CBSE 12TH BIOLOGY - Online Test
Q1. A metastatic cancerous tissue is termed ‘sarcoma’ if the disorder is in
Answer : Option B
Explaination / Solution:
A metastatic cancerous tissue is called sarcoma if the disorder is in fibroblast. The property of cancerous cells to reach from one part of the body to other through blood is called metastasis.
Q2. Okazaki is known for his contribution to the understanding of
Answer : Option C
Explaination / Solution:
Reiji Okazaki (October 8, 1930 – August 1, 1975) was a pioneer Japanese molecular biologist, known for his research on DNA replication and especially for describing the role of Okazaki fragments along with his wife Tsuneko.
He proposed the concept of semi-conservative nature of replication of DNA molecules.
Q3. Which of the following algae can be used as single cell protein?
Answer : Option B
Explaination / Solution:
Spirulina is single celled algae that can be easily grown in starch containing medium life waste water from potato processing plants. It contains high quantity of protein that can be easily used by human beings.
Q4. Interpret from the following graph :
Answer : Option D
Explaination / Solution:
Extinction rates are unaffected due to immigration near island and immigration far island. Extinction rate is affected by human interference.
Q5. Interstitial cells or leydig cells are present between
Answer : Option B
Explaination / Solution:
Leydig cells or interstitial cells are present between seminiferous tubules. Leydig cells secrete testosterone and other androgens hormones in human males.
Q6. Chromosome theory of XY sex determination was proposed by
Answer : Option A
Explaination / Solution:
Nettie Stevens and Edmund Beecher Wilson independently discovered the chromosomal XY sex-determination system (that males have XY and females have XX sex chromosomes).
Wilson made some of the discoveries in his partially correct 1900 paper, while Steven’s 1905 paper filled in the blanks and corrected some of Wilson’s errors.
Stevens and Wilson worked independently of each other in their discovery of the chromosomal basis of sexual differentiation.
Q7. The most important of the symbiotic nitrogen fixing bacteria which forms nodules on the roots of legume plants is
Answer : Option D
Explaination / Solution:
Rhizobium are bacteria that fix nitrogen after becoming established inside root nodules of legumes. In order to express genes for nitrogen fixation, rhizobia require a plant host; they cannot independently fix nitrogen
Rhizobium bacteria is found in the nodule of leguminous plants root. It increases the fertility of soil.
Q8.
There are two types of ozone
i. Good ozone and bad ozone.
ii. Good ozone is present in stratosphere while bad ozone is present in troposphere.
Answer : Option A
Explaination / Solution:
There are two types of ozone, bad ozone and good ozone.
Bad ozone is present in troposphere, it is bad because it is a type of pollution. Ozone and other compounds in car exhaust form smog.
Good ozone is present in stratosphere, it is good because it protect us from harmful UV radiations from the Sun.
Q9. The separation and purification of recombinant protein product is called as
Answer : Option A
Explaination / Solution:
Downstream processing is the separation and purification of recombinant protein product. Downstream processing and quality control testing vary for different products.
Q10. The theory of use and disuse was given by
Answer : Option D
Explaination / Solution:
The theory of use and disuse was given by Lamarck. In his theory of organic evolution he stressed that those traits or organs are used more evolve faster and those are not used degenerate in course of time.
