CBSE 12TH BIOLOGY - Online Test
Q1. Which of the following is not a radioactive isotope
Answer : Option B
Explaination / Solution:
Lead 207 Metal (Lead-207) is a stable (non-radioactive) isotope of Lead. It is both naturally occurring and a produced by fission.
Lead 207 Metal is one of over 250 stable Metallic isotopes produced by American Elements for biological and biomedical labeling, as target materials and other applications.
Lead Metal 207 additionally has special application in isotope dilution to measure lead levels in blood
Q2. Rop genes in pBR322 codes for
Answer : Option A
Explaination / Solution:
The plasmid pBR322 contains a Rop gene coding for the Rop protein, which promotes conversion of the unstable RNA I – RNA II complex to a stable complex.
Rop genes in pBR322 codes for protein involved in replication of plasmid. Plasmid are able to take the foreign gene and to be transferred to target cells.
Q3. The diagram represents Miller experiment. Choose the correct combination of labeling.
Answer : Option D
Explaination / Solution:
In Urey and Miller experiment the set up labeled as A – electrodes, B – (NH3 + H2 + H2O + CH4), C – cold water, D – Vacuum, E – U Trap.
Q4. More complex organism cannot give rise to new individuals through regeneration because
Answer : Option A
Explaination / Solution:
Complex multicellular organisms have division of labour and tissues are specialized to perform specific function. In regeneration, new individual regains the lost body parts but higher organism cells are not capable to produce all kind of cells.
Q5. The individual transitional communities to inhabit an area are commonly called as:
Answer : Option C
Explaination / Solution:
A seral community (or sere) is an intermediate stage found in ecological succession in an ecosystem advancing towards its climax community. In many cases more than one seral stage evolves until climax conditions are attained. seral communities leads to climax communities.
Q6. How many documented varieties of Basmati rice are grown in India?
Answer : Option C
Explaination / Solution:
Basmati rice is distinct for its unique aroma and flavour and 27 documented varieties of Basmati are grown in India.
India grows 650.000 tonnes of Basmati annually.
Q7. Which period of menstrual cycle is called risky period of conception?
Answer : Option B
Explaination / Solution:
10th to 17th day of menstrual cycle is called risky period of conception as during which ovulation takes. If sexual intercourse occurs during this period, there is a very high chance of fertilisation that may leads to pregnancy.
Q8. The coconut water from tender coconut is nothing but
Answer : Option B
Explaination / Solution:
The coconut water from tender coconut is nothing but free nuclear endosperm made up of thousands of nuclei. The surrounding white kernel is the cellular endosperm.
Q9. Which statement explains amensalism?
Answer : Option A
Explaination / Solution:
One type of relationship that has been classified by biologists and ecologists is amensalism.
Amensalism is any relationship between organisms of different species in which one organism is inhibited or destroyed while the other organism remains unaffected.
Q10. Cirrhosis of liver is caused by the chronic intake of
Answer : Option B
Explaination / Solution:
Cirrhosis of liver is caused by the chronic intake of alcohol. Regular consumption of alcohol damages the liver cells. Cirrhosis of liver is a serious condition when normal liver tissue is replaced by scar tissue.
