Biology: In DNA replication, do both DNA strands act as a template strand?

In this biology question I was doing, it said "Both polypeptide strands act as a template" was an incorrect statement (The Q was to cross incorrect statements). I thought each strand in a DNA molecule in replication is a template strand, so each new DNA molecule has a strand from the original as part of semi conservative replication.
Could someone please explain this? I am sorry in advance if it is really simple and if I waste anyone's time. Thanks :smile:

Reply 1

Reality Check

22

Original post by Shar1738

In this biology question I was doing, it said "Both polypeptide strands act as a template" was an incorrect statement (The Q was to cross incorrect statements). I thought each strand in a DNA molecule in replication is a template strand, so each new DNA molecule has a strand from the original as part of semi conservative replication.
Could someone please explain this? I am sorry in advance if it is really simple and if I waste anyone's time. Thanks :smile:

You need to post the question. In semiconservative DNA replication, both strands are used as template strands in antiparallel directions: each double-strand of DNA gives rise to two double-stranded DNA copies, each containing one strand of the original DNA (hence semiconservative).

Reply 2

TriplexA

18

Original post by Shar1738

In this biology question I was doing, it said "Both polypeptide strands act as a template" was an incorrect statement (The Q was to cross incorrect statements). I thought each strand in a DNA molecule in replication is a template strand, so each new DNA molecule has a strand from the original as part of semi conservative replication.
Could someone please explain this? I am sorry in advance if it is really simple and if I waste anyone's time. Thanks :smile:

@Reality Check has provided a great explanation.

Bio mark schemes can be very picky so in theory both are template strands but the mark scheme may have just wanted the process for the formation of one (new) DNA molecule via semi conservative replication hence why saying both would be wrong.

Try to look for clues in the Q and answer accordingly.

Hope this makes sense :smile:

(edited 2 years ago)

Reply 3

caitlinmeadwell

10

Original post by Shar1738

In this biology question I was doing, it said "Both polypeptide strands act as a template" was an incorrect statement (The Q was to cross incorrect statements). I thought each strand in a DNA molecule in replication is a template strand, so each new DNA molecule has a strand from the original as part of semi conservative replication.
Could someone please explain this? I am sorry in advance if it is really simple and if I waste anyone's time. Thanks :smile:

Both strands do act as template strands, but the statement is incorrect as they aren’t polypeptides.

Reply 4

sciencewatches

11

In transcription only one strand is used as the template. The other strand is regarded as nonsense strand

Reply 5

Shar1738

OP

4

Original post by Reality Check

You need to post the question. In semiconservative DNA replication, both strands are used as template strands in antiparallel directions: each double-strand of DNA gives rise to two double-stranded DNA copies, each containing one strand of the original DNA (hence semiconservative).

Oh ok

Table 5.1 contains a list of statements about DNA replication. Some of these statements are
incorrect.
Put a cross (X) in the box next to each incorrect statement.

The DNA molecule unwinds
Hydrogen bonds between the base pairs break
Free RNA nucleotides join to bases on the exposed DNA strands
Both polypeptide strands act as a template
Hydrogen bonds form between complementary bases
Three hydrogen bonds form between bases A and T
DNA polymerase links the new nucleotides
Covalent bonds form between the phosphate of one nucleotide
and the pentose sugar of the next nucleotide

I got the other 2 statements but I don't understand the both polypeptide option