CBSE 12TH BIOLOGY - Online Test
Q1. Brief exposure of cells to an electric field also allow the bacteria to take up DNA and this process is called as
Answer : Option B
Explaination / Solution:
Electroporation, or electropermeabilization, is a microbiology technique in which an electrical field is applied to cells in order to increase the permeability of the cell membrane, allowing chemicals, drugs, or DNA to be introduced into the cell.
Q2. Fossils are most commonly preserved in
Answer : Option B
Explaination / Solution:
Fossils are dead remains of plants and animals buried inside the earth crust millions of year ago. Fossils are commonly preserved in sedimentary rock as this kinds of rocks are formed layer by layer in course of time.
Q3. A binomial nomenclature has _________________ words.
Answer : Option D
Explaination / Solution:
The first word in a biological name represents the genus while the second component denotes the specific epithet. Hence, the correct option is Two.
Q4. Bt toxin is coded by which gene?
Answer : Option D
Explaination / Solution:
The Bt toxin is encoded by the cry gene. The cry I AC and cry II Ab control cotton boll worms, while the cry I Ab controls corn borer. Bt gene produces Bt toxin. This toxin provides resistance to plants against lepidopteron, coleopteron and dipterans pests.
Q5. In ET technique embryo is transferred into
Answer : Option B
Explaination / Solution:
In ET (embryo transfer) technique, in vitro fertilized embryo is transferred into fallopian tube or uterus for further development.
Q6. Which of the following statements is/are incorrect:
Answer : Option B
Explaination / Solution:
Inside the human intestine a number of microbes lives that helps in digestion of food and formation of vitaminK. so, human intestine is also an unique habitat.
Q7. Hemozoin is released into blood during the infection of Plasmodium vivax every
Answer : Option C
Explaination / Solution:
Plasmodium vivax protozoa cause malaria in human beings having high fever and chill effect at the regular interval of time. Hemozoin is released in blood stream by plasmodium that cause high fever at the interval of 48 hours.
Q8. DNA is made of two chains that twist about one another in the shape of a
Answer : Option C
Explaination / Solution:
Double helix is the description of the structure of a DNA molecule. A DNA molecule consists of two strands that wind around each other like a twisted ladder. Each strand has a backbone made of alternating groups of sugar (deoxyribose) and phosphate groups.
Q9. Term ecosystem was introduced by :
Answer : Option A
Explaination / Solution:
The term "ecosystem" was first used in 1935 in a publication by British ecologist Arthur Tansley.
Tansley devised the concept to draw attention to the importance of transfers of materials between organisms and their environment.
Ecosystem is the functional unit of nature where living and non-living components interact with each other.
Q10. Picking up plants with superior phenotype for further propagation is
Answer : Option A
Explaination / Solution:
Mass selection is a simplest , common and oldest method of crop improvement, in which large number of plants of similar superior phenotype are selected and their seeds are harvested and mixed together to constitute the new variety.
