Biology - Online Test
Q1. The organism that completely lack a cell wall and are smallest living cell know, can survive without oxygen is
Answer : Option D
Explaination / Solution:
Mycoplasmas are group of organism that lack cell wall and are smallest living organisms. They can survive without oxygen. Mycoplasmas are also called as PPLO (pleuro pneumonia like organism).
Q2. Removal of introns and joining of exons in a defined order during transcription is called
Answer : Option C
Explaination / Solution:
The mRNA produced by transcription of DNA consists of exons and introns. The removal of introns and joining of exons to obtain mature mRNA is called splicing. It is followed by capping and tailing.
Q3. Which of the following control the function of Sertoli cell?
Answer : Option A
Explaination / Solution:
FSH (follicle stimulating hormone) stimulates Sertoli cells to secrete spermatogenic substance. Sertoli cells function as nurse cells for differentiating spermatozoa.
Q4. Shifting cultivation practiced in India is called
Answer : Option B
Explaination / Solution:
Shifting cultivation practiced in India is called jhum cultivation in which forest is cleaned for agriculture practice and after few years this area is abandoned and another forest land is cleared.
Q5. In animal cells, Cytokinesis takes place by furrow deepening centripetally and formation of two daughter cells. This method is known as
Answer : Option D
Explaination / Solution:
In animal cell, cytokinesis takes place by furrow which appears at the margins of plasma membrane and gradually deepens towards the central part of the cell. Ultimately the furrow divides the cell into two halves. This method of cytokinesis is known as cleavage cytokinesis.
Q6. Genetic drift is found in
Answer : Option B
Explaination / Solution:
Genetic drift is found in small population with or without mutated genes. Loss of some member of species having small population leads to decrease in variation called genetic drift.
Q7. Plant and animal specimens may also be preserved as dry specimens in
Answer : Option A
Explaination / Solution:
Plant and animal specimens may also be preserved as dry specimens in museums. Hence, the correct option is Museum.
Q8. Natural method of birth control in which the couples avoid from coitus from day 10 to 17 of menstrual cycle is called
Answer : Option C
Explaination / Solution:
periodic abstinence is a natural method of birth control in which the couples avoid from sexual intercourse form day 10 to 17 of menstrual cycle during which ovulation takes place in female.
Q9. Blood plasma contains ----------------- % water.
Answer : Option B
Explaination / Solution:
Blood consists of blood plasma, formed cells ( RBC, WBC, Platelets) along with sugar, proteins etc. Blood plasma contains about 90% water with a number of salts and few circulating hormones.
Q10. What does "lac" refer to in what we call the lac operon?
Answer : Option D
Explaination / Solution:
The lac operon (lactose operon) is an operon required for the transport and metabolism of lactose in Escherichia coli and many other enteric bacteria. Although glucose is the preferred carbon source for most bacteria, the lac operon allows for the effective digestion of lactose when glucose is not available.
