Tag: growth and development

Questions Related to growth and development

Growth curve is

biology plant growth growth rates and conditions for growth population ecology growth and development

  1. S-shaped

  2. Sigmoid

  3. L-shaped

  4. Both (A) and (B)

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Correct Option: D
Explanation:

In most systems, the initial growth is slow (lag phase), and it increases rapidly thereafter,  at an exponential rate (log or exponential phase). Here, both the progeny cells following mitotic cell division retain the ability to divide and continue to do so. However, with limited nutrient supply, the growth slows down leading to a stationary phase. If we plot the parameter of growth against time, we get a typical sigmoid or S-curve. A sigmoid curve is a characteristic of living organism growing in a natural environment. It is typical for all cells, tissues and organs of a plant.

Thus, the correct answer is option D.

The usual shape of growth curve is 

biology plant growth growth rates and conditions for growth population ecology growth and development

  1. Linear

  2. Inverted bell shaped

  3. Sigmoidal

  4. Zig-zag

Show answer
Correct Option: C
Explanation:

It is a 'S' shaped curve obtained when we plot growth against time. It is also called as sigmoid curve. This curve mainly shows four phases of growth -
1. Initial slow growth (lag phase) .

2. The rapid period of growth (log phase), where maximum growth is seen in a short period.
3. The diminishing phase, where growth will be slow.
4. Stationary phase, where finally growth stops.

Rate of growth can be expressed by 

biology plant growth growth rates and conditions for growth population ecology growth and development

  1. $V=\frac{dw}{dt}\times \frac{1}{w}$

  2. $V=\frac{dt}{dw}\times w$

  3. $V=\frac{w}{dw}\times dt$

  4. $V=\frac{w}{dt}\times dw$

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Correct Option: A

Triplet fibrils of a centriole are tilted at an angle of

biology plant growth growth rates and conditions for growth population ecology growth and development

  1. $40^o$

  2. $30^o$

  3. $20^o$

  4. $10^o$.

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Correct Option: A

In organs of plants there is a variation in rate of growth. It is first slow, then accelerated upto maximum and slows down to stand still. The period of vigorous growth is known as

biology plant growth growth rates and conditions for growth population ecology growth and development

  1. Lag phase

  2. Period of growth

  3. Grand period of growth

  4. Log phase

Show answer
Correct Option: D
Explanation:
In organs of plants, there is a variation in rate of growth. Growth is divided into four phases, namely lag phase, log phase, stationary phase and death phase. Lag phase is slow. In this, there is very little or no bacterial growth. In this phase, bacteria are adjusting to environment and synthesizing biochemicals and nutrients. In log phase, the number of bacterial cells doubles at an exponential rate. It is the period of vigorous growth . In stationary phase, the rate of cell death is equal to the rate of cell division. In death phase, there is decrease in the bacterial population due to lack of nutrients and high toxin concentration.
Thus, the correct answer is option D.

Prenatal growth in higher vertebrate is 

biology plant growth growth rates and conditions for growth population ecology growth and development

  1. Auxetic

  2. Accretionary

  3. Multipilicative

  4. None of the above

Show answer
Correct Option: C
Explanation:

During pre-natal growth, there is an increase in the number of cells of the organism. So, this kind of growth is referred to as multiplicative or embryonic growth.
Hence, the correct answer is option (C), 'Multiplicative'.

The maximum growth phase is

biology plant growth growth rates and conditions for growth population ecology growth and development

  1. Lag phase

  2. Steady phase

  3. Log phase

  4. Senescent phase

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Correct Option: C
Explanation:
Bacterial growth is divided into four phases, namely lag phase, log phase, stationary phase and death phase. In lag phase, there is very little or no bacterial growth. In this phase, bacteria are adjusting to environment and synthesizing biochemicals and nutrients. In log phase, the number of bacterial cells doubles at an exponential rate. The maximum growth phase is log phase. In stationary phase, the rate of cell death is equal to the rate of cell division. In death phase, there is decrease in the bacterial population due to lack of nutrients and high toxin concentration.
Thus, the correct answer is option C.

Growth curve indicates 

biology plant growth growth rates and conditions for growth population ecology growth and development

  1. A growth parameter at various intervals

  2. Absolute growth

  3. Absolute increase

  4. None of the above

Show answer
Correct Option: A
Explanation:

Growth curve has three different phases as :
1. Lag phase (where cell prepares for growth),
2. Log phase (where cell actually grows) and
3. Stationary phase (growth ceases).
Thus, these three phases indicates different parameters of growth at different levels. Hence, the correct answer is option (A) - 'A growth parameter at various interval'.

Exponential growth is expressed as

biology plant growth growth rates and conditions for growth population ecology growth and development

  1. $Lt = {L} _{0} + rt$

  2. ${L} _{0} = L{e}^{rt}$

  3. ${W} _{1} = {W} _{0} {e}^{rt}$

  4. ${W} _{0} = {W} _{1} {e}^{rt}$

Show answer
Correct Option: C
Explanation:
Bacterial growth is divided into four phases, namely lag phase, log phase, stationary phase, and death phase. In lag phase, there is very little or no bacterial growth. In log phase, the number of bacterial cells doubles at an exponential rate. The maximum growth phase is log phase. In stationary phase, the rate of cell death is equal to the rate of cell division. The exponential growth is expressed as W$ _1$ = W$ _0$e$^{rt}$, where
W$ _1$ = final size
W$ _0$ = initial size 
r = growth rate
t = time of growth
e = base of natural logarithms

Thus, the correct answer is option C.

Exponential growth occurs in

biology plant growth growth rates and conditions for growth population ecology growth and development

  1. Yeast

  2. Bacteria

  3. Asexual reproduction

  4. All of the above

Show answer
Correct Option: D
Explanation:

Exponential growth is the increase in number or size at a constantly growing rate. It occurs when resources availability is unlimited each species has the ability to realise fully its potential to grow in number.

So, the correct option is 'All of the above'.