Biology: CBSE Sample Question Paper- 8 | Sample Papers for Class 12 Medical and Non-Medical PDF Download

 Page 1


d o n e Biology - Sample Paper-9
1) Define internal syngamy.
Answer:
When fusion of male and female gametes takes place inside the female body, it is called internal syngamy or internal fertilization.
2) What is pollination?
Answer:
Pollination is defined as transfer of pollen grains from anther to the stigma.
3) Give example of a plant in which pollination occur with the help of water.
Answer:
Vallisneria  
4) What is called the bag-like fluid structure surrounding the human embryo?
Answer:
Amnion.   
5) What is artificial insemination?
Answer:
Artificial deposition of semen collected from a male animal into the vagina of female animal. 
6)
What is the relation between Gross Primary Productivity and Net Primary
Productivity?
OR
What is gestation period?
Answer:
Gross Primary Productivity (GPP): It is the rate of production of biomass or accumulation of energy by green plants per unit area
per unit time. It is also referred as (gross) photosynthetic or total assimilation. It depends upon chlorophyll content. Net Primary
Productivity (NPP): It is the rate of storage of organic matter in plant tissues in excess of the respiratory utilization by plant
during the measurement period. GPP - R=NPP Gross primary productivity - Respiratory loss = Net Primary productivity  OR
Gestation period is the fetal development period from the time of conception until birth. The average length of human gestation
is 280 days or 40 week from the first day of the women's last menstrual period.
7) How is polyspermy prevented?
Answer:
An egg reacts rapidly to the entry of the sperms. First, the egg becomes activated and undergoes depolarization of its
membrane. Second the egg exhibit cortical reaction & shows zona reactions. The plasma membrane is altered immediately to
make the egg impervious to any other sperm.
8) Define natality? What does it represented?
Answer:
The natality or birth rate can be defined as the number of individuals born in a given population during a given period of time. It
represents an addition or increase in the number of new individuals in a population, increasing its size. It only represents one
component of the population growth.
  
Page 2


d o n e Biology - Sample Paper-9
1) Define internal syngamy.
Answer:
When fusion of male and female gametes takes place inside the female body, it is called internal syngamy or internal fertilization.
2) What is pollination?
Answer:
Pollination is defined as transfer of pollen grains from anther to the stigma.
3) Give example of a plant in which pollination occur with the help of water.
Answer:
Vallisneria  
4) What is called the bag-like fluid structure surrounding the human embryo?
Answer:
Amnion.   
5) What is artificial insemination?
Answer:
Artificial deposition of semen collected from a male animal into the vagina of female animal. 
6)
What is the relation between Gross Primary Productivity and Net Primary
Productivity?
OR
What is gestation period?
Answer:
Gross Primary Productivity (GPP): It is the rate of production of biomass or accumulation of energy by green plants per unit area
per unit time. It is also referred as (gross) photosynthetic or total assimilation. It depends upon chlorophyll content. Net Primary
Productivity (NPP): It is the rate of storage of organic matter in plant tissues in excess of the respiratory utilization by plant
during the measurement period. GPP - R=NPP Gross primary productivity - Respiratory loss = Net Primary productivity  OR
Gestation period is the fetal development period from the time of conception until birth. The average length of human gestation
is 280 days or 40 week from the first day of the women's last menstrual period.
7) How is polyspermy prevented?
Answer:
An egg reacts rapidly to the entry of the sperms. First, the egg becomes activated and undergoes depolarization of its
membrane. Second the egg exhibit cortical reaction & shows zona reactions. The plasma membrane is altered immediately to
make the egg impervious to any other sperm.
8) Define natality? What does it represented?
Answer:
The natality or birth rate can be defined as the number of individuals born in a given population during a given period of time. It
represents an addition or increase in the number of new individuals in a population, increasing its size. It only represents one
component of the population growth.
  
9) What is the purpose of Ganga Action Plan?
Answer:
Ganga Action Plan is a project of Ministry of Environment and Forests, initiated to save major rivers of our country from pollution.
Only treated sewage may be discharged into the rivers.  
10) How a food chain or food web is formed?
Answer:
In an ecosystem the producers and consumers interact with each other. Plants are producers. The animal feeds on a plant or on
another animal and in turn serves as food for other animal. This interdependency of organisms led to the formation of food chain
or web. 
11)
Define binary fission. What is the difference between binary fission in Plasmodium and
Euglena?
OR
(i) Where is female reproductive system situated in the body?
(ii) What is ovarian cycle?
Answer:
Binary fission is the division of the parent into two offspring which are morphologically & genetically similar to the parent and to
each other. During this process, nuclear division is followed by cytoplasmic division. There are three modes of binary fission
simple binary fission, transverse binary fission and longitudinal binary fission. Plasmodium reproduces by transverse binary
fission. In this method, the plane of cytoplasmic division coincides with the transverse axis of the individual whereas Euglena
reproduces by longitudinal binary fission. In this mode, the plane of cytoplasmic division coincides with the longitudinal axis of
the individual. OR (i) The female gonads, ovaries, are located within the lower abdominal cavity. The ovary contains many follicles
composed of a developing egg surrounded by an outer layer of follicle cells. (ii) After puberty, the ovary cycles between a
follicular phase (maturing follicles) and luteal phase (presence of the corpus luteum) and menstruation phase. These cyclic
phases are interrupted only by pregnancy and continue until menopause, when reproductive capability ends.
12) Certain molecular processes are given in column (A) Give the term to these processes in column (B) after selecting them
from the following terms: Recombination, gene regulation, prokaryotic, transcription, eukaryotic transcription, translation,
replication, gene transfer, DNA fingerprinting
Column A Column B
DNA DNA
DNA hnDNA
niRNA Protein
Represser protein + Operator No transcription
Answer:
Column B
(i) Replication
(ii) Transcription
(iii) Translation
(iv) Gene regulation       
13) Differentiate between entomophilous flowers and hydrophilous flower.
Answer:
The main difference between entomophilous and hydrophilous flower are as follows :-
S.
No.
Entomophilous flower Hydrophilous flower
1. The flowers are large or if small, they group
to form a large mass.
The flowers are small and
inconspicuous.
Page 3


d o n e Biology - Sample Paper-9
1) Define internal syngamy.
Answer:
When fusion of male and female gametes takes place inside the female body, it is called internal syngamy or internal fertilization.
2) What is pollination?
Answer:
Pollination is defined as transfer of pollen grains from anther to the stigma.
3) Give example of a plant in which pollination occur with the help of water.
Answer:
Vallisneria  
4) What is called the bag-like fluid structure surrounding the human embryo?
Answer:
Amnion.   
5) What is artificial insemination?
Answer:
Artificial deposition of semen collected from a male animal into the vagina of female animal. 
6)
What is the relation between Gross Primary Productivity and Net Primary
Productivity?
OR
What is gestation period?
Answer:
Gross Primary Productivity (GPP): It is the rate of production of biomass or accumulation of energy by green plants per unit area
per unit time. It is also referred as (gross) photosynthetic or total assimilation. It depends upon chlorophyll content. Net Primary
Productivity (NPP): It is the rate of storage of organic matter in plant tissues in excess of the respiratory utilization by plant
during the measurement period. GPP - R=NPP Gross primary productivity - Respiratory loss = Net Primary productivity  OR
Gestation period is the fetal development period from the time of conception until birth. The average length of human gestation
is 280 days or 40 week from the first day of the women's last menstrual period.
7) How is polyspermy prevented?
Answer:
An egg reacts rapidly to the entry of the sperms. First, the egg becomes activated and undergoes depolarization of its
membrane. Second the egg exhibit cortical reaction & shows zona reactions. The plasma membrane is altered immediately to
make the egg impervious to any other sperm.
8) Define natality? What does it represented?
Answer:
The natality or birth rate can be defined as the number of individuals born in a given population during a given period of time. It
represents an addition or increase in the number of new individuals in a population, increasing its size. It only represents one
component of the population growth.
  
9) What is the purpose of Ganga Action Plan?
Answer:
Ganga Action Plan is a project of Ministry of Environment and Forests, initiated to save major rivers of our country from pollution.
Only treated sewage may be discharged into the rivers.  
10) How a food chain or food web is formed?
Answer:
In an ecosystem the producers and consumers interact with each other. Plants are producers. The animal feeds on a plant or on
another animal and in turn serves as food for other animal. This interdependency of organisms led to the formation of food chain
or web. 
11)
Define binary fission. What is the difference between binary fission in Plasmodium and
Euglena?
OR
(i) Where is female reproductive system situated in the body?
(ii) What is ovarian cycle?
Answer:
Binary fission is the division of the parent into two offspring which are morphologically & genetically similar to the parent and to
each other. During this process, nuclear division is followed by cytoplasmic division. There are three modes of binary fission
simple binary fission, transverse binary fission and longitudinal binary fission. Plasmodium reproduces by transverse binary
fission. In this method, the plane of cytoplasmic division coincides with the transverse axis of the individual whereas Euglena
reproduces by longitudinal binary fission. In this mode, the plane of cytoplasmic division coincides with the longitudinal axis of
the individual. OR (i) The female gonads, ovaries, are located within the lower abdominal cavity. The ovary contains many follicles
composed of a developing egg surrounded by an outer layer of follicle cells. (ii) After puberty, the ovary cycles between a
follicular phase (maturing follicles) and luteal phase (presence of the corpus luteum) and menstruation phase. These cyclic
phases are interrupted only by pregnancy and continue until menopause, when reproductive capability ends.
12) Certain molecular processes are given in column (A) Give the term to these processes in column (B) after selecting them
from the following terms: Recombination, gene regulation, prokaryotic, transcription, eukaryotic transcription, translation,
replication, gene transfer, DNA fingerprinting
Column A Column B
DNA DNA
DNA hnDNA
niRNA Protein
Represser protein + Operator No transcription
Answer:
Column B
(i) Replication
(ii) Transcription
(iii) Translation
(iv) Gene regulation       
13) Differentiate between entomophilous flowers and hydrophilous flower.
Answer:
The main difference between entomophilous and hydrophilous flower are as follows :-
S.
No.
Entomophilous flower Hydrophilous flower
1. The flowers are large or if small, they group
to form a large mass.
The flowers are small and
inconspicuous.
2. Odour is commonly present and the flowers
usually posses nectar or edible pollen.
Nectar and odour are absent.
3. Pollen grains are heavy and surrounded by a
yellow sticky substance called pollenkitt.
Pollen grains are light and unwettable
due to mucilage cover.
4. Stigmas are usually branched and sticky. Stigmas are long, sticky but
unwettable.
5. Rosa, Yucca, Amorphophallus are few
examples of entomophilous flower,
Vallisneria, Zoster a, Ceratophyllum
are few examples of hydrophilous
flower.
14) What is ART?
Answer:
ART is a term that describes several different methods used to help infertile couples. ART involves removing eggs from a
woman's body, mixing them with sperm in the laboratory and putting the early embryos into a woman's body or donating them to
another woman. Success rates vary depending on many factors. Something that affects the success rate of ART includes:
(i) age of the partners
(ii) reason for infertility
(iii) clinic
(iv) type of ART
(v) if the egg is fresh or frozen
(vi) if the embryo is fresh or frozen
Common methods of ART include:
(i) In vitro fertilization (IVF)
(ii) Intra cytoplasmic sperm injection (ICSI)
(iii) Gamete intra fallopian transfer (GIFT)
(iv) Zygote intra fallopian transfer (ZIFT)
(v) Surrogacy or use of a gestational carrier    
15) Explain aneuploidy. Write a short note on mongolism.
Answer:
The loss or addition of one or more chromosomes to the basic chromosome complement is called aneuploidy. Failure of
segregation ofchromatids during cell division give rise to aneuploidy. In humans there are 46 chromosomes or 23 pairs. Out of
these, there are 22 pairs ofautosomes and one pair of sex chromosome. Sometimes an additional set of chromosomes are
present or a set of chromosomes is lacking which leads to an abnormal condition in organisms like Down's syndrome, Turner's
syndrome, Klinefelter 's syndrome etc. All these are chromosomal disorders.                                             Down's syndrome (also
called mongolism) is due to presence of an additional copy of chromosome 21 which is also called trisomy of 21 i.e., (2n + 1). It
leads to an abnormal condition in organisms called mongolism or mongolian idiocy. This disorder was first discovered by
Langdon Down (1886). The affected individual is short statured with small round head, furrowed tongue and partially open
mouth. The individual is physically and mentally retarded. Heart and other organs may be defective. Gonads and genitalia are
underdeveloped. 
16) What is mutation. Give names of some mutagens. How mutations are significant in agriculture?
Answer:
Mutations are sudden inheritable changes which results in alteration of DNA sequences and changes the genotype and
phenotype of an organism. Mutation leads to variation. There are various chemical and physical factors that can induce
mutations. These are called mutagens. Physical mutagens include temperature and radiations, a, P, y rays. X-rays, ultra violet rays
cause mutations in organisms. Some chemical mutagens are nitrous acid, alkylating agents, acridine dyes. Mutations have
played a significant role in agriculture by crop improvement. Plant breeders use mutations for improvement of plants for higher
yield, nutritive value, disease resistance etc. Sharbati Sonora, a wheat variety was developed through mutations. A high yielding
rice variety called Reimei was produced by gamma irradiation. Cauliflower and cabbage are mutants developed from wild
cabbage. Mutations are induced in plants to enhance their beauty and fragrance e.g., Dahlia, Rosa. Many crop plants like wheat,
rice, maize, gram, cotton, potato, sugarcane, banana developed by mutations in nature. In vegetatively propagated plants,
mutations are the only source of improvement and development of variability. Seedless varities of grapes and oranges are
successfully produced through mutations.
Page 4


d o n e Biology - Sample Paper-9
1) Define internal syngamy.
Answer:
When fusion of male and female gametes takes place inside the female body, it is called internal syngamy or internal fertilization.
2) What is pollination?
Answer:
Pollination is defined as transfer of pollen grains from anther to the stigma.
3) Give example of a plant in which pollination occur with the help of water.
Answer:
Vallisneria  
4) What is called the bag-like fluid structure surrounding the human embryo?
Answer:
Amnion.   
5) What is artificial insemination?
Answer:
Artificial deposition of semen collected from a male animal into the vagina of female animal. 
6)
What is the relation between Gross Primary Productivity and Net Primary
Productivity?
OR
What is gestation period?
Answer:
Gross Primary Productivity (GPP): It is the rate of production of biomass or accumulation of energy by green plants per unit area
per unit time. It is also referred as (gross) photosynthetic or total assimilation. It depends upon chlorophyll content. Net Primary
Productivity (NPP): It is the rate of storage of organic matter in plant tissues in excess of the respiratory utilization by plant
during the measurement period. GPP - R=NPP Gross primary productivity - Respiratory loss = Net Primary productivity  OR
Gestation period is the fetal development period from the time of conception until birth. The average length of human gestation
is 280 days or 40 week from the first day of the women's last menstrual period.
7) How is polyspermy prevented?
Answer:
An egg reacts rapidly to the entry of the sperms. First, the egg becomes activated and undergoes depolarization of its
membrane. Second the egg exhibit cortical reaction & shows zona reactions. The plasma membrane is altered immediately to
make the egg impervious to any other sperm.
8) Define natality? What does it represented?
Answer:
The natality or birth rate can be defined as the number of individuals born in a given population during a given period of time. It
represents an addition or increase in the number of new individuals in a population, increasing its size. It only represents one
component of the population growth.
  
9) What is the purpose of Ganga Action Plan?
Answer:
Ganga Action Plan is a project of Ministry of Environment and Forests, initiated to save major rivers of our country from pollution.
Only treated sewage may be discharged into the rivers.  
10) How a food chain or food web is formed?
Answer:
In an ecosystem the producers and consumers interact with each other. Plants are producers. The animal feeds on a plant or on
another animal and in turn serves as food for other animal. This interdependency of organisms led to the formation of food chain
or web. 
11)
Define binary fission. What is the difference between binary fission in Plasmodium and
Euglena?
OR
(i) Where is female reproductive system situated in the body?
(ii) What is ovarian cycle?
Answer:
Binary fission is the division of the parent into two offspring which are morphologically & genetically similar to the parent and to
each other. During this process, nuclear division is followed by cytoplasmic division. There are three modes of binary fission
simple binary fission, transverse binary fission and longitudinal binary fission. Plasmodium reproduces by transverse binary
fission. In this method, the plane of cytoplasmic division coincides with the transverse axis of the individual whereas Euglena
reproduces by longitudinal binary fission. In this mode, the plane of cytoplasmic division coincides with the longitudinal axis of
the individual. OR (i) The female gonads, ovaries, are located within the lower abdominal cavity. The ovary contains many follicles
composed of a developing egg surrounded by an outer layer of follicle cells. (ii) After puberty, the ovary cycles between a
follicular phase (maturing follicles) and luteal phase (presence of the corpus luteum) and menstruation phase. These cyclic
phases are interrupted only by pregnancy and continue until menopause, when reproductive capability ends.
12) Certain molecular processes are given in column (A) Give the term to these processes in column (B) after selecting them
from the following terms: Recombination, gene regulation, prokaryotic, transcription, eukaryotic transcription, translation,
replication, gene transfer, DNA fingerprinting
Column A Column B
DNA DNA
DNA hnDNA
niRNA Protein
Represser protein + Operator No transcription
Answer:
Column B
(i) Replication
(ii) Transcription
(iii) Translation
(iv) Gene regulation       
13) Differentiate between entomophilous flowers and hydrophilous flower.
Answer:
The main difference between entomophilous and hydrophilous flower are as follows :-
S.
No.
Entomophilous flower Hydrophilous flower
1. The flowers are large or if small, they group
to form a large mass.
The flowers are small and
inconspicuous.
2. Odour is commonly present and the flowers
usually posses nectar or edible pollen.
Nectar and odour are absent.
3. Pollen grains are heavy and surrounded by a
yellow sticky substance called pollenkitt.
Pollen grains are light and unwettable
due to mucilage cover.
4. Stigmas are usually branched and sticky. Stigmas are long, sticky but
unwettable.
5. Rosa, Yucca, Amorphophallus are few
examples of entomophilous flower,
Vallisneria, Zoster a, Ceratophyllum
are few examples of hydrophilous
flower.
14) What is ART?
Answer:
ART is a term that describes several different methods used to help infertile couples. ART involves removing eggs from a
woman's body, mixing them with sperm in the laboratory and putting the early embryos into a woman's body or donating them to
another woman. Success rates vary depending on many factors. Something that affects the success rate of ART includes:
(i) age of the partners
(ii) reason for infertility
(iii) clinic
(iv) type of ART
(v) if the egg is fresh or frozen
(vi) if the embryo is fresh or frozen
Common methods of ART include:
(i) In vitro fertilization (IVF)
(ii) Intra cytoplasmic sperm injection (ICSI)
(iii) Gamete intra fallopian transfer (GIFT)
(iv) Zygote intra fallopian transfer (ZIFT)
(v) Surrogacy or use of a gestational carrier    
15) Explain aneuploidy. Write a short note on mongolism.
Answer:
The loss or addition of one or more chromosomes to the basic chromosome complement is called aneuploidy. Failure of
segregation ofchromatids during cell division give rise to aneuploidy. In humans there are 46 chromosomes or 23 pairs. Out of
these, there are 22 pairs ofautosomes and one pair of sex chromosome. Sometimes an additional set of chromosomes are
present or a set of chromosomes is lacking which leads to an abnormal condition in organisms like Down's syndrome, Turner's
syndrome, Klinefelter 's syndrome etc. All these are chromosomal disorders.                                             Down's syndrome (also
called mongolism) is due to presence of an additional copy of chromosome 21 which is also called trisomy of 21 i.e., (2n + 1). It
leads to an abnormal condition in organisms called mongolism or mongolian idiocy. This disorder was first discovered by
Langdon Down (1886). The affected individual is short statured with small round head, furrowed tongue and partially open
mouth. The individual is physically and mentally retarded. Heart and other organs may be defective. Gonads and genitalia are
underdeveloped. 
16) What is mutation. Give names of some mutagens. How mutations are significant in agriculture?
Answer:
Mutations are sudden inheritable changes which results in alteration of DNA sequences and changes the genotype and
phenotype of an organism. Mutation leads to variation. There are various chemical and physical factors that can induce
mutations. These are called mutagens. Physical mutagens include temperature and radiations, a, P, y rays. X-rays, ultra violet rays
cause mutations in organisms. Some chemical mutagens are nitrous acid, alkylating agents, acridine dyes. Mutations have
played a significant role in agriculture by crop improvement. Plant breeders use mutations for improvement of plants for higher
yield, nutritive value, disease resistance etc. Sharbati Sonora, a wheat variety was developed through mutations. A high yielding
rice variety called Reimei was produced by gamma irradiation. Cauliflower and cabbage are mutants developed from wild
cabbage. Mutations are induced in plants to enhance their beauty and fragrance e.g., Dahlia, Rosa. Many crop plants like wheat,
rice, maize, gram, cotton, potato, sugarcane, banana developed by mutations in nature. In vegetatively propagated plants,
mutations are the only source of improvement and development of variability. Seedless varities of grapes and oranges are
successfully produced through mutations.
17) What is the reason of extinction of dinosaurs?
Answer:
Dinosaurs become extinct about 65 million years ago. The probable reason of their extinction was climatic changes. Dinasaur
extinctions was named as "The Cretaceous Tertiary extinction or K-T extinction", it was said that the big meteorite crashed into
Earth, changing the climatic condition. Ash and gas spewing from volcanoes suffocated them and food chain imbalances lead to
extinction of dinosaurs.
18) Write a note on immunization during pregnancy.
Answer:
Vaccines are given to pregnant women to develop immunity against certain diseases. Immunization protects both mother and
foetus. Immunization should be done before gestation because some vaccines are not safe during pregnancy. However in case
of breakdown of an epidemic, pregnant women are vaccinated. Vaccines which are safe during pregnancy include Tetanus,
Influenza, Poliomyelitis, Cholera, Hepatitis B. Small pox vaccine, Oral Poliomyelitis vaccine, Rubella vaccine should be avoided
during pregnancy as they are harmful for both mother and foetus. Immunization of pregnant women comes under health care
programme of government. It can be done at different health centres set up by government. The only need is to generate
awareness among people to use these facilities. 
19) Describe the measures to be taken in poultry farm management.
Answer:
Management procedures that are employed in poultry farm management involves the
following steps -
(i) Selection of disease free breeds
(ii) Proper feeding of birds
(iii) Maintenance of hygienic conditions
(iv) Proper medication
(v) Veterinary supervision
20) Write about production and use of lactic acid, citric acid, acetic acid.
Answer:
Present Bacteria Starting Use
Lactic acid Lactobacillus milk sugar Curd, cheese production
Citric acid Aspergillus niger fruit sugar Medicine, food preservation
Acetic acid Clostridium
acetobutylicum
wine and beer Food preservative
21) What is advantage of GM plants? Discuss.
Answer:
Advantages of genetically modified plants are -
(i) Pest resistance - Crop losses from insects pests can be incredible, resulting in financial loss for
farmers and starvation in developing countries. Growing GM foods such as BT corn, Bt cotton etc.
can help eliminate the application of chemical pesticides & reduce the cost of bringing a crop to
market.
(ii) Disease resistance-There are many viruses, fungi & bacteria which causes plant diseases. Plant
biologists are working to create plants with genetically engineered resistance to these disease.
(iii) Cold tolerance - Unexpected frost can destroy sensitive seedlings. An antifreeze gene from cold
water fish has been introduced into plants such as tobacco and potato.
(iv) Nutrition - Generally, rice does not contain adequate amounts of all necessary nutrients to
prevent malnutrition. If rice could be genetically engineered to contain all additional vitamins
minerals, nutritional differences could be alleviated.
Plants were underway to develop golden rice that a Whas increased iron content.
Page 5


d o n e Biology - Sample Paper-9
1) Define internal syngamy.
Answer:
When fusion of male and female gametes takes place inside the female body, it is called internal syngamy or internal fertilization.
2) What is pollination?
Answer:
Pollination is defined as transfer of pollen grains from anther to the stigma.
3) Give example of a plant in which pollination occur with the help of water.
Answer:
Vallisneria  
4) What is called the bag-like fluid structure surrounding the human embryo?
Answer:
Amnion.   
5) What is artificial insemination?
Answer:
Artificial deposition of semen collected from a male animal into the vagina of female animal. 
6)
What is the relation between Gross Primary Productivity and Net Primary
Productivity?
OR
What is gestation period?
Answer:
Gross Primary Productivity (GPP): It is the rate of production of biomass or accumulation of energy by green plants per unit area
per unit time. It is also referred as (gross) photosynthetic or total assimilation. It depends upon chlorophyll content. Net Primary
Productivity (NPP): It is the rate of storage of organic matter in plant tissues in excess of the respiratory utilization by plant
during the measurement period. GPP - R=NPP Gross primary productivity - Respiratory loss = Net Primary productivity  OR
Gestation period is the fetal development period from the time of conception until birth. The average length of human gestation
is 280 days or 40 week from the first day of the women's last menstrual period.
7) How is polyspermy prevented?
Answer:
An egg reacts rapidly to the entry of the sperms. First, the egg becomes activated and undergoes depolarization of its
membrane. Second the egg exhibit cortical reaction & shows zona reactions. The plasma membrane is altered immediately to
make the egg impervious to any other sperm.
8) Define natality? What does it represented?
Answer:
The natality or birth rate can be defined as the number of individuals born in a given population during a given period of time. It
represents an addition or increase in the number of new individuals in a population, increasing its size. It only represents one
component of the population growth.
  
9) What is the purpose of Ganga Action Plan?
Answer:
Ganga Action Plan is a project of Ministry of Environment and Forests, initiated to save major rivers of our country from pollution.
Only treated sewage may be discharged into the rivers.  
10) How a food chain or food web is formed?
Answer:
In an ecosystem the producers and consumers interact with each other. Plants are producers. The animal feeds on a plant or on
another animal and in turn serves as food for other animal. This interdependency of organisms led to the formation of food chain
or web. 
11)
Define binary fission. What is the difference between binary fission in Plasmodium and
Euglena?
OR
(i) Where is female reproductive system situated in the body?
(ii) What is ovarian cycle?
Answer:
Binary fission is the division of the parent into two offspring which are morphologically & genetically similar to the parent and to
each other. During this process, nuclear division is followed by cytoplasmic division. There are three modes of binary fission
simple binary fission, transverse binary fission and longitudinal binary fission. Plasmodium reproduces by transverse binary
fission. In this method, the plane of cytoplasmic division coincides with the transverse axis of the individual whereas Euglena
reproduces by longitudinal binary fission. In this mode, the plane of cytoplasmic division coincides with the longitudinal axis of
the individual. OR (i) The female gonads, ovaries, are located within the lower abdominal cavity. The ovary contains many follicles
composed of a developing egg surrounded by an outer layer of follicle cells. (ii) After puberty, the ovary cycles between a
follicular phase (maturing follicles) and luteal phase (presence of the corpus luteum) and menstruation phase. These cyclic
phases are interrupted only by pregnancy and continue until menopause, when reproductive capability ends.
12) Certain molecular processes are given in column (A) Give the term to these processes in column (B) after selecting them
from the following terms: Recombination, gene regulation, prokaryotic, transcription, eukaryotic transcription, translation,
replication, gene transfer, DNA fingerprinting
Column A Column B
DNA DNA
DNA hnDNA
niRNA Protein
Represser protein + Operator No transcription
Answer:
Column B
(i) Replication
(ii) Transcription
(iii) Translation
(iv) Gene regulation       
13) Differentiate between entomophilous flowers and hydrophilous flower.
Answer:
The main difference between entomophilous and hydrophilous flower are as follows :-
S.
No.
Entomophilous flower Hydrophilous flower
1. The flowers are large or if small, they group
to form a large mass.
The flowers are small and
inconspicuous.
2. Odour is commonly present and the flowers
usually posses nectar or edible pollen.
Nectar and odour are absent.
3. Pollen grains are heavy and surrounded by a
yellow sticky substance called pollenkitt.
Pollen grains are light and unwettable
due to mucilage cover.
4. Stigmas are usually branched and sticky. Stigmas are long, sticky but
unwettable.
5. Rosa, Yucca, Amorphophallus are few
examples of entomophilous flower,
Vallisneria, Zoster a, Ceratophyllum
are few examples of hydrophilous
flower.
14) What is ART?
Answer:
ART is a term that describes several different methods used to help infertile couples. ART involves removing eggs from a
woman's body, mixing them with sperm in the laboratory and putting the early embryos into a woman's body or donating them to
another woman. Success rates vary depending on many factors. Something that affects the success rate of ART includes:
(i) age of the partners
(ii) reason for infertility
(iii) clinic
(iv) type of ART
(v) if the egg is fresh or frozen
(vi) if the embryo is fresh or frozen
Common methods of ART include:
(i) In vitro fertilization (IVF)
(ii) Intra cytoplasmic sperm injection (ICSI)
(iii) Gamete intra fallopian transfer (GIFT)
(iv) Zygote intra fallopian transfer (ZIFT)
(v) Surrogacy or use of a gestational carrier    
15) Explain aneuploidy. Write a short note on mongolism.
Answer:
The loss or addition of one or more chromosomes to the basic chromosome complement is called aneuploidy. Failure of
segregation ofchromatids during cell division give rise to aneuploidy. In humans there are 46 chromosomes or 23 pairs. Out of
these, there are 22 pairs ofautosomes and one pair of sex chromosome. Sometimes an additional set of chromosomes are
present or a set of chromosomes is lacking which leads to an abnormal condition in organisms like Down's syndrome, Turner's
syndrome, Klinefelter 's syndrome etc. All these are chromosomal disorders.                                             Down's syndrome (also
called mongolism) is due to presence of an additional copy of chromosome 21 which is also called trisomy of 21 i.e., (2n + 1). It
leads to an abnormal condition in organisms called mongolism or mongolian idiocy. This disorder was first discovered by
Langdon Down (1886). The affected individual is short statured with small round head, furrowed tongue and partially open
mouth. The individual is physically and mentally retarded. Heart and other organs may be defective. Gonads and genitalia are
underdeveloped. 
16) What is mutation. Give names of some mutagens. How mutations are significant in agriculture?
Answer:
Mutations are sudden inheritable changes which results in alteration of DNA sequences and changes the genotype and
phenotype of an organism. Mutation leads to variation. There are various chemical and physical factors that can induce
mutations. These are called mutagens. Physical mutagens include temperature and radiations, a, P, y rays. X-rays, ultra violet rays
cause mutations in organisms. Some chemical mutagens are nitrous acid, alkylating agents, acridine dyes. Mutations have
played a significant role in agriculture by crop improvement. Plant breeders use mutations for improvement of plants for higher
yield, nutritive value, disease resistance etc. Sharbati Sonora, a wheat variety was developed through mutations. A high yielding
rice variety called Reimei was produced by gamma irradiation. Cauliflower and cabbage are mutants developed from wild
cabbage. Mutations are induced in plants to enhance their beauty and fragrance e.g., Dahlia, Rosa. Many crop plants like wheat,
rice, maize, gram, cotton, potato, sugarcane, banana developed by mutations in nature. In vegetatively propagated plants,
mutations are the only source of improvement and development of variability. Seedless varities of grapes and oranges are
successfully produced through mutations.
17) What is the reason of extinction of dinosaurs?
Answer:
Dinosaurs become extinct about 65 million years ago. The probable reason of their extinction was climatic changes. Dinasaur
extinctions was named as "The Cretaceous Tertiary extinction or K-T extinction", it was said that the big meteorite crashed into
Earth, changing the climatic condition. Ash and gas spewing from volcanoes suffocated them and food chain imbalances lead to
extinction of dinosaurs.
18) Write a note on immunization during pregnancy.
Answer:
Vaccines are given to pregnant women to develop immunity against certain diseases. Immunization protects both mother and
foetus. Immunization should be done before gestation because some vaccines are not safe during pregnancy. However in case
of breakdown of an epidemic, pregnant women are vaccinated. Vaccines which are safe during pregnancy include Tetanus,
Influenza, Poliomyelitis, Cholera, Hepatitis B. Small pox vaccine, Oral Poliomyelitis vaccine, Rubella vaccine should be avoided
during pregnancy as they are harmful for both mother and foetus. Immunization of pregnant women comes under health care
programme of government. It can be done at different health centres set up by government. The only need is to generate
awareness among people to use these facilities. 
19) Describe the measures to be taken in poultry farm management.
Answer:
Management procedures that are employed in poultry farm management involves the
following steps -
(i) Selection of disease free breeds
(ii) Proper feeding of birds
(iii) Maintenance of hygienic conditions
(iv) Proper medication
(v) Veterinary supervision
20) Write about production and use of lactic acid, citric acid, acetic acid.
Answer:
Present Bacteria Starting Use
Lactic acid Lactobacillus milk sugar Curd, cheese production
Citric acid Aspergillus niger fruit sugar Medicine, food preservation
Acetic acid Clostridium
acetobutylicum
wine and beer Food preservative
21) What is advantage of GM plants? Discuss.
Answer:
Advantages of genetically modified plants are -
(i) Pest resistance - Crop losses from insects pests can be incredible, resulting in financial loss for
farmers and starvation in developing countries. Growing GM foods such as BT corn, Bt cotton etc.
can help eliminate the application of chemical pesticides & reduce the cost of bringing a crop to
market.
(ii) Disease resistance-There are many viruses, fungi & bacteria which causes plant diseases. Plant
biologists are working to create plants with genetically engineered resistance to these disease.
(iii) Cold tolerance - Unexpected frost can destroy sensitive seedlings. An antifreeze gene from cold
water fish has been introduced into plants such as tobacco and potato.
(iv) Nutrition - Generally, rice does not contain adequate amounts of all necessary nutrients to
prevent malnutrition. If rice could be genetically engineered to contain all additional vitamins
minerals, nutritional differences could be alleviated.
Plants were underway to develop golden rice that a Whas increased iron content.
22) How do plants in desert regions reduce evaporative loss of water?
Answer:
Plants have evolved following mechanisms to survive in a semi-arid or desert environment: 
(i) By reducing the leaf area by dropping the leaves at the onset of drought period and developing
new leaves on the onset of rain.    
(ii) Desert plants employ CAM type of photosynthesis and close their stomata during the day and
opens them at night.
(iii) When the water is limited, many plant species reorient the angle of their leaves, so there leaf
surface are paralled to sun rays reducing leaf temperature and also rate of transpiration.
Slump succulent niants can store water in their tissues, using this water during periods of drought
and stress.
23) Describe briefly the human role in carbon cycling.
Answer:
Anthropogenic activities, particularly fossil fuel burning and deforestation, are releasing carbon dioxide into the atmosphere.
When we mine coal and extract oil from the Earth's crust and then bum these fossil fuels for transportation, heating, cooking,
electricity and manufacturing. We are effectively moving carbon more rapidly into the atmosphere than is being added to
lithosphere naturally through the sedimentation of carbon, ultimately causing atmospheric carbon dioxide concentration
increase.
24) Read the following article regarding "Gene therapy" and answer the following questions, The ultimate goal of gene therapy is
the gene replacement therapy. Gene replacement therapy permits physiological regulation of the transgenes and elimination of
the possibility of insertional activation of other cellular gene which occur at the time of random integration of the foreign gene. At
present the current strategy for gene therapy largely centres around gene augmentatious therapy, where the foreign gene
replaces the defective or missing gene.
(a) What is gene therapy?
(b) How is gene therapy being used in treating ADA deficiency patients?
(c) Mention the cause and the body system affected by ADA deficiency in humans.
(d) Name the vector used for transferring ADA-DNA into the recipient cells in humans. Name the
recipients cell.
Answer:
(a) Gene therapy involve switching off the defective gene and to substitute a healthy gene copy in a
person diagnosed to carry a defective gene.
(b) ADA is caused due to the deletion of gene for adenosine deaminase.
Lymphocytes from patient's blood were grown in a culture and functional ADA and cDNA was
introduced in these lymphocytes using a retroviral vector.
Lymphocytes were transferred into the patient's body. Periodic infusion of such genetically
engineered lymphocyte is done because these cells are mortal.
For permanent cure, gene isolated from the bone marrow cells producing ADA at early embryonic
stage can be possible cure.
(c) ADA is caused due to deletion of gene for adenosine deaminase.
Immune system of body is affected due to this.
(d) Retroviral vector is used to transfer ADA-DNA into the recipient cells of human.
Recipient cells-Lymphocytes. 
25)
What are biofertilizers? Explain with examples.
OR
(a) Why are thalassemia and haemophilia categorized as Mendelian disorders? Write the symptoms
of these diseases. Explain their pattern of inheritance in humans.
(b) Write the genotypes of the normal parents producing a haemophilic son.
Answer:
Chemical fertilizers like NPK are used in agriculture to increase the fertility of soil and thereby increase the productivity. But the
harmful effects of chemical fertilizers have compelled us to look out for an alternative source of fertilizers of biological origin.