Biology - Online Test
Q1. S-shaped graph produced on plotting growth against time is called
Answer : Option A
Explaination / Solution:
S- Shaped growth curve (Sigmoid growth curve) A pattern of growth in which, in a new environment, the population density of an organism increases slowly initially, in a positive acceleration phase; then increases rapidly approaching an exponential growth rate; but then declines in a negative acceleration phase until at zero growth rate the population stabilizes.
This slowing of the rate of growth reflects increasing environmental resistance which becomes proportionately more important at higher population densities.
This type of population growth is termed ‘density dependent’.
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Q2. In a scientific name, the name of the author is printed in
Answer : Option B
Explaination / Solution:
Name of the author appears after the specific epithet, i.e., at the end of the biological name and is written in an abbreviated form, e.g., MangiferaindicaLinn. It indicates that this species was first described by Linnaeus. Hence, the correct option is Abbreviated.
Q3. Which of the following statements is/are incorrect about sliding filament theory of muscle contraction?
Answer : Option B
Explaination / Solution:
During contraction, the ‘I’ bands get reduced, whereas the ‘A’ bands retain the length.
Q4. Expand RIA
Answer : Option C
Explaination / Solution:
Radioimmunoassay (RIA) is a very sensitive in vitro assay technique used to measure concentrations of antigens (for example, hormone levels in blood) by use of antibodies. As such, it can be seen as the inverse of a radiobinding assay, which quantifies an antibody by use of corresponding antigens
Q5. The maximum growth rate occur in
Answer : Option A
Explaination / Solution:
Maximum growth of individuals occurs during exponential phase of growth. This phase is followed by stationary phase of growth.
Q6. When water moves out of the cell and the cell membrane of a plant cell shrinks away from its cell is called
Answer : Option C
Explaination / Solution:
Plasmolysis is the process of shrinkage or contraction of the protoplasm of a plant cell as a result of loss of water from the cell.
Plasmolysis is one of the results of osmosis and occurs very rarely in nature, but it happens in some extreme conditions.
Q7. The junctions which help to stop substances from leaking across a tissue is
Answer : Option A
Explaination / Solution:
Tight junctions hold cells together. They are narrow belts that circle around the upper part of lateral surfaces of the adjacent epithelial cells to create a fusion point. They stop substances from leaking across a tissue as they prevent passage of molecules and ions through space between adjacent cells.
Q8. Which one is not a characteristic feature of prokaryotes?
Answer : Option D
Explaination / Solution:
Prokaryotic organisms generally do not reproduce by sexual reproduction in favorable conditions. The most common method of reproduction is asexual.
Q9. Read the following :
i. Major pineal hormone is melatonin.
ii. In human beings, melatonin secretion increases in light and decreases in dark.
iii. Abnormally high levels of melatonin in children causes delayed sexual development.
Answer : Option A
Explaination / Solution:
Melatonin is a hormone secreted by the pineal gland in the brain. In helps regulate other hormones and maintains the body circadian rhythm. Abnormally high levels of melatonin is children causes delayed sexual development.
Q10. Match the following:
column I
(i) Migrate
(ii) Suspend
(iii) Regulate
(iv) Conform
Column II
(a) hibernation and aestivation
(b) sweat it out
(c) inability to maintain a constant internal environment
(d) people going from Rajasthan to Kashmir during summer
(i) Migrate
(ii) Suspend
(iii) Regulate
(iv) Conform
Column II
(a) hibernation and aestivation
(b) sweat it out
(c) inability to maintain a constant internal environment
(d) people going from Rajasthan to Kashmir during summer
Answer : Option D
Explaination / Solution:
People going from Rajasthan to Kashmir during summer is a kind of migration. During hibernation and aestivation organism suspends life proceeses to minimum levels. To regulate the body temperature sweating occurs and inability to maintain consistent internal environment is called conformation.
