Tag: zoology

Questions Related to zoology

The genetic information in the body is encoded in the

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

  1. Structural proteins

  2. Enzymes

  3. DNA

  4. DNA and enzymes

Show answer
Correct Option: C
Explanation:

Deoxyribose Nucleic Acid or DNA carries the genetic information in the form of small segments known as genes and is also the genetic material in various organisms including humans.

Structural proteins and enzymes are the gene products that are synthesised from DNA through the process of translation.
Hence, the correct answer is 'DNA'.

Information from X-ray crystallographic data collected by was used by Watson and Crick in their development of the model of DNA.

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

  1. Chargaff

  2. Griffith

  3. Franklin

  4. Hershey and Chase

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Correct Option: C
Explanation:

Although the discovery of the structure of DNA was attributed to Watson and Crick, a keynote player in helping them discover this structure was a scientist by the name of Rosalind Franklin. Rosalind Franklin, along with Francis Wilkins, worked on DNA applying X-ray crystallography to find out its structural properties. X-ray crystallography required the process of exposing a crystal specimen (DNA) to X-rays to determine the locations of the atoms in the “molecules that comprises basic unit of crystal called unit cell”. 

So, the correct option is 'Franklin'.

The purines of DNA are represented by guanine and thymine.

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

  1. True

  2. False

Show answer
Correct Option: B
Explanation:

Adenine and Guanine are the two purines found in DNA and RNA. The pyrimidines of DNA are represented by thymine and cytosine. 

Hence, the correct answer is false. 

Which of the following general statement about the structure of DNA is true?

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

  1. The hydrogen bonds connecting base pairs exist in a polar environment.

  2. Both major and minor grooves are formed between the phosphate-sugar backbone.

  3. The same C and N atoms are present in each groove.

  4. The amount of energy required to break down the AT and GC pairs is the same.

Show answer
Correct Option: A
Explanation:

The DNA double helical structure has two different environments. The nitrogenous bases have an aromatic ring structure and are hydrophobic and interact with each other through base pair stacking interactions. At the same time, the back bone of DNA formed by phosphodiester bonds is hydrophilic and interacts with water. The nitrogenous bases of one nucleotide chain form hydrogen bonds with the nitrogenous bases present directly opposite them on the other chain. The hydrogen bonds are formed in polar aqueous environment. The adenine base pairs with thymine with two hydrogen bonds and guanine base pairs with cytosine with three hydrogen bonds.
So, the correct answer is option A.

If there are 10,000 base pairs in DNA, then its length

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

  1. 340 nm

  2. 3400 nm

  3. 34000 nm

  4. 340000 nm

Show answer
Correct Option: B
Explanation:

According to the most widely accepted model of DNA structure, the distance between any two base pairs in DNA is approximately 3.4 angstroms. Thus for a DNA molecule having 10,000 base pairs; the length will be 10,000 x 3.4 or 34000 angstroms or 3400 nanometers.
So, the correct answer is option B.

In a DNA sample the proportion of A is 17%, the amount of G + T and C will be respectively.

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

  1. 50% and 33%

  2. 66% and 17%

  3. 66% and 33%

  4. 33% and 50%

Show answer
Correct Option: A
Explanation:

In any double stranded DNA, adenine (A) pairs with a thymine (T) and Guanine (G) pairs with a cytosine (C).
Now, since each A always pairs with a T, the percentage of A and T will always be the same. Therefore, percentage of T will also be 17%.
So we can conclude that A+T=17+17=34%
The rest would account for G+C which would be 100-34=66%, thus G+C=66%.

Now, since each G always pairs with a C, thus the individual proportions of G and C will be 33%. 
So we get the base composition of DNA as A=T=17% and G=C=33%
Therefore, G+T=33+17=50% and C=33%.
Hence the correct answer is '50% and 33%'.

The eukaryotic chromosome contains nucleosome spools.

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

  1. True

  2. False

Show answer
Correct Option: A
Explanation:
A nucleosome is a basic unit of DNA packaging in eukaryotes, consisting of a segment of a DNA wound in sequence around eight histone protein octamer cores. This structure is often compared to thread wrapped around a spool. Nucleosome constitutes the repeating unit of a structure in nucleus called chromatin, thread-like stained (colored) seen in the nucleus. The negatively charged DNA is wrapped around the positively charged histone octamer to form a structure called DNA helix.
So, the statement is 'True'.

How many amino acids will be coded by the given sequence of ribonucleotides, if the 15$^{th}$ base is substituted by G?
'5AUGGUGUAGAGGUACCAU3'

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

  1. Four

  2. Five

  3. Six

  4. Two

Show answer
Correct Option: D
Explanation:

Amino acid synthesis stops when any STOP codon is encountered by ribosome. There are total 3 stop codons, UAG, UGA, UAA. Codons are always read in triplets. So the given ribonucleotide sequence will be read as: AUG,GUG, UAG, and so on. Notice that the third codon (UAG) is a stop codon, so the protein synthesis will stop at the third codon itself. It doesn't matter if the 15th base is substituted by G or not, the given sequence will code for only two amino acids, AUG (methionine) and GUG (Methionine)

So, the correct answer is 'Two'.

DNA cannot pass through a cell membrane as

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

  1. It is too big to cross the membrane

  2. It is a hydrophilic molecule

  3. Membrane does not have specific proteins to facilitate the transport

  4. None of these

Show answer
Correct Option: B
Explanation:

DNA cannot pass through a cell membrane as it is hydrophilic in nature whereas cell membrane is made up of lipid bilayer. 

So, the correct option is 'Option B' .

Feulgen test, is unique for DNA, is a

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

  1. Gentian violet

  2. Neutral red

  3. Basic fuchsin

  4. Cotton blue

Show answer
Correct Option: C
Explanation:
  • The feulgen test is a staining technique discovered by Robert Feulgen and used in histology to identify chromosomal material or DNA in cell specimens.
  • The Feulgen test, is unique for DNA, is a Basic Fuchsin.
  • It is used for demonstration of DNA (deoxyribonucleic acid) in tissue sections. 
  • So, the correct answer is 'Basic fuchsin',