List of practice Questions

Read the following passage and answer the questions that follow.
Spermatogenesis is an important primary sex characteristic in humans and all other vertebrates. The process is coordinated and controlled under the influence of hormones. It starts with the onset of puberty in humans and thereafter continues. The primordial cells within the embryonic testis which differentiate into spermatogonia are the precursors of the sperms. These are located at the outer walls of the seminiferous tubules where the process of spermatogenesis proceeds.
(a) State the site of action of FSH in the testes and describe its action thereafter.
OR
(a) Describe the role of LH in the process of spermatogenesis.
(b) Name the cells and their products which undergo:
(i) Mitosis and Differentiation
(ii) Meiosis I and Meiosis II
(c) Name the accessory ducts that the sperms travel through from seminiferous tubules to reach the epididymis.
Predation is referred to as a detrimental interaction. Explain any three positive roles, supported by an example each, that a predator plays in an ecosystem.
(a) Redraw the pie chart identifying the groups ’A’, ’B’, ’C’, and ’D’ in their respective positions. 
(b) Mention two examples of recently extinct animals.
pie chart identifying the groups ’A’, ’B’, ’C’, and ’D’ in their respective positions.
The picture given below shows:
Roots of a typical control tobacco crop plant (infected)

(a) Roots of a typical control tobacco crop plant (infected).
(b) Transgenic tobacco plant showing healthy roots even after deliberate infection by nematode.
Explain how this transformation was achieved in the tobacco plant.
(a) Differentiate between humoral immune response and cell-mediated immune response.
(b) Draw a schematic diagram of an antibody molecule and label any four parts.
(a) Explain the process by which amino acid gets attached to the tRNA molecule during translation process.
(b) How does the translation process get terminated?
(c) Expand ‘UTR’. Where are they located?
(a) (i) Write the karyotype and the genetic disorder of an individual who has developed from a zygote formed from an ‘XX’ egg fertilized by a ‘Y’ sperm.
(ii) Mention any two symptoms of this genetic disorder.
(iii) Write the possible reason that leads to the formation of this ‘XX’ egg.
OR
(b) In case of any dispute, a very small sample of tissue or even a drop of blood can help us to determine the paternity of a child. Provide a scientific explanation to substantiate the statement.
(a) Why is “in vitro fertilization (IVF)” so named? State its importance.
(b) Distinguish between GIFT and ZIFT.
How is the rate of decomposition affected by the nature of detritus and temperature?
Write the role of ’ori’ and restriction site in the cloning vector pBR322.
Although Hemophilia and sickle cell anemia are two blood-related Mendelian disorders, yet they differ in their pattern of inheritance. State any two differences.
(a) Name any two copper releasing intra-uterine devices. State two reasons that make them effective contraceptives.
(b) Name any two outbreeding devices that flowering plants have developed and explain how they help in encouraging cross-pollination.
Assertion (A): Loss of biodiversity can occur due to overexploitation of resources.
Reason (R): Introduction of Clarias gariepinus in Indian rivers has led to a decline in native Indian fishes.
Assertion (A): Specific enzymes are used to degrade the cell wall in organisms to isolate the DNA from the cell.
Reason (R): Fungal cell wall is degraded by the enzyme cellulase.
Assertion (A): Virus-infected cells produce interferons.
Reason (R): Interferons can cause inflammation of virus-infected cells.
Assertion (A): RNA is unstable and can mutate at a faster rate.
Reason (R): The presence of 2’-OH group in every nucleotide of RNA makes it labile and easily degradable.
The pyramid of biomass in the sea is generally inverted because in the sea:
Which one of the following is not a feature of plasmids?
Which one of the following pairs is not correctly matched?
The vector for dengue fever is:
A woman with normal vision has a colour blind father. She marries a man with normal vision. The percentage chance of their progeny being colour blind is:
In a ’transcription unit’, the ’terminator’ is located towards the:
In the double helical structure of DNA molecule, the strands are:
A population is in genetic equilibrium/Hardy-Weinberg equilibrium for a gene with 2 alleles (dominant allele is ‘A’ and recessive allele ‘a’). If the frequency of allele ‘A’ is 0.6, then the frequency of genotype ‘Aa’ is:
Which one of the following statements is not true?