Biology paper, ICSE, Class10

Biology practice paper ,class10.         MM30.
1.name the following
A. crossing over takes place.
B. a cell organelle (except nucleus)without  DNA.
C.a cell that do not divide
D.phase in which chromosomes get
arranged at equator .
E.A term for division of cytoplasm . 5.

2/choose the correct answer from each of four options below.
1.chromosomes reach at poles in
A.anaphase B.telophase
C.prophase  D .metaphase
2.meiosis occurs in
A. Testis B. Anthers
C. Ovaries D.all of these
3.chromosome number after meiosis is
A. 2n B. n
C.3n.  D.4n. 3

3. In each of set of terms given below, there is an odd one and cannot be grouped in the same category towhich other two belong.identify the odd term in each set and name the category to which remaining two catogories belong.
1.asters,furrow,cell plate
2.G1,S,anaphase
3.mitochondria,lysosome,chloroplasts 3.
4/complete the following paragraph by filling the blanks.
A. In interphase RNA and proteins are z synthesised in ..........phase.the cell may enter .......phase or enter in next .......phase for DNA synthesis.more DNA and proteins are synthesised in ........
Phase.                                                4.

5.A.draw a labelled diagram of an animal cell in late prophase
B. How is it different from prophase in plant cell.
C.name the phase next to prophase.3
6.give technical term for the folowing
A. The chromosomes received from mother
B.exchange of parts of chromatids between homologous chromosomes in meiosis
7.give reason
A.meiosis1 is a reductional division but not meiosis2
B. Number of chromosomes in cell formed by mitosis remains same. 2.
8/.state the exact location of the following structures
A.pole of spindle
B.equator of spindle. 2.
9.given below are 7 terms .of these 6 can be placed into 3 matching pairs.
Cytokinesis,equator ,metaphase,haploid,meiosis,G2,cell plate.     3
10.differentiate between the followi ng pairs on the basis of what is mentioned in the brackets
1. Mitosis and meiosis ( division of cytoplasm)
2/mitosis and meiosis ,,( variations).  2.

11.differentiate between chromosome and chromatid.  1/

Noise Pollution

Noise pollution is any disturbing sound that adversely affects the living organisms .technically the sound sound level above 30 decibel fall in the category of noise .sound frequency is measured in hertz. human hearing range is from 50 heartz to15000 Hertz .the sound waves having frequency below 50 hertz are called infrasonic and the sound waves having frequency above 15000 Hertz are called ultrasonic. power of sound per unit area is called sound intensity . Its unit is watt per metre squareW/m2. decibel is named after Graham Bell. General conversation producers 60 dB, loud conversation producers 70 dB ,scooter engine 80dB and truck engine produces about 90 dB, jet engine about 150 dB and rocket propulsion about 180 dB of noise.

sources of noise pollution: Industries vehicles ,loudspeakers, agriculture machinery ,crackers ,Dynamite blast at construction sites, domestic gadgets like mixture grinder ,vacuum cleaner television, radio army tanks,ammunition explosion etc are some common sources of pollution .

Effects: noise pollution adversely affects hearing ability of person .sound above 150 dB can permanently damage eardrum or dislocate ear ossicles .regular daytime exposure of sound above 80 decibel can reduce 15 dB hearing capacity in 10 years .person feels uncomfortable ,anxiety increases which in turn  can cause hypertension ,hormonal changes ,headache, digestion problem, increase in heartbeat ,Insomnia etc.exposure to high noise level can have bad effect on nervous system of developing baby .



effect on animals : high noise level have adverse affect on hearing ability, causes anxiety ,hormonal changes in animals .studies have shown that Exposure to high noise levels for longer. Studies have shown that exposure to high sound levels for longer periods in animals disturb  egg laying and hatching from eggs.

 control of noise pollution noise pollution :
laws should be implemented strictly .machines should be designed in such a way that they produce minimum noise. use of loudspeakers should be regulated strictly by law .use of crackers should be minimum .noiseless cracker or low sound crackers should be used .big cities should be divided into four zones .silence zone ,it is near hospitals and educational Institutes . there is residential zone, commercial zone and industrial zone .in Silence zone use of loudspeakers ,use of horns is not allowed .building should be designed in such a way that minimum noise enters the building from outside. green muffler or green belt can also reduce the noise level  .vegetation absorbs sound waves, therefore it is called green muffler .green muffler should be maintained on either side of road and railway tracks. it not only reduces noise but also reduces air pollution and dispersal of dust generated by moving vehicles. wide tree belts should be grown around industrial areas .we can use ear plugs and muffs to protect our ears from high noise levels .they block the entry of noise in ears.

Flluid Mosaic Model of Plasma Membrane

It was well known that biomembranes can contract, expand,undergo fusion and can quickly repair  themselves. on the basis of these properties Singer and Nicolson (1972)proposed that

biomembranes are not solid but quassi fluid .according to this model the membranes do not have uniform arrangement of lipids and proteins but they are mosaic of two  There is a bilayer of phospholipid molecules proteins are present in between phospholipid molecules ,on the outer side of phospholipid bilayer and on the inner side of phospholipid bilayer. the proteins which are embedded in the phospholipid bilayer are called integral or intrinsic proteins. the proteins present on outer surface of phospholipid bilayer are called extrinsic proteins or peripheral proteins. The lipid bilayer is semi fluid .it allows the lateral movement of proteins .some proteins act as enzymes. some proteins help in active transport .some carbohydrate molecules may be attached to the phospholipid molecules forming glycolipids .the carbohydrates attached to proteins form glycoproteins 

Sciophytes

Sciophytes plants are also known as shade plants because they are adapted to low intensity of lights. stems are soft with large internodes. the  leaves are thinwith thin cuticle.stomata lie at level of surface of leaves and are resent on both the surfaces of leaves. root system his less extensive . they have low photosynthetic and metabolic rate.

Direct development vs Indirect development

Direct development vs indirect development

in case of direct development  the young ones resemble the adult in most of features except that they may be smaller in size, may have different color and are sexually immature.

On the other hand , in indirect development the young one do not resemble the adults in most of the features.

in case of direct development there is no larval stage whereas in case of indirect development there may be one or more larval stages.

in case of direct development the young ones have same ecological niche as that of parents whereas in case of indirect development young ones that is larvae have ecological nitch different  from that of parents .

in direct development  reorganization of internal and external structures occur during  transformation of young one to adults whereas in case of indirect development reorganization off internal and external   structures occur during  transformation of larvae to adults.

Ovipary, Vivipary and Ovovivipary

Ovipary,vivipary and ovovivipary

in ovipary the embryo develops inside the egg and eggs are laid before development of embryo. in other words the development of embryo occurs outside the body of female but inside the egg .after completion of embryonic development young ones hatch out of the egg.

Vivipary: the embryo develops inside body of female in her uterus. in the body of female the embryo is nourished through placenta .it occurs in eutherian and metatherian  mammals.

ovovivipary: egg is fertilized inside the body of female but it is not laid but returned within the reproductive tract of female until embryogenesis is complete. female gives birth to young one but young one develops in the egg within body of female and during development it is not nourished through placenta but it consumes food stored in the egg. examples sharks Rattle snake.

Characteristics of prokaryotic cell

1.Prokaryotic cells lack well organised nucleus 
2.the genetic material is present in the form of circular DNA .
3. DNA is not packed in chromosomes 4.the nuclear membrane is lacking 
5the DNA is not complexed with histones
6. different types of Pilli present 
7.mitochondria are lacking in prokaryotic cells 
8.chloroplast is absent. photosynthetic lamellae may be present in photosynthetic bacteria
9. membrane bound organelle  like endoplasmic reticulum, Golgi ,lysosomes are absent 10.the ribosomes are of 70s type 11.cytoplasmic streaming is not seen in the cells
12. the microtubules form cytoskeleton 
13.the cell wall consists of  mucopeptides which is known as 14.the flagella simple and do not have 9 + 2 pattern
Post by: ashwani kumar, biology teacher@ vigyan tutorials, phagwara.