Cell Divison- Mitosis

Question 1

The Cell Cycle

Answer 1

-Growth and DNA replication (interphase)
-Cell division (mitosis)

Question 2

Interphase

Answer 2

The cells DNA is unravelled and replicated, to double its genetic content. The organelles are also replicated so it has spare ones, and its ATP content is increased (ATP provides the energy needed for cell division)

Question 3

Mitosis (definition + importance)

Answer 3

-A parent cell divides to produce two genetically identical daughter cells
-Needed for growth of multicellular organisms and to repair damaged tissues

Question 4

Structure of chromosomes in mitosis

Answer 4

Two chromatids joined in the middle by a centromere. Two stands on the same chromosomes are called sister chromotids. The identical strands are made during interphase (Makes a copy)

Question 5

What are the stages of mitosis

Answer 5

1.Prophase
2.Metaphase
3.Anaphase
4.Telophase

Question 6

What happens during prophase

Answer 6

The chromosomes condense, getting shorter and fatter.
Tiny bundles of protein called centrioles start moving to opposite ends of the cell, forming a network of protein fibres across it called the spindle.
The nuclear envelope (the membrane around the nucleus) breaks down and chromosomes lie free in the cytoplasm.

Question 7

What happens during metaphase

Answer 7

The chromosomes (each with two chromatids) line up along the middle of the cell and become attached to the spindle by their centromere.

Question 8

What happens during anaphase

Answer 8

The centromeres divide, separating each pair of sister chromatids.
The spindles contract, pulling chromatids to opposite poles (ends) of the spindle, centromere first. This makes the chromatids appear v-shaped.

Question 9

What happens during telophase

Answer 9

The chromatids reach the opposite poles on the spindle. They uncoil and become long and thin again. They’re now called chromosomes again.
• A nuclear envelope forms around each group of chromosomes, so there are now two nuclei.
Division of the cytoplasm (cytokinesis, which starts in anaphase) finishes in telophase. There are now two daughter cells that are genetically identical to the original cell and to each other.
Mitosis is finished and each daughter cell starts the interphase part of the cell cycle to get ready for the next round of mitosis.

Question 10

How are cancers form

Answer 10

Mutation in the genes, cell division becomes out of control, cells keep dividing until the form a tumor

Question 11

Cancer treatments

Answer 11

Designed to control the rate of cell division