Tag: biology

Questions Related to biology

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

Show answer
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. $10^o$.

Show answer
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

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 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'.

The sequence of various components of a growth curve are

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

  1. Lag, log, stationary

  2. Log, lag, stationary

  3. Log, stationary, lag

  4. Stationary, log, lag

Show answer
Correct Option: A
Explanation:
Growth curve 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 'Lag, log, stationary'.

Maximum of growth occurs in

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

  1. Exponential phase

  2. Decline phase

  3. Stationary phase

  4. Lag phase

Show answer
Correct Option: A
Explanation:
Bacterial growth is divided into four phases, namely lag phase, exponential phase, stationary phase and decline 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 exponential phase, the number of bacterial cells doubles at an exponential rate. The maximum growth occurs in this phase. In stationary phase, the rate of cell death is equal to the rate of cell division. In decline phase, there is decrease in the bacterial population due to lack of nutrients and high toxin concentration
So, the correct answer is 'Exponential phase'