List of top Biology Questions

E.coli cells with a mutated Z gene of the lac operon cannot grow in medium containing only lactose as the source of energy because :
For retting of jute the fermenting microbe used is
Which one of the following depresses brain activity and produces feelings of calmness, relaxation and drowsiness.
AIDS is caused by HIV that principally infects:
G-6-P dehydrogenase deficiency is associated with haemolysis of
The most biodiversity rich zone in India
Which one of the following phenomena supports Darwin's concept of natural selection in organic evolution ?
A micro-organism, when viewed under a compound microscope with an objective lens of 40 X and an eye piece of 10 X magnification measured 4000 � in length. The same microorganism when observed under a dissection microscope with a lens of 10 X magnification, would measure........
A nucleosome is a portion of the chromonema containing_______
How many times a red blood corpuscle will have to pass through the heart in its journey from hepatic artery to the aorta ?
Osmoregulation in Paramecium is a function of
Which one of the following is not a characteristic feature of bryophytes ?
Which one of the following types of silk is being produced extensively in South India?
The macronutrient which is an essential component of all organic compounds, yet not obtained by plants from soil is
How many human teeth appear twice during the life span of an individual ?
The following diagram indicates the reflex arc. Identify the parts labelled as A,B,C,D,E,F and G. Choose the correct option
If a germ cell in a female gonad and a germ cell in a male gonad begin undergoing meiosis simultaneously, what will be the ratio of ova and sperms produced ?
An important step in the manufacture of pulp for paper industry from the woody tissues of plants is the :
A man and a woman, who do not show any apparent signs of a certain inherited disease, have seven children (2 daughters and 5sons).Three of the sons suffer from the given disease but none of the daughters are affected. Which of the following mode of inheritance do you suggest for this disease?
In order to find out the different types of gametes produced by a pea plant having the genotype AaBb, it should be crossed to a plant with the genotype
A woman with 47 chromosomes due to three copies of chromosome 21 is characterized by:
Genes for cytoplasmic male sterility in plants are generally located in
More than 70% of world's freshwater is contained in
Which of the following pairs is correctly matched ?
An acromion process is characteristically found in the :