FORM 4 BIOLOGY PP3 END TERM 2 EXAMS PLUS MARKING SCHEMES

NAME ………………………………………………ADM. NO ………………CLASS:……….

DATE……………..

231/3

BIOLOGY

PAPER 3

PRACTICAL

MARCH/APRIL

TIME: 1³/₄HRS

KENYA CERTIFICATE OF SECONDARY EDUCATION

Instruction to Candidates

• Write yourName, Adm. No., Class and Date in the spaces provided
• Answer all the questions in section A in the spaces provided.
• You are required to spend the first 15 minutes of the 1³/₄Hrs around for this paper reading the whole paper carefully before commencing your work
• The paper consists of six printed pages.

QUESTION	MAXIMUM SCORE	CANDIDATE’S SCORE
1 2 3	15   14   11
TOTAL SCORE	40

 

1. You are provided with a specimen labelled Q and hydrogen peroxide.
2. What part of the plant is specimen Q? (1mk)

 

1. Cut two equal cubes whose sides are about 1cm from specimen Q. place one of the cubes into a boiling tube labelled A. Crush theother cube using pestle and mortar. Place the crushed material in another boiling tube labelled B. To each boiling tube add 4ml of hydrogen peroxide.
2. Record your observations (2mks)

Test tube A:…………………………………………………………………….

 

Test tube B:…………………………………………………………………….

 

1. Account for the results in b)(i) above (2mks)

 

 

 

 

 

 

• Write an equation for the break down of hydrogen peroxide (1mk)

 

 

 

 

1. Peel half of specimen Q and crush in a mortar. Use the reagent provided to test for the various food substances in the extract obtained from the crushed material. Record the procedure, observation and conclusion in the table below (9mks)

Food Substance	Procedure	Observation	Conclusion

 

2. The photograph below represents the lower and upper jaw of a mammal. Study it and answer the questions that follow.

 

 

1. Name the parts labelled (5mks)

A –

B –

C –

D –

F –

1. Name one observable structural difference between B and C (1mk)

 

 

 

 

1. i) Draw and label the external structure of part labelled B (3mks)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1. i) Define the term “dental formula” (1mk)

 

 

 

 

 

1. ii) Write the dental formula from the diagram above (1mk)

 

 

 

 

 

1. Suggest the mode of feeding in the above animal (1mk)

 

 

 

 

1. Name one common disease that affect part labelled D (1mk)

 

 

 

 

1. What class of food is digested in the cavity shown in the diagram? (1mk)

 

 

 

 

 

 

 

3. You are provided with the photographs below labelled A, B, C, D, E, F, G and a dichotomous key. Use them to answer questions that follow.

 

1. Fill the missing information in the dichotomous key below (2mks)

 

1    (a)       Animals with jointed appendages ……………………go to 3

(b)       Animals without jointed appendages …………………go to 2

 

2    (a)       Animals with a slender long body ……………………Nematoda

(b)       Animals with a thick short body ……………………..Mollusca

 

3    (a)       ………………………………………………………..go to 5

(b)       Animals without wings ………………………………go to 4

4    (a)       Animals with numerous legs ……………………….Myrioponda

(b)       ………………………………………………………Hymenoptera

 

5    (a)       Animals with short antenna …………………………Diptera

(b)       Animals with a pair of long antenna ………………..go to 6

 

6    (a)       Animals with cuticulized forewings ………………..Dictyoptera

(b)       Animals with a pair of membranous wings………….Hymenoptera

 

1. Use the completed dichotomous key to identify the family to which each plant belongs (7mks)

Identity                                         Steps followed

 

A   ………………………………       …………………………………………..

B   ………………………………       …………………………………………..

C   ………………………………      …………………………………………..

D   ………………………………      …………………………………………..

E    ………………………………      …………………………………………..

F    ………………………………      …………………………………………..

G   ………………………………      …………………………………………..

 

1. Name two features that are used to classify B as phylum arthropoda.(2mks)

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EXAMS TERM 2

FORM 3 BIOLOGY P3 MARKING SCHEME

1. (a) (i) Test tube X

Liquid becomes cloudy/turbid suspension formedÖ/oil broken up into small droplets which are                dispersed throughout the liquid. Ö (The oil becomes emulsified)

Test tube Y

Oil floats on the water/two separate/immiscible layers are formedÖ

(ii) Emulsification Ö

(iii) Increased surface area for action of enzyme lipase Ö (answer tied to a (ii))

(iv) BileÖ

(v) DuodenumÖ (tied to (a) (ii) and (iv) )

(b) (i) Blue black Ö

(ii) Starch Ö

(iii) Contents of F remain unchanged. Blue black colour in E disappears/fades/changes to pale/light yellow/light brown/orange. (Answer tied to b (ii) )

(iv) Enzyme/Amylase in potatoÖ breaks down starch/converts/hydrolyses/changes/digests Östarch   into maltose/reducing sugarsÖ/simple sugars that do not give a blue black colour with iodine.Ö(1mk)

 

Procedure

(c) (i) Add equal amount of Benedict’s solution to paste and boil in a hot water bath

Food being tested	Procedure	Observation	Conclusion
Reducing sugarÖ	To the food substance add equal amounts of Benedict’s solution and heat/boil (in a hot water bath) Ö	Colour changes from blue to green to yellow to orange and finally brown Öor colour changes to brown	Reducing sugars present Ö

 

⁴/₂ max 2mks

(ii) Starch Öin potato is converted to maltose/glucose/reducing sugar Öby enzyme                amylase/maltose/diastaseÖ. Rejptylin

                             

Q2.   The photographs labelled J, K and L are all related to mammalian kidney.

 

(a)    Name the hormone produced by the structure labelled P.: Adrenaline  ;aldosterone                              (1 mk)

 

• Name the parts labelled Q – Cortex    R –pelvis  T- Collecting tubule                                                       (3mks)

 

• State the process by which wastes are filtered from blood in the structure labelled S. – Ultrafiltration (1 mks)

 

(d) (i)     Give two components of blood that that are not filtered at structure S. – Blood cells / Plasma protein           (2 mks)

(ii)     Give reason why the components you have named in d (i) above are not filtered.          (2mks)

They have very large molecules; structures that can filter through the pores in the glomerulus.

 

(e) Give two nutrients reabsorbed at the part labelled S – Glucose / Amino acids                              (2 mks)

(f)     What three adaptations would be expected in the structure L in a desert animal like a camel.                (3 mks)

• Small glomerulus to reduce filtration of water.
• Long loop of Henle to maximize reabsorption of minerals (sodium salt)
• Very long distal convoluted lobule to increase surface area for water reabsorption.
• Highly coiled distal convoluted lobule to allow more time for water re-absorption.

 

 

3. a) Reproduction ;
4. b) R                                                                                        Q

Superior  / hypogynous Ovary ;	Inferior / Ovary;Epigynous ovary
Monocarpous ;	Polycarpous / apocarpous / free capels

;

1. c)

C – Anther ;

D- Sepal / Calyx ;

1. d) The petals degenerate / weather and are shed ;

The ovary develop into a fruit ;

The ovules develop into seeds

The ovary wall develop into a pericarp;

1. e) Class – dicotyledonae ;

Reason – The floral structure (anthers ) are in five in Q and 12 ( multiple of 4) in R ;