Cell Growth, Differentiation and Percentile Charts

What is mitosis used for?

Growth, repair and asexual reproduction

When does mitosis happen?

Normally cells only divide by mitosis when new diploid cells are needed for: growth, repair (replacement of damaged cells) and asexual reproduction

What can happen to cells after growth?

After growth, cells can then differentiate into specialised cells.

What are cancer cells?

Cancer cells are abnormal cells that divide uncontrollably by mitosis to form at tumour.

When do cells usually stop dividing?

Cells usually stop dividing when growth has finished, except when repair is needed.

What happens if the cell doens’t stop dividing?

Sometimes the controls that tell cells when to stop dividing go wrong which leads to cancer.

In animals, what divides using mitosis to produce genetically identical daughter cells?

A fertilised egg or zygote. These cells grow and divide by mitosis, and eventually differentiate into different types of cells to make up a whole organism.

What does differentiation create? Give examples.

Differentiation creates specialised cells adapted to carry out a particular function. Examples of specialised animal cells include:

• Red blood cells

• Egg and sperm cells

• Nerve cells

• Bone cells

• Smooth muscle cells

How do plant cells divide by mitosis?

Plant cells divide by mitosis, just behind the tips of shoots and roots. After this the cells grow by enlarging.

Why do young cells have small vacuoles?

Young cells have small vacuoles which take in water by osmosis and enlarge, causing the cells to elongate.

Most plant cells can continue to grow and differentiate throughout life. Give some examples of specialised plant cells.

• Xylem

• Mesophyll cells

• Stoma cells

• Phloem

• Root hair cells

What is growth?

Growth is a permanent increase in size.

What can percentile charts help us to do?

Percentile charts can help to show if a child is growing faster or slower their is normal for their age.