2022 Mock Examinations Biology Paper 3 with Answers-Kapsabet High School

INSTRUCTIONS TO CANDIDATES

Answer all the questions in the spaces provided.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.Candidates may be penalized for recording irrelevant information and for incorrect spelling especially of technical terms.

1. You are provided with an unknown mixture labelled J You are also provided with Benedict’s solution, dilute hydrochloric acid solution, iodine solution, Dichlorophenol-Indophenol (DCPIP) solution. Sodium hydrogen-carbonate solution, means of heating, test tubes, test tube holder and a test tube rack.

a. Using the reagent provided only, test for the food substances in mixture J. Record in the table below the chemical test, the procedure of the test, your observations and conclusions. 8mks

Chemical test	Procedure	Observations	Conclusions

b. Which of the components of mixture J does not undergo digestion in the mammalian digestive system? 1mk

c. Name a deficiency disease that may result from a deficiency of the component identified in (b) above. 1mk

d. Name a common carbohydrate that could be present in mixture J. 1mk

e. State the role of hydrochloric acid and sodium hydrogen carbonate in the experiment. 2mks

i. Hydrochloric Acid

ii. Sodium Hydrogen Carbonate

2. The photographs below show a flower specimen. Study it carefully and use to answer the questions that follow.

a. On the photograph, label the following parts 3mks

i. Stigma

ii. Style

iii. Staminal tube

b.i. Classify the plant from which the flower was picked into the taxonomic groups listed below. 4mks

I. Kingdom

II. Division

III. Sub division

IV. Class

ii. Name three observable features from the photograph of the class you named in (a) (i) above. 3mks

c. Suggest the pollination agent of this flower. Give reasons for your answer.

i. Pollinating agent 1mk

ii. Reasons 2mks

d. For parts (d) below, an actual specimen is required

i. Examine one flower and describe the following parts. (8mks)

I. calyc

II. corolla

III. androecium

IV. Gynoecium

3. Below are photographs of two specimens, J and K. Both of them belong to the same Phylum and Class. Observe them carefully before you answer the questions that follow.

a. Name the class to which J and K belong and support your answer with two reasons.

i. Class 1mk

ii. Reasons 2mks

b. Suggest why the transport fluid in J and K has no haemoglobin. 2mks

c. Describe the type of evolution that has occured to cause the diffrence in the two sepcimens.3mks

i. type of evolution

ii. Reason

d. Below is a diagram showing the life cycle of specimen J.

i. Identify the stage labeled D. 1mk

ii. Name the hormone responsible for the change from D to A. 1mk

iii. Explain the differences in the change from C2 to C3 and from C3 to D. 2mks

I. C2 to C3

II. C3 to D

iv. State the importance of the process illustrated above in the life cycle of the organism 2mk

Confidential

1.a. Mixture J: Solution containing a mixture of sucrose and vitamin C

b. Benedict’s solution, dilute hydrochloric acid solution. Iodine solution Dichlorophenol – Indophenol (DCPIP) solution, sodium hydrogen – carbonate, means of heating, 5 test tubes, test tube holder and a test tube rack

2.a. Photograph Q: complete hibiscus flower

b. Photograph Q: Half flower of hibiscus

c. Scarpel

Marking Scheme

1. You are provided with an unknown mixture labled J You are also provided with Benedict’s solution, dilute hydrochloric acid solution, iodine solution, dichlorophenol-indophenol (DCPIP) solution. Sodium hydrogen-carbonate solution means of heating, test tubes, test tube holder and a test tube rack.

a. Using the reagent provided only, test for the food substances in mixture J. Record the able below the food substance tested, the procedure of the test, your observations and conclusions. (12 mks)

Chemical test	Procedure	Observations	Conclusions
Starch	StarchTo about 2 ml of solution J add 3 drops of iodine and mix	Yellow / brown colour. Colour of iodine solution
Reducing sugar	To about 2 ml of solution J add an equal volume of Benedict’s solution, s hake to mix and heat to boil	Blue colour of Benedict’s solution remains	Reducing sugar absent
Non reducing sugar	To about 2 ml of solution J add 6 drops dilute Hcl and heat. \Cool and the add NaHCO3 solution drop wise until fizzing stops. Add about 2 ml Benedict’s solution and heat to boil	Colour changes to yellow / orange / brown	Non – reducing sugar present
Vitamin C	To about 2 ml of DCPIP add solution J dropwise.	DCPIP is decourized	Vitamin C present

b. Which of the components of mixture J does not undergo digestion in the mammalian digestive system. (1mk)Vitamin C c. Name a common carbohydrate that could be present in mixture J (1mk)Sucrose d. State the role of hydrochloric acid and sodium hydrogen carbonate in the experiment (2mks)Hydrochloric acid hydrolyzes non-reducing sugar (s) into simple sugars / monosaccharides reducing sugars e. Name a deficiency disease that may result from a deficiency of one of the substances present in mixture J. (1mk)scurvy f. Give one common symptoms of the disease you have stated in € (i) above.1mk)bleeding gums 2. The photographs below show a flower specimen labelled M and a section of the same flower labelled M1

i. Classify the plant from which the flower was picked into the taxonomic groups listed below. (4mks)kingdom plantaedivision spermatophytesub division angiospermae / angiospermatophytaclass dicotyledonae

ii. Name three observable features from the photographs of the class you named in (a) (i) above. (3mks)Five petals: five stigmas; petals have network veins iii. State the plane through which the flower has been cut to obtain M1. (1mk) Longitudinal section c. Suggest the pollination agent of this flower. Give reasons for your answer (3mks)Pollinating agent insectReasons brightly colouored petalsLarge / conspicuous petals d. For parts (d) below, an actual specimen is required

i. Examine one flower and describe the following parts. (8mks)

I. Calyc: five green sepals, fused in the lower half but free at the upper half pointed tips

II. Corolla: five large, brightly coloured petals which are separate and overlapping/ polypetalours corolla, petals have rounded ends and prominent nectary guides

III. Androecium many anthers each of which is attached to a short filament. The filaments fuse to form a stamen tube that encloses the style. Anthers lie below the stigma IV. Gynoecium a green superior / hypognours and syncapous ovary with several ovules.

A long, white style that branches near the tip. Each style branch to supports a red, round stgma 3. Below are photographs of two specimens, J and K. Both of them belong to the same phylum and class.

Observe them carefully before you answer the questions that follow.

a. Name the class to which J and K belong and support your answer with two reasons.

i. Class Insecta; 1mk Rej. insect

ii. Reasons 2mks

i. Six legs; three body parts; two antennae; two compound eyes;

b. Suggest why the circulatory fluid in J and K has no haemoglobin. 2mks

i. Haemoglobin used to transport oxygen/ carbon (IV) oxide in the body; oxygen is taken directly to tissues/ carbon (IV) oxide taken directly from tissues by tracheoles; i. divergent evolution; 1mk

ii. Reason one pair of wings in J reduced to halters/ are vestigial; but both are functional in K 2mks

i. pupa stage; 1mk

ii. Ecdysone; accept Moulting hormone4mks

iii.

I. C2 to C3 – moulting hormone / Ecdysone induce moulting; but presence of juvenile hormone prevent formation of pupa;

II. C3 to D – moulting hormone / Ecdysone induce moulting; but abscence of juvenile hormone lead to formation of pupa;