Cells and Control: Mitosis and Growth
Mitosis is your body's way of creating new cells for growth, healing cuts, and reproduction in some organisms. Think of it as nature's photocopier - it makes exact copies of cells when your body needs them.
During mitosis, one parent cell divides to create two identical daughter cells. These new cells have exactly the same genetic information as the original, which is why both your arms look the same even though they're made of billions of different cells.
The process happens in clear stages: interphase (DNA copying), prophase (chromosomes become visible), metaphase (chromosomes line up), anaphase (chromosomes separate), and telophase (cell splits in two). Each stage ensures the genetic material gets distributed perfectly.
Key Point: Mitosis only happens in body cells, not in the cells that make sex cells (gametes) - that's a different process entirely.
Percentile charts help doctors track if children are growing normally by comparing their development to other kids their age. If a baby falls below the 5th percentile or above the 95th, it might signal growth problems.
When mitosis goes wrong and cells divide uncontrollably, it leads to cancer. Normally, cells know when to stop dividing, but cancer cells have lost this control mechanism and keep multiplying to form tumours.
Animal growth starts with a fertilised egg dividing repeatedly through mitosis. These cells eventually differentiate into specialised types like red blood cells, nerve cells, and muscle cells - each perfectly designed for specific jobs.
Plant growth works differently - cell division happens mainly at shoot and root tips. After dividing, plant cells grow by enlarging their vacuoles with water, causing them to stretch. Unlike animal cells, most plant cells can keep growing and changing throughout the plant's entire life, creating specialised cells like xylem, phloem, and root hair cells.