Growth rates and conditions for growth - class-XII
Description: growth rates and conditions for growth | |
Number of Questions: 32 | |
Created by: Vijay Puri | |
Tags: option c: ecology and conservation growth and development biology plant growth plant growth and development |
Fastest phase of S-shaped growth curve is
-
Lag phase
-
Log Phase
-
Stationary phase
-
Both (a) and (B).
- S-shaped logistic growth curve includes 3 phases:
- Lag phase - When some organisms are introduced in an area, the population growth begins slowly.
- Log phase - The conditions are ideal and the maximum growth rate is reached.
- Stationary phase - Growth rate begins to slow down as factors such as food, water and space become limiting.
Most realistic growth curve is
-
J-shaped
-
Sigmoid
-
Parabolic
-
Both (A) & (B)
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 :
What is wrong w.r.t annual rings ?
-
These are also called growth ring
-
One annual ring includes one circle of spring wood and one circle of autumn wood
-
Annual rings are distinct in plants of tropical regions
-
they give an estimate of the age of tree
Most realistic growth curve
-
J shaped
-
Sigmoid
-
Parabolic
-
Bith A and B
Fastest phase of S-shaped growth curve is?
-
Lag phase
-
Log phase
-
Stationary phase
-
Both $(1)$ and $(2)$
Maximum cytoplasmic growth occurs in?
-
$G _1$-phase
-
S-phase
-
$G _2$-phase
-
M-phase
$G _1-$ phase is the period when the cell grows and carries out normal metabolism.
In growth curve, maximum growth occurs during
-
Lag phase
-
Senescent phase
-
Decline phase
-
Exponential phase
Ectomycorrhiza is an association of ________.
-
Bacterial and plant roots
-
Cyanobacterial and plant root
-
Fungi and plant roots
-
Bacteria and fungi
The growth curve of meristematic cells at growing tip of a plant and an embryo will be?
-
Linear and Y-shaped respectively
-
J-shaped and Y-shaped respectively
-
Y-shaped and J-shaped respectively
-
Linear and J-shaped respectively
Process, container is being emptied into collection vehicles at point of collection is known as:
-
Hauled Container System
-
Stationary Container System
-
Collection System
-
Pulverization
Growth curve is
-
S-shaped
-
Sigmoid
-
L-shaped
-
Both (A) and (B)
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.
The usual shape of growth curve is
-
Linear
-
Inverted bell shaped
-
Sigmoidal
-
Zig-zag
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) .
3. The diminishing phase, where growth will be slow.
4. Stationary phase, where finally growth stops.
Rate of growth can be expressed by
-
$V=\frac{dw}{dt}\times \frac{1}{w}$
-
$V=\frac{dt}{dw}\times w$
-
$V=\frac{w}{dw}\times dt$
-
$V=\frac{w}{dt}\times dw$
Triplet fibrils of a centriole are tilted at an angle of
-
$40^o$
-
$30^o$
-
$20^o$
-
$10^o$.
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
-
Lag phase
-
Period of growth
-
Grand period of growth
-
Log phase
Prenatal growth in higher vertebrate is
-
Auxetic
-
Accretionary
-
Multipilicative
-
None of the above
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
-
Lag phase
-
Steady phase
-
Log phase
-
Senescent phase
Growth curve indicates
-
A growth parameter at various intervals
-
Absolute growth
-
Absolute increase
-
None of the above
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
-
$Lt = {L} _{0} + rt$
-
${L} _{0} = L{e}^{rt}$
-
${W} _{1} = {W} _{0} {e}^{rt}$
-
${W} _{0} = {W} _{1} {e}^{rt}$
Exponential growth occurs in
-
Yeast
-
Bacteria
-
Asexual reproduction
-
All of the above
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
-
Lag, log, stationary
-
Log, lag, stationary
-
Log, stationary, lag
-
Stationary, log, lag
Maximum of growth occurs in
-
Exponential phase
-
Decline phase
-
Stationary phase
-
Lag phase
A tracheid is distinguished from a vessel elements on the basic of.
-
Length
-
Thickness
-
Side-wall pitting
-
End-wall perforation
What is the maximum period of growth?
-
Slow growth rate
-
Steady growth rate
-
Speedy growth rate
-
Senescence phase
If division and differentiation are cocurrent then growthi will be
-
Geometric
-
Logistic
-
Linear
-
Infinite
There are two types of population growth, geometric growth and logistic growth. Geometric growth is also called as exponential growth. Logistic growth is S shaped growth. Arithmetic growth is a linear growth. During cell division, cell divides into two. It increases cell number. During cell differentiation, cell specializes into different cell type. If division and differentiation are cocurrent then there will be negative control. It will regulate the cell division. Hence, the growth will be logistic.
In signoid growth curve, upper asymptote represents period of
-
Establishment
-
Negative acceleration
-
Positive acceleration
-
Equilibrium
In a sigmoid growth curve, there are three phases, lag phase, exponential phase and steady state phase. The upper limit of the curve is called as upper asymptote. It represents the period of equilibrium. At this stage, birth rate and death rate are at balance. It is said to be at equilibrium because at this stage, there is equilibrium between biotic potential and environmental resistance.
State whether the following statements are true or false.
Ethylene stimulates leaf release, while auxin keeps leaves from falling.
-
True
-
False
Ethylene is a gaseous hormone which stimulates the transverse growth but inhibits the longitudinal growth. Auxin delays the abscission of young leaves and provides nutrition to it so that they do not die down while ethylene increases the senescence of leaves and flowers and produces more gas which leads to loss of leaves.
Which of the following is not a feature of a J-shaped growth form of population?
-
It is found in stable type of population.
-
Exponential phase is very rapid.
-
A crash phase occurs at the end of the growth.
-
Environmental resistance does not operate.
J-shaped growth curve is a curve on a graph that records the situation in which, in a new environment, the population density of an organism increases rapidly in and exponential or logarithmic form, but then stops abruptly as environmental resistance or some other factor suddenly becomes effective. The actual rate of population change depends on the biotic potential and population size. It may be summarized mathematically as
Because of the which of the following reason/s, growth stops completely during the stationary phase?
-
Lack of nutrients
-
Saturation of nutrients
-
Over availability of nutrients
-
None of the above
The stationary phase is the phase in which the growth of lant generally stops and the plant proceeds towards maturity it may occur due to the lack of nutrients majorly seen in the unfavourable season.
Incorrect about geometrical growth
-
After mitosis both daughter cells retain the capacity of division
-
Growth pattern follows sigmoid curve
-
Less common than arithmetic growth in the plants
-
Growth rapidly increases
In geometrical growth both the progeny cells following mitotic cell division retain the ability to divide and continue to do so. However, with a limited supply of nutrients, the growth becomes slow which lead to the stationary stage. A sigmoid curve is the characteristic of organism living is the natural environment.
Exponential growth is shown during
-
Lag phase
-
Log phase
-
Maturation phase
-
Senescence phase
Choose the correct answer from the alternatives given.
The auxanometer is used for measuring the:
-
growth of a fruit
-
growth of a cell
-
width of the stem
-
length of the stem