Answer:
A. S phase
Explanation:
The cell cycle involves all the series of division events that occurs to an organism. Cell division, which can be meiosis or mitosis, involves two main stages viz: Interphase and M phase.
Interphase describes the resting stage of the cell i.e. when the cell is not dividing. The cell uses this time to prepare itself for the next round of division. Interphase stage further consists of three main phases viz: G1, S and G2 phases.
In the S phase or synthesis phase of Interphase, the cell duplicates its genetic material (DNA). Hence, an onion cell observed by a student to have loosely coiled chromatin depicting DNA duplication is in the S-PHASE.
More enzymes more useful collisions
Answer:
- Individuals are variable.
- Some variations are passed down.
- More offspring are produced than can survive;
- Survival and reproduction are not random.
- The history of earth is long.
Explanation:
The two enzymes that are used during DNA replication is helicase
and polymerase. Each enzyme has distinct role that made it a vital part of the replication.
In the course of DNA replication, the initial stage is to unzip the double
helix structure of the DNA molecule by the enzyme helicase, which breaks the
hydrogen bonds that holds the complementary bases of DNA.
Moreover, the DNA polymerase has the ability to exactly copy a
DNA template. This enzyme binds to the leading strand and then adding a new
complementary nucleotide bases to the DNA strand. In addition, it catalyzes the joining of
deoxyribonucleoside 5′-triphosphates (dNTPs) to form the increasing DNA chain.
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