Human Nutrition - Option D.1

Question 1

Distinguish between essential and non-essential nutrients.

Answer 1

Essential nutrients CANNOT be synthesized by the human body.
Non-essential nutrients CAN be synthesized by the human body.

Question 2

Outline how to determine the energy content of food.

Answer 2

• Calorimetry - burning a food sample // measuring the heat energy released from the burning food using a calorimeter
• Heat from the burning food is transferred to the water
• Temperature increase of the water is used to calculate the energy content of the food:
  Mass of water (g) x 4.2 (J/g℃) x Temp increase (℃)

Question 3

What must be kept constant when determining the energy content of food?

Answer 3

• mass of food sample
• mass / volume of water (1g = 1ml)
• starting temperature of water
• distance between calorimeter and burning food sample

Question 4

What could cause errors during calorimetry?

Answer 4

Heat loss to environment or incomplete combustion of food sample.

Question 5

Outline the causes and consequences of Vitamin D deficiency in humans.

Answer 5

Causes - lack of UV light exposure and lack of it in the diet.
Consequences - affects bone mineralization, rickets in children (bones near growth plates don’t develop properly) // osteomalacia in adults (soft bones, pain, increased fractures)

Question 6

What part of the brain controls the appetite?

Answer 6

Hypothalamus.

Question 7

Define malnutrition.

Answer 7

A health condition that is caused by a deficiency, imbalance, or excess nutrients in the diet.

Question 8

Outline the health consequences of obesity.

Answer 8

More likely to suffer from hypertension(high blood pressure) and type II diabetes(desensitized to insulin).

Question 8

Outline the health consequences of starvation.

Answer 8

-Body will begin to break down OWN tissue bc not receiving enough energy from diet.
- Adipose (fat) tissue broken down FIRST bc fats contain more energy and breakdown does not disrupt homeostasis
- Muscle tissue broken down SECOND to provide proteins

Question 9

Outline the health consequences of anorexia.

Answer 9

• Anorexia; eating disorder where individuals severely limit food intake.
• In severe cases, body breaks down heart muscle (blood pressure drops, heart may develop arrhythmias (irregular rhythms) due to electrolyte imbalances)

Question 10

Explain how cholesterol levels in the blood are an indicator of the risk of CHD (coronary heart disease).

Answer 10

• CHD is the development of atherosclerosis in the coronary arteries, which can lead to heart attack and stroke
• Atherosclerosis: high lvls of cholesterol in the blood that lead to the hardening and narrowing of the arteries due to a build up of plaque
• Restricts blood flow and reduces elasticity of the arterial wall