CBSE 12TH BIOLOGY - Online Test
Q1. There is no DNA in
Answer : Option D
Explaination / Solution:
Because of the lack of nuclei and organelles, mature red blood cells do not contain DNA and cannot synthesize any RNA, and consequently cannot divide and have limited repair capabilities. The inability to carry out protein synthesis means that no virus can evolve to target mammalian red blood cells.
Q2. Which of the following can be categorised as a photoautotroph ?
Answer : Option D
Explaination / Solution:
Photoautotrophs are organism that perform photosynthesis in presence of sunlight. Euglena contains chlorophyll and fixes the solar energy so, it acts as photoautotrophs.
Q3. Taichung Native-1”, a rice variety was introduced in India from
Answer : Option D
Explaination / Solution:
Taichung Native-1 is a rice variety introduced in India from Taiwan. This variety of rice is medium sized having long inflorescence. The maturity period is also shorter than usual varieties of rice.
Q4. When we compare the relationship between species richness and area for wide variety of taxa, the graph appears to be a :
Answer : Option A
Explaination / Solution:
Explanation:
- Alexander Von Humboldt has observed that within a region, species richness gets increased when explored area is increased, but only up to a limit.
- The relationship between species richness and area for a number of taxa like angiospermic plants, fresh water fishes and birds is found to be a rectangular hyperbola.
The equation is described by –
log S = log C + Z log A
S – Species Richness
Z – Slope of the line (regression coefficient)
A – Area
C – y-intercept
Q5. Which of the following plant contain unisexual flower
Answer : Option A
Explaination / Solution:
The flower which contains either male or female reproductive part is called unisexual flower. Papaya plant produce either male or female flower in separate plants.
Q6. Head of epididymis is called as
Answer : Option D
Explaination / Solution:
Epididymis is a long narrow coiled tube attached to the surface of the testis in mammals and reptiles. It acts as temporary storage organ of spermatozoa received from seminiferous tubules. The head of it is called caput epididymis.
Q7. Who is regarded as the father of genetics?
Answer : Option A
Explaination / Solution:
Mendel is regarded as the father of genetics due to his initial law of inheritance given by him on the basis of Hybridisation conducted by him on garden pea.
Q8. Which of the following bacterium produces butyric acid?
Answer : Option A
Explaination / Solution:
Clostridium butylicum is used to produce butyric acid. Butyric acid is important industrial chemicals used to process food items.
Q9. In normal adults, the enzyme which catalyses conversion of MHb into Hb is :
Answer : Option C
Explaination / Solution:
Methemoglobin cannot bind oxygen, unlike oxyhemoglobin. It is bluish chocolate-brown in color.
In human blood a trace amount of methemoglobin is normally produced spontaneously, but when present in excess the blood becomes abnormally dark bluish brown.
The NADH-dependent enzyme methemoglobin reductase (MHbreductase enzyme) is responsible for converting methemoglobin back to hemoglobin. . MHb is inactive forms that is converted into Hb that carries oxygen in blood.
Q10. Largest bird is
Answer : Option C
Explaination / Solution:
Ostrich is a large sized bird. It is not able to fly long distance. The egg of ostrich is considered largest cell which is about one meter in diameter.
