Biology 1 Part 1- Diet and Exercise

Seven components of a healthy diet

Carbohydrates
Proteins
Fats
Minerals
Vitamins
Fibre
Water

Metabolism- all the chemical reactions that occur in cells
Metabolic rate- how quickly all the reactions that occur in cells happen

What happens when you exercise?

Muscles contract to move limbs
They need energy to contract
Muscle cells respire more, to release energy
To provide energy the body needs more food
Exercise increases the amount of energy expended by the body

Obesity

Obesity (having a BMI of 30 or above) can lead to type 2 diabetes, arthritis, breast cancer and an increased risk of strokes, heart disease and heart attacks.

Underwight

Being underwight (having a BMI of less than 18) can lead to an ineffective immune system, deficiency diseases such as rickets due to a lack of a component in a diet, and women can have irregular periods.

Malnourishment

Some people do not eat a balanced diet. They eat the wrong amount of types of foods. A person is malnourished if their diet is not balanced.

Muscle to fat proportions in the body

Fat cells- fat cells store fat. They are inactive and have a low rate of respiration to ensure they don't use stored fat.

Muscle cells- they are active. Muscle cells need energy from respiration to contract. Their rate of respiration is high.

More muscle than fat= high metabolic rate

Males generally have more muscle and less fat in their bodies than women. This is largely determined by genes.

Inherited Factors and Metabolic Rate

Tall people have a higher metabolic rate as they lose more heat from their body surface

Contrary to popular belief overweight people have a higher metabolism than slimmer people as their bodies are larger and need more energy to work

An underactive thyroid gland leads to a lower metabolic rate

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Biology 1 Part 1- Diet and Exercise