Biology - Online Test
Q1. The arrows represent :[upward to downward]
Answer : Option C
Explaination / Solution:
The figure shows the muscular sac called the gall bladder. The duct of gall bladder (cystic duct) along with the hepatic duct from the liver forms the common bile duct.
Q2. The primary and secondary immune response are carried out with the help of two special types of lymphocytes present in our blood called
Answer : Option A
Explaination / Solution:
T cells (thymus cells) and B cells (bone marrow- or bursa-derived cells) are the major cellular components of the adaptive immune response. T cells are involved in cell-mediated immunity, whereas B cells are primarily responsible for humoral immunity (relating to antibodies).
Q3. A region on retina of human eye which is free from rods and cones is :
Answer : Option A
Explaination / Solution:
The optic nerves leave the eye and the retinal blood vessels enter it at a point medial to and slightly above the posterior pole of the eye ball. Photoreceptor cells are not present in that region and hence it is called the blind spot.
Q4. Asexual reproduction in liverworts takes place by specialised structures, commonly known as
Answer : Option D
Explaination / Solution:
Asexual reproduction in liverworts takes place by the formation of specialised structures called gemmae (sing. gemma). Gemmae are green, multicellular, asexual buds, which develop in small receptacles called gemma cups located on the thalli. The gemmae become detached from the parent body and germinate to form new individuals.
Q5. Lipid molecules of plasma membrane occur
Answer : Option A
Explaination / Solution:
The lipid molecules occur in chains. In plasma membrane two molecular chains of lipids remain parallel to each other.
Q6. HIV is classified as a retrovirus because its genetic information is carried in
Answer : Option C
Explaination / Solution:
Retrovirus is a type of virus that uses RNA as its genetic material. After infecting a cell, a retrovirus uses an enzyme called reverse transcriptase to convert its RNA into DNA.
The retrovirus then integrates its viral DNA into the DNA of the host cell, which allows the retrovirus to replicate. HIV, the virus that causes AIDS, is a retrovirus.
Q7. The more fundamental type of ecological pyramid showing the quantitative relationships of the standing crops will be
Answer : Option C
Explaination / Solution:
The pyramid of biomass is more fundamental, they represent the quantitative relationships of the standing crops.
In this pyramid there is a gradual decrease in the biomass from the producers to the higher trophic levels. The biomass here the net organisms collected from each feeding level and are then dried and weighed.
This dry weight is the biomass and it represents the amount of energy available in the form of organic matter of the organisms. In this pyramid the net dry weight is plotted to that of the producers, herbivores, carnivores, etc. More the number of crop plants higher the biomass.
Q8. The stroma of chloroplast contains
Answer : Option D
Explaination / Solution:
In stroma, enzymatic reactions incorporate into the plant leading tothe synthesis of sugar, whichare not directly light driven but are dependent on the products of light reactions (ATP and NADPH). Hence, to distinguish the latter they are called, by convention, as dark reactions. However, this should not be construed to mean that they occur in darkness or that they are not lightdependent.
Q9. Air breathing animals lose a large amount of precious water from their respiratory surface through :
Answer : Option C
Explaination / Solution:
Water is released in atmosphere along with expired air during respiratory cycle. Air breathing animals lose a large amount of precious water from their respiratory surface through evaporation.
Q10. "Jaya" and "Ratna" developed for green revolution in India are the varieties of
Answer : Option D
Explaination / Solution:
Jaya and Ratna are varieties of maize developed by Indian council of agricultural research. These varieties are high yielding and resistance to disease.
