HERIDITY

1. Define heredity and hereditary characters.
- The process of transferring genetic characters from the parents to the offspring is called heredity.
- The characters which transfer from the parents to the offspring are known as hereditary characters.

2. Define genetics. Who is known as the father of genetics?
- The branch of biology which deals with heredity, variation and mutation is called genetics.
Gregor Johann Mendel is known  as the father of genetics.

3. Why did Mendel choose the pea plant for his experiment?
-  Mendel selected the pea plant for his experiment because of following reason:
a. Pea plant has a closed bisexual flower. It helps in self-pollination.
b. It has a very short life cycle. So, results can be obtained in a short time.
c. It has lots of varieties.
d. Artificial cross pollination can be carried out.

4. Define dominant and recessive character.
- The character which can be seen in first filial generation when a cross is made between the same kinds of organisms having contrasting characters is known as dominant character.
- The charter which cannot be seen in first filial generation when cross is made between the same kind of organisms having contrasting character is known as recessive character.

5. Define hybrid.
- The organism which is obtained in the first filial generation after the crossing of two pure contrasting characters is known as hybrid. It is represented by Tt.

6. Define Genotype and Phenotype.
- The genetic make-up of an organism is known as genotype.
- The morphological appearance of an organism is known as phenotype.

7. Define monohybrid and dihybrid cross.
- The cross-pollination between two plants which have one pair of contrasting character is known as monohybrid cross. For example, the cross between a pure tall pea plant and a pure dwarf pea plant.
-  The cross-pollination between two plants which have two pairs of contrasting characters is known as dihybrid cross. For example, the cross between two pea plants which have yellow round and wrinkled seed.

ASEXUAL AND SEXUAL REPRODUCTION

1. What is reproduction? What are its type.
- The biological process of producing own kind of new organisms by a living being is called reproduction. Its types are:
a. Asexual Reproduction
b. Sexual reproduction

2. Define asexual and sexual reproduction.
- The reproduction in which new organisms are formed from the parts of a parental body instead of formation of gametes is known as asexual reproduction. It occurs in organisms like amoeba, hydra etc.
- The reproduction in which new organisms are formed due to the fusion of male and female gametes is known as sexual reproduction. It occurs in organisms like human beings, cat etc.

3. What are the advantages of asexual reproduction?
- The advantages of asexual reproduction are:
a. It is easy, fast and economic.
b. The offspring are genetically similar to the parents.
c. Only one organism is involved.

4. Define fission with types.
- The process of formation of two or more organisms by dividing a fully developed organism is called fission. Its types are:
a. Binary fission-- Amoeba, bacteria etc.
b. Multiple fission-- Plasmodium, Chlamydomonas etc.

5. Define budding, fragmentation and sporulation.
- The type of asexual reproduction due to the formation of buds is known as budding. For example hydra, yeast etc.
- The type of reproduction in which the body of an organisms breaks down into two or more parts and then each parts develop into new organisms is known as fragmentation. For eg. spirogyra
- The kind of asexual reproduction that takes place due to formation of spores is known as sporulation. For eg. Fern, mucor etc.

6. Define vegetative reproduction and give examples of plant reproducing by this method.
- The type of asexual reproduction which takes place by the parts of plant like stem, root, leaves etc is known as vegetative reproduction. For example:
a. From roots- Sweet potato,Dahlia
b. From leaves- Bryophyllum, Begonia
c. From shoot- Potato, Rose plant.

CHROMOSOMES AND SEX DETERMINATION

1. Define chromosomes and describe its structure.
- The ribbon shaped clear, thick and long microscopic threads which can be seen during the cell division are called chromosomes. Its structure can be described in following points:
a. Chromosomes have many genes.
b. Each chromosome is made up of DNA and protein.
c. Each chromosome has constriction.

2. Define centromere or kinetochore.
- The constriction present in the chromosome is called  centromere or kinetochore.

3. Enlist the function of chromosomes.
- The function of chromosomes are as follows-
a. They determine the characteristics of plant and animals.
b. It transfer characteristics from one generation to another.

4. Describe types of chromosomes on the basis of position of centromere.
- On the basis of position of centromere, chromosomes are divided into four types:
a. Metacentric chromosomes-  It has centromere in middle of chromosome. Both arms of chromosomes are equal.
b. Sub-metacentric chromosomes- It has centromere near the middle of chromosome. Both arms are unequal.
c. Acrocentric chromosomes- It has centromere near the end of chromosome.
d. Telocentric chromosomes- It has centromere at the end of chromosomes.

5. What are the types of chromosome on the basis of characteristics?
- On the basis features, chromosomes are divided into two types:
a. Autosome:  Autosomes determine the characteristics of the body. There are 22 pairs of autosomes in the nucleus in the nucleus of the human body cell.
b. Sex chromosome: Sex chromosome determines the sex of upcoming generation. In the nucleus of human body cell, there are 1 pair of sex chromosomes (XX OR XY) .

6. What are the type of cell on the basis of number of chromosomes?
- On the basis of number of chromosomes cells are divided into two types:
a. Diploid cells- The cells in which half the number of chromosomes come from the mother and half from father to make "2n" are called diploid cells. Generally somatic cells are diploid.
b. Haploid cells- Cells with the half number of chromosomes are called haploid cell. They are denoted by "n".

BLOOD CIRCULATORY SYSTEM IN HUMAN BODY

1. Define Circulatory system with its parts.
- The conducting system of the body which co-ordinates the transportation of nutrients, oxygen, enzyme, medicine etc to the tissues and collection of waste products from the tissues to the excretory sites is known as the circulatory system. Its parts are:

a. Blood               b. Blood vessel                  c. Heart                                                                             
2. Define blood.
- The thick red colored liquid connecting tissue containing 55% of plasma and 45% of blood cells is known as blood.

3. Define plasma. Enlist function of plasma.
-  The yellowish transparent liquid found in blood is called plasma. It contains 90% water and 10% protein, fat, salt and carbohydrate. Its functions are;
a. Fibrinogen in plasma helps in blood clotting.
b. It controls the flow and composition of water in blood.
c. It carries carbon dioxide from cells to lungs.
d. It transport hormones to the tissues.

4. Write the functions of blood cells.
- The functions of blood cells are as follows:
R.B.Cs or erythrocytes
a. It contains the red pigment called haemoglobin which makes blood red in color.
b. To pick up oxygen from the lungs and deliver it to the tissues elsewhere. 
WBCs or leucocytes
a. It help fight infections by attacking bacteria, viruses and germs that invade body.
b. It aids the immune system.
Platelets or thrombocytes.
a. It helps in blood clotting.
b. They protect body from loss of blood.
5. What are the disease caused due to deficiency and more count of RBCs and WBCs?
- The diseases caused due to the deficiency of RBCs and WBCs are anemia and polycythemia respectively and that due to more count is leucopenia and leukemia respectively.