CBSE 12TH BIOLOGY - Online Test
Q1. Which of the following is not a use of transgenic animals?
Answer : Option D
Explaination / Solution:
Transgenic animals are developed to study normal physiology and development, vaccine testing, chemical safety testing, obtaining biological product etc. These animals are not used to study viral disease.
Q2.
Assertion: There is a statutory ban amniocentesis on sex determination in India.
Reason: Amniocentesis is used to determine sex of foetus for female foeticide.
Answer : Option C
Explaination / Solution:
The statutory ban on amniocentesis for sex determination is due to increasing female foeticide after knowing the sex of baby using the chromosomal pattern of amniotic fluid surrounding the foetus.
Q3. The meiocyte of an onion plant contains 32 chromosomes. Calculate the number of chromosomes found in its endosperm
Answer : Option C
Explaination / Solution:
The meiocyte cell are diploid so, haploid cell will contain 16 chromosomes. The endosperm cell are formed by fusion of two polar nuclei and one male gametes so, endosperm cells are triploid that will contain 16x3= 48 chromosomes.
Q4. Species facing competition might evolve mechanism that promotes co-existence rather than exclusion and that mechanism can be
Answer : Option B
Explaination / Solution:
Species facing completion might evolve mechanism that promotes co-existence rather than exclusion that mechanism is called resource partitioning. In which they avoid completion by choosing different times of feeding or different foraging patterns
Q5. The virus that causes AIDS is
Answer : Option B
Explaination / Solution:
Lymphadenopathy-associated virus (LAV) A former name for HIV is the virus that causes AIDS. It is membrane of lymph nodes. Lymph node get affected and destroy the defense mechanism of human body.
Q6. Amino acid + ATP →Aminoacyl-AMP + P–P , depicts
Answer : Option A
Explaination / Solution:
Amino acid activation refers to the attachment of an amino acid to its Transfer RNA (tRNA).
Aminoacyl transferase binds Adenosine triphosphate (ATP) to amino acid, PP is released. Aminoacyl transferase binds AMP-amino acid to tRNA. Activated amino acids combine with t-RNA.
Q7. The thousands of plants obtained through micro-propagation called soma clones because
Answer : Option C
Explaination / Solution:
The method of producing thousands of plants through tissue culture is called micro-propagation. All these plants will be genetically identical to original plant from which they are grown.
Q8. A category containing those species whose members survive only in captivity or as artificially supported populations far outside their historical geographic range is grouped under:
Answer : Option A
Explaination / Solution:
A taxon known only to survive in cultivation, in captivity or as a naturalized population (or populations) well outside the past range. A taxon is presumed Extinct in the Wild when exhaustive surveys in known and/or expected habitat, at appropriate times (diurnal, seasonal, annual), throughout its historic range have failed to record an individual. Surveys should be over a time frame appropriate to the taxon’s life cycle and life form.
Q9. Lyding cells synthesize and secretes testicular hormone called
Answer : Option B
Explaination / Solution:
Lyding cells synthesize and secrete testicular hormones called androgens. Androgens help in development of secondary sexual characters.
Q10. The phenomenon of having more than two sets of chromosome is called
Answer : Option A
Explaination / Solution:
Polyploidy is the phenomenon of having more than two genomes or sets of chromosomes in the nucleus of cell of an organism. It may be triploid, tetraploid etc. polyploidy with odd number of genomes are sexually sterile.
