Biology - Online Test
Q1. What is the main excretory organ in insects?
Answer : Option B
Explaination / Solution:
The insects belong to phylum Arthropoda and hence, the excretory organ is Malphighian tubules.
Q2. What is the number of sperms released in vagina in single insemination?
Answer : Option B
Explaination / Solution:
In single insemination during coitus about 200-300 millions of sperms are released in the vagina of female. About 60% of them must have normal shape and size along with vigorous motility for fertilisation of ovum.
Q3. Liverworts are closely related to
Answer : Option D
Explaination / Solution:
The bryophytes are divided into liverworts and mosses so they closely related to each other.
Q4. Length of DNA with 23 base pairs is
Answer : Option C
Explaination / Solution:
The distance between two base pairs in DNA is 3.4 . The length of DNA with 23 base pairs is 23x 3.4 = 78.2 .
Q5. Two genes R and Y are located very close on the chromosomal linkage map of maize plant. When RRYY and rryy genotypes are hybridized, the F2 segregation will show:
Answer : Option B
Explaination / Solution:
Two genes located very close on the chromosomal linkage map. Segregation of R and Y will not takes place due to linkage and passes to same gamete together but overall segregation can be expected as usual as dihybrid cross, 9:3:3:1.
Q6. Semi-conservative replication of DNA was first demonstrated in
Answer : Option A
Explaination / Solution:
Semi-conservative replication of DNA was first demonstrated in bacterium Escherichia coli as it contain single chromosome within the cell without nuclear membrane.
Q7. Which of the following is a not a green house gas
Answer : Option D
Explaination / Solution:
Green house gas is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range. This process is the fundamental cause of the greenhouse effect.
Many greenhouse gases occur naturally in the atmosphere, such as carbon dioxide, methane, water vapor, and nitrous oxide, while others are synthetic. Those that are man-made include the chlorofluorocarbons (CFCs), hydrofluorocarbons (HFCs) and Perfluorocarbons (PFCs), as well as sulfur hexafluoride (SF6). Oxygen is not a green house gas.
Q8. Dough kept overnight in warm place becomes soft and spongy due to
Answer : Option C
Explaination / Solution:
Fermentation is a kind of anaerobic respiration in absence of oxygen to produce ethanol and carbon dioxide gas. Dough kept overnight in warm place becomes soft and spongy due to carbon dioxide gas released during fermentation.
Q9. Cell growth results in disturbing the ratio between
Answer : Option B
Explaination / Solution:
Cell growth results in disturbing the ratio between the nucleus and the cytoplasm. It therefore becomes essential for the cell to divide to restore the nucleo-cytoplasmic ratio. Cell becomes stable when N/C ratio is 1.
Q10. PCR was discovered by
Answer : Option D
Explaination / Solution:
Polymerase chain reaction (PCR) was discovered by Kary Mullis. PCR technique is used to amplify the DNA segments to obtain large number of identical copies.
