Biology Chapter 6: Proteins and Nutrition
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Questions and Answers

What is the primary function of proteins in the human body?

  • To store genetic information
  • To provide energy
  • To facilitate metabolism, immunity, fluid balance, and nutrient transport (correct)
  • To regulate body temperature

    • What are essential amino acids characterized by?

  • They cannot be produced by the human body and must be obtained through diet (correct)
  • They can be produced by the human body
  • They are only found in plant-based foods
  • They are only necessary for muscle growth

    • What is the process of converting genetic information from RNA to assemble amino acids in a specific sequence?

  • Mutation
  • Translation (correct)
  • Gene expression
  • Transcription

    • What is the term for the unique 3-dimensional shape of a protein?

    <p>Tertiary and quaternary structure</p> Signup and view all the answers

    What happens to a protein when it loses its unique shape?

    <p>It loses its function irreversibly</p> Signup and view all the answers

    What is a complete protein?

    <p>A protein that contains all essential amino acids in sufficient quantities</p> Signup and view all the answers

    What is the term for combining two incomplete proteins to make a complete protein?

    <p>Mutual supplementation</p> Signup and view all the answers

    What are two protein sources that together supply all 9 essential amino acids?

    <p>Complementary proteins</p> Signup and view all the answers

    What is one of the reasons why we need proteins?

    <p>All of the above</p> Signup and view all the answers

    What happens to proteins in the stomach?

    <p>They are broken down into short polypeptides</p> Signup and view all the answers

    Who requires more protein?

    <p>All of the above</p> Signup and view all the answers

    What is the recommended daily intake of protein?

    <p>0.8 grams of protein per kilogram of body weight</p> Signup and view all the answers

    What is a risk of consuming too much protein?

    <p>Both A and B</p> Signup and view all the answers

    What is protein-energy malnutrition?

    <p>A disorder caused by inadequate intake of protein and energy</p> Signup and view all the answers

    What is marasmus?

    <p>A disease caused by severely inadequate intake of protein and energy</p> Signup and view all the answers

    Why do some people adopt a vegetarian diet?

    <p>All of the above</p> Signup and view all the answers

    What is a challenge of a vegetarian diet?

    <p>It can be low in certain vitamins and minerals</p> Signup and view all the answers

    What is the role of vitamin B12?

    <p>Assisting with DNA synthesis and nerve fiber protection and growth</p> Signup and view all the answers

    Which vitamin promotes cell growth?

    <p>Vitamin D</p> Signup and view all the answers

    What is the primary function of iron in the body?

    <p>Assisting with oxygen transport and amino acid creation</p> Signup and view all the answers

    Which of the following is a characteristic of fat-soluble vitamins?

    <p>They can lead to toxicity if consumed in excess</p> Signup and view all the answers

    What is the main difference between macronutrients and micronutrients?

    <p>Macronutrients provide energy, while micronutrients do not</p> Signup and view all the answers

    Which of the following is NOT a characteristic of water-soluble vitamins?

    <p>They can lead to toxicity if consumed in excess</p> Signup and view all the answers

    What is the primary function of calcium in the body?

    <p>Maintaining bone health and muscle contraction</p> Signup and view all the answers

    What is the primary function of zinc in the body?

    <p>Assisting with immune function and growth</p> Signup and view all the answers

    What is the main difference between micronutrients and macronutrients in terms of absorption?

    <p>Macronutrients have a higher absorption rate than micronutrients</p> Signup and view all the answers

    What is the daily requirement of major minerals in the body?

    <p>100mg/day</p> Signup and view all the answers

    What is the total number of essential trace minerals in the body?

    <p>8</p> Signup and view all the answers

    Which of the following factors can affect the absorption of micronutrients?

    <p>Chemical form of the nutrient</p> Signup and view all the answers

    What is a potential risk of supplementing micronutrients?

    <p>Developing toxicity</p> Signup and view all the answers

    Which of the following minerals has been associated with a reduced risk of hypertension?

    <p>Calcium</p> Signup and view all the answers

    Which of the following substances may prove to be essential in the diet?

    <p>All of the above</p> Signup and view all the answers

    Study Notes

    Proteins

    • Critical molecules for metabolism, immunity, fluid balance, and nutrient transport
    • Provide energy and are a form of nitrogen that the body uses
    • Function: metabolism, immunity, fluid balance, and nutrient transport

    Amino Acids

    • Nitrogen-containing molecules that form proteins
    • Essential amino acids: 9 out of 20, cannot be produced by the body, and must be obtained from food
    • Nonessential amino acids: made by the body

    Protein Synthesis

    • 2 amino acids join to form a dipeptide through a peptide bond
    • 10 or more amino acids bond together to form a polypeptide
    • Proteins are made by combining multiple amino acids through transcription and translation
    • Transcription: genetic information in DNA is copied to make RNA
    • Translation: conversion of genetic information in RNA to assemble amino acids in the sequence to synthesize a protein on the ribosome

    Protein Structure

    • Primary structure: sequential order of amino acids
    • Secondary structure: spiral shape due to chemical bonding between amino acids
    • Tertiary and quaternary structure: folding into a unique 3-dimensional shape that may be globular or fibrous
    • Denaturation: loss of protein shape due to heat, acids/bases, heavy metals, or alcohols, resulting in an irreversible loss in protein function

    Protein Quality

    • Incomplete protein: lacks essential amino acids in sufficient quantities, compromising growth and health
    • Complete protein: contains sufficient amounts of all 9 essential amino acids, considered a "high-quality" protein
    • Mutual supplementation: combining 2 incomplete proteins to make a complete protein
    • Complementary proteins: 2 protein sources that together supply all 9 essential amino acids

    Importance of Proteins

    • Cell growth, repair, and maintenance
    • Enzymes, hormones, and antibodies
    • Fluid and electrolyte balance, PH balance, and energy source
    • Transport and storage of nutrients

    Protein Digestion and Absorption

    • Stomach acids and enzymes break proteins into short polypeptides
    • Digestion continues in the small intestine, where polypeptides are further broken down
    • Pancreatic enzymes called proteases complete the digestion of proteins into single amino acids
    • Protein digestibility affects protein quality

    Protein Requirements

    • Nitrogen balance: relationship between nitrogen consumption and excretion
    • Recommended dietary allowance (RDA): 0.8 grams of protein per kilogram of body weight per day, 10-35% of total energy intake
    • Certain groups require more protein: children, adolescents, pregnant or lactating women, athletes, and vegetarians

    Protein Sources

    • Animal protein sources (meat, dairy), soy products, and legumes are highly digestible
    • Grains and veggie proteins are less digestible
    • Legumes, nuts, and "new" foods (quorn, quinoa, amaranth, teff, millet, and sorghum) are alternative protein sources

    Risks of Excessive Protein Intake

    • High cholesterol and heart disease
    • Kidney disease in people who are susceptible
    • No evidence that high-protein diets lead to bone loss, except in people consuming inadequate calcium

    Protein-Energy Malnutrition

    • Disorder caused by inadequate intake of protein and energy
    • Two most common forms: marasmus and kwashiorkor
    • Marasmus: disease resulting from severely inadequate intakes of protein, energy, and other nutrients, characterized by extreme tissue wasting and stunted growth and development
    • Kwashiorkor: disease resulting from extremely low protein intake, characterized by weight loss, muscle wasting, and edema, often seen in children in developing countries

    Vegetarianism

    • Restricting the diet to foods of plant origin
    • Many versions and reasons to adopt a vegetarian diet, including health benefits, ecological, religious, ethical, and food safety concerns

    Health Benefits of Vegetarianism

    • Lower intake of fat and total energy
    • Lower blood pressure
    • Reduced risk of heart disease, certain types of cancer, and kidney disease
    • Fewer digestive problems

    Challenges of Vegetarianism

    • Can be low in some vitamins and minerals (iron, calcium, zinc, vitamin D, and vitamin B12)
    • Must plan a balanced and adequate diet
    • Soy products are an excellent protein source
    • Should include complementary proteins

    Vitamins and Minerals

    • Macronutrients: carbohydrates, fats, and protein, provide energy, require large amounts
    • Micronutrients: vitamins and minerals, don't supply energy, small amounts, assist body functions, and may have low absorption rates
    • Fat-soluble vitamins: A, D, E, and K, have large storage, toxicity, and deficiency symptoms may take months to develop
    • Water-soluble vitamins: 9 vitamins, have minimal storage, toxicity is rare, and deficiency symptoms occur quickly
    • Minerals: inorganic, can't be synthesized by plants/animals, 2 classifications based on need: major minerals (100mg/day required, 5g or higher in body) and trace minerals (less than 100mg/day required, body contains less than 5g)
    • Absorption of micronutrients depends on factors: chemical form, food components, other nutrients, and supplementation
    • Adequate intake of micronutrients has been associated with lowered disease risks

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    Description

    This quiz covers the basics of proteins, their functions, and importance in nutrition. Learn about amino acids, essential and nonessential ones, and how proteins are made.

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