DNA Replication and The Cell Cycle

Question 1

Cell Cycle, orderly sequence of events by which a somatic cell duplicates its contents and divides into two cells. 2 main phases

Answer 1

Interphase, where the DNA is replicated

Mitotic Phase, where the nucleus and rest of cell is divided forming two identical ‘daughter’ cells

Question 2

DNA Replication, 3 steps

Answer 2

1. Enzymes break the weak hydrogen bonds between the bases in the DNA molecule.
2. Free DNA nucleotides in the nucleus base-pair with the ‘exposed’ bases on each strand of the original DNA molecule.
3. Two new, identical molecules of DNA are synthesized.

DNA replication occurs when a cell divides, mitosis

Question 3

Mitosis cell division needed for (3)

Answer 3

Growth (tissue growth)
Repair (damaged parts of the body)
Maintenance (replacement of lost cells i.e skin cells)