Biology - Online Test
Q1. Digestion can be defined as :
Answer : Option C
Explaination / Solution:
Digestion is the breakdown of large insoluble food molecules into small water-soluble food molecules so that they can be absorbed into the watery blood plasma.
In certain organisms, these smaller substances are absorbed through the small intestine into the blood stream.
Q2. Aedesaegypti is a vector for
Answer : Option D
Explaination / Solution:
Dengue fever and yellow fever, both are transmitted to human beings through a mosquito called Aedesaegypti. This mosquito breeds in clean stagnant water and carry the disease causing virus form infected person to healthy person.
Q3. Due to refractory period , a nerve fibre in human body on an average transmits about :
Answer : Option B
Explaination / Solution:
Refractory period is the time taken to nerve become ready to conduct other impulse. Due to this refractory period, a nerve fibre in human body on an average transmits about 1000 impulses per seconds.
Q4. The process of fusion between one large and non-motile female gamete with smaller, motile male gamete is termed as
Answer : Option D
Explaination / Solution:
Fusion between one large, non-motile female gamete and a smaller, motile male gamete is termed as oogamous e.g., Volvox, Fucus.
Q5. The photograph or diagram of metaphasic chromosome arranged in homologous pair according to their length and thickness, position of centromere is called
Answer : Option D
Explaination / Solution:
Idiogram is a diagrammatic or systematized representation of the chromosome complement of an individual, species, or other group of organisms, indicating the number of chromosomes and their lengths, arm length ratio, centromere position, banding pattern.
Q6. In a DNA strand the nucleotides are held together by:
Answer : Option B
Explaination / Solution:
When nucleotides are incorporated into DNA, adjacent nucleotides are linked by a phosphodiester bond: a covalent bond is formed between the 5' phosphate group of one nucleotide and the 3'-OH group of another.
In this manner, each strand of DNA has a “backbone” of phosphate-sugar-phosphate-sugar-phosphate
Q7. Functional and dynamic unit of nature where living and non-living components interact with each-other is
Answer : Option C
Explaination / Solution:
An ecosystem is a dynamic complex of plant, animal and micro-organism communities and the abiotic environment interacting as a functional unit. Ecosystems are not static but dynamic and discontinuous systems with interactions and connections which continually evolve both spatially and temporally. They represent ecological processes and the resources they provide can be expressed in terms of goods and services.
Q8.
PGA as the first fixation product was discovered in photosynthesis of
Answer : Option B
Explaination / Solution:
The pathway of photosynthesis was discovered by Melvin Calvin after experiment on single celled algae. The first stable product of C3 cycle is a three carbon compound called PGA (phosphoglyceric acid).
Q9. Respiration in insects is direct due to exchange of gases
Answer : Option C
Explaination / Solution:
Insects have spiracles on their exoskeletons to allow air to enter the trachea. In insects, the tracheal tubes primarily deliver oxygen directly into the insects' tissues. The spiracles can be opened and closed in an efficient manner to reduce water loss. This is done by contracting closer muscles surrounding the spiracle.
Q10. The best way to obtain bacteria and viruses free plants through tissue culture is
Answer : Option C
Explaination / Solution:
Many important plants contain systemic viruses which substantially reduce their potential yield and quality. It is, therefore, important to produce virus free stocks which can be multiplied. Generally, highly meristematic tissue of a virus infected plant remains free from virus due to their fast mitotic activity. Therefore, shoot tips and meristems of a virus infected plant are the ideal explants to produce a virus free stock.
