="100">D3</td>
<td width="181"> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</td>
<td width="508"> ;</p>
<p> ;</td>
</tr>
<tr>
<td width="100">D4</td>
<td width="181"> ;</p>
<p> ;</p>
<p> ;</p>
<p> ;</td>
<td width="508"> ;</td>
</tr>
</tbody>
</table>
<ol start="3">
<li>You are provided with the following. Solution<strong> P</strong>, <strong>Q </strong>and <strong>Z</strong>.</li>
</ol>
<ul>
<li>(i) Put 2 cm<sup>3</sup> of solution<strong> P</strong> into two test tubes labeled <strong>A </strong>and<strong> B</strong>. Add iodine solution drops into test tube <strong>A</strong>. Observe and record. <strong>(1 mark)</strong></li>
</ul>
<p> ;</p>
<p>…………………………………………………………………………………………..</p>
<p>(ii)To test tube <strong>B</strong>, add an equal amount of Benedict’s solution. Heat to boil. Record your observation. <strong>(1 mark)</strong></p>
<p> ;</p>
<p>…………………………………………………………………………………………..</p>
<p>(iii) From the results in (a) (i) and (ii), identify solution <strong>P</strong>. <strong>(1 mark)</strong></p>
<p> ;</p>
<p>…………………………………………………………………………………………..</p>
<p>(iv). Put 2cm<sup>3</sup> of solution <strong>Z</strong> into a clean test tube labelled <strong>C</strong>. Add equal volume of Benedict’s solution. Heat to boil. <strong>(1 mark)</strong></p>
<p> ;</p>
<p>……………………………………………………………………………………..……</p>
<p>(v) Open the visking tubing provided, Pour solution <strong>P </strong>into the visking tubing and add 1cm<sup>3</sup> of the solution<strong> R</strong>. Tie the visking tubing and ensure there is no leakage. Pour solution<strong> Z</strong> into a clean beaker till it is half full. Immerse visking tube in the solution <strong>Z</strong> in the beaker. Allow it to stand for 30 minutes. After 30 minutes, take 2cm<sup>3 </sup>of solution <strong>Z</strong> from the beaker into a clean test tube labelled <strong>D</strong>. Add equal amount of Benedict’s solution. Heat to boil. Record your observation. <strong> (1 mark)</strong></p>
<p> ;</p>
<p>…………………………………………………………………………………………..</p>
<p> ;</p>
<p>(vi)Account for the observation made in (v) above. <strong> (3 marks)</strong></p>
<p> ;</p>
<p>…………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………..</p>
<ul>
<li>i) Pour 2 cm<sup>3</sup> of solution <strong>Q</strong> into a clean test tube. Observe and record the color of solution <strong>(1 mark)</strong></li>
</ul>
<p> ;</p>
<p>…………………………………………………………………………………………</p>
<ol>
<li>ii) Add 1 cm<sup>3</sup> of sodium hydroxide into test tube containing solution <strong>Q</strong>. Record your observation. <strong>(1 mark)</strong></li>
</ol>
<p>……………………………………………………………..……………………………</p>
<p>iii) Explain the results observed in (b)(ii) above. <strong>(2 marks)</strong></p>
<p> ;</p>
<p>………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………….…………….</p>
<p>iv). what is the identity of solution <strong>R? (1 mark)</strong></p>
<p>……………………………………………………………..……………………………v) State <strong>one</strong> factor that can affect the process demonstrated in 3a<strong> (v</strong>) above<strong> (1 mark)</strong></p>
<p>……………………………………………………………..……………………………</p>
<hr />
<p><strong><em>KASSU BIOLOGY PAPER 3 MARKING SCHEME </em></strong></p>
<p>1.You are provided with the photomicrograph of an onion outer epidermis as seen under light microscope</p>
<p> ;</p>
<ol>
<li>a) On the photograph, name parts labelled A, C, and D <strong>(3marks)</strong></li>
</ol>
<p><strong>A <em>chloroplast ;</em></strong></p>
<p><strong>C <em>cell membrane</em> ;</strong></p>
<p><strong>D <em>cytoplasm ;</em></strong></p>
<ol>
<li>Explain how the part <strong>labelled B</strong>isadapted to itsfunction <strong>(2marks)</strong></li>
</ol>
<p><strong><em>Cellwallcontain the polysaccharide cellulose; thatgivemechanical support </em></strong></p>
<ol>
<li>Calculate the actual size of the cell<strong>marked K</strong>, giveyouranswer in micrometres</li>
</ol>
<p><strong>(2marks)</strong></p>
<p><strong>Mg =</strong> <strong><em><u>image size</u></em></strong></p>
<p><strong><em> Actual size</em></strong></p>
<p><em>1500= <strong><u>4.4×10,000 ;</u></strong></em></p>
<p><strong><em> Actual size</em></strong></p>
<p><em> =<u>44000 </u></em></p>
<p><em> 1500</em></p>
<p><em> <u>=29.3um ; units</u></em></p>
<ol>
<li>The differencesbetween the cells in the photograph and thoseobtainedfrom an animal epithelialcells <strong>(3marks)</strong></li>
</ol>
<table width="815">
<tbody>
<tr>
<td width="418">Onionepidermalcells</td>
<td width="397">Animal epithelialcells</td>
</tr>
<tr>
<td width="418"><em>Cellwallpresent</em></td>
<td width="397"><em>Cellwall absent ;</em></td>
</tr>
<tr>
<td width="418"><em>Chloroplastpresent</em></td>
<td width="397"><em>Chloroplast absent ;</em></td>
</tr>
<tr>
<td width="418"><em>Nucleus locatedat the periphery</em></td>
<td width="397"><em>Centralised nucleus ;</em></td>
</tr>
</tbody>
</table>
<p> ;</p>
<ol>
<li>State the processthatmake the structures in the cellaboveappear more distinct <strong>(1mark)</strong></li>
</ol>
<p><em>Staining ;</em></p>
<ol>
<li>In microscopicprocedurein 1 (e) abovenamewhatwasused to achieve the process<strong>(1mark)</strong></li>
</ol>
<p><strong><em>Iodinestain,;methyleneblue ;eosinacceptany one </em></strong></p>
<ol start="2">
<li>The photographs below represent specimen labeled A, B, C and D</li>
</ol>
<table>
<tbody>
<tr>
<td width="374"><strong>SPECIMEN A</strong></td>
<td width="367"><strong>SPECIMEN B</strong></td>
</tr>
<tr>
<td width="374"></td>
<td width="367"></td>
</tr>
<tr>
<td width="374"><strong>SPECIMEN C</strong></td>
<td width="367"><strong>SPECIMEN D</strong></td>
</tr>
<tr>
<td width="374"> ;</td>
<td width="367"></td>
</tr>
</tbody>
</table>
<ol>
<li>Name the type of placentation shown in specimen A and B <strong>(2 marks)</strong></li>
</ol>
<p><strong><em>A Axile;</em></strong></p>
<p><em>B <strong>free central;</strong></em></p>
<ol>
<li>Identify the type of sections from which specimen <strong>C</strong> and D was obtained?</li>
</ol>
<p><strong>(2 marks)</strong></p>
<p><strong><em>Ccross section/transverse section;</em></strong></p>
<ol>
<li><strong><em>Longitudinal section;</em></strong></li>
</ol>
<ul>
<li>Classify the above specimen labeled D <strong> (1mark)</strong></li>
</ul>
<p><strong><em>Succulent;</em></strong></p>
<ol start="4">
<li>You are provided with specimen labeled <strong>D1, D2, D3</strong> and<strong> D4</strong>. Examine them</li>
</ol>
<p>Draw and label specimen labeled<strong> D2</strong> <strong>(3marks)</strong></p>
<ol>
<li>Giving a reason and state the agent of dispersal of the specimen <strong>(6marks)</strong></li>
</ol>
<table width="789">
<tbody>
<tr>
<td width="100"><strong>Specimen </strong></td>
<td width="181"><strong>Agent of dispersal </strong></td>
<td width="508"><strong>Reason </strong></td>
</tr>
<tr>
<td width="100">D1</td>
<td width="181"><strong><em> </em></strong></p>
<p><strong><em>Animal ;</em></strong></p>
<p><strong><em> </em></strong></td>
<td width="508"><strong><em> </em></strong></p>
<p><strong><em>Have hook-like structures which stick on fur/clothes of passing animals;</em></strong></td>
</tr>
<tr>
<td width="100">D3</td>
<td width="181"><strong><em> </em></strong></p>
<p><strong><em>Wind;</em></strong></p>
<p><strong><em> </em></strong></p>
<p><strong><em> </em></strong></td>
<td width="508"><strong><em> </em></strong></p>
<p><strong><em>Has wing like structures to increase surface area for it to be carried by wind;</em></strong></td>
</tr>
<tr>
<td width="100">D4</td>
<td width="181"><strong><em> </em></strong></p>
<p><strong><em>Animal ;</em></strong></p>
<p><strong><em> </em></strong></p>
<p><strong><em> </em></strong></td>
<td width="508"><strong><em>Brightly coloured, succulent to attract animals that feed on it;</em></strong></td>
</tr>
</tbody>
</table>
<p> ;</p>
<p> ;</p>
<ol start="3">
<li>You are provided with the following. Solution P, Q and Z.</li>
</ol>
<ul>
<li>(i) Put 2 cm3 of solution P into two test tubes labeled A and B. Add iodine solution drops into test tube A. Observe and record. <strong> (1 mark)</strong></li>
</ul>
<p><strong><em>Blue-black colour observed;</em></strong></p>
<p>(ii)To test tube B, add an equal amount of Benedict’s solution. Heat to boil. Record your observation. <strong>(1 mark)</strong></p>
<p><strong><em>Blue-black of Benedict’s solution persist;</em></strong></p>
<p>(iii) From the results in (a) (i) and (ii), Identify solution P<strong>. (1 mark)</strong></p>
<p><strong><em>Starch solution;</em></strong></p>
<p>(iv) put 2cm3 of solution Z into a clean test tube labelled C. Add equal volume of Benedicts solution. Heat to boil. <strong>(1 mark)</strong></p>
<p><strong><em>Blue colour of Benedict’s solution persist;</em></strong></p>
<p>(v) Open the visking tubing provided. Pour solution P into the visking tubing and add 1cm3 of the solution R. Tie the visking tubing and ensure there is no leakage. Pour solution Z into a clean beaker till it is half full. Immerse visking tube in the solution Z in the beaker. Allow it to stand for 30 minutes. After 30 minutes, take 2cm3 of solution Z from the beaker into a clean test tube labelled D. Add equal amount of Benedict’s solution. Heat to boil. Record your observation. <strong> (1 mark)</strong></p>
<p><strong><em> Colour changes from Blue-green- yellow- orange</em></strong><em>;</em></p>
<p>(vi)Account for the observation made in (v) above. <strong>(3 marks)</strong></p>
<p><strong><em>Starch is hydrolysed into maltose by enzyme diastase; maltose molecules are small enough to diffuse through the small pores of the visking tubing; maltose reacted with Benedict’s solution producing an orange colour;</em></strong></p>
<ul>
<li>(i)Pour 2 cm3 of solution Q into a clean test tube. Observe and record the color of solution Q. <strong>(1 mark)</strong></li>
</ul>
<p><strong><em>White/turbid/ cloudy;</em></strong></p>
<p>(ii)Add 1 cm3 of sodium hydroxide into test tube containing solution Q. Record your observation. <strong>(1 mark)</strong></p>
<p><strong><em>Solution Q clears/ white colour fades off;</em></strong></p>
<p>(iii)Explain the results observed in (b)(ii) above. <strong>(2 marks)</strong></p>
<p><em>` <strong>Sodium Hydroxide breaks down the protein molecules into peptides; peptides form a clear solution;</strong></em></p>
<p>iv). what is the identity of solution <strong>R? (1 mark)</strong></p>
<p><strong><em>Enzyme/diastase </em></strong></p>
<ol>
<li>v) State <strong>one</strong> factor that can affect the process demonstrated in 3a<strong> (v</strong>) above<strong> (1 mark)</strong></li>
</ol>
<p><strong><em>Increase in temperature </em></strong></p>

