Tag: heredity

Quizzes (18) Questions (51)

Questions Related to heredity

Multiple choice dna replication replication and protein synthesis nucleic acids and protein synthesis heredity biology

In bacterial DNA replication, synthesis starting from the site of origin of replication

  1. Involves RNA primers

  2. Requires telomerase

  3. Proceeds unidirectionally

  4. Moves bidirectionally
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In circular bacterial DNA, replication begins at a single origin and proceeds in both directions simultaneously around the circle, known as bidirectional replication.

Multiple choice dna replication replication and protein synthesis nucleic acids and protein synthesis heredity biology

Consider the following statements and choose the correct option.

In eukaryotes
(i) RNA polymerase I transcribes rRNA.
(ii) RNA polymerase I transcribes snRNA.
(iii) RNA polymerases II transcribes tRNA.
(iv) RNA polymerase II transcribes hnRNA.

  1. 1 and 2 are correct.

  2. 1 and 3 are correct.

  3. 1, 2 and 4 are correct.

  4. 2 and 3 are correct.

  5. 1 and 4 are correct.
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Eukaryotes have three RNA polymerases which are structurally distinct complexes, though share certain subunits in common, and have a specific function and specific promoter sequence. RNA polymerase I synthesize preribosomal RNA (pre-rRNA), which contains the precursor for the 18S, 5.8S, and 28S rRNAs.

RNA polymerase II transcribes the presursor of mRNA which is heterogenous RNA (hnRNA). 
RNA polymerase III makes tRNAs, the 5S rRNA, and sNRNAs. 
Therefore, the correct answer is option (E).

Multiple choice dna replication replication and protein synthesis nucleic acids and protein synthesis heredity biology

Choose the correct answer from the alternatives given.
A restriction enzyme breaks bonds between the

  1. base pairs of a DNA molecule

  2. sugar and phosphate components of a nucleic acid molecule

  3. base pairs of a DNA-RNA hybrid molecule.

  4. exons and introns of a DNA molecule
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Restriction enzymes are the enzymes that have the capability to cleave the phosphodiester bonds between the sugar molecule and the phosphate molecule. It has a property of cleaving DNA molecules at or near a specific sequence of bases. This is produced by certain strains of bacteria. Each restriction enzyme cleaves around a specific DNA sequence. Example: EcoR1 splices around sequence GAATTC, BamH1 cleaves around GGATCC, etc.

So, the correct option is 'sugar and phosphate components of a nucleic acid molecule'.

Multiple choice dna replication replication and protein synthesis nucleic acids and protein synthesis heredity biology

Replication of DNA on its lagging strand is initiated by.

  1. DNA polymerase III

  2. RNA primer

  3. DNA polymerase I

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

DNA polymerases cannot initiate synthesis de novo and require a free 3 prime hydroxyl group provided by a short RNA primer to begin replication, particularly on the lagging strand for each Okazaki fragment.

Multiple choice dna replication replication and protein synthesis nucleic acids and protein synthesis heredity biology

Choose the correct answers from the alternatives given :
Which enzyme catalyzes the synthesis of a new strand for a DNA molecule by linking nucleotides to the developing strand?

  1. DNA ligase

  2. DNA polymerase

  3. Single-strand binding proteins

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

DNA polymerase is an enzyme that synthesis DNA molecules from deoxyribonucleotides which are the building blocks of DNA. Each nucleotide contains a sugar molecule (deoxyribose sugar), a phosphate molecule, and any one of the nucleotides (adenine, guanine, cytosine and thymine). They basically help in DNA replication by working in pairs to form a new DNA molecule. 

So, the correct option is 'DNA polymerase'.

Multiple choice dna replication replication and protein synthesis nucleic acids and protein synthesis heredity biology

A bacterium with completely non-radioactive DNA was allowed to replicate in radioactive medium for three generation what $ \%$ of the bacteria should contain radioactive DNA:

  1. $ 25\%$
  2. $ 75\%$
  3. $ 0\%$
  4. $ 100\%$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In semi-conservative DNA replication, every newly formed bacterium will inherit at least one strand of DNA that has incorporated radioactive nucleotides after three generations of replication in a radioactive medium. Therefore, 100 percent of the bacteria will contain some amount of radioactive DNA.

Multiple choice dna replication replication and protein synthesis nucleic acids and protein synthesis heredity biology

Choose the correct answers from the alternatives given :
In DNA replication, the Okazaki fragments on the lagging strand are joined together by

  1. DNA ligase

  2. DNA polymerase

  3. Primase

  4. Helicase
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

DNA ligase is an enzyme that facilitates the joining of the strands of the DNA by assisting the formation of phosphodiester bonds between two nucleotides.

DNA polymerase is an enzyme that helps in DNA replication by the formation of deoxyribonucleotides, building blocks of DNA.
Primase is an enzyme that synthesis short RNA sequences called primers that help in the initiation of DNA synthesis.
Helicase is an enzyme that helps in winding and unwinding of the double-stranded structure of the DNA.
So, the correct option is 'DNA ligase'

Multiple choice dna replication replication and protein synthesis nucleic acids and protein synthesis heredity biology

During replication, DNA gyrases takes part in 

  1. Nicking DNA in eucaryotes

  2. Nicking DNA in procaryotes

  3. Synthesis of prier in eucaryotes

  4. Synthesis of primer in procaryotes
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

DNA gyrase is a type II topoisomerase in prokaryotes that relieves torsional strain ahead of the replication fork by nicking and re-sealing DNA strands.