Differbetween
Bacterial and eukaryotic cells share many of the same basic features of replication; for instance, initiation requires a primer, elongation is always in the 5'-to-3' direction, and replication is always continuous along the leading strand and discontinuous along the lagging strand.
- What is the 5 to 3 direction?
- What is the overall direction of DNA strand elongation?
- Why can new nucleotides only be added in a 5 to 3 direction?
- What extends primers with DNA?
- Is RNA synthesized 5 to 3?
- Is the lagging strand 5 to 3?
- Why do Okazaki fragments form?
- Why does DNA synthesis occur in the 5 '- 3 direction?
- What are the three steps of each PCR cycle?
- Why does DNA polymerase 3 need a primer?
- Why is it called 3 and 5 end?
- What are the fragments called on the 5 to 3 strand?
What is the 5 to 3 direction?
5' - 3' direction refers to the orientation of nucleotides of a single strand of DNA or RNA. ... Any single strand of DNA/RNA will always have an unbound 5' phosphate at one end and an unbound 3' hydroxyl group at the opposite end.
What is the overall direction of DNA strand elongation?
The process in which an existing DNA strand is extended in a net 3' to 5' direction by activities including the addition of nucleotides to the 3' end of the strand, complementary to an existing template, as part of DNA replication.
Why can new nucleotides only be added in a 5 to 3 direction?
DNA pol uses the energy provided by hydrolysis of the high-energy phosphate bond at the 5' end of the incoming nucleotide to add it to the 3' end of the growing DNA. ... Without the high-energy phosphate bond, the correct nucleotide can not be added. Without proofreading, life wouldn't be good.
What extends primers with DNA?
DNA polymerase III extends the primers, adding on to the 3' end, to make the bulk of the new DNA. RNA primers are removed and replaced with DNA by DNA polymerase I. The gaps between DNA fragments are sealed by DNA ligase.
Is RNA synthesized 5 to 3?
The RNA is always synthesized in the 5′ → 3′ direction (Figures 10-10 and 10-11), with nucleoside triphosphates (NTPs) acting as substrates for the enzyme.
Is the lagging strand 5 to 3?
Lagging strand: ... Chunks of DNA, called Okazaki fragments, are then added to the lagging strand also in the 5' to 3' direction. This type of replication is called discontinuous as the Okazaki fragments will need to be joined up later.
Why do Okazaki fragments form?
Okazaki fragments form because the lagging strand that is being formed have to be formed in segments of 100–200 nucleotides. This is done DNA polymerase making small RNA primers along the lagging strand which are produced much more slowly than the process of DNA synthesis on the leading strand.
Why does DNA synthesis occur in the 5 '- 3 direction?
DNA is always synthesized in the 5'-to-3' direction, meaning that nucleotides are added only to the 3' end of the growing strand. As shown in Figure 2, the 5'-phosphate group of the new nucleotide binds to the 3'-OH group of the last nucleotide of the growing strand.
What are the three steps of each PCR cycle?
Three steps of PCR─denaturation, annealing, and extension─as shown in the first cycle, and the exponential amplification of target DNA with repeated cycling.
Why does DNA polymerase 3 need a primer?
DNA polymerases add nucleotides to the 3′ end of a polynucleotide chain. ... To initiate this reaction, DNA polymerases require a primer with a free 3′-hydroxyl group already base-paired to the template. They cannot start from scratch by adding nucleotides to a free single-stranded DNA template.
Why is it called 3 and 5 end?
Each end of DNA molecule has a number. One end is referred to as 5' (five prime) and the other end is referred to as 3' (three prime). The 5' and 3' designations refer to the number of carbon atom in a deoxyribose sugar molecule to which a phosphate group bonds.
What are the fragments called on the 5 to 3 strand?
This lagging strand is synthesized in pieces because the DNA polymerase can only synthesize in the 5′ to 3′ direction, and so it constantly encounters the previously-synthesized new strand. The pieces are called Okazaki fragments, and each fragment begins with its own RNA primer.
