Tag: biology

Questions Related to biology

Blackman's law was conceived in connection with

biology plant nutrition limiting factors factors affecting photosynthesis photosynthesis in higher plants

  1. Photosynthesis

  2. Respiration

  3. Transpiration

  4. Root pressure.

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Correct Option: A
Explanation:

In the twentieth century, Blackman (1905) proposed his principle of limiting factors. According to this principle, the rate of photosynthesis controlled by several factors is only as rapid as the slowest factor permits. He claimed that, if all other factors are kept constant the factor under consideration will affect the rate of photosynthesis, starting at a minimum below which no photosynthesis takes place and ending with an optimum at which a horizontal would be established, that is, the rate would remain constant despite further increases in that factor. At this point some other factor becomes limiting.

So, the correct option is 'Photosynthesis'.

Which one of the following is limiting rate of photosynthesis in nature

biology plant nutrition limiting factors factors affecting photosynthesis photosynthesis in higher plants

  1. Light

  2. $CO _2$

  3. $O _2$

  4. Chlorophyll

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Correct Option: B
Explanation:

Carbon dioxide is a major limiting factor influencing the rate of photosynthesis. The concentration of $CO _{2}$ is very low in the atmosphere (between 0.03 percent and 0.04 percent). This level of carbon dioxide is far below the requirement for optimum photosynthesis. Increase in concentration up to 0.05 percent can cause an increase in the rate of photosynthesis but beyond this level, it becomes damaging over longer periods.

Law of limiting factor is

biology plant nutrition limiting factors factors affecting photosynthesis photosynthesis in higher plants

  1. Law of maximum

  2. Law of minimum

  3. Law of optimum

  4. All of the above

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Correct Option: B
Explanation:

The concept of limiting factors is based on Liebig's Law of the Minimum, which states that growth is controlled not by the total amount of resources available, but by the scarcest resource. For example, space is a limiting factor.


So, the correct option is 'Law of minimum'.

Which one of the following would not be limiting factor in photosynthesis?

biology plant nutrition limiting factors factors affecting photosynthesis photosynthesis in higher plants

  1. $O _2$

  2. $CO _2$

  3. Chlorophyll

  4. Light

Show answer
Correct Option: A
Explanation:

Photosynthesis is the process in which sunlight is used to form carbohydrate mainly glucose by reduction of carbon dioxide and oxidation of water.

Factors that affect photosynthesis are:-
  1. Light.
  2. Temperature. 
  3. Carbon dioxide concentration.
  4. Water
oxygen does not play any role as it is released as the waste product after splitting of water.
So the correct option is 'O$ _2$'

Which part of the photosynthetic process does not require light and temperature?

biology plant nutrition limiting factors factors affecting photosynthesis photosynthesis in higher plants

  1. Hill's reaction

  2. Blackman's reaction

  3. Warburg's reaction

  4. Emerson's reaction

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Correct Option: B
Explanation:

The process of carbon assimilation occurs in light independent way. It is called as a dark reaction. Since, Blackman demonstrated the existence of dark reaction, the reaction is also called as Blackman’s reaction.

Thus, the correct answer is option B.

Blackman demonstrated that increasing illumination increased the photosynthetic rate upto a point when $CO _{2}$ become limiting. If light was not limiting, temperature become limiting. Emerson found that maximum $CO _{2}$ fixation could be achieved with brief flashes of light. Choose the correct statement from the following.

biology plant nutrition limiting factors factors affecting photosynthesis photosynthesis in higher plants

  1. Only one factor can be limited in photosynthesis.

  2. Photosynthesis consists of a light and dark reaction.

  3. The trapping of light by chloroplast is temperature dependent.

  4. The trapping of light by chloroplast can occur if $CO _{2}$ is present.

Show answer
Correct Option: A
Explanation:

Blackman proposed the law of limiting factors in 1905. According to this law, when a process depends on a number of factors, its rate is limited by the pace of the slowest factor. Blackman's law of limiting factors determines the rate of photosynthesis. Emerson found that maximum $CO _2$ fixation could be achieved with brief flashes of light. From both observations we can say that only one factor can be limiting in photosynthesis at a time. 

The law of limiting factors for photosynthesis was enunciated by

biology plant nutrition limiting factors factors affecting photosynthesis photosynthesis in higher plants

  1. R. Hill

  2. Calvin

  3. Krebs

  4. Blackman

Show answer
Correct Option: D
Explanation:

In the year 1905, Blackman proposed the law of limiting factors for photosynthesis. According to this law the process totally depends upon the light factors and its rate is limited by the pace of the slowest factor. This law of limiting factor determines the rate of the photosynthesis.

so the correct option is D.

Blackman's law of limiting factor is applied to ...........

biology plant nutrition limiting factors factors affecting photosynthesis photosynthesis in higher plants

  1. Respiration

  2. Transpiration

  3. Photorespiration

  4. Photosynthesis

Show answer
Correct Option: D
Explanation:

Law of Limiting factor was given by Blackman This law governs the rate of photosynthesis According to this law, the process of photosynthesis is controlled by many factors but the rate of photosynthesis will depend on the factor which is present in limited quantity.

For example, photosynthesis depends upon carbon dioxide concentration, light intensity, water, presence of chlorophyll. If all factors are present but light intensity is low then light will become the limiting factor and rate of photosynthesis will depend only on light, the limiting factor. Hence option D is correct.

Choose the correct answer from the alternatives given.
The rate of photosynthesis declines in the presence of 

biology plant nutrition limiting factors factors affecting photosynthesis photosynthesis in higher plants

  1. Green light

  2. blue light

  3. orange light

  4. far red light

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Correct Option: A
Explanation:
The wavelength of light is also important in the process of photosynthesis. As we know that the  PSI absorbs energy most efficiently at 700 nm and PSII at 680 nm. Light with a higher proportion of the energy of different wavelengths will produce a different rate of photosynthesis i.e the more the wavelength the effective photosynthesis occur. Certain red and blue wavelengths of light are the most effective in photosynthesis because they have exactly the right amount of energy to energize, or excite, chlorophyll electrons. Greenlight is considered the least efficient wavelength in the visible spectrum for photosynthesis, but it is still useful in photosynthesis.
So the correct option is 'Green light'.
The law of limiting factors' was given by _______ in the year _______.
biology plant nutrition limiting factors factors affecting photosynthesis photosynthesis in higher plants

  1. Blackman, 1905

  2. Blackman, 1804

  3. Engelmann, 1909

  4. Warburg, 1920

Show answer
Correct Option: A
Explanation:

Blackman's (1905) law of limiting factors states that if a chemical process is affected by more than one factor, then its rate will be determined by the factor which is nearest to its minimal value; it is the factor which directly affects the process if its quantity is changed. 

So the correct option is A.