7th Grade Science Student ebook

10.1 THE ROLE OF DNA IN HEREDITY

Chapter 10: The Code of Life

DNA replication

What is DNA

replication?

We learned in Chapter 8 that before mitosis, the amount of DNA

doubles. DNA replication is the process of a DNA molecule making

a copy of itself. DNA replication occurs before mitosis begins and

before the first division of meiosis. It ensures that each daughter

cell has an exact copy of the genetic material from the parent cell.

DNA replication ensures that each

daughter cell has an exact copy of

the DNA from the parent cell.

The process of

DNA replication

DNA replication results in one DNA molecule

becoming two daughter molecules—each an exact

copy of the original molecule. The steps of the process

are outlined below.

1. DNA replication begins with the partial unwinding
   of the double helix. The base pairs separate.


2. A special molecule moves along each original
   strand of DNA and “reads” the bases.


3. A new strand is assembled along each original
   strand. The pieces are assembled from molecules
   in the cytoplasm.


4. When the process is complete, two daughter
   molecules will have been produced. Each daughter
   molecule is identical to the original molecule.


5. Both strands of the original DNA molecule have
   remained intact. Each daughter molecule is made
   of one original strand and one new strand.

DNA replication - the process of

a DNA molecule making a copy of

itself.