To Access the full content, Please Purchase
Why is banana considered a good example of parthenocarpy?Marks:1
Parthenocarpic fruits are either seedless or contain non-viable seeds as in banana fruits. Hence, banana is considered a good example of parthenocarpy.
State two different roles of spleen in the human body.Marks:1
Two different roles of spleen in the human body are:
i) Mechanical filtration of blood as it contains lymphocytes and phagocytes.ii) Acts as a large reservoir of erythrocytes (RBCs)
A garden pea plant produced axial white flowers. Another of the same species produced terminal violet flowers. Identify the dominant traits.Marks:1
The trait with respect production of axial white flowers is dominant over the trait responsible for production of terminal violet flowers.
Why is it desirable to use unleaded petrol in vehicles fitted with catalytic converters?Marks:1
Vehicles fitted with catalytic converters should use unleaded petrol because lead in the petrol inactivates the metal catalyst present in the converter.
Where is acrosome present in humans? Write its function.Marks:1
Acrosome is a cap-like structure present in the anterior part of sperm head. It contains the enzyme hyaluronidase, which hydrolyses the outer egg membrane and thus it facilitates penetration of the egg at the time of fertilisation.
Write the name of the following:
(a) The most common species of bees suitable for apiculture
(b) An improved breed of chickenMarks:1
(a) Apis indica is the most common species of bee suitable for apiculture.
(b) Leghorn or Minorca are the improved breeds of chicken
Comment on the similarity between the wing of a cockroach and the wing of a bird. What do you infer from the above with reference to evolution?Marks:1
Wing of a cockroach and wing of a bird are analogous organs as their origin is not the same but they perform similar functions. From the above example one can infer the evolutionary relationship between organisms.
Mention the role of cyanobacteria as a biofertiliser.Marks:1
Cyanobacteria such as Anabaena and Nostoc, fix atmospheric nitrogen. They serve as important bio-fertilisers especially in paddy fields.
(a) Draw a neat labelled diagram of a nucleosome.
(b) Mention what enables histones to acquire a positive charge.Marks:2
(a) Diagram of a nucleosome
(b) Histones are positively charged because they are rich in the basic amino acid residues lysine and arginine. These amino acids carry positive charges in their side chains.
State one advantage and one disadvantage of cleistogamy.Marks:2
Flowers which do not open at all are called cleistogamous flowers.
Advantage of cleistogamy:
Produce seed-set even in the absence of pollinators and thus cleistogamous plant can propagate itself even in the absence of pollinating agents.
Disadvantage of cleistogamy:Undergo self pollination which reduces the chances of variation and evolution of genetically superior progeny.