West Bengal Board Model Questions & Answers : Class-12 Life Science

Disclaimer: This website is NOT associated with CBSE, for official website of CBSE visit - www.cbse.gov.in

West bengal logo

West Bengal Board Model Questions & Answers : Class-12

 

Exam Name :  West Bengal Board Model Questions & Answers

Subject :  Life Science (Sample Paper's I,II & III )

Class : 12th 

 

Model Question Biology 3

Sankari Prasad Bhattacharyay

Ballygunj  Govt. High School

Group ‘A’

Q1.      Answer the following questions :  (Alternatives are to be noted)        2 x 7 = 14

(a)            State two differences between tracheid & trachea.

Ans.

Tracheid                                            Trachea

1.

Structure

1.

Presence of all types of

1.

Presence of all types of

 

 

 

thickening except

 

thickening including

 

 

 

bordered pits.

 

bordered pits.

2.

Function

2.

Major  conducting   xylem

2.

Major     conducting      xylem

 

 

 

element of non−flowering

 

plants.

 

elements of flowering plants.

(b)       State two differences between the vascular bundle of Root and Stem.

Ans.

Vascular bundle of stem                Vascular bundle of root

1.

Number

1.

Many vesicular bundle

 

arranged in a ring in dicot

1.

Number of vascular bundles

 

and less i.e. 2 − 5 in number

 

 

 

stem.

 

in Dicot root.

 

 

 

Numbers vascular

 

The vascular bundles are 6 −

 

 

 

bundles are scattered in

 

the ground tissue in

 

8 in number in monocot root.

 

 

 

monocot stem.

 

 

2.

Types

2.

Conjoint, collateral or

2.

Radial, closed

 

 

 

bicollateral

 

 

(c)       State two differences between Penaeid & Non penaeid Prawn.

 

Ans.                Peneid                                     Non−peneid

 

Habitat        1.      Saline Water prawn             1.    Fresh water prawn

 

Structure     2.      The  first  three  thoracic legs are chelate

Ex − Penacus indicus                                       Ex − Macrobrachium rosen burgii

 

OR      Write the scientific names of two Pearl oysters.

 

Ans :

1.

Pinctada fucata

 

2.

Pinctada atropurpurea

(d)       Write one symptom each of Flacherie & Muscardine of silkworm.

Ans :  1.     Flacherie :  (i) The body of the larva becomes soft and black.

2.    Muscardiine :  (i)  The body of the larva becomes stiff and is covered with powdery white material.

 

(e)       State the name of four abnormal composition of urine.

Ans :  (i) Blood, (ii) Pus Cells, (iii) Protein (albumin)     (iv) Ketone bodies.

OR      State the role of skin in excretion.

Ans :  (i)         The skin excretes    water, salts,    uric acid etc.    through sweat and irreversible respiration.

(ii)        The  skin  excretes  waxes,  hydrocarbons,  cholesterol  etc.  through  sebum. Hence  the skin is called accessory excretory organ.

 

(f)        Write the now of four hormones secreted from placenta.

Ans :  (1)  Human chronic gonadotrophin (HCG)     (2)  Estrogen  (3)  Progesterone

 

(4) Placental prolactic.

OR      State the one function each of somatostation & Prostaglandin.

Ans :  (1)    Somatostaion −    It  inhibits the secretion of insulin and glucagon from the pancreatic islets.

(2)       Prostaglandins − Inhibit gastric acid secretion and formation of peptic ulcer.

   

Courtesy: West Bengal Board