Biology - Online Test
Q1. In biochemical genetics the term gene is being replaced by
Answer : Option B
Explaination / Solution:
In biochemical genetics the term gene is being replaced by cistron. Cistron is a segment of DNA consisting of a stretch of deoxyribonucleotides which code for a biochemical controlling other cistron.
Q2. The gaseous hormone that help in switching over its respiratory and circulatory system just after delivery is
Answer : Option D
Explaination / Solution:
The gaseous hormone that help in switching over its respiratory and circulatory system just after delivery is Nitroc Oxide (NO).
Q3. Select the two correct statements out of the four (a–d) given below about lac operon.
(a) Glucose or galactose may bind with the repressor and inactivate it
(b) In the absence of lactose the repressor binds with the operator region
(c) The z-gene codes for permease
(d) This was elucidated by Francois Jacob and Jacque Mono.
The correct statements are
(a) Glucose or galactose may bind with the repressor and inactivate it
(b) In the absence of lactose the repressor binds with the operator region
(c) The z-gene codes for permease
(d) This was elucidated by Francois Jacob and Jacque Mono.
The correct statements are
Answer : Option B
Explaination / Solution:
In lac operon, Francois Jacob and Jacque Mono elucidated that in absence of lactose the repressor binds with the operator gene and forms the particular protein to express itself.
Q4. Parturition is induced by complex
Answer : Option D
Explaination / Solution:
Parturition is induced by a complex neuroendocrine mechanism. Fully developed foetus triggers signal from uterus to release oxytocin hormone from pituitary hormones.
Q5. E. coli cells with a mutated z gene of the lac operon cannot grow in medium containing only lactose as the source of energy because
Answer : Option B
Explaination / Solution:
Bacterium E.coli with a mutated z gene of the lac operon cannot grow in medium containing only lactose as the source of energy because E.coli cannot synthesize functional beta galactosidase essential for cell wall formation.
Q6. The mammary glands of female starts producing milk
Answer : Option B
Explaination / Solution:
Memory gland of female undergo differentiation during the pregnancy and start producing milk towards the end of pregnancy by the process of lactation.
Q7. H-bonds between Cytosine and Guanine are
Answer : Option A
Explaination / Solution:
In DNA molecules nitrogenous base of complementary strands binds with hydrogen bonds. In cytosine and guanine there are 3 hydrogen bonds and in adenine and thymine, the number of hydrogen bond is 2.
Q8. Monozygotic twins are produced when
Answer : Option A
Explaination / Solution:
Monozygotic twins are produced when first cleavage of zygote is followed by separation into two parts that develops independently into two babies.
Q9. Transcription of DNA into mRNA occurs in the nucleus of the cell but translation occurs in
Answer : Option D
Explaination / Solution:
Transcription is the process of copying DNA code into mRNA. It occurs in the nucleus of the cell. The mRNA comes out of nucleus then its translation occurs into cytoplasm to form protein.
Q10. Human embryo is about an inch in length after
Answer : Option D
Explaination / Solution:
Human embryo is about one inch in length after eight weeks. The heart is formed first after one month of pregnancy.
