Tag: biology

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Questions Related to biology

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

What is wrong w.r.t annual rings ?

  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
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Annual rings are distinct and prominent in plants growing in temperate regions where climatic conditions vary sharply between seasons. In tropical regions, seasonal variations are not distinct, so annual rings are typically indistinct or absent.

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

Most realistic growth curve 

  1. J shaped

  2. Sigmoid

  3. Parabolic

  4. Bith A and B
Reveal answer Fill a bubble to check yourself
B Correct answer
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'.
Multiple choice biology plant growth growth rates and conditions for growth population ecology growth and development

Fastest phase of S-shaped growth curve is?

  1. Lag phase

  2. Log phase

  3. Stationary phase
  4. Both $(1)$ and $(2)$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In a typical sigmoid (S-shaped) growth curve, the growth rate is slow initially during the lag phase, accelerates exponentially to its maximum during the log (exponential) phase, and finally slows down in the stationary phase.

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

In growth curve, maximum growth occurs during

  1. Lag phase

  2. Senescent phase

  3. Decline phase

  4. Exponential phase
Reveal answer Fill a bubble to check yourself
D Correct answer
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.
Multiple choice biology plant growth growth rates and conditions for growth population ecology growth and development

Ectomycorrhiza is an association of ________.

  1. Bacterial and plant roots

  2. Cyanobacterial and plant root

  3. Fungi and plant roots

  4. Bacteria and fungi
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Ectomycorrhiza is a symbiotic association between fungi and the roots of higher plants, where the fungal hyphae form a sheath around the root and inter-cellularly network in the cortex.

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

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

  1. Hauled Container System

  2. Stationary Container System

  3. Collection System

  4. Pulverization
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In a stationary container system, the collection vehicle travels to the site, empties the container, and moves to the next, whereas in a hauled container system, the entire container is removed.

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

Growth curve is

  1. S-shaped

  2. Sigmoid

  3. L-shaped

  4. Both (A) and (B)
Reveal answer Fill a bubble to check yourself
D Correct answer
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.

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

The usual shape of growth curve is 

  1. Linear

  2. Inverted bell shaped

  3. Sigmoidal

  4. Zig-zag
Reveal answer Fill a bubble to check yourself
C Correct answer
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.