Tag: biology

Questions Related to biology

Total oxygen that can be carried by blood is?

production of blood cells body fluids and circulation biology

  1. $1000-1200$ ml

  2. $2000-3000$ml

  3. $200$ml

  4. $100$ml

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Correct Option: A

In normal healthy individuals , the percentage of adult and fetal haemoglobin , HbA : HbA2 : HbF is ____________.

production of blood cells body fluids and circulation biology

  1. 96 :2 : 2

  2. 45 : 45 : 10

  3. 50 : 45 : 5

  4. 80 : 10 : 10

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Correct Option: A

Choose correct alternative in the following statements:
Nucleus is absent in

production of blood cells body fluids and circulation biology

  1. RBCs

  2. WBCs

  3. All blood cells

  4. Liver cells

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Correct Option: A
Explanation:

The nucleus is absent in red blood cells in order to accomodate more space for haemoglobin. It also allows the cell to maintain its biconcave shape which aids diffusion. 

Hence, the correct answer is 'RBCs' .

Cells formed in bone marrow include

production of blood cells body fluids and circulation biology

  1. RBC

  2. RBC and leucocytes

  3. Leucocytes

  4. Lymphocytes

Show answer
Correct Option: B
Explanation:
RBCs (Red blood cells) or erythrocytes transport oxygen in the body and formed in bone marrow. They are roughly circular and lack nucleus and other organelles.
Leucocytes or white blood cells (WBCs) may be granular or agranular. Granulocytes include basophils, eosinophils, neutrophils and agranulocytes include monocytes and lymphocytes. These cells are also formed in bone marrow. 
So, the correct answer is 'RBC and leucocytes'.

The law of limiting factor for photosynthesis was enunciated by 

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

  1. Blackman

  2. Hill

  3. Ruben

  4. Kalmen

Show answer
Correct Option: A
Explanation:

The main factors affecting rate of photosynthesis are light intensity, carbon dioxide concentration and temperature. In any given situation any one of these may become a limiting factor, in other words, the factors that directly affects the rate at which photosynthesis can take place masking the effects of the other factors. A limiting factor in a system is an input or variable such that a small change in it from the present value would cause a non-negligible change in an output or other measure of the system.  

According to Sachs, photosynthesis takes place at the

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

  1. Minimum value.

  2. Maximum value.

  3. Optimum value.

  4. All of the above.

Show answer
Correct Option: C
Explanation:

Blackman's Law of limiting factors are the various factors which affect the rate of photosynthesis. It is considered that when the other factors are constant, the factor which is least or minimum has the direct effect on the rate of photosynthesis. Sachs developed three cardinal points for each factor which affects the rate of photosynthesis. These cardinals have minimum, optimum and maximum values. The process of photosynthesis starts at the minimum and takes place at the optimum value. the rate of photosynthesis is much smaller at the maximum value and stops above this point.

Thus, the correct answer is option C. 

The Blackman's law of limiting factor is an elaboration of

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

  1. Liebig's law of minimum.

  2. Hatch and Slack mechanism.

  3. Sach's cardinal points.

  4. None of the above.

Show answer
Correct Option: A
Explanation:

Blackman's Law of limiting factors was the elaborated form of the law of minimum given by Liebig. These are the various factors which affect the rate of photosynthesis. It is considered that when the other factors are constant, the factor which is least or minimum has the direct effect on the rate of photosynthesis. 

Thus, the correct answer is option A. 

A plant is exposed to an optimum amount of light intensity, with a limited supply of CO$ _2$. As the carbon dioxide, concentration increases the rate of photosynthesis increases. Which of the following act as limiting factor in above-given case?

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

  1. Carbon dioxide

  2. Light

  3. Temperature

  4. Both A and B

Show answer
Correct Option: A
Explanation:
Blackman's law of limiting factors are the various factors which affect the rate of photosynthesis. It is considered that when the other factors are constant, the factor which is least or minimum has the direct effect on the rate of photosynthesis. When the light intensity is maintained at the optimum level, the other factor which is CO$ _2$ supply is reduced. This causes the rate of reaction to completely depend on CO$ _2$. When the carbon dioxide concentration increases, the rate of reaction increases. This explains that the limiting factor is carbon dioxide. 
Thus, the correct answer is option A. 

A plant is exposed to an optimum amount of carbon dioxide, with a limited light intensity. As the intensity of light increases, the rate of photosynthesis increases. Which of the following act as limiting factor in above-given case?

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

  1. Light

  2. Carbon dioxide

  3. Temperature

  4. All of the above

Show answer
Correct Option: A
Explanation:
Blackman's law is applicable to photosynthesis. It states that a process  is controlled by many factors but the rate of photosynthesis will depend on the factor which is present in limited quantity. 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. The level of carbon dioxide is maintained constant and so light is the limiting factor. 
Thus, the correct answer is option A.

At high temperatures, the enzymes of photosynthesis gets deactivated because 

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

  1. They get denatured.

  2. They are proteinous in nature.

  3. They have optimum range of temperature at which they are functional.

  4. All of the above.

Show answer
Correct Option: D
Explanation:

Enzymes are biological catalysts which can normally function at body temperatures. There are various different enzymes involved in the process of photosynthesis. The enzymes have optimum temperature range. This is the range in which they show maximum activity. The enzymes are proteins which gets denatured at higher temperature. The structure of these enzymes gets modified and the active sites are destroyed. This results in the inactivation of the enzymes. 

Thus, the correct answer is option D.