: LET'S SOLVE THE FOLLOWING QUESTIONS :
: CIRCLES :
Friday, 18 December 2015
Wednesday, 25 November 2015
Monday, 23 November 2015
EXTRA QUESTIONS (Quadratic Equations) SET-1
PODAR INTERNATIONAL SCHOOL (CBSE)
Topic : Quadratic Equations
1. The number of quadratic equations having real roots and which do not change by
squaring their root is :
(a) 4 (b) 3
(c) 2 (d) 1
2. For what value of k are the roots of the quadratic equation 3x+ 2 kx+ 27 = 0 are
real and equal?
3. An express train takes 1 hour less than a passenger train to travel 132 km between
Agra and Delhi( without taking into consideration the time they stop at intermediate
stations).If the average speed of the express train is 11km/hr more than that of the
passenger train, find the average speed of two trains
4. A takes 3 days longer than B to finish a work. But if they work together, then work
is completed in 2 days. How long would each take to do it separately? Can you say
cooperation helps to get more efficiency?
5. If x = 1 is a common root of ax2+ ax + 3 = 0 and x2+ x + b = 0, then ab = ?
a. 3 b. - 3
c. 4 d. 6
6. If x2+ 2 ( k + 2) x + 9 k = 0 has a repeated root, thenk = ?
(Repeated root means two roots are equal)
a. 1 or 4 b. 1 or - 4
c. - 1 or 4 d. - 1 or - 4
7. If x2- 4x + p = 0 has real roots, then
a. p ≥4 b. p ≤4
c. p ≥5 d. p ≤- 4
8. Which of the following is not a quadratic equation?
a. x2+ 2 x + 1 = 0 b. 2 x - x2= x2- 5
c. x2+ 9 = 3x2- 5x d. ( x2+ 1 )2= x2+ 3x + 9
9. If is a root of the equation x2+ kx - = 0, then the value of k is
a. 2 b. - 2
c. 1/4 d. 1/2
10 For what value of k ≠0, the polynomial kx2- 3 kx + 9 is a perfect square ?
a. k = 1 b. k = 2
c. k = 3 d. k = 4
11. If D is the discriminant of a quadratic polynomial,the false statement of the following is
a. D can hold negative value b. D can hold positive value
c. D can hold a zero value d. D = 0 always
12. The positive root of the quadratic equation x2+ ( x + 1)2 = 313 is
a. 12 b. 13
c. 12 and - 13 d. 12 and 13
13 The roots of the equation x2+ x - ( k + 1 ) ( k + 2) = 0 are
a. k + 1 b. - ( k + 2 )
c. k + 2 d. k + 1 and - ( k + 2)
14 .The equation 3x2 + 4√3x + 4 = 0 has
a. Two distinct real roots b. Two equal real roots
c. No real roots d. More than two real roots
15 Which of the following equations has the sum of itsroots as 3?
a. 2 x2- 3 x + 6 = 0 b. - x2+ 3 x - 3 = 0
c.√2x2- √x + 1 = 0 d. 3 x2 - 3x + 3 = 0
16.Which of the following equations has the product of its roots as
a. 2 x2+ 7 = 0 b. 2x2+ 4x + 7 = 0
c. 2x2- 4x + 7 = 0 d. 2 x2+ 4 x - 7 = 0
17 Which of the following has no real roots
a.x2- 4x + 3√2 = 0 b. x2+ 4 x - 3√2= 0
c. x2- 4x - 3√2 = 0 d. 3x2+ 4 √3 x + 4 = 0
xv If no roots of the equation x2- px + 1 = 0 is real, then
a. p >2 b. p < - 2
c. p = 2 d. - 2 <p < 2
18. Which constant must be added and subtracted to solve the quadratic equation
9x2+ 6 x - 5 = 0?
a. 1 b. 14
c. 18 d. 49
19. Two numbers whose sum is 27 and the product is 182,is
a. 8, 19 b. 11, 16
c. 13, 14 d. 15, 12
20. Two consecutive odd positive integers , sum of whose squares is 290 are
a. 9, 11 b. 11, 13
c. - 11, - 13 d. 12, 13
21. The hypotenuse of a right angled triangle is √52cm. If the smaller and the larger of the
remaining two sides are respectively tripled and doubled, then the new hypotenuse will be
√288cm. The original lengths of these two sides were ,respectively
a. 4cm and 6 cm b. 2 cm and 3 cm
c. 6cm and 8 cm c. 5 cm and 12 cm
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EXTRA QUESTIONS (Application of trigonometry) SET-1
PODAR INTERNATIONAL SCHOOL (CBSE)
Topic : Heights & Distances
1.The angle of elevation of the top of a tower is 30°. If the height of the tower is doubled ,
then the angle of elevation of its top will also be doubled. Is it true?
2. If the angle of depression of an object from a 75m high tower is 30°.Find the distance of the
object from the base of the tower.
3. A balloon is connected to a meteorological ground station by a cable of length 215 m
inclined at 60° to the horizontal. Determine the height of the balloon from the ground.
Assume that there is no slack in the cable.
4. A tree of 12 m height is broken by the wind in sucha way that its top touches the ground
and makes an angle 60° with the ground. At what height from the bottom, the tree is broken
by the wind?
5. The angle of elevation of the top of a hill from the foot of a tower is 60° and the angle of
elevation of top of the tower from the foot of the hill is 30°. If the tower is 50 m high, what
is the height of the hill?
6. Two men on opposite sides of the cliff 80 m high observe the angles of elevation of the top
of the cliff to be 30° and 60° respectively. Find the distance between the two men.
7. A ladder is placed against a wall such that it reaches the top of the wall. The foot of the
ladder is 1.5 m away from the wall and the ladder is inclinedat an angle of 60° with the ground. Find
the height of the wall.
8. Find the angle of elevation of the Sun (Sun's altitude) when the length of the shadow of a
vertical pole is equal to its height.
9. From a point 20 m away from the foot of a tower, the angle of elevation of the top of the
tower is 30°. Find the height of the tower.
10. The horizontal distance between two towers is 140 m. The angle of elevation of the top of
the first tower when seen from the top of the second tower is 30°.If the height of the second
tower is 60 m, find the height of the first tower.
11. Find the angular elevation of the Sun when the shadow of a 10 m long pole is 10 √3m.
12. The angles of elevation of the top of a hill, at the city centres of two towns on either side of
the hill are observed to be 30° and 60°.If the distance uphill from the first city centre is 9
km, find the distance uphill from the other city centre in kilometres up to two places of
decimals.
13. An aeroplane flying horizontally 1 km above the ground is observed at an elevation of 60°.
After 10 seconds its elevation is observed to be 30°. Find the speed of the aeroplane in km/
hr.
14. An aeroplane at an altitude of 200 m observes the angles of depression of opposite points
on the two banks of a river to be 45° and 60°. findin metres, the width of the river.
15. The angle of elevation of the top of the tower fromtwo points at a distance of 25m and
36m from the base of the tower and in the same straight line with it are complementary. Prove
that the height of the tower is 30m.
16. Monica is a 1.5 m tall girl. She is standing at a distance of 28.5 m from a multi-storeyed
building. The angle of elevation of the top of thebuilding from her eyes is 45°.Find the
height of the multi - storey building.
17. Two pillars of equal heights are on either side of a road, which is 100 m wide. At a point on
the road between the pillars, the angles of elevation of the top of the pillars are 60° and 30°
respectively. Find the position of the point between the pillars and the height of each pillar.
18. The angle of elevation of an aeroplane from a pointon the ground is 45°.After a flight of 15
seconds, the elevation changes to 30°.If the aeroplane is flying at a constant height of 3000
metres, find the speed of the aeroplane.
19. An aeroplane, when 3000 m high , passes vertically above another aeroplane at an instant
when the angles of elevation of the two aeroplanes from the same point on the ground are
60° and 45° respectively. Find the vertical distance between the two planes.
20. From the top and foot of a tower 40m high, the angles of elevation of the top of a lighthouse
are found to be 30° and 60° respectively. Find the height of the light house. Also find the
distance of the top of the light house from the foot of the tower.
21. A 1.6 m tall girl stands at a distance of 3.2 m from a lamp - post and casts a shadow of 4.8 m
on the ground. Find the height of the lamp - post by using
a. Trigonometric ratios b. property of similar triangles
22. A man on a cliff observes a boat at an angle of depression of 30° which is approaching the
shore to the point immediately beneath the observerwith a uniform speed. Six minutes later,
the angle of depression of the boat is found to be 60°.Find the time taken by the boat to
reach the shore.
23. A man standing on the deck of a ship, which is 10 mabove the water level, observes the
angle of elevation of the top of a hill as 60° and the angle of depression of the base of the
hill as 30°. Calculate the distance of the hill from the ship and the height of the hill.
24. A man standing on the deck of a ship, which is 10 mabove the water level, observes the
angle of elevation of the top of the hill as 60° and the angle of depression of the base of the
hill as 30°, calculate the distance of the hill from the ship and the height of the hill.
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EXTRA QUESTIONS (Application of trigonometry) SET-1
PODAR INTERNATIONAL SCHOOL (CBSE)
Topic :Heights & Distances
1. From a point A, in level with the foot of a vertical pole 25m from it, the angle of
elevation of the top of the pole from point A is 30°.Calculate the height of the pole.
2. A tree casts a shadow 4m long on the ground when the angle of elevation of the Sun
is 45°.Find the height of the tree.
3. An electrician has to repair an electric fault on apole of height 4m. He needs to
reach a point 1.3 m below the top of the pole to undertake the repair work. What
should be the length of the ladder that he should use which when inclined at an
angle of 60 to the horizontal would enable him to reach the required position?
4. While dashing to the destination point on the ground, the pilot of the aeroplane
declines his aeroplane by 30°and drives straight to the ground. The average speed
of the aeroplane is 200 km/hr. It takes 54 seconds to reach the ground. How high
was the aeroplane before it started its dash ?
5. The shadow of a flag staff is three times as long as its shadow, when the sunrays
meet the ground at an angle of 60°. Find the angle between the sunrays and the
ground at the time of the longer shadow.
6. A boy standing on a horizontal plane finds a bird flying at a distance of 100 m from
him at an elevation of 30°.A girl standing on the roof of a 20 m high building ,
finds the angle of elevation of the same bird to be45°.Both the boy and girl are
on the opposite sides of the bird. Find the distance of the bird from the girl.
7. A man on the top of a vertical observation tower observes a car moving at a uniform
speed coming directly towards it. If it takes 12 minutes for the angle of depression to
change from 30°to 45°, how soon after this will the car reach the tower ? Give your
answer correct to the nearest second.
8. The angle of elevation of the top Q of a vertical tower PQ from a point X on the
ground is 60°.At a point Y, 40 m vertically above X, the angle of elevation is 45°.
Find the height of the tower PQ and the distance XQ.
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Sunday, 22 November 2015
EXTRA QUESTIONS OF AP SET-3
PODAR INTERNATIONAL SCHOOL (CBSE)
Practice Sheet
Std : X Subject: Mathematics
Topic: Arithmetic Progression
1. In the following APs find the missing terms
(i) 2,____ , 26
(ii) 5,____ ,_____ , 9 (1/2)
2. Find a3, a5 and a8, if an = ( - 1)n × n + 1
3. Find the 21st and 42 nd terms of the sequence defined by
tn = 0, if n is odd.AND 1, if n is even
4. Find the sum of n terms of the sequence {an } where an = 5 - 6n , n Belongs to N
5. Find the 27 th and the nth terms of the sequence 5, 2, -1,- 4, -7, .....
6. A sequence { an } is given by the formula an = 10 - 3n. Prove that it is an A.P.
7 .If m times the m th term of an A. P. is equal to n times its n th term, prove that
( m + n ) th term of an A. P. is zero. [ Delhi 2004 ]
8. Find 10th term from each end of an A.P. 5, 7......, 159.
9. How many terms are there in an A.P. whose first and fifth terms are - 14 and 2 respectively
and the sum of the terms is 40?
10. The 4th term of an AP is equal to 3 times the first term and the 7th term exceeds twice the
third term by 1. Find the 1st term and the AP.
11. Find the sum of all three digit numbers which leave the remainder 3 when divided by 5.
4 marks questions:
12. Amrita buys a house for ` 22,000.She pays `4,000 cash and agrees to pay the balance in
annual installments of ` 1,000 plus 10 % interest on the unpaid amount. What will the house
cost for her?
13. How many terms of the A.P. - 6 , -11/2,- 5 , are needed to give the sum -25? Explain the
double answer.
14. If the p th, q th, r th terms of an A.P. be x, y, z respectively. Show that
x ( q - r ) + y ( r - p ) + z ( p - q) = 0
15. Find the sum of 32 terms of an A.P. whose third term is 1 and 6th term is -11.
16. Find the 17th term and the nth term of A.P
3, 3 + √2 , 3 + 2 √2 , 3 + 3 √2....
17. Supreet deposits a sum of ` 5000 in State Bank of India. Bank pays simple interest of 5 % per
annum on the money deposited. Calculate the interest at the end of 1, 2, 3,.... years .Verify that
the sequence of interest forms an AP. Also find the interest earned after 40 years by using the
idea of AP.
18. A contract on construction job specifies a penalty for delay of completion beyond certain date
as follows : `200 for the first day,`250 for the second day, `300 for the third day, etc. , the
penalty for each succeeding day being `50 more than for the preceding day. How much
money the contractor has to pay as penalty if he has delayed the work by 30 days?
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PODAR INTERNATIONAL SCHOOL (CBSE)
Std : X Subject : Mathematics
Topic : Arithmetic Progression Set : 9 (b
1. Find the 16 th term of the AP 3, 5, 7, 9, 11...
2. If the 2nd term of an AP is 13 and 5th term is 25, what is its 7th term?
3. The taxi fare after each km, when the fare is `15 for the first km and `8 for each
additional km, does not form an AP as the total fare ( in `) after each km is 15, 8, 8,
8,.....Is the statement true ? Give reasons.
4. Is 0 a term of the AP 31, 28, 25,...? Justify your answer.
5. Determine the AP whose 5th term is 19 and the difference of the eighth term from
the thirteenth term is 20.
6. How many numbers lie between 10 and 300, which divided by 4 leave a remainder
3?
7. Jaspal Singh repays his total loan of `1,18,000 by paying every month starting with
the first installment of `1000. If he increases the installment by `100 every month,
what amount will be paid by him in the 30 th installment? What amount of loan does
he still have to pay after the 30 th installment?
8. If the sum of first 4 terms of an AP is 40 and that of first 14 terms is 280, find the
sum of its first n terms.
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EXTRA QUESTIONS OF AP
PODAR INTERNATIONAL SCHOOL (CBSE)
MCQ
Std : X Subject: Mathematics
Topic : Arithmetic progression
Q1 Select the correct option.
i. Fourth term of the A.P. √2, √8, √18,……. is
a. √22 b. √32
c. 6 d. 5
ii. An A. P. whose second term and common difference are 7 and - 4 respectively is
a. 3, - 4, - 11,… b. -11, - 4, 3 ….
c. 11, 7, 3…. d. 1, 3, 7 …..
iii. In an A. P. if d = - 3 and a6 = 4, then a is
a. 19 b. 9
c. 7 d. 21
iv. If an = √7 n + √5 represents the nth term of an A.P., then the common difference is
equal to
a. 1 b. 2√7
c. √5 d. √7
v Which term of the A. P. 21, 42, 63, 84,….. is 231?
a. 9 th b. 10 th
c. 11 th d. 12 th
vi If x + 2, x2 – 2, 3x ,…. is an A.P. then the 5th term will be
a. - 7 or 13 b. - 1 or 3
c. 13 or 15 d. - 5 or - 7
vii In an A.P. , if d = - 4, n = 7, an = 4, then a is
a. 6 b. 7
c. 20 d. 28
viii In an A. P. , if a = 3.5, an = 3.5, n = 201, then d is
a. 0 b. 3.5
c. 203.5 d. 204.5
ix The 19 th term of an A. P. whose first two terms are - 3 and 4 is
a. 16 b. 23
c. 126 d. 123
x The 11th term of the A. P. - 7, -7/2 , 0,7/2 , …..is
a. - 28 b. 28
c. - 35 d. 35
xi. The 4th term from the end of the A. P.: - 11, - 8, - 5,…., 49 is
a. 37 b. 40
c. 43 d. 58
xii. If the common difference of an A.P. is 5, then a18 – a13 is
a. 5 b. 20
c. 25 d. 30
xiii The two A.P's have the same common difference. The first term of one AP is - 1 and
that of the other is - 8. Then the difference between their 4th terms is
a. -1 b. - 8
c. 7 d. -9
xiv. The sum of first seven multiples of 5 is
a. 130 b. 140
c. 160 d. 150
xv If 7 times the 7th term of an AP is equal to 11 times its 11th term, then its 18th term
will be
a. 7 b. 11
c. 18 d. 0
xvi The famous Mathematician associated with finding the sum of first 100 natural
numbers is
a. Pythagoras b. Newton
c. Gauss d. Euclid
xvii In an AP , if a = - 5, l = 2 l and S = 200, then n is equal to
a. 50 b. 40
c. 32 d. 25
xviii The number of two digit numbers which are divisible by 3 is
a. 33 b. 31
c. 30 d. 29
xix In an AP , if a = 3 and S8 = 192, then d is
a. 8 b. 7
c. 6 d. 4
xx If the 2nd term of an AP is 13 and the 5th term is 25, then its 7th term is
a. 30 b. 33
c. 37 d. 38
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Friday, 23 October 2015
note book work for reproduction in animals
The 3 methods of asexual reproduction as
1. Fission
2. Budding
3. Regeneration
Fission :-
As the name suggests
in this method the body of the parent splits into parts, and
each part grows up as an individual.
If the body splits into 2, the method is called Binary
Fission as in Amoeba
If it splits up into more than 2 parts, it is called as
Multiple fission as in Amoeba,
Paramoecium, Leishmania ( causes Black fever or kala azar )
If the body of the parent splits into more than 2 parts it
is called multiple fission
as in the case of Plasmodium, the malaria causing bacteria.
During multiple fission, during unfavourable conditions, the
organism develops a
protective wall around itself inside which the cell matter
remains protected. This is
the cyst. The nucleus undergoes fission to form daughter
nuclei. Each one collects
a little cytoplasm around.
During favourable conditions, when the cyst breaks open,
these nuclei with their
cytoplasm are thrown out and each one lives life as an
interdependent organism
Budding :-
It is a process in which an outgrowth Is produced from the
body of the parent .
This outgrowth grows a little and then falls out and grows
into a new organism eg.
Hydra, Yeast
Regeneration :-
Definition :-
It is the process by which a new complete organism develops
from any cut part of
the body of a parent organism.
This is possible in the case of simple organisms where the
body is not developed into
specialized organs and tissues.
Eg. Hydra, Flat worm or planaria.
Sexual Reproduction in animals :-
This requires the
presence of 2 separate sexes with their own reproductive cells.
The terms used for male and female gametes in animals as
sperms and ova
respectively
‘Fertilization’ as an equivalent to pollination
There are 2 types of fertilization
iii. External
iv. Internal
Definition :- The union of a male gamete with the female
ovum during sexual fertilization to form
a zygote is called fertilization
The single fused cell which is the zygote multiplies and
forms a multicellular new
organism.
Human Sperm :-
Is an extremely small cell. It has a big head and a long
tail. The head contains the
nucleus which fuses with that of the egg.
The sperm also has a long tail which helps in the movement
of the sperm to the
egg and guides it to it.
The egg is slightly larger than the sperm. It contains
cytoplasm, nucleus, food and
water.
Gametes in humans contain half the no. of chromosomes as
that of a general cell.
Fertilisation :- This union of a sperm and the ovum may take
place outside the body of the
organism --- External Fertilisation or inside the body of
the female ---- Internal
Fertilisation
External fertilization takes place in the case of animals
like the frog or the fish,
where the female animal lays the eggs in water and then the
male spreads the
spermatic fluid over it.
Internal fertilization takes place in mammals, birds and
reptiles. In this method
the male gametes or the sperms are released in the body of
the female during
copulation process.
The fertilized egg called the zygote over a period of time
develops into an embryo
that grows into a young one inside the body of the mother
who then gives birth to it
as in the case of cats, dogs, humans.
In birds, the fertilized egg comes out in the form of the
egg as in the birds. This grows
into an embryo outside the body of the mother who gives it
warmth by sitting on it
( hatching ) and the young baby breaks open the shell and
comes out as a young
Nature has to prepare the body for the process of
reproduction and this period
or phenomenon is called Puberty
Definition :- The age at which the sex hormones and gametes
begin to be produced
by the individual who then becomes sexually mature is called
Puberty.
The onset of puberty is the stage of Adolescence ranging
from 10 to 12 in girls
and 13 to 15 in boys.
Sex hormones are produced in this period which gives the
distinct
characteristics to the external structures and physiological
traits to the two
sexes.
The changes that occur in girls are ---
i. Growth of hair in the arm pits and the pubic region
ii. Enlarging and development of mammary glands
iii. Broadening of hips
iv. Enlarging of the fallopian tubes, uterus, vagina
v. Start of the Menstrual cycle.
vi. Feeling of sexual drive.
The changes that occur in the boys are ---
i. Hair in the arm pits and the pubic ( genital ) area and
chest
ii. Facial hair in the form of moustache, and beard
iii. Penis and testes become larger
iv. Cracking of voice
v. Development of muscles and broadening of shoulders
vi. Feeling of sexual drive ( produced by the hormones )
The start of the menstrual cycles is called Menarche ( 10-12
yrs )
The end of menstrual cycles is called Menopause ( 45-50 yrs.
)
Definition :- The permanent stoppage of the menstrual cycle
is called Menopause
Male reproductive system:-
Gametes : Sperms . They are produced in large nos.
Location : Produced in the testes. Testes also produce the
male sex hormone
called Testosterone ( responsible for the male
characteristics )
scrotum. The
temperature outside the abdominal cavity is lower than the temp.
inside and hence it is a suitable environment for the
production and survival .
Testes are held
outside the abdominal cavity in a sac called the
Journey of the sperms
:- There is a layer on the outside of the testes called the Epididymis which
has a sac –like structure on the upper part of the testes to hold the sperms
for a short period of
From the epididymis they
enter a tube called the Vas Deference
and travel down
it. Along their journey the mix with the secretions of the Seminal Vesicles and the
Prostrate Glands.
These secretions provide nutrition to the sperms and also form a
fluid with them and help the sperms to travel smoothly.
The thick liquid formed by the secretions of the Seminal
Vesicles and the Prostrate
glands along with the sperms is called the Semen.
The Vas Deference meets a tube from the urinary bladder . It
is the Urethra which
carries the sperms to an organ called the Penis. It is the
common passage for the
urine and the semen.
The sperms are deposited in the vagina of the female during
mating.
Female Reproductive System
it is more complex than the male reproductive system as it
is the meeting place of
the 2 reproductive cells and also the growth of the embryo
into an individual and
the its birth.
Gametes : Ova or eggs.
Location : In the ovaries. They are the two primary
reproductive organs placed
inside the abdominal cavity near the kidneys. They produce
the ova and the
female sex hormones called the Oestrogen and Progesterone.
The unripe ova are called the follicles. They mature and are
ready for fertilisation at
puberty.
Journey of the ovum :
The ova are produced by the ovary.
These ova enter the funnel of the Fallopian Tube or the
Oviduct which cover the
ovaries . All the eggs grow, but only one grows maximum and
it is the one that will
get fertilized by the sperm
The sperm meets the ovum in the oviduct and fertilisation
takes place here.
The fertilized egg travels along the oviduct.
The 2 oviducts open into a pouch-like organ called the
Uterus.
The growth of the fertilized egg into a foetus takes place
in the uterus.
At the time of birth the baby is sent out of the body of the
mother through the
vagina or the birth canal
Menstruation :- The Ova receive the sperm and fertilisation
takes place.
Simultaneously the uterus prepares itself to receive the
feritilised egg. It develops a
thick lining on its inner walls and the blood supply to this
region increases.
In case the fertilisation does not take place, the uterus
sheds this thick wall along
with blood, which comes out through the vagina.
This is Menstruation. This cycle takes place every 28 days
as the uterus keeps on
prepares itself to receive the fertilized egg.
Fertilisation :- Definition :- The union of the male and
female gametes to form the Zygote is called Fertilisation.
In humans the sperms which are deposited in hundreds in the
vagina of the female
travel upwards with the help of their long tails through the
uterus into the oviducts
where there is only one egg ready for fertilisation.
One sperm out of these unites with one egg. Their nuclei
unite and the haploid
nucleus becomes diploid
This is why the reproductive cells have half the no. of
chromosomes as that of a
normal cell, so that the fertilized cell ultimately has the
full set of chromosomes half
the set coming from each parent.
The zygote travels to the uterus and lodges into a pit in
the thick wall of the uterus .
This is called implantation.
After the embryo has implanted itself a special tissue
called PLacenta is formed
between the foetus and the uterine wall
The foetus ( unborn baby )receives nutrition from the mother
through the umbilical cord. The period during which the embryo grows into a
fully grown baby is called
Gestation which is 280 days
At the time of birth the uterus starts contracting and
pushes the baby out along the Vagina or the birth canal.
When the baby is born, the uterine wall along with the
placenta also comes out.
Cutting of the umbilical cord cuts off the physiological
attachment of the infant
with the mother.
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notebook work for reproduction in plants
Reproduction is the process by which an organism gives birth
to young ones of
the same species
Different species have different methods of reproduction.
Reproduction in plants:-
There are certain plants that have 2 different sexes ---
either on the sameplant/flower -- ( bisexual) or on different plants/flowers---
( unisexual )
Some plants do not show any sex discriminated in their
structure eg. rose.
Plants produce sexually or asexually.
Asexual reproduction in plants :-
It takes place in the following ways :- 1) Spore formation
2) Fragmentation
3) Vegetative propagation
Spore formation :-- Spores are microscopic reproductive
units produced in the sac called the
sporangium
Plants that reproduce by spore formation are the common
bread mould orRhizopus, mucor, ferns, penicillium from which the antibiotic
penicillin isproduced.
Spores float around in the air and under favourable
conditions germinate and give rise to a new plant.
In the beginning the bread mould ig white, but later in a
few days it turnsblack.
This is because on germination the spore gives rise to a new
fungus plant with thread like branches called Hyphae having a spore sac at its
tip. It is white.
As the spores mature the sporangium develops a black colour.
Fragmentation :-
It is the process in which the body of a multicellular plant
on maturity breaks into many pieces called fragments and each fragment gives
rise to a new plant.
eg. spirogyra
It is different from fission where a unicellular organism
gives rise to new organisms.
Vegetative propagation :-
It is the process in which any part of the plant body like
the stem, root, leaves give rise to a new plant with the help of the buds on
them.
eg. root --- Dahlia
Stem ---- potato, ginger
stem ---- money plant, stolons
leaf ---- bryophyllum
Vegetative propagation can happen either naturally as stated
above or artificially as given below.
– a. Cutting
:---
It is a process in which one part of the stem with a node is
cut off and planted in the soil with favourable conditions. It gives rise to a
new plant
eg. rose, sugarcane, banana
b. Layering:-
In this process a branch of the plant is pulled down and pushed
under
the soil. It is then layered with soil and after a few days
it gives rise to a new plant.
This branch can then be cut off from the parent plant.
eg. strawberry, raspberry, bougainvillea, hibiscus, lemon
c. Grafting :---
In this process stems of 2 different plants are cut and
joined together and they grow as a single plant.
The stem that is put into the soil should have the roots to
hold it in place and provide for the plant.It is called as the stock. It has a
slanting cut made in it.
The stem that fits into it is called the scion which also
has a slanting such that fits
into the stock. The joint is coated with manure and the tied
together firmly. It is
covered with a protective covering in the form of a
polythene bag to protect form infection.
The cambium of the 2 parts which contains the meristematic
tissue rapidly
produces new cells and the 2 parts fuse and grow as a single
plant having the
desired characteristics of both the plants.
eg. Fruitless trees like the guava, papaya, rose plants with
different colour combinations.
Advantages of grafting --- 1. Desired characteristics of
plants can be grown
2. A young scion can produce fruits faster. A short plant
can bear a lot of fruits
3. A variety of seedless fruits can be grown
4. By grafting scions of different plants, a variety of
different flowers with different colours can be grown on the same plant.
5. Plants grown by grafting require less attention.
d. Tissue culture :- Also called Micropropagation
In this method a few cells from the growing part of the
plant are placed in a medium containing nutrients in the form of jelly. These
help in the growth of the cells into a mass called Callus.
It is transferred to another medium which contains hormones
that stimulate the growth of roots.
Lastly it is placed in another medium having hormones to
stimulate the growth of the shoot.
The small plantlets formed are then transplanted in pots.
eg. orchids, carnations, chrysanthemum
Advantages :--
1. Many plants can be cultivated in a small area
2. They can be cultivated irrespective of the season,
climate, and favourable conditions.
3. Take a short time to grow
4. New plants are disease free.
Sexual reproduction in plants :- This requires the
1. 2 sexes to be present in one flower or on the same plant
with one flower having one sex and another one having the other, or on 2 different
plants each having all flowers of one sex only.
2. It requires special cells from each sex.
3. These cells are called gametes
4. They fuse to form the Zygote
5. The male gametes called the pollen grains are in the
anther lobes at the tip of the filament together called as the Androecium
6. The female gametes called the ovules are found in the
ovary found at the end of a tube called the style which has the stigma at its
tip on which the pollen grains deposit
7. The stigma, style , and the ovary together form the
Gynoecium
8. The nucleus of the pollen grain travels down the style
and enters the ovary and fuses with the nucleus of the ovule and fertilization
is said to have taken place, which results in the formation of the zygote
9. After fertilsation the ovary turns into a fruit and the
ovules develop into the seeds from which new plants grow
10. The carpel is the gynoecium.stigma of the same or
different flower
define the following terms
1. Pollination is the process of the deposition of the
pollen grains on the
2. Fertilisation is the process in which the nuclei of the
male and femalegametes fuse.
3. Germination is the process by which a seed grows into a
new plant
note book work for our environment
Answer the
following questions
1. Explain the
Effect of adding waste to the environment
Ans ---Human
activities produce a lot of waste materials which are thrown away into
the environment. These wastes cause
pollution of air,
water and soil.
The waste
materials produced are of two main types. They
are biodegradable
wastes and non biodegradable wastes.
i) Biodegradable
wastes :- are wastes which are
decomposed into
harmless substances by microorganisms.
Eg :- vegetables,
fruits, pulses, cereals, cotton, jute, wool,
wood, leather,
paper, animal dung, animal bones etc.
ii) Non
biodegradable wastes :- are wastes which are not
decomposed by
microorganisms.
Eg :- polythene
bags, plastics, synthetic fibres, glass,
metals, synthetic
rubber, insecticides, pesticides etc.
2. Write a note on
the ecosystem and its component
Ecosystem and its
components :-
a) Ecosystem :- An
ecosystem consists of all the living organisms in an
area along with
the non living components and their interaction. There are different types of
ecosystems. They are :-
i) Natural
ecosystems :- like forests, deserts, grass lands, mountains, ponds, lakes,
rivers, oceans etc.
ii) Artificial
ecosystems :- like gardens, parks, crop fields, aquarium, zoo etc.
b) Components of
an ecosystem :-
An ecosystem
consists of two main components. They are biotic and abiotic components.
i) Biotic
components :- are the living components like plants, animals and
microorganisms. They consist of producers, consumers and decomposers.
Producers :- are
green plants which produce food by photosynthesis.
Consumers :- are
herbivores which get their food directly from plants, carnivores which get
their food indirectly from plants and omnivores which get their food directly
or indirectly from plants.
Decomposers :- are
microorganisms which decompose dead plants and animals. They decompose complex
organic substances into simple inorganic substances in the soil which are again
used by plants.
ii) Abiotic
components :- are the non living components like air, water, soil, minerals,
sunlight , temperature, wind
3. Explain food
chain and food web
3a) Food chain :-
A food chain is
the flow of food energy from one organism to the next and to the next and so
on. They usually start with a producer (plants) and end with a carnivore. In a
food chain an organism gets food from one group of organisms.
eaten by eaten by
Eg:- Grass
-----Deer ------------Lion
(producer)
(primary consumer) (secondary consumer)
Grass-------
Insects---------- Frog -------------------Snake
(producer)
(primary consumer) (secondary consumer) (tertiary consumer
Grass
----Moth----------------- Frog ---------------Snake ---------------Hawk
(producer)
(primary consumer) (secondary consumer) (tertiary consumer) (quarternary
consumer
b) Food web :-
Food web is a
group of several interconnected food chains. In a food web an organism gets
food from more than one group of organisms.
4. Explain trophic
level
Trophic levels :-
Each step in a
food chain where transfer of food energy takes place is called trophic level.
The first trophic
level consists of producers.
The second trophic
level consists of primary consumers.
The third trophic
level consists of secondary consumers.
The fourth trophic
level consists of tertiary consumers.
Since the transfer
of food energy decreases at every trophic level, the number of trophic levels
are limited and do not exceed four or five.
draw diagram from
text book
5. Explain
biomagnification
Biological
magnification (Biomagnification) :-
Harmful chemicals
like insecticides and pesticides which are used to protect crops from insects
and pests are absorbed by plants and enter the food chain. Since these
chemicals are non biodegradable, they get accumulated at every trophic level
and their concentration increases. Since human beings occupy the highest
trophic level, the concentration of these harmful chemicals is maximum in our
bodies.
The increase in
concentration of harmful chemicals in the bodies of organisms at higher trophic
levels is called biological magnification.
6. Explain energy
flow in an ecosystem
Energy flow in
trophic levels :-
Green plants
(producers) absorb about 1% of solar energy falling on the leaves and stores it
as food energy during photosynthesis.
During the
transfer of food energy from one trophic level to the next, 90% of the energy
is lost to the environment and only 10% is transferred to the next trophic
level. So there is a decrease in the amount of food energy transferred at every
trophic level by 10%. This is known as the 10% law.
7)Explain human
activities affect the environment
a) Depletion of
ozone layer in the atmosphere :-
Ozone molecule
contains three oxygen atoms (O3). At higher levels in the atmosphere the UV
radiation splits some oxygen molecules (O2) into free oxygen atoms which
combines with oxygen molecules (O2) to form ozone. It is highly poisonous.
UV radiation
O2
---------------O + O
O2 + O
-----------O3
The ozone layer
present in the higher layer of the atmosphere protects the earth from the
harmful UV radiation from the sun. UV radiation causes skin cancer in humans.
The ozone layer is
being damaged by the use of chemicals like chloro fluoro carbons (CFCs) used in
refrigerators and fire extinguishers. So the use of CFCs is now being reduced
to protect the ozone layer
b. Managing the
garbage we produce :-
The household
waste is called garbage. Some of the garbage is biodegradable and some are non
biodegradable. Garbage causes pollution of air, water and soil. So it should be
disposed properly.
Some of the
methods of garbage disposal are :-
i) Land fills
ii) Recycling
iii) Production of
biogas and manure
iv) Preparation of
compost
v) Incineration
vi) Sewage
treatment
Thursday, 24 September 2015
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Monday, 14 September 2015
answerkey of science mock test
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