Tag: heredity and inheritance

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

In the DNA molecule,

  1. The proportion of adenine in relation to thymine varies with the organism.
  2. There are two strands which run antiparallel one in $5'\rightarrow 3'$ direction and other in $3'\rightarrow 5'$.

  3. The total amount of purine nucleotides and pyrimidine nucleotides is not always equal.
  4. There are two strands which run parallel in the $5'\rightarrow 3'$ direction.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

DNA (Deoxyribonucleic Acid) is composed of two polynucleotide strands (the polymers of nucleotides), which form what looks like a ladder. The nitrogenous bases in DNA store the instructions for making polypeptide chains, essentially coding for every feature of the entire organism. The two polynucleotide strands run 'antiparallel' to each other, with nitrogenous bases projecting inwards. The term 'antiparallel' means that the strands run in opposite directions, parallel to one another. The antiparallel strands twist in a complete DNA structure, forming a double helix.

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

In the speculation concering the origins of life, one theory states that the combination of purines, pyrimidines, sugars, and phosphates is called as______________.

  1. Nucleotides

  2. Nucleosides

  3. Carbohydrates

  4. Fats

  5. Proteins
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Nucleotides are formed by the combination of purines or pyrimidines (nitrogenous bases), sugars (pentose), and phosphates. Nucleosides lack the phosphate group, making option A the correct answer.

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

If one strand of DNA sequence is - 5'-GAATTG-3' - then the sequence of the opposite strand is

  1. 5'-CAATTC-3'

  2. 5'-CTTAAC-3'

  3. 5'-GAATTG-3'

  4. 5'-GTTAAG-3'

  5. 5'-TAATTC-3'
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A DNA strand is complementary. This means adenine pairs with thymine and cytosine pairs with guanine in the opposite strand. The given strand has a sequence 5'-GAATTG-3'. Hence the complementary strand will have a sequence 5'-CAATTC-3'. Thus the correct answer is option A.

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

DNA is directly involved in the synthesis except that of

  1. DNA

  2. Protein

  3. tRNA

  4. mRNA
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
DNA is genetic material found in the living cell. It helps to carry characters from one generation to the other. The process by which the DNA replicated and forms another DNA molecule is known as replication. Parent strand of the DNA strand act as a template for synthesis of another DNA molecule.
Transcription is the process by which DNA is converted into RNA. The enzyme RNA polymerase plays an important role in transcription. The sequence of the nitrogenous base on the DNA acts as a template and determines the sequence of the nitrogenous base on the RNA. The RNA formed by the DNA are messenger RNA, t- RNA and ribosomal RNA.
Protein is formed by the m-RNA by process of translation.
So, the correct answer is option B.
Multiple choice zoology structure of chromosome, cell cycle and cell division structure of dna nucleic acid heredity and inheritance

A $340\overset{o}{A}$ long segment of DNA molecule has $20$ thymine nitrogenous bases, what will be the number of guanine nitrogen bases in the same segment?

  1. $10$
  2. $40$
  3. $30$
  4. $160$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Option (C) 30

$ 34A = 10 $ nucleotides
$ 340A = 100 $ nuclotides
$ A = T = 20 $
$ 100-40 = 60 $ nucleotides
$ G = C = 60 $
Hence $ G = 60/2 = 30 $ nuclotides
Multiple choice zoology structure of chromosome, cell cycle and cell division structure of dna nucleic acid heredity and inheritance

The DNA strands are antiparallel because of the presence of

  1. H-bonds

  2. Peptide bonds

  3. Disulphide bonds

  4. Phosphate-diester bonds

  5. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

When DNA strands run in opposite direction one strand from 5 prime to 3 prime and another strand from 3 prime to 5 prime is called as antiparallel. The 5 prime end have phosphate in 5$^{th}$position of sugar and 3 prime end have a hydroxyl group on 3$^{rd}$ position of sugar. DNA strands are antiparallel because of the presence of hydrogen bond. Hydrogen bond binds the complementary bases (purine and pyrimidine)

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

In DNA, adenine pairs with

  1. Guanine

  2. Thymine

  3. Cytosine

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

The nitrogenous bases present in the DNA are purines and pyrimidines. The purines are adenine and guanine. The pyrimidines are thymine and cytosine. The purines are double ring structure while the pyrimidines are the single ring made up of carbon and nitrogen. Purines pair with the pyrimidines by hydrogen bonds. Adenine pairs with thymine by two hydrogen bond while the cytosine pairs with the guanosine by three hydrogen bonds.

So, the correct answer is option B.

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

DNA is composed of repeating units of

  1. Ribonucleosides

  2. Deoxyribonucleosides

  3. Ribonucleotides

  4. Deoxyribonucleotides
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
DNA is a chain of polynucleotide which are joined by the phosphodiester bonds. The nucleotide consists of a deoxyribose sugar, nitrogenous bases, and phosphate.The two nucleotide is linked by the phosphodiester bond. It is formed by the linkage between the 3' carbon atom of one sugar molecule and the 5' carbon atom of another. Two hydroxyls (OH) groups on the phosphate molecule bind to the 3’ and 5’ carbons on two independent pentose sugars to form a bond.
So, the correct answer is option D.
Multiple choice zoology structure of chromosome, cell cycle and cell division structure of dna nucleic acid heredity and inheritance

Major and minor grooves can be seen in

  1. Polypeptide

  2. RNA

  3. DNA

  4. Chromatin
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
DNA has the double helical structure where the two strands are tightly coiled over each other. B- DNA has right-handed helix with the major and minor groove. The diameter of the DNA is 20 A$^o$. The number of base pairs in one turn is 10 and the distance between base pairs is 3.4 A$^o$. At major grooves, the base pairs are far apart while at minor groove the base pairs are closer. Major grooves have base pairs at a distance the DNA binding protein can easily interact with the bases.
So, the correct answer is option A.
Multiple choice zoology structure of chromosome, cell cycle and cell division structure of dna nucleic acid heredity and inheritance

Base pairs present in one turn of DNA are

  1. $12$
  2. $11$
  3. $10$
  4. $9$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
DNA has the double helical structure where the two strands are tightly coiled over each other. B- DNA has right-handed helix with the major and minor groove. The diameter of the DNA is 20 A$^o$. The distance between base pairs is 3.4 A$^o$. The total length of one turn of DNA is 34 A$^o$. The total number of the base pair in each turn is 34/3.4 = 10.
So, the correct answer is option C.