Form 3, chapter 5, growth (summary)

• Growth is defined as an increase in size, the number of cells, changes in shape and function of an organism.
• Growth in unicellular organisms only involves increase in mass or size.
• In multi cellular organisms, growth involves cell divisions, cell growth and cell differentiation to form new tissues and organs.
• The growth in multicellular organisms are permanent and irreversible.
• Human growth can be divided into infancy, childhood, adolescence, adulthood and old age.
• Growth rate differs at each stage.
• There are differences between growth rate of males and females.
• Girl normally reach puberty at the age of 12 years, while boys usually reach puberty at the age of 14 years.
• Females reach maximum growth earlier than males.
• Males have a longer period for physical growth compared to females.
• A balanced diet with proper nutrition is important for children to have healthy mental and physical growth.
• Carbohydrates and fats are essential to provide sufficient energy for active children and teenagers.
• Proteins are needed to repair damaged tissues and also for growth.
• A continuos lack of protein causes kwashiokor.
• Calcium is needed to build healthy bones and teeth.
• Rickets is a disease caused by a lack of calcium.
• The formation of healthy haemoglobin in red blood cells requires iron.
• Anaemia can be caused by insufficient iron in the body.
• Good health can be maintained with the help of vitamins.
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