List of top Biology Questions

Large scale industrial production of citric acid for human welfare is done using the microbe:
Which enzyme(s) will be produced in a bacterial cell in which ‘UAG’ is inserted in the ‘lac-y gene’ due to mutation? Choose the correct option:
Assertion (A): To generate only a part of the plant from a cell is totipotency.
Reason (R): Suitable special nutrient media and sterile conditions are required in ‘in vitro’ conditions for the division of cells in explants.
Assertion (A): Lymphocytes arise from the bone marrow and present in the blood and lymph serve as natural killer cells.
Reason (R): Lymphocytes migrate to thymus, where they develop into T-cells and begin to mature.

Match the terms in Column-I with their description in Column-II and choose the correct option.

In the pedigree chart given below, what should be the genotype of the indicated member?

Unisexuality of flowers prevents which process?
The lobed organ located near the heart and beneath the breast bone in humans is:
Isolation of DNA from a bacterial cell can be achieved by using:
The approach of sequencing the whole set of genome, including all the coding and non-coding sequences in HGP is:
The region of chromatin that are actively transcribed are thought to be:

Student to attempt either option (A) or (B):
(A) 
(i) Draw a diagrammatic sectional view of human seminiferous tubule (enlarged) and label the following: 
(a) Cell that undergoes spermiogenesis 
(b) Cell that nourish male gametes 
(c) Cell which undergoes meiosis I and meiosis II. 
(ii) State what is seminal plasma. Mention two constituents of seminal plasma. How is it different from semen? 
OR 
(B) 
(i) Mention the event that induces the completion of the meiotic division of the secondary oocyte in humans. 
(ii) Trace the journey of the zygote until its implantation inside the uterus.

How does the process of Natural Selection affect Hardy-Weinberg equilibrium? Explain with the help of graphs.
(a) Write two closely linked genes that control \(\alpha\)-thalassemia.
(b) Differentiate between thalassemia and sickle cell anaemia on the basis of their effect on globin molecule of Haemoglobin.
Assertion (A): A patient of ADA-deficiency requires periodic or repeated infusion of genetically-engineered lymphocytes.
Reason (R): Lymphocytes are not immortal, but have life span.

Student to attempt either option (A) or (B):
 
(i) Identify ‘P’ and ‘Q’ labelled in the diagram. 
(ii) Specify the source of the hormone ‘P’ and ‘Q’ marked in the diagram. 
OR  
(i) Identify ‘P’ and ‘Q’ labelled in the above diagram. 
(ii) Write down the role of hormone ‘P’ in both males and females.

Student to attempt either option (A) or (B):
(A) Construct a pyramid of biomass starting with phytoplankton, label its three trophic levels. Is the pyramid upright or inverted? Justify your answer. 
OR 
(B) Draw a pyramid of number where a large population of insects feed upon a very big tree. The insects in turn, are eaten by small birds which in turn are fed upon by big birds.

(a) Abbreviations used for the different modes of assisted reproductive technology are given below. Expand the abbreviations:
(i) ZIFT (ii) ICSI (iii) IUT (iv) GIFT
(b) Why is there a statutory ban on Amniocentesis? Give at least two reasons.
During gel electrophoresis migration of DNA fragments leading to their separation takes place on the agarose gel. Choose the correct option:
Identify the organism whose product has been commercialised as blood cholesterol lowering agent.
Assertion (A): XX – XY type of sex-determination mechanism is an example of male heterogamety.
Reason (R): In birds male heterogamety is observed as males produce two different types of gametes.
Assertion (A): Secondary immune response is quicker and stronger than the primary immune response.
Reason (R): Our body appears to have the memory of the first encounter therefore response to the subsequent encounter with the same pathogen is quick.
A diploid organism is heterozygous for three loci, how many types of gametes can be produced by that organism?
The foetus receives some antibodies from their mother through the placenta during pregnancy. Choose the correct option that shows the type of immunity developed in the foetus.

The process of copying the genetic information from one strand of DNA into RNA is termed as transcription. The principle of complementarity of bases governs the process of transcription, also except that uracil comes in place of thymine.
Study the complete transcription unit given below and answer the following questions: 

(a) Name the main enzyme involved in the process of transcription. 
(b) Identify coding strand and template strand of DNA in the transcription unit. 
Attempt either sub-part (c) or (d): 
(c) Identify (C) and (D) in the diagram, mention their significance in the process of transcription. 
OR 
(d) Describe the location of (C) and (D) in the transcription unit.}