Biology - Online Test
Q1. Crossing over occurs in
Answer : Option D
Explaination / Solution:
Crossing over occurs in pachytene sub-stage of prophase of meiosis I. During which exchange of genetic materials takes place between homologous chromosomes.
Q2. Molecular scissors are
Answer : Option A
Explaination / Solution:
Restriction enzymes are also called 'molecular scissors' as they cleave DNA at or near specific recognition sequences known as restriction sites. These enzymes make one incision on each of the two strands of DNA and are also called restriction endonucleases.
Q3.
Read the following for hemodialysis :
i. Blood of patient is pumped from vein into cellophane tube which is suspended within dialysing solution.
ii. Dialysing solution is of the same composition as blood plasma but no urea.
iii. The risk of formation of blood clots is associated with artificial kidney.
iv. Blood is therefore mixed with anti-heparin to prevent clot formation.
Answer : Option B
Explaination / Solution:
During hemodialysis, blood from patient if pumped out from vein and passes through dialysis having dialyzing solution having same composition as blood plasma without urea. Anti heparin is added to blood to prevent clotting of blood.
Q4. Selective breeding of organisms (Animal husbandry and plant breeding programs) for specific desirable characteristics are examples of
Answer : Option C
Explaination / Solution:
In animal husbandry and plant breeding, specific desirable characteristics are obtained by selective breeding. The plants or animals having specific traits are crossed to obtain required traits. It is a kind of artificial selection.
Q5. “SystemaNaturae” is a book written by
Answer : Option A
Explaination / Solution:
‘SystemaNaturae’is a book written by Carolus Linneaus. This books gives in depth details of classification system and binomial nomenclature of organisms.
Q6. Upper surface of leaf is
Answer : Option C
Explaination / Solution:
Epidermal cells are present on both side of leaves. The lower side contain more stomata. The upper surface of leaf is called as adaxial epidermis.
Q7. The ovary belonging to a single free carpel is called
Answer : Option C
Explaination / Solution:
When more than one carpel is present, they may be free, it is called apocarpous
Q8. The most commonly used compound as a source of ethylene
Answer : Option B
Explaination / Solution:
The most widely used compound as source of ethylene is ethephon. Ethephon in an aqueous solution is readily absorbed and transported within the plant and releases ethylene slowly.
Q9. Among desert plants, which of the following will become a limiting for primary production
Answer : Option B
Explaination / Solution:
Primary productivity is of plants depends upon availability of water, sunlight, chlorophyll, carbon dioxide etc. but in desert plants water is the main limiting factor as very less amount of water is available to plants in deserts.
Q10. Myasthenia gravis leads to fatigue and weakness. It is not :
Answer : Option B
Explaination / Solution:
Myasthenia gravis is an auto immune disorder affecting neuromuscular junction leading to fatigue, weakening and paralysis of skeletal muscle.
