”The sex of the children is determined by what they inherit from their father and not their mother.” Justify.
It is because a child who inherits an X chromosome from her father will be a girl and one who inherits a Y chromosome from his father will be a boy. But all children inherit a X chromosome from their mother regardless of whether they are boys or girls.
(a) If a normal human cell has 46 chromosomes, how many chromosomes will be there in a human (;) sperm cell, and (ii) zygote ?
(b) What sizes of plants are produced if both parents have genes Tt ?
Will geographical isolation be a major factor in the speciation of an organism that reproduces asexually ? Why or why not ?
How are fossils formed? Describe, in brief, two methods of determining the age of fossils. [All India]
a) Name the scientist who gave the theory of origin of life on earth. What is this theory ?
(b) How are those species which are now ‘extinct’ studied ?
State whether the following statement is true or false :
The sex of an infant is not a case of inheritance of characteristics.
Does genetic combination of mother play a significant role in determining the sex of a new born baby ?
State one characteristic which shows that the birds are very closely related to dinosaurs.
Out of bacteria, spider, fish and chimpanzee, which organism has a better body design in evolutionary terms ? Give reason for your answer.
A woman has only daughters. Analyse the situation genetically and provide a suitable explanation.
A man with blood group A marries a woman with blood O and their daughter has blood group O. Is this information enough to tell you which of the traits blood group A or O is dominant ? Why or why not ?
Give an example of characteristics being used to determine how close two species am in evolutionary terms ?
In evolutionary terms, can we say which among bacteria, spiders, fish and chimpanzees have a ‘better body design’ why or why not ?
During which stage can the chromosomes be seen clearly? Write the features of the eukaryotic and prokaryotic chromosomes.
Who provided the evidence of DNA as the genetic material? Write the names of the components of the DNA molecule.
What do you understand by the double helical structure of DNA? Who proposed this structure?
Define variation in relation to a species. Why is variation beneficial to the species? [Delhi]
Give an example of body characteristics used to determine how close two species are in terms of evolution and explain it. [All India]
The gene for red hair is recessive to the gene for black hair. What will be the hair colour of a person if he inherits a gene for red hair from his mother and a gene for black hair from his father ?
Fill in the following blanks with suitable words :Fill in the following blanks with suitable words :
(a) Genes always work in …………………
(b) In pea plants, the gene for dwarfness is………………… whereas that for tallness is…………………
(c) Most people have………………… earlobes but some have………………… earlobes.
(d) A human gamete contains………………… chromosomes whereas a normal body cell has………………… chromosomes in it.
(e) All races of man have………………… blood groups.
(f) The………………… chromosomes for a………………… are XX whereas that for a………………… are XY.
In the F2 generation of a cross, progeny having different traits are produced in the ratio 3:1. State whether it is a monohybrid cross or a dihybrid cross ? Give one example of such a cross.
(a) What are genes ? Where are they located in our body ?(a) What are genes ? Where are they located in our body ?
(b) What is meant by dominant genes and recessive genes ? Give one example of each.
(c) Explain how, characteristics (or traits) are inherited through genes.
Write the names of at least three inorganic molecules which helped in the origin of life on the earth.
Choose the one term from the following which includes the other three :
broccoli, wild cabbage, cauliflower, cabbage
Why are the small numbers of surviving tigers a cause of worry from the point of view of genetics ?
Will geographical isolation be a major factor in the speciation of an organism that reproduces asexually ? Give reason for your answer.
Does the occurrence of diversity of animals on earth suggest their diverse ancestry also? Discuss this point in the light of evolution.
Why are the small numbers of surviving tigers a cause of worry from the point of view of genetics ?
Only variations that confer an advantage to an individual organism will survive in a population. Do you agree with this statement ? Why or why not ?
