Read the summary and the most important questions on Introduction to nutrition and metabolism | 9781420043129 | David A. Bender.

• 1 Why eat?

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• 1.2 Metabolic fuels

• What are the dietary sources of metabolic energy (fuels)?

  Carbohydrates, fats, protein and alcohol.

• 1.2.2 The need for protein

• What causes the continual loss of protein from the body? (At least two)

  1. Hair

  2. Shed skin cells

  3. Enzymes

  4. Other protein secreted from the gut

• 1.3.1 Hunger and satiety-short term control of feeding

• What part of the brain stimulates us to eat and stop eating?

  Hunger: Lateral hypothalmus through neurons that uses neuropeptide Y as transmitter.

  Satiety: Ventro-medial hypothalamus through neurons that use pro-opiomelanocortin (POMC)

• 1.3.2 Long term control of food intake and energy expenditure

• How does leptin act to increase energy expenditure and loss of adipose tissue?

  1. Increased expression of uncoupling proteins in adipose tissue and muscle;

  resulting in relatively uncontrolled oxidaion of metabolic fuel.

  2. Increased activity of lipase in adipose tissue;

  resulting in a breakdown of triacylglycerol reserves and release of nonesterified fatty acids, which are either oxidized or re esterified in liver/transpored to adipose tissue; costing energy.

  3. Decreased expression of acetyl CoA carboxylase in adipose tissue;

  decreasing both syntheses and increased oxidation of fatty acids.

  4. Increased apoptose in adipose tissue;

  reducing availability storing fat.

• 1.3.3 Appetite

• What are the five basic tastes the tongue can distinguish?

  1. Salt

  2. Savory

  3. Sweet

  4. bitter

  5. Sour

   

  NB: Also the ability to taste fat.

• When do we response in sensitivity for salt (sodium)?

  In a response to the state of sodium balance in the body, the active salt receptors will increase at times of sodium depletion.

• Why is the taste of savoriness important to us?

  Largely due to the presence of free amino acids in food and permits detection of protein-rich foods

• What can we detect with the taste of sweetness?

  Carbohydrates (energy sources)

• Why are sourness and bitterness an unpleasant sensation?

  Because many toxins occur in food that have a bitter and sour flavor.

• 2 Enzymes and metabolic pathways

• On what do all metabolic processes depend?

  Reactions between molecules, with breaking covelant bonds, forming others and yielding compounds from starting material.