Biology - Online Test
Q1. S phase marks
Answer : Option D
Explaination / Solution:
S phase marks the phase of DNA replication and chromosome duplication. In this phase increase in the amount of DNA takes place. No synthesis of proteins or RNA takes place.
Q2. In Genetic Engineering, to cut DNA at a specific site, the enzyme used is
Answer : Option C
Explaination / Solution:
In genetic engineering, restriction enzymes (or restriction endonucleases) are used to cut DNA into smaller fragments. The cuts are always made at specific nucleotide sequences. Different restriction enzymes recognise and cut different DNA sequences. These fragments are joined together using another enzyme called ligase.
Q3. Vasa recta is absent or reduced in:
Answer : Option B
Explaination / Solution:
The efferent arteriole emerging from the glomerulus forms a fine capillary network around the renal tubule called the peritubular capillaries.
A minute vessel of this network runs parallel to the Henle’s loop forming a ‘U’ shaped vasa recta. Vasa recta is absent or highly reduced in cortical nephrons.
Q4. Jurassic period of the Mesozoic era characterized by
Answer : Option D
Explaination / Solution:
Jurassic period of Mesozoic era characterized presence of Gymnosperms as dominant plant and first birds evolved from reptiles. Dianasours are also a kind of reptiles.
Q5. Which among the following are elongated or tube like cells with thick and lignified walls and tapering ends?
Answer : Option D
Explaination / Solution:
Tracheids are elongated cells in the xylem of vascular plants that serve in the transport of water and mineral salts. Tracheids are one of two types of tracheary elements, vessel elements being the other.
Q6. Auxanometer is used to measure
Answer : Option D
Explaination / Solution:
An auxanometer (Gr. auxain, "to grow" + metron, "measure") is an apparatus for measuring increase or rate of growth in plants.
In case of an arc-auxanometer (see picture), there is a wire fixed with the plant apex on one end and a dead-weight on the other.
Q7. Sometimes different authors give different names to one and the same species. In such a situation
Answer : Option B
Explaination / Solution:
In MangiferaindicaLinn, the word ‘Linn’ indicates that this species was first described by Linnaeus. Hence, the correct option is The name under which the species was first described is valid name.
Q8. Look at the following figure of myofibrils
figure (1), (2), (3), (4) : showing ?
figure (1), (2), (3), (4) : showing ?
Answer : Option D
Explaination / Solution:
Myofibrils are present in muscles fibers which are parallelly arranged filaments in sarcoplasm. Figure 1 and 2 present relaxed state while figure 3 and 4 represents cross bridge formation.
Q9. Insulin earlier was extracted from
Answer : Option C
Explaination / Solution:
insulin is taken from the pancreases of animals, usually pigs (porcine or pork insulin) and cows (bovine or beef insulin).
The insulin is purified which reduces the chance of the insulin user developing a reaction to the insulin.This insulin caused allergy in diabetic patients.
Q10. Acquired Immuno Deficiency Syndrome is
Answer : Option B
Explaination / Solution:
AIDS is mainly caused due to reduction of Helper-T cells that provide immunity against the different kinds of infection. It is located in WBCs.
