Tag: zoology

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Questions Related to zoology

Multiple choice zoology structure of chromosome, cell cycle and cell division structure of dna nucleic acid heredity and inheritance

Bonding between deoxyribose and base in pyrimidine nucleoside molecule is :-

  1. $1'-1'$ glycosidic linkage
  2. $1'-6'$ glycosidic linkage
  3. $1'-9'$ glycosidic linkage
  4. $1'-4'$ glycosidic linkage
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Bonding between deoxyribose and base in pyrimidine nucleoside molecule is $1'-1'$ glycosidic linkage because 


when the base is pyrimidine, then $N-1$ is bonded to $C-1$ of the sugar.

Multiple choice zoology structure of chromosome, cell cycle and cell division structure of dna nucleic acid heredity and inheritance

Which of the following is not related to Watson and Crick model of DNA?

  1. X-ray crystallography

  2. The Meselson-Stahl experiment

  3. Chargaff's rules

  4. The different sizes of purines and pyrimidines

  5. The transforming principle of Avery et al
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Meselson-Stahl experiment -  DNA Replication is Semiconservative.

Meselson and Stahl proved that the semiconservative model of DNA replication was correct.
Watson-Crick Structure of DNA. Deoxyribonucleic Acid (DNA) is a double-stranded, helical molecule. It consists of two sugar-phosphate backbones on the outside, held together by hydrogen bonds between pairs of nitrogenous bases on the inside.
X-ray crystallography - the study of crystals and their structure by means of the diffraction of X-rays by the regularly spaced atoms of crystalline materials. X-ray crystallography is a tool used for identifying the atomic and molecular structure of a crystal, in which the crystalline atoms cause a beam of incident X-rays to diffract into many specific directions.

Chargaff's rules states that DNA from any cell of all organisms should have a 1:1 ratio (base Pair Rule) of pyrimidine and purine bases and, more specifically, that the amount of guanine is equal to cytosine and the amount of adenine is equal to thymine.
Avery's experiments showed that DNA is the transforming principle. It stated that bacterial transformation was caused by DNA. It is not correlated with Watson and crick model of DNA.
So, the correct answer is option E.

Multiple choice zoology human influences on the environment carbon cycle ozone layer depletion and causes depletion of ozone layer

Greenhouse effect is due to

  1. accumulation of $ { O } _{ 3 } $ and depletion of $ { CO } _{ 2 } $
  2. accumulation of both $ { O } _{ 3 } $ and $ { CO } _{ 2 } $
  3. accumulation of $ { CO } _{ 2 } $ and depletion of $ { O } _{ 3 } $

  4. presence of green plants on the Earth.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Greenhouse effect, a warming of Earth’s surface and troposphere (the lowest layer of the atmosphere) is caused by the presence of water vapour, carbon dioxide, methane, and certain other gases in the air. Of those gases, known as greenhouse gases, water vapour has the largest effect. The atmosphere allows most of the visible light from the Sun to pass through and reach Earth’s surface. As Earth’s surface is heated by sunlight, it radiates part of this energy back toward space as infrared radiation. This radiation, unlike visible light, tends to be absorbed by the greenhouse gases in the atmosphere, raising its temperature. The heated atmosphere in turn radiates infrared radiation back toward Earth’s surface. 
So the correct option is 'accumulation of CO$ _2$ and depletion of O$ _3$'.

Multiple choice zoology human influences on the environment carbon cycle ozone layer depletion and causes depletion of ozone layer

Read the given statements and select the correct option.


Statement 1: The average temperature of Earth has increased by $ 0.6 $ during the past century.
Statement 2: There has been a progressive increase in the use of fossil fuels generating more greenhouse gases.

  1. Both statements 1 and 2 are correct.

  2. Statement 1 is correct but statement 2 is incorrect.

  3. Statement 1 is incorrect but statement 2 is correct.

  4. Both statements 1 and 2 are incorrect.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The various greenhouse gases are $ { CO } _{ 2 }, { CH } _{ 4 }, { CFC } _{ s } $ and $ { N } _{ 2 }{ O } $. Excessive use of fossil fuel is adding more $ { CO } _{ 2 } $ to atmosphere. This increase in concentration of greenhouse gases has led to considerable heating of earth leading to global warming. During the pas century, the temperature of earth has increased by $ 0.6 $.

Multiple choice zoology natural resources - air, water and land carbon cycle ozone layer depletion and causes depletion of ozone layer

Identify the incorrect statement from the following

  1. Oxides of nitrogen in the atmosphere can cause the depletion of ozone layer

  2. Ozone absorbs the intense ultraviolet radiations of the sun

  3. Depletion of ozone layer is because of its chemical reactions with CFC

  4. Ozone absorbs infrared radiations
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Ozone doesn't absorb infrared radiation , it absorbs ultraviolet radiations .

Multiple choice zoology physical resources carbon cycle ozone layer depletion and causes depletion of ozone layer

In absence of Green House Gases, the temperature of Earth shall fall down to ___

  1. -18 degree Celcius

  2. -15 degree Celcius

  3. -20 degree Celcius

  4. -10 degree Celcius
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Because Green House Gases are responsible to trap heat in earth surface. If green house gases are absent, the temperature of Earth shall fall down to -18 degree Celcius

So, the correct answer is '-18$^0$

Multiple choice zoology physical resources carbon cycle ozone layer depletion and causes depletion of ozone layer

Correct percentage of two green house gases is

  1. $N _2O-6\%, CO _2-86\%$
  2. $CH _4-20\%, N _2O-18\%$
  3. $CO _2-40\%, CFC-30\%$
  4. $CFC-14\%, CH _4-20\%$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
The warming of earth's surface when sun radiations are absorbed and trapped in earth's atmosphere, is called greenhouse effect. The gases responsible for green house effect are called green house gases which trap the radiations and don't let them reflect back from the earth's surface. The green house gases are Chlorofluorocarbons (CFC's), Carbon dioxide (CO2), Methane (CH4) and Nitrous Oxide (N2O). 
The approximate percentage of different greenhouse gases in the atmosphere is:
CFCs - 14%
CO2 - 60%
‎CH4 - 20%
N2O - 6%
So, the correct answer is 'CFC−14%, CH4 - 20%

Multiple choice zoology human influences on the environment carbon cycle ozone layer depletion and causes depletion of ozone layer

Which of the following is a green house gas?

  1. Methane

  2. CO

  3. Water vapour

  4. Oxygen
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
The warming of earth's surface when sun radiations are absorbed and trapped in earth's atmosphere, is called greenhouse effect. The gases responsible for green house effect are called green house gases which trap the radiations and don't let them reflect back from the earth's surface. The green house gases are Chlorofluorocarbons (CFCs), Carbon dioxide (CO2), Methane (CH4) and Nitrous Oxide (N2O). 
So, the correct answer is 'Methane'.
Multiple choice zoology human influences on the environment carbon cycle ozone layer depletion and causes depletion of ozone layer

Carbon dioxide is called a green house gas because

  1. It emits light

  2. It traps infra red radiations

  3. It traps ultraviolet radiations

  4. It is involved in photosynthesis
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
The warming of earth's surface when sun radiations are absorbed and trapped in earth's atmosphere, is called greenhouse effect. The gases responsible for green house effect are called green house gases which trap the radiations and don't let them reflect back from the earth's surface. Carbon dioxide traps the infra red radiations and accounts for greatest contribution to greenhouse effect.
So, the correct answer is 'It traps infra red radiations'.