ISC 2014 BIOLOGY - Guide For School · BIOLOGY PAPER 2 (PRACTICAL) Question 1 [5] (a) You are provided with two flower specimensD-41 and D-42. Describe the floral characteristics

BIOLOGY PAPER-2 (PRACTICAL)

ISC 2014

Md. Zeeshan Akhtar

BIOLOGY PAPER 2 (PRACTICAL)

Question 1 [5]

(a) You are provided with two flower specimens D-41 and D-42. Describe the floralcharacteristics of each in semi-technical terms. (The details of individual whorls arenot required.)

(b) With a sharp razor blade, cut a longitudinal section of flower specimen D-41. Placeone of the cut surfaces on a moist filter paper. Show it to the Visiting Examiner.

Draw a neat and labelled diagram of the cut surface.

(c) Cut a longitudinal section of flower specimen D-42 with a sharp razor blade.Arrange one cut surface on a moist filter paper and draw a neat and labelled diagramof this cut surface.

(d) Observe the cut surfaces of the flower specimens D-41 and D-42 with the hand-lensprovided and record your observations of the following features in a tabular form asfollows:

D-41 D-42(i) Corolla

Shape

(ii) Androecium:

(1) Relation of stamens to eachother

(2) Relation of stamens to petals

Gynoecium

(1) Number of locule(s)

(2) Type of placentation

(e) Take a fresh specimen D-42. Isolate its pistil. Cut a transverse section of its ovary.Draw a neat labelled diagram of the transverse section.

(f) Name the families to which each specimen D-41 and D-42 respectively belong.

(g) Write two characteristic features of each family you have mentioned in (f) above.

(h) Draw a floral diagram of specimen D-42.

(i) Write the floral formulae of D-41 and D-42.

(j) Mention the botanical name of one economically important plant belonging to eachfamily that you have named in (f) above.

www.guideforschool.com

GFSfollows:

DD--4141 DD--4242

GGFFFSSSSGFSS(i)(i) CorollaCorollaShapeShapeGGFFFSSSSGFSS(ii)(ii) AndroAndroececium:ium:GGFFFSSSSGFSS(1) Relation of stamens to eachRelation of stamens to each

otherotherGGGGFFFSSSSGGFSS(2)(2) Relation of stamens to petalsation of stamens to petalsGGGGFFFSSSSGGFSSGynoeciumGynoeciumGGGGFFFSSSSGFSS(1)(1) Number of loculeNumber of locul (s)GGGGFFFSSSSGGFSS(2) T f l t tif l t

GGGGFFFSSSSGGFSS

Comments of Examiners

(a) Several candidates wrote in details on all the floralwhorls instead of describing the floral characteristics insemi-technical terms. Spelling errors were common.

(b) & (c) D-41 and D-42Some common mistakes made by candidates are asfollows:(i) Gamopetalous/gamosepalous conditions were not

shown correctly;(ii) Epipetalous condition was not represented;(iii) Shape of the flower was incorrect;(iv) Fixation not clear;(v) Bifid stigma was not clear;(vi) Ovules were not attached to the placenta;(vii) Labelling was incorrect.

(d) (i) Specific terms for the shape was not mentioned bysome candidates. Most of the candidates explained indetail.(ii) Candidates were not sure about the term

‘polyandrous’. Several candidates made spellingmistakes while writing the type of placentation.

(e) A few candidates drew the L.S. of the ovary instead ofthe T.S. In some cases, the placenta and marginalplacentation were wrongly drawn. Guidelines were notconnected properly in several cases. The elongated andnarrow locule was not shown in some diagrams.

(f) A number of candidates spelt the family namesincorrectly. In place of family name, many mentionedthe sub-family name.

(g) The characteristic features of each family were givencorrectly by most candidates.

(h) The Mother axis was not shown by many candidates.Orientation of the whorls was incorrect in several cases.

(i) Incomplete floral formulae were written by manycandidates. A few candidates used commas.

(j) The rules for binomial nomenclature were not followedwhile writing the scientific names. In several cases,spelling mistakes were made by candidates.

Suggestions for teachersAdvise students to read thequestions repeatedly.Stress upon the correct spelling.Explain the meaning of semi-technical term. Emphasize on theuse of correct semi-technicalterms with correct spelling.Emphasize on the importance ofneat labelled diagram.Students should be taught todraw by observing the specimenduring practical period and notfrom the book later.Laboratory manuals should beregularly corrected and mistakesshould be pointed out before thenext practical class.Difference between L.S. and T.S.must be clearly explained.Candidates should be encouragedto prepare both the types of slidesand observe them under themicroscope.The concept of the mother axismust be clearly explained.Orientation of the various whorlsin relation to the mother axismust be understood.Teacher should write the floralformula on the board and shouldexplain the use of the varioussigns and symbols.Teach students the rules forBinomial nomenclature.


GFsome candidatesdidates. Most of the. Most of candidatendidates explained ins explained indetail.etail.(ii)(ii) CandidateCandidates were not sure about the terms were not sure about the term

‘‘polyandrouspolyandrous’’. Several candidates made spellingSeveral candidates made spellingmistakes while writing themistake type of placentation.of placentatio

(e)(e) A fA fewewfff candidatecand s drewrew thethe L.S. of the ovary insL.S. of the ovary instead oftthethe T.S.T.S. In some cases, the psome cases, the lacenta and marginalenta and marginalplacentationplacentatio werewere wrongly drawn.wrongly dra GuidelinesGuidelines were notwere notconnected properly in several cases. The econnected properly in several cases. The elongatedlongated andandnarrow locule was not shown in some diagrams.narrow locule was not shown in some diagrams.

(f)(f) A number of candidates spelt the family nameA number of candidates spelt the family sincorrectlyincorrectly. In place of family name. In place of family name,, many mentionedmany menthethe subsub--family name.family name.

(g) The characteristic features of each family were givenhe characteristic features of each family were correctly by most candidates.andidates.FSF

regularly corrected and mistakesshould be pointed out before the

practical class.erence between L.S. and T

st be clearly expndidates should be enprepare both the types of slides

observe them under thecope

e mother axisclearly explained.

ntation of the various whorlselation to the mother axbe understood.er sho

MARKING SCHEME

Question 1.

(a) D-41 (Petunia): Ebracteate, pedicellate, actinomorphic/regular, complete, bisexual /hermaphrodite, pentamerous, hypogynous, cyclic.

D-41 (Dhatura): Ebracteate, pedicellate, cyclic, hypogynous, actinomorphic/regular,bisexual/hermaphrodite, infundibuliform/campanulate, complete.

D-42 Complete, Ebracteate/bracteate, pedicellate, hermaphrodite, zygomorphic, hypogynous,papillionaceous, pentamerous.

(b) Drawing:

Drawing points:

1. 2 sepals (long) shown

2. 2-3 gamopetalous, bell shaped petals shown

3. 2-3 epipetalous stamens shown

4. Long basifixed anther shown

5. Prominent style with bifid stigma shown

6. Style shorter than petals

7. 2 locules visible in the ovary

8. 2 rows of ovules attached to the placenta


GFS

(c) Drawing: D – 42

D-42 – V S

Drawing points:

2 sepals shown

Standard, wing and keel shown

At least three stamens shown

Bent style shown

One chambered ovary shown

4-5 ovules shown attached to the upper margin

Pedicel shown

(d) D-41 D-42

Corolla

(i) Shape Bell shaped/ Infundibuliform/campanulate

papillionaceous

Androecium

i) Relation of stamens to eachother

Polyandrous/ free Diadelphous/ 2 bundles

ii) Relation of stamens to petals Epipetalous Free

Gynoecium

i) Number of locules in the ovary Two One

ii) Type of placentation Axile Marginal


DD--4242 –– V SV S

Drawing pointsDrawing points:

2 sepals shown2 sepals

Standard, wing and keelStandard, wing and keel shownsho

At leastAt leas threeree stamenstamenss shownshown

Bent style shownBent style shown

One chambered ovary shownOne chambered ovary shown

44--5 ovules shown attached to the upper margin5 ovules shown attached to the upper margin

Pedicel shownicel shown

(d) D 41 D 42

(e) Diagram:

T.S. of ovary of D-42

Drawing Points Labelling Points

Narrow, elongated locule shown Locule

One locule drawn Ovary wall

Marginal placentation shown Placenta

One ovule connected with the placenta Ovule

(f) D-41 Solanaceae

D-42 Leguminosae / Fabaceae

(g) D-41 obliquely placed ovary, swollen placenta, bifid stigma, epipetalous stamen with longprominent anther.

D-42

Papilionaceous corolla

Diadelphous stamens

Marginal placentation

Vexillary aestivation (any two)


GFSNarrow, elongated locule shownw, elongated locule shown LoculeLocule

GFOne locule drawnOne locule drawn Ovary wallOvary wall

GGFFFSGFMarginal placentation shownMarginal placentation sh PlacentaPlacentaGGFFFSGFOne ovule connected with theOne ovu placentaacenta OvuleGGFFFSGGGFFFFS(f)(f) DD--4141 Solanaceaeanaceae

DD--4242 Leguminoguminossae / Fabaceaeae / Fabac

(g)(g) DD--41 o41 obliquely placed ovary,bliquely placed ova swollen placentawollen placen , bifid stigma, epipetalous stamen with longmen with longprominent anther.prominent anther.

DD--4242

Papilionaceous corollaPapilionaceous corolla

Diadelphous stamensmens

(h) F.D. D-42

• Mother axis

• One bract shown (according to flower)

• 5 joined sepals with correct orientation

• 5 petals in vexillary aestivation

• 10, diadelphous stamens, (9) + 1

• unilocular ovary with one ovule attached

• showing marginal placentation

(i)

Br % ♂ K(5) ,C

1 + 2 +(2) A1 + (9)

G1

(j) D-41: Solanum tuberosum, Capsicum annuum, Lycopersicum esculentum, Datura stramonium,Bombax malabaricum

D-42: Arachis hypogaea, Pisum sativum, Glycine max, Phaseolus vulgaris

--- Floral formula of D-41

--- Floral formula of D-42

O+

Br K(5) C(5)A5 G(2)


GFS(i)(i)

Br %Br % ♂♂ KK(5) ,(5) ,CC

11 + 2 +(2)+ 2 +(2 A1 + (9)(9)

GG11

------ Floral formula of DFlor -41

------ Floral formula of DF -4242

OO++GBrBr KK(5)(5) CC(5)(5)AA55 GG(2)(2)GG

Question 2 [5]

(a) You are provided with glassware and twigs of plant D-43 to set up an experiment todemonstrate photosynthesis. Set up the experiment using tap water and one or twotwigs of plant D-43.

(b) Keep the set-up at a distance of 5 cm, from the source of light. When gas bubblesstart emerging from the cut end of the twig(s), show the experimental set-up to theVisiting Examiner.

Draw a neat and fully labelled diagram of the experimental set-up.

(c) Count the number of bubbles evolved in one minute and record it. Repeat yourobservations for two more readings in this set-up.

Tabulate the readings as shown in the table in (f). Calculate the average number ofbubbles (x) evolved in one minute.

(d) Now, place the experimental set-up at a distance of 15 cm. from the source of light.Wait for two minutes. Count the number of gas bubbles evolved in one minute.Take three readings. Calculate and record the average number of bubbles (y)evolved in one minute.

(e) Shift the set-up at a distance of 25 cm. from the source of light. Wait for twominutes. Count the number of gas bubbles evolved in one minute. Again take threereadings. Calculate and record the average value (z).

(f) Tabulate your observations as follows:

Distance of set-up fromlight source

Number of gas bubbles evolved per minute

I II III Averagevalue

(c) 5 cm (x)

(d) 15 cm (y)

(e) 25 cm (z)

(g) Explain your observations with reference to each average value, (x), (y) and (z),recorded by you in the table above.

(h) Name the plant specimen D-43.

(i) Mention two precautions taken by you while setting up this experiment.

(j) What is concluded from this experiment?


GFS(d) NowNow,, place the experimental setplace the experimental set--upup at a distance ofat a distance of 15 cm.15 cm. ffrom thef source of light.source of light.

Wait for two minutes. Count the number of gas bubbles evolved in one minute.Wait for two minutes. Count the number of gas bubbles evolved in one minute.Take three readings. Calculate and record the average number of bubbles (Take three readings. Calculate and record the average number of bubbles (yy))evolved in one minute.evolved

(e)(e) Shift the setShift the set--upup at a distance ofat a distance of 25 cm. from the25 cm. from the source of light. Wsource of light. Wait for twoait for twominutes. Cminutes. Count the number of gas bubbles evolved in one minute.ount the number of gas bubbles evolved in one minute. Again take threeAgain take threereadings. Calculate and record the average value (readings. Calculate and record the average value (zz).)

(f)(f) TabulateTabulate your observations asyour observations follows:llows:

Distance of setDistance of set--up fromup fromlight sourcelight source

Number of gas bubbles evolved per minuteNumber of gas bubbles evolved per minuteGGFSSG SII II III AverageAveragevaluevalue

GFFFFFSSSSGFFSS


(a) A number of candidates did not follow the instructionsgiven. Some common errors made by candidates were asfollows:

The stem of Hydrilla was not placed pointingtowards the neck of the funnel;Too many twigs were used in the funnel.

(b) Candidates made the following errors while drawing theexperimental setup:

Light source was not shown;The test tube did not touch the funnel;The stem of the funnel was drawn above the level ofwater in the beaker;Bubbles were drawn in blank spaces.

(d) In a number of cases, the number of bubbles evolved inone minute was either too less or too many.

(f) A few candidates calculated the average value ofnumber of bubbles and wrote the answer in fraction.

(g) Some candidates did not explain each observationseparately. Most candidates gave a general report. Somecandidates simply copied the chart.

(j) A number of candidates did not write ‘Rate of photosynthesis’ and failed to explain its relationshipwith the intensity of light.

MARKING SCHEME

Question 2.

(b)

Suggestions for teachersEach student must set up allphysiological set ups individuallyand not in groups.Teachers must monitor eachstudent individually.Students must be encouraged todraw diagrams by observing thephysiological set up and not fromany book.Students must be trained to takethe readings carefully. They mustalso be told to write observationand explanation separately.The relationships between therate of photosynthesis and thenature of light intensity must beexplained.


GFSone minute was either too less or too many.her too less or too many.

(f) A fewwf candidatecandidates calculated the average value ofs calculated the average value ofnumber of bubbles and wrote the answer in fraction.number of bubbles and wrote the answer in fraction.

(g)) Some candidates did not explain eSome candidates did not explain each observationach observationseparately. Mostseparately. Most candidates gave a general report. Someeneral report. candidatescandidates simply copied the chart.s

(j)(j) AA number of candidatesnumber of candidates did not write ‘Rate of photosynthesis’ and failed to explain its relationshipdid not write ‘Rate of photosynthesis’ and failed to explain its relwith the intensity of light.with the intensity of light.

MARKING SCHEMEMARKING SCHEME

Question 2.Question 2.GFS(b)(b) FSFSThe relationships between therate of photosynthesis and thenature of light intensity must be

ained.

Drawing points: Labelling points:

Stem of the twigs pointed towards the neckof the funnel

Light

Water

Test tube rests on the funnel Test tube

Stem of the funnel under water Gas bubbles / air bubbles

Light source shown Beaker

Bubbles shown in the test tube in water Funnel

Hydrilla/aquatic plant

(f)Distance of set-upfrom light source

Number of gas bubbles evolved per minute

I II III Average value

(c) 5 cm Observation Observation Observation (X) Maximum

(d) 15 cm Observation Observation Observation (Y) Medium

(e) 25 cm Observation Observation Observation (Z) Minimum

(g) (X) Shows maximum value as set-up was close to light source; more photosynthesis; more gasbubbles evolved.

(Y) Average value decreased, as light intensity has decreased due to increase in the distance;photosynthesis decreased; less gas bubbles evolved.

(Z) Minimum average value as light intensity decreased further; rate of photosynthesis less;few gas bubbles evolved.

(two each)

(h) Hydrilla / Elodea

(i) (i) Stem of funnel should be completely under water

(ii) Cut end of the twig(s) should be in the mouth of the stem of the funnel.

(iii) Test tube should be completely filled with water for inverting over the funnel.

(iv) Light source should be present.

(v) Fresh twigs should be used. (any two)

(j) The rate of photosynthesis depends on the intensity of light.


Hydrilla / ElodeaHydrilla / Elodea

(i)

GFSGGGFFS(d)(d) 15 cm15 cm Observationrvation ObservationObservation ObservationObservation ((YY) Medium) Medium

GGGGGGFFFFFSSSGGGFFS(e)(e) 25 cm25 cm Observationrvation ObservationObservation ObservationObservation ((ZZ) Minimum) Minimum

GGGGGGFFFFFSSSGGGGGGGGGFFFFFFFSSSS(g)g) ((XX) Shows maximum value as set) Shows maximum value as set--up was close to light source; more photosynthesis; moreup was close to light source; more photosynt gasbubbles evolvedbubbles evolved..

(Y)(Y) Average valueAverage value decreased,decreas as light intensity has decreased due to increase in the distancelight intensity has decreased due to increase in the distance;photosynthesis decreased; lessphotosynthesis decreased; less gasgas bubbles evolved.bubbles evolved.

(Z)(Z) Minimum average value as light intensity decreased further; rate of photosynthesis less;Minimum average value as light intensity decreased further; rate of photosynthesis less;fewfew gasgas bubbles evolved.bubbles evolve

((twotwo each)each

(h)

(i) Stem of funnel should bennel should b completely under water

Question 3 [5]

(a) With the sharp razor/blade provided, cut thin transverse sections of specimen D-44.Select a good transverse section and stain with safranin. Mount the section inglycerine.

Observe it under low power of the microscope and show it to the VisitingExaminer.

(b) Draw a neat labelled outline of the mount as observed under the microscope.(Cellular details are not required.)

(c) Answer the following questions:

(i) Identify the given specimen.

(ii) Give two reasons to support your answer in (c)(i) above.


(a) Candidates of a few centres were unable to prepareslides properly. Common mistakes made bycandidates were:

Overstaining or understaining;Oblique/thick section;Improper mounting.

(b) Some errors made by candidates in the drawing wereas follows:

Indistinct pith not clear;Many candidates were not sure of theendodermis and pericycle. In some cases, epiblema was labelled as epidermis.Thick cortex was not shown.

(c) Many candidates were unaware of the difference between ‘general features’ and ‘identifyingfeatures’. Some failed to mention the nature of vascular bundles and the exact number.

Suggestions for teachersStudents must be trained to drawan outline diagram and to showthe structure of vascular bundlesclearly.Students must be trained toobserve the most distinctivefeatures under the microscope.


GFS(a) Candidates of a few centres were unable to preparedates of a few centres were unable to prepare

slides properly. Commonslides properly. Com mistakes made bymistakes made bycandidatescandidates were:were:

Overstaining or understaining;Overstaining or understaining;Oblique/thick section;ObliqImproper mounting.Improper mounting.

(b)(b) Some errors made by candidates in the drawing wereSome errors made by candidates in the drawing wereas follows:as follows:

IndistinctIndistinct pith not clear;pith not clear;Many candidates were not sure of theMany candidates were not sure oendodermis and pericycle. In some cases, epiblema was labelled as epidermis.endodermis and pericycle. In some cases, epiblema was labelled as epidermis.Thick cortex was not shown.Thick cortex was not sh

(c)(c) Many candidates were unaware of the difference between ‘general features’ and ‘identifyingMany candidates were unaware of the difference between ‘general features’ and ‘identifyinfeaturefeatures’. Some failed to mention the nature of vascular bundles and the exact number.s’. Some failed to mention the nature of vascular bundles and the exact number.FSFS

Suggestions for teachers

FSStudents must be trained to draw

utline diagram and to showstructure of vascular b

arly.dents must be trerve the most distinctivetures under the microscope.

11

MARKING SCHEME

Question 3.

(b)


Root hair shown Root hair

Epiblema shown Epiblema

Thick cortex shown Cortex

Endodermis shown Endodermis

Pericycle shown Pericycle

4-5 radial vascular bundle shown 4-5 radial vascular bundle

Pith poorly developed/absent Pith

Xylem, Phloem

(c) (i) Identification of T.S. of dicotyledonous root :

(ii) Reasons:

– Vascular bundles are radial

– Number of vascular bundles between 2 – 6

– Xylem is exarch

– Pith is poorly developed.

– Epidermal hair are unicellular (any two)


GFSDrawing points:Drawing points: Labelling points:ts:GGFFFSGFRoot hair shownRoot hair shown RootRoot hairhairGGFFFSGFEpiblema shownEpiblema shown EpiblemaEpiblemaGGFFFSGFThick cortex shownThick cortex shown CortexGGFFFSGFEndodermis shownEndodermis shown EndodermisGGFFFSGFPericycle shownPericycle shown PericycleGGFFFSGF4-5 radial vascular bundle showncular bundle shown 4-5 radial vascular bundler bundleGGFFFSGF

12

Question 4 [5]

Identify the given specimens A to E. Give two reasons to support your answer in each case.Draw a neat labelled diagram of each specimen. You are not allowed to spend more thanthree minutes for each spot.

Note: Hand over your continuation booklet to the Supervising Examiner after you finishanswering this question.


Specimen ACommon errors made by candidates were as follows:

Incomplete identification was done by a number ofcandidates. Many did not mention ‘T.S. or‘Mammalian’.In several cases, candidates did not label the diagramcompletely.A few candidates did not mention ‘seminiferoustubules’.In some cases, the labelling and the reason foridentification did not match.

Specimen BA number of candidates did not mention ‘T.S.’ in theidentification.In some cases, the gap between the inner mass of cellsand zona pellucida was not drawn distinctly.Many did not label ‘zona pellucida’ and also did notmention it in the reason.

Specimen C‘T.S.’ was not mentioned by many candidates in theidentification.

In several cases, spongy and palisade parenchyma could not be distinguished in the diagram.In many cases, the labelling was incomplete.

Specimen D

A few candidates identified the spot as ‘Hibiscus’ / ‘self-pollinated’ flower / ‘L.S. of flower’instead of entomophilous flower.In many cases the labelling was incomplete.

Specimen EWrong or incomplete identification was done by candidates.In some cases, the shape of the thistle funnel was not drawn correctly.In a few cases, the thistle funnel was not labelled.The initial and final level was not clearly mentioned by some candidates.

Suggestions for teachersStudents must be trained to makecorrect observation to identifythe given specimen. They shouldbe able to match the drawing,labelling and identifyingremarks.Explain the importance ofmaking a simple and completelylabelled diagram.Tell students that the distinctidentifying features should bementioned and not generalfeatures.Tell students that the drawingshould match the identifyingfeatures and that the guide linesmust not cross over; all apparatusmust be labelled.


GFScompletely.A few candidates did not mention ‘seminiferousfew candidates did not mention ‘seminiferoustubules’.tubules’.In some cases, the labelling and the reason forIn some cases, the labelling and the reason foridentification did not match.identification di

Specimen BSpecimen BGA number of candidates did not mention ‘TA number of candidates did not mention ‘T.S.’ in the.S.’ in theidentification.identificatiIn some cases, the gap between the inner mass of cellsIn some cases, the gap between the inner mass of cellsand zona pellucida was not drawn distinctly.and zona pellucida was not drawn distinctly.Many did not label ‘zona pellucida’ and also did notMany did not label ‘zona pellucida’ and also dmention it in the reason.mention it in the reason.

Specimen Cecimen CG‘T.S.’ was not mentioned by many candimentioned by many candidates in thedatesid tifi ti

FSFSl identifyingrExplain the importance of

ng a simple and completelylled diagram.

students thantifying features shoulntioned and not generaltures.

ents that the drawinghe identifying

res and that the guide linesnot cross over; all apparatusbe labelled.

13

MARKING SCHEME

Question 4.

Spot A:

Identification of T.S. Testis of mammal:


Seminiferous tubules shown Seminiferous tubules

Leydig cells in between seminiferous tubulesshown

Leydig cells

Elongated Sertoli cells shown Sertoli cells

Spermatogania/ spermatocyte/ spermatids/spermatozoa

Spermatogania/ spermatocyte/ spermatids/spermatozoa

Connective tissue shown in between tubules Connective tissue

Reasons:

(i) Seminiferous tubules showing spermatogenesis

(ii) Sperms in the centre of the tubules

(iii) Leydig cells in the matrix (any two)


Drawing points:Drawing points: Labelling points:LGGFFFSGFSeminiferous tubules shownshown Seminiferous tubulesGGFFFSGF

14

Spot B: Identification.

T.S. of Morula.


Spherical mass of cells in the centre shown. Blastomere/ Inner cell Mass.

Zona pellucida shown Zona pellucida

Gap shown between mass of cells and zonapellucida

Reasons: - Spherical mass of cells visible / many blastomeres.

- Mass of cells surrounded by a thin layer of tissues (any two)

Spot C:

Identification of T.S. of dicotyledonous leaf/ Dorsiventral leaf:


Palisade tissue shown Palisade parenchyma

Spongy parenchyma shown Spongy parenchyma


GFSDrawing points:ints: Labelling points:Labelling point

GFSpherical mass of cells in the centre shown.herical mass of cells in the centre shown. BBlastomerelastomere/ Inner cell Mass/ Inner cell Mass..

GGFFFSGFZona pellucida shownZona pellucida shown ZonaZona pellucidapellucidaGGFFFSGFGap shown between mass of cells and zonaGap shown between mass of cells and zonapellucidapellucidaGGFFFSGGGFFFFSReasons:Reasons: -- SSpherical mass of cellspherical mass of cells visible / many blastomeresvisible / many blastome .

- Mass of cells surrounded by a thin layer of tissuesass of cells surrounded by a thin l (any two)(any two)

Spot C:Spot C:

Identification of T.S. of dicotyledonous leafIdentification of T.S. of dicotyledonous leaf/ Dorsiventral leaf/ Dorsivenfff :

15

Lower epidermis with stoma shown Epidermis (lower/upper)

Vascular bundle shown Stoma/stomata

Thick cuticle in the upper epidermis shown Cuticle

Vascular bundle

Reasons:

- Mesophyll is differentiated into Palisade and Spongy parenchyma

- Stomata mainly present on the lower epidermis

- Thick cuticle in the upper epidermis (any two)

SPOT D

Identification: Hibiscus rosa sinensis – Entomophilous flower/correct explanation.

Drawing: - Large flower shown

- Large petals shown

- Monadelphous stamen shown

- Prominent stigma shown

Labelling: Bright petal, pollen grain/anthers, stigma, staminal tube

Reasons: - Large brightly coloured showy flower.

- Many anthers (with pollen grains).

- Stigmatic surface sticky. (any two)


GFSDra ing: L fl hfl h

16

SPOT E

Identification : Experiment to demonstrate osmosis

Drawing Points: Labelling Points:

Beaker with water shown Beaker with water

Mouth of thistle funnel is covered with semipermeable membrane

Thistle funnel

Thistle funnel filled with hypertonic solution Semi-permeable membrane

Initial level of hypertonic solution is less thanthe final level in the stem of the funnel

Hypertonic solution

Initial level, final level

Reasons: - Mouth of thistle funnel tied with semipermeable membrane

- Beaker has water, thistle funnel has hypertonic solution

- Final level of solution in the stem of the funnel higher than initial level

(any two)


GFSDrawing Points:Drawing Points: Labelling Points:Labelling PoiGGFFFSGFBeaker with water shownBeaker with water shown Beaker with waterBeaker with wGGFFFSGFMouth of thistle funnel is covered with semiMouth of thistle funnel is covered with semipermeable membranepermeable mem

Thistle funnelThistle funnelGGFFFSGFThistle funnel filled with hypertonic solutionThistle funnel filled with hypertonic solution SSemi-permeable membranembraneGGFFFSGFInitial level of hypertonic solution is less thanInitial level of hypertonic solution is less thanthe final level in the stem of the funnelnal level in the stem of the fu

HypertonicH solutionGGFFFSGFInitial level final level

GG SG

17

Question 5

Show the following to the Visiting Examiner for assessment:

(a) Project [7]

(b) Biology Practical File. [3]

GENERAL COMMENTS:

(a) Topics found difficult by candidates in the Question Paper:

Question 1 – Floral formula, floral diagram and botanical names.

Question 2 – Interpretation of the Observation.

Question 4 – Identification of Morula.

(b) Concepts in which candidates got confused:

– Gamosepalous and epipetalous condition.

– Exarch and endarch xylem, epidermis and epiblema.

– Leydig cell and Sertoli cell.

– Anemophily and Entomophily.

(c) Suggestions for candidates:

– Think logically and establish a cause and effort relationship while setting up a physiologicalexperiment.

– Conceptual understanding is important.

– Learn the semi-technical terms with correct spellings.

– Practice drawing all the diagrams through observation.

– Read each question carefully and then answer.

– Make a neat presentation.


GFS– Gamosepalous and epipetalous condition.epalous and epipetalous condition.

–– Exarch and endarch xylem, epidermis and epiblema.Exarch and endarch xylem, epidermis and epiblema.

–– Leydig cell and Sertoli cell.Leydig cell and Sertoli ce

–– Anemophily and Entomophily.Anemop

(c)(c) Suggestions forSuggestions for candidatecandidates:s:

–– Think logically and establish a cause and effort relationship while setting up a physiologicalThink logically and establish a cause and effort relationship while setting up a physiologicalexperiment.experi

–– Conceptual understanding is important.Conceptual understanding is important.

–– Learn the semiLearn the semi--technical terms with correct spellings.technical terms with correct spe

–– Practice drawing all the diagrams through oPractice drawing all the diagrams through observation.bse

– Read each question carefully and then answer.tion carefully and then ans

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ISC 2014 BIOLOGY - Guide For School · BIOLOGY PAPER 2 (PRACTICAL) Question 1 [5] (a) You are provided with two flower specimensD-41 and D-42. Describe the floral characteristics