Question

The template strand of DNA is read in the _________ direction to allow for synthesis of _______ in the __________ direction? How can cells with the exact same genome give rise to different cell types?

Answer 1

The DNA template strand is read in the 3' to 5' direction to facilitate DNA synthesis in the 5' to 3' direction. DNA polymerase adds nucleotides only in the 5' to 3' direction, resulting in continuous synthesis on the leading strand and the creation of Okazaki fragments on the lagging strand. Cells differentiate into various types by expressing different genes despite having the same genome.

Step-by-step explanation:

The template strand of DNA is read in the 3' to 5' direction to allow for the synthesis of DNA in the 5' to 3' direction. The enzyme DNA polymerase is responsible for adding nucleotides to the new DNA strand, and it can only add nucleotides in the 5' to 3' direction. Therefore, on the leading strand, DNA synthesis occurs continuously in the direction of the replication fork. However, on the lagging strand, DNA is synthesized in short stretches called Okazaki fragments, which are created in the direction away from the replication fork and later joined together.

Different cell types can arise from cells with the same genome due to a process known as cellular differentiation. This process involves the regulated expression of different genes within the cell's DNA, leading to the production of different proteins and thus different cell characteristics, despite having identical genetic information.