Question

24. At the end of DNA synthesis in prokaryotes, the two conjoined circular genomes are said to be .

26. Codons, mRNA, and complementary DNA of mRNA's template, are all  strands of nucleic acid.

28. This protein works with GTP/GDP to power the ribosome's movement along the mRNA template .

29. The initiation site of DNA synthesis in bacteria

Answer 1

24. At the end of DNA synthesis in prokaryotes, termination of DNA replication occurs.

The resulting conjoined circular chromosomes are said to be concatenated which means the circular chromosomes are interlocked and must be separated from each other.

Decatenation of interlocked circles is done by topoisomerase IV ,which is a type of Type II topoisomerase which introduces double-stranded breaks into DNA molecules,which allows the two circles to separate from each other and the enzyme ligase then reseals the circular chromosomes.

26. Nucleic acids(Polynucleotide)are mixture of basic protein and phosphorus containing organic acid.

There are two types of nucleic acid - DNA and RNA.

The monomeric unit of nucleic acids are called nucleotides which are phosphate esters of nucleosides which consists of 3 components:

a. Nitrogenous base (i.e. Purine or Pyrimidine)

b Penrose sugar

c. An ion of phosphoric acid

DNA is a double stranded molecule in which 1 strand holds the information that code for various genes; this strand is often called template or antisense strand .

The other strand is called Complementary or Coding or Sense strand.

Since m-RNA is made from the template strand,it has the same information as the coding strand.

Codons are sequence of three DNA or RNA nucleotides that corresponds with a specific amino acid.

The question that you have mentioned will now are clear from the above statements that codon, m-RNA and c-DNA are all strands of nucleic acid.

28. EF-G(Translocase) is an elongation factor in prokaryotic translation process.

It is driven by splitting a GTP to GDP.

The new peptidyl-tRNA in the A-site is translocated to the P-site as the ribosome moves exactly 3 nucleotides along the m-RNA molecule,going in the 5' to 3' direction.

The enzyme Translocase is the enzyme(basically protein) has the role in movement of ribosome.

29. The initiation site of DNA synthesis in bacteria (prokaryotes) is oriC .

It spans approximately 245 bp of DNA which contains two short repeat motifs,one of 9 nucleotides and other of 13 nucleotides.

The 9nucleotide repeat,5 copies of which are dispersed throughout the oriC ,is the binding site of DnaA .

The result of DnaA binding is that double helix opens up within the tendem array of three AT-rich,13 nucleotide repeats located at one end of the oriC sequence.

DnaA protein (promotes helicase activity) binds to 9-mers(base pair sequence) in oriC forming an initial complex.

Binding of DnaA to oriC facilitates initial strand separation or melting which occurs at oriC requires13-mers.This process requires ATP and forms open complex which leads to the initiation of replication process.

Hope this helps you...Thank you?