Sunday, August 31, 2014

Time: 3 Hrs                                                                                                                                  MM: 90


Section A

1.            Intercalary meristem.

2.            The direction of velocity is along the tangent drawn on the circle at given point.

3.            Higher yield, wider adaptability and shorter duration of crop.

4.            Sugar on heating melts to give liquid state, ammonium chloride sublimes on heating and change to vapor form.

5.            Mitochondria is a double membranous organelle which is also called as “power house of the cell”. The outer membrane is smooth and permeable where as the inner membrane is thrown into folds to form cristate.

6.            Apples on the tree are in state of rest. When Harsh shook the branches of apple tree, the branches acquired state of motion. However, apples remained in rest due to the inertia of rest. So, some apples got separated from the branches.

7.            (a) There are colloidal particles of mist in the forest. Light passing from the canopy of forest is scattered and we can see the Tyndall effect.

(b)  Smoke, milk.

8.            Air shows the property of its constituents. It can be separated by physical process and no new compound is formed.

9.            (a) She applied tincture iodine of iodine on the wound because iodine is antiseptic.

(b)    The solute is iodine and the solvent is alcohol.

10.        (a) Arenchyma- large air cavities.

(b)  Tendon- great strength but limited flexibility.

(c)  Sclereids- broad thick walled.

11.        Striated and cardiac muscles are similar to each other in having alternate light and dark band. Both of them have cylindrical cells.

Striated muscles are voluntary in nature but cardiac muscles are involuntary in nature. Striated muscles are multinucleate but cardiac muscles are uninucleate.

12.        M = 6 x 1024 kg, m = 7.4 x 1022 kg, d = 3.84 x 108 m.

F = GxMxm/d2.

F= 6.67 x 10-11 (6 x 1024) (7.4 x 1022)/ (3.84 x 108 m)2.

=  2.0 x 1020 N.

13.        u= 11m/s. s= 4 m, g = 9.8 m/s2. S = ut + ½ at2

=  -4 = 11x t x ½ x -9.8 x t2

t= 2.56s.

14.        (a) uniform motion.

(b)  constant speed but after half time the direction of motion is reversed.

(c)  non-uniform motion.

15.        A force may start motion in an object in rest. Toy train starts moving on applying force. A force my slow down the motion. Car stops when break is applied.

A force may change the shape of an object. Balloon change in shape on application of force.

16.        I will prefer Italian honey bee Apis mellifera because of following reasons:

(a)  Italian honey bee stays in a beehive for longer period.

(b)  It breeds well.

(c)  It has high honey collecting capacity.

17.        Insects pests attack the crop plants in following three ways:

(a)  They cut the root, stem and leaf.

(b)  They bore into the stem and fruit.

(c)  They suck the cell sap from various parts of the plant.

18.        Storage grain can be protected from degradation and loss in weight by adopting following preventive measures.

(a)  Proper drying of the produce.

(b)  Strict cleaning of the produce before storage.

(c)  Fumigation using chemicals that can kill pests.

19.        (a) (i) In a physical change a change in the physical state of substance takes place. Such as melting of ice.

(ii)   In a chemical change two or more substances react to form a new substance which has different properties from original substance.

(b) (i) Metals are good conductor of heat.

(ii) Metals are good conductor of electricity.

20.         (a) In solids, the particles are closely packed and their positions are fixed due to strong force of attraction.

(b)  Air at sea level is compressed by the mass of air above it. Hence, air is more dense at sea level.

(c)  There are empty spaces in the packing of water molecules in ice. On heating ice changes into water and molecules come closer.

(d)  Diffusion and Brownian motion.

21.  A – xylem
B- phloem
E- Xylem parenchyma
F- Xylem Fibres
G- Sieve tubes
F- Companion cells
I-phloem fibres
J-phloem parenchyma

22.        It states that the total momentum of an isolated system of particles remains conserved and does not change due to mutual action-reaction forces amongst the particles of system.

M= 10 g = 0.01 kg. u1 = 400 m/s, m= 900g= 0.90 kg, u2 = 0. Mu1 + mu2 = (m1 = m2)v

V= 0.01x 400+ 0.90 x 0/ 0.01 + 0.90 = 4.4 m/s.

23.        (a) Mass of an object is a measure of its inertia and does not change from one place to another. Weight = mass x acceleration. As value of g varies from place to place, the weight of a bar of metal of given mass decrease when it is brought to equator.

(b)   As value of g is maximum at the poles, hence weight is more than the corresponding weight of the object at the equator.

(c)  Value of g is zero at the centre of earth.

(d)  If there is no acceleration due to gravity then any object may continue to move, even in vertically upward direction, with constant speed.

24.         (a) Mixed cropping is raising of different types of crops on the same farm at same time. It insures good returns to the farmers in case of crop failure.

Inter-cropping is growing two or more crops simultaneously in different rows in a same field in definite pattern.

(b)  The growing of different crops on a piece of land in preplanned succession is known as crop rotation.

(c)  Depending upon the duration, crop rotation is done for different crop combinations. The availability of moisture and irrigation facilities decide the choice of the crop be cultivated after one harvest.

In mixed cropping the selection of crops depends upon root pattern, water requirement, nutrient demand etc.

Section B

25.              (d)

26.              ( a)

27.              (b)

28.              (a)

29.              (d)

30.              (a)

31.              (a)

32.              (b)

33.              (d)

34.        Suspension cannot pass through the filter. True solution forms transparent solution as solute and solvents are uniformly intermixed.

35.        The temperature remain constant because the heat energy is used to increase the kinetic energy of the particles.

36.        The percentage of water absorbed by raisins = final mass- initial mass/initial mass*100. = (y-x)/x*100.

Saturday, June 14, 2014

questions of bio

Answer the following questions
1.   What is cell
2.   What are prokaryotic cell
3.   What are eukaryotic cell
4.   What is plasma membrane
5.   What is protoplasm
6.   Name the biomolecules present in plasma membrane
7.   What is meant by selectively permeable
8.   Define diffusion
9.   What is osmosis
10.                     Define hypertonic, hypotonic and isotonic solution
11.                     What is the main function of each of the following organelles. (a) ribosome (b) cell wall
12.                     Write main function of golgi bodies and vacuole.

13.                     Distinguish between prokaryotic and eukaryotic cells
14.                     Write down difference between organ and organelles
15.                     Write down the difference between diffusion and osmosis
16.                     Write difference between plant and animal cell
17.                     Distinguish between chloroplast and chloroplast
18.                     What will happen in a cell if its nucleus is removed? Give reason in support of your answer
19.                     Lysosomes are known as suicide bags’ why?
20.                     Write the name of cell organelles
21.                     Which organelles is the power house of cell. Write in brief its function
22.                     Write its location in cell . chromatin , chromosomes, tonoplast, nucleolus
23.                     Where do ribosome  get synthesized

24.                     Draw a well labeled diagram of animal cell and plant cell and mention one function of the main cell organelles

25.                     Write a short note on mitochondria and Golgi apparatus