Mitosis & DNA replication

Question 1

Steps of DNA replication

Answer 1

Step 1 - The DNA of the double helix unzips meaning each base splits from its complementary pair. This occurs due to an enzyme It leaves all of the bases exposed.
Step 2 – A specialised enzyme begins to attach free bases with the exposed bases on each strand of the DNA helix. They follow the complementary base pairing rules.
Step 3 – The result is now two double helix strands which are completely identical to each other.

At the end of DNA replication, each strand of the replicated chromosome is called a “Chromatid”. They are joined in the centre by a structure called a “Centromere”. Now that the DNA in the cell has replicated, the cell is now ready to divide into two new cells. This cell division process called “Mitosis”.

Question 2

Base pairing rules

Answer 2

A = T
G = C
Apple in Tree
Car in the Garage

Question 3

Interphase

Answer 3

Chromosomes are copied and they appear as thread like coils

Question 4

Prophase

Answer 4

Mitosis beings, centrioles appear and begin to move to opposite ends of the cell, and spindle fibres form between the poles. Chromosomes appear, thicken and shorten.

Question 5

Metaphase

Answer 5

Chromosomes line up at the spindle fibres at the equator of the cell, and the centromere of the chromosomes attach to the spindle fibres.

Question 6

Anaphase

Answer 6

The chromatids separate at the centromere, and are again known as chromosomes. The chromosomes are pulled apart and move to opposite ends of the spindle.

Question 7

Telophase

Answer 7

Two new daughter cells are formed and cell division ends. 2