CBSE 12TH BIOLOGY - Online Test
Q1. Plasmid used to produce humulin is
Answer : Option B
Explaination / Solution:
Plasmid are extra nuclear genetic materials present in bacterial humulin is produced by using plasmid Pbr322. It is an E.coli plasmid vector containing the origin of replication.
Q2. Cutting and tiding of fallopian tube to avoid pregnancy is called
Answer : Option C
Explaination / Solution:
Cutting and tiding of fallopian tube to avoid pregnancy is called tubectomy. It is a surgical method of contraception. This method is used only when no more child is required in future. It can be done only in female.
Q3. Cultivation of hybrids has increased productivity although it is not used extensively
Answer : Option D
Explaination / Solution:
Hybrid seeds are produced to increase the productivity, resistivity and nutritional value of seed and fruit. It is not used extensively as hybrid seeds have to be produced every year so it becomes costly to farmers.
Q4. Temperature is an environmental factor that does not affect
Answer : Option C
Explaination / Solution:
Temperature is an environmental factor that influence the type and number of species in a given habitat. Temperature may change the enzyme kinetics, physiology and geographical distribution of species. Photoperiod is the duration of light that fall on plant and not affected by temperature.
Q5. Which of the following organism produce gemmules as asexual reproductive structure?
Answer : Option B
Explaination / Solution:
Gemmules are asexual reproductive structure produced by sponges. Chlamydomonas produce zoospores, hydra produce buds and Penicillium produces conidia.
Q6. Protein secreted by virus infected cells is called
Answer : Option B
Explaination / Solution:
Interferons (IFNs) are a group of signaling proteins made and released by host and infected cells in response to the presence of several pathogens, such as viruses, bacteria, parasites, and also tumor cells. which protect non- cancerous cells from infection.
Q7. Repressor proteins are coded by ______ genes.
Answer : Option D
Explaination / Solution:
Regulator genes codes for repressor proteins during translation of DNA into protein via mRNA.
Q8. Bread wheat is
Answer : Option B
Explaination / Solution:
Polyploidy is a condition in which multiple sets of chromosome is present in same cell in place of usual two sets (diploid). Bread wheat is generally hexaploid.
Q9. Match the following:
Ecologist
a) Edward Wilson
b) Paul Ehlrich
c) A.V.Humboldt
d) Robert May
Contribution
i) estimated global species diversity
ii) term biodiversity
iii) Rivet Popper Hypothesis
iv) relation b/w species richness & explored area
Ecologist
a) Edward Wilson
b) Paul Ehlrich
c) A.V.Humboldt
d) Robert May
Contribution
i) estimated global species diversity
ii) term biodiversity
iii) Rivet Popper Hypothesis
iv) relation b/w species richness & explored area
Answer : Option A
Explaination / Solution:
Edward Wilson coined the term biodiversity. Paul Ehlrich proposed Rivet Popper Hypothesis. A.V. Humboldt shows relation between species richness and explored area. Robert May estimated global species diversity.
Q10. Conversion of spematid into a spermatozoan is called
Answer : Option B
Explaination / Solution:
Each spermatid undergoes metamorphosis to develop into spermatozoa or sperms having head, neck and tail. Acrosome is present at the tip of head that contain enzyme for hydrolysis of wall of ovum during fertilisation.
