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 BIOLOGY PRACTICAL QUESTIONS – SOTIK DISTRICT

 

 1.  Each candidate should have one fruit of;

  • Black jack labeled P
  • Tomato (ripe one – money maker variety) labeled Q
    • Bean/pea (mature one) labelled R
  • Sonchus /fleabane/dandelion labeled S

 

 2.  Each candidate should have access to :-

  • DCPIP solution
  • Ethanol
  • Benedict’s solution
  • Iodine solution
  • Hot water bath
  • Clean water

N/B Use clean droppers where applicable to minimize contamination of reagents.

 

 3.  Each candidate should be provided with;

(i) 4 test-tubes in a test tube rack.

(ii) Razor blade (or they can be asked to bring theirs).

 

1.  You are provided with specimens labeled P, Q, R and S

 (a) State the type of fruits represented by each of the specimens  

(b) Explain how specimens R and S are adapted to their agents of dispersal

 (c) Cut the specimen Q transversely in the middle. Draw a well labeled diagram of the

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face of the cut surface of one of the halves

(d) State the placentation of specimen Q  

 
 

 

2.  (a) Wash of the halves of specimen Q and place it in a mortar and grind it using the pestle to

obtain its juice. Then add clean water enough to fill a test tube and shake. Then decant the

juice into a clean test tube. Using the apparatus and the chemicals provided subject

 (b) Explain how digestions of the components of the food sample are digested in the ileum

  of a mammal  (c) What is the importance of specimen Q in the human diet?

3.  The photographs W and Z below are of plants obtained from different habitats Image From EcoleBooks.comImage From EcoleBooks.com

Image From EcoleBooks.com

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Image From EcoleBooks.comImage From EcoleBooks.comImage From EcoleBooks.com

 

 (a) Suggest the possible habitat of specimen W

 (b) (i) Name the structure labeled Y in specimen W

(ii) State the function of the structure named in (b) (i) above

SOTIK DISTRICT BIOLOGY PRACTICAL MARKING SCHEME (ANSWERS)

1.  a)  SPECIMEN TYPE OF FRUIT

P Cypsella  

Q Berry

R Legume  

S Cypsella  

 b) R has two lines of weaknesses (sutures) along which it splits; to release seeds by explosive

mechanism;

Accept Self dopersal for explosive mechanism

Reject self explosion or self explosive mechanism

Agent = 1 mk, adaptation = 1 mk; reason = 1 mk

  S is very small; with pappus; making it light; to float easily to be dispersed by wind;

Agent = wind 1 mk Any one adaptive feature & explanation

Adaptation = 1 mk Reason = 1 mk

 

 

 

 

 

 

 c)

 

 

 

 

 

 

 

 

 

 

 d) Axile placentation

 

 2.  a)

FOOD

PROCEDURE

OBSERVATION

CONCLUSION

Lipids

4cm3 of food sample mixed with 4cm3 of ethanol then add clean water( 1 mk)

No change in colour

Absence of lipids

Reducing sugar

2cm3 of food sample in mixed with 2cm3 of Benedicts solution and heated in the hot water bath(1mk )

The colour changes from blue to brown

1mk

Presence of reducing sugar

1 mk

Ascorbic acid (Vitamin C)

2cm3 of DCIP is put in a test tube. Add food sample droplisively (1mk)

The DCIP is decolorized (1mk)

Ascorbic acid (Vitamin C) present(1 mk)

Starch

2cm3 of food sample placed in a test tube and four drops of iodine solution added (1 mk)

The colour of the solution turned brown 1 mk

Starch is absent

1 mk

 

 b) Since a carbohydrate is present, maltase; acts on maltose; producing glucose; or lactase;

acts on lactose; into galactose and glucose; i.e. enzymes in ileum; product;

c) Provides simple carbohydrates e.g. glucose which can be broken down in body cells to

liberate energy; or it is a source of vitamin C which is necessary for proper development

of epithelial tissues controlling scurvy; OWITTE Any two fully explained answers  

3.  a)  i) W – Aquatic (water)

ii) Z – Desert or semi- desert or dry land

 b)  i) Y- Flower  

ii) Sexual reproduction  Reject reproductive alone

 c) Observable features apply i.e. has thick succulent stem; for storage of water; and

respiratory; its leaves are reduced into spines; to lower the SA for transpiration; or for

protection against herbivores

 




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