GEN BIO: CELL CYCLE

cell cycle

It involves distinct and regular phases of growth, DNA duplication

and cell division that are needed to allow growth and repair.

• interphase

• prophase

• metaphase

• anaphase

• telophase

stages of cell cycle

interphase

is the growth period in the cell cycle and is divided into three parts

gap 1 (growth phase)

First part of the cell cycle , the cell carries out its normal metabolic function.

Cells are specialized based on their function.

synthesis (s)

this is the time that the cell makes a copy of the genetic material in the form of nuclear DNA.

dna replication

the process of copying and duplicating a dna molecule

• unwinding

• complementary base pairing

• results

dna replication process

unwinding

The double-stranded DNA unzips with the help of enzyme - helicase.

complementary base pairing

● Each original strand acts as a template.

● Free nucleotides in the nucleus pair with the exposed

bases:

○ A pairs with T, G pairs with C

joining

Enzyme DNA polymerase (molecular copier) links the new nucleotides together to form a new strand.

result

• Appearance of two identical sister chromatids

• The DNA has doubled, but the cell still has one nucleus

• Centrosomes are also duplicated in preparation for mitosis

gap 2

A checkpoint happens before transitioning to the next stage.

mitosis

Division of the nucleus and the genetic material.

cytokinesis

Division of the cytoplasm of the cell.

prophase

chromatin (loose complex DNA and protein materials in the nucleus) materials condenses into tightly coiled chromosomes.

metaphase

the spindle fiber attached to the kinetochore of the sister chromatids

facilitates the movement of the chromosomes

anaphase

cohesin breaks down and the sister chromatids pull away from each other towards the opposite ends of the cell.

telophase

two complete set of identical chromosomes are now positioned at each

pole of the cell