Tag: biology

Questions Related to biology

What is wrong w.r.t annual rings ?

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

  1. These are also called growth ring

  2. One annual ring includes one circle of spring wood and one circle of autumn wood

  3. Annual rings are distinct in plants of tropical regions

  4. they give an estimate of the age of tree

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Correct Option: A

Most realistic growth curve 

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

  1. J shaped

  2. Sigmoid

  3. Parabolic

  4. Bith A and B

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Correct Option: B
Explanation:
The resources for the growth of most animal population are finite and become limiting sooner or later, thus the logistic growth model is considered more realistic. The equation for model gives a sigmoid shaped graph when plotted against the N in relation to time.  
The equation is :
$\dfrac{dN}{dT}$ = $rN$ $\dfrac{(K-N)}{K}$ 
where, 
N is Population density at time t
r is the intrinsic rate of natural increase 
K is carrying capacity.
So, the correct answer to the question is 'Sigmoid'.

Fastest phase of S-shaped growth curve is?

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

  1. Lag phase

  2. Log phase

  3. Stationary phase

  4. Both $(1)$ and $(2)$

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Correct Option: A

Maximum cytoplasmic growth occurs in?

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

  1. $G _1$-phase

  2. S-phase

  3. $G _2$-phase

  4. M-phase

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Correct Option: A
Explanation:

$G _1-$ phase is the period when the cell grows and carries out normal metabolism. 

In growth curve, maximum growth occurs during

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

  1. Lag phase

  2. Senescent phase

  3. Decline phase

  4. Exponential phase

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Correct Option: D
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 the environment and synthesizing biochemicals and nutrients. In log phase, the number of bacterial cells doubles at an exponential rate. The maximum growth phase is the exponential phase. In stationary phase, the rate of cell death is equal to the rate of cell division. In decline phase, there is the decrease in the bacterial population due to lack of nutrients and high toxin concentration.
Thus, the correct answer is option D.

Ectomycorrhiza is an association of ________.

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

  1. Bacterial and plant roots

  2. Cyanobacterial and plant root

  3. Fungi and plant roots

  4. Bacteria and fungi

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Correct Option: A

The growth curve of meristematic cells at growing tip of a plant and an embryo will be?

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

  1. Linear and Y-shaped respectively

  2. J-shaped and Y-shaped respectively

  3. Y-shaped and J-shaped respectively

  4. Linear and J-shaped respectively

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Correct Option: A

Process, container is being emptied into collection vehicles at point of collection is known as:

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

  1. Hauled Container System

  2. Stationary Container System

  3. Collection System

  4. Pulverization

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Correct Option: B

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.