Nutrition Lecture 2 structured
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Questions and Answers

What is the primary role of amylase in digestion?

  • To digest proteins
  • To break down carbohydrates (correct)
  • To emulsify fats
  • To transport nutrients

The digestion of lipids primarily begins in the stomach.

False (B)

What is the process called that involves the removal of metabolic waste products from the body?

Excretion

Proteins are broken down in the stomach by _____ and hydrochloric acid.

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

Match each nutrient to its primary enzyme involved in digestion:

<p>Carbohydrates = Amylase Proteins = Pepsin Fats = Lipase Nucleic Acids = Nucleases</p> Signup and view all the answers

Which stage of feeding involves the physical breakdown of food?

<p>Digestion (B)</p> Signup and view all the answers

Absorption is the process where nutrients pass into the bloodstream for distribution.

<p>True (A)</p> Signup and view all the answers

What are the end products of lipid digestion?

<p>Fatty acids and glycerol</p> Signup and view all the answers

What are the end products of pyruvate oxidation per pyruvate molecule?

<p>ACoA, CO₂, NADH (C)</p> Signup and view all the answers

The Krebs cycle produces one molecule of FADH₂ per Acetyl-CoA.

<p>True (A)</p> Signup and view all the answers

What is the primary energy carrier in the cell?

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

The process of breaking down complex molecules into simpler ones is called ______.

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

Match the metabolic processes with their definitions:

<p>Anabolism = Building complex molecules from simpler ones Catabolism = Breaking down complex molecules into simpler ones Gluconeogenesis = Creation of glucose from non-carbohydrate sources Lipolysis = Breakdown of fats into fatty acids and glycerol</p> Signup and view all the answers

What is produced in the electron transport chain as a final product of oxygen accepting electrons?

<p>Water (B)</p> Signup and view all the answers

Hypometabolism is associated with an increased metabolic rate.

<p>False (B)</p> Signup and view all the answers

What type of process is pyruvate oxidation?

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

Cells failing to respond to insulin is known as ______.

<p>insulin resistance</p> Signup and view all the answers

How many molecules of ATP are produced from one molecule of glucose in the electron transport chain?

<p>32-34 (C)</p> Signup and view all the answers

Which factor does NOT affect Basal Metabolic Rate (BMR)?

<p>Diet Composition (A)</p> Signup and view all the answers

Metabolism refers to the chemical reactions that convert food into energy.

<p>True (A)</p> Signup and view all the answers

What is the simplified estimate of BMR in kcal/kg/day for a person at rest?

<p>24</p> Signup and view all the answers

The Glycemic Index (GI) categorizes foods into low, medium, and high GI, with high GI foods causing a rapid spike in __________ levels.

<p>blood sugar</p> Signup and view all the answers

Match the following GI categories with their examples:

<p>Low GI = White bread Medium GI = Brown rice High GI = Lentils</p> Signup and view all the answers

Which of the following best describes a positive energy balance?

<p>More calories consumed than burned (D)</p> Signup and view all the answers

Ghrelin is a hormone that signals satiety and decreases food intake.

<p>False (B)</p> Signup and view all the answers

What is the primary function of antioxidants like ascorbic acid (vitamin C)?

<p>To neutralize free radicals</p> Signup and view all the answers

The energy expended through non-exercise activities, such as fidgeting, is known as __________.

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

Match the following hormones to their functions:

<p>Insulin = Regulates glucose uptake Glucagon = Promotes glucose release Leptin = Signals fullness Ghrelin = Stimulates hunger</p> Signup and view all the answers

What is the net gain of ATP molecules from glycolysis?

<p>2 (D)</p> Signup and view all the answers

Underweight and malnutrition are associated with chronic positive energy balance.

<p>False (B)</p> Signup and view all the answers

What is the classification of foods with a Glycemic Index (GI) of 70 or higher?

<p>High GI foods</p> Signup and view all the answers

The Harris-Benedict equation is used to estimate __________.

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

What is the primary reason for food processing?

<p>To enhance product quality (D)</p> Signup and view all the answers

Frying food maintains the same level of water-soluble vitamins compared to other cooking methods.

<p>False (B)</p> Signup and view all the answers

What kind of processing utilizes microbial processes?

<p>Biological processing</p> Signup and view all the answers

The process of _____ involves using microorganisms to convert sugars into acids or alcohol.

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

Match each cooking technique with its nutrient impact:

<p>Grilling = Moderate loss of water-soluble vitamins Steaming = Preserves most nutrients Boiling = Significant loss of water-soluble vitamins Baking = Loss of heat-sensitive vitamins</p> Signup and view all the answers

Which mechanical processing technique primarily affects texture and flavor release?

<p>Grinding (D)</p> Signup and view all the answers

Chemical additives are used solely to enhance flavor without any health concerns.

<p>False (B)</p> Signup and view all the answers

Name two heat-sensitive vitamins lost during baking.

<p>Thiamin and vitamin C</p> Signup and view all the answers

____ processing involves physical methods such as grinding and chopping.

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

How does boiling food primarily impact nutrient retention?

<p>Leaches out water-soluble vitamins (D)</p> Signup and view all the answers

An emulsifier is used to mix water-based and oil-based ingredients.

<p>True (A)</p> Signup and view all the answers

What is the impact of hydrogenation on fats?

<p>Produces unhealthy trans fats</p> Signup and view all the answers

The technique of _____ involves quick submersion of food in boiling water followed by cooling.

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

What effect does microwaving have on nutrients?

<p>Retention of thiamin and riboflavin (B)</p> Signup and view all the answers

Match the following chemical additives with their function:

<p>Preservatives = Prevent spoilage Antioxidants = Prevent oxidation Flavor enhancers = Enhance taste Color additives = Restore food color</p> Signup and view all the answers

Flashcards

Digestion

The process that breaks down nutrients in food into forms that the digestive system can absorb.

Mechanical Digestion

The physical process of breaking down food, like chewing and churning.

Chemical Digestion

The chemical breakdown of food using enzymes, like amylase for carbs, pepsin for proteins, and lipase for fats.

Absorption

The process of moving nutrients from the digestive tract into the bloodstream or lymphatic system for the body to use.

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Assimilation

The use of absorbed nutrients by cells for energy, growth, and repair.

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Respiration

The metabolic pathways that extract energy from food, mainly carbohydrates, in a series of steps.

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Excretion/Egestion

The removal of waste products and undigested food from the body.

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Fat Digestion

The process of breaking down fats into fatty acids and glycerol using bile and lipase.

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What is food processing?

Transforming raw ingredients into edible food products through various methods, including mechanical, thermal, chemical, or biological processes.

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Why is food processed?

Ensuring food safety by reducing risks from harmful microbes or chemicals.

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What is mechanical processing?

Methods that physically alter food, like grinding, chopping, or mixing, without changing its chemical composition.

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What is thermal processing?

Using heat to cook or preserve food, like baking bread or canning fruits.

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What is chemical processing?

Adding substances that alter food's properties, like preservatives, colorants, and flavor enhancers.

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What is biological processing?

Employing living organisms, like bacteria or yeast, to transform food, for example, fermentation of yogurt or making bread.

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What factors influence nutrient retention during food processing?

The stability of the nutrient, processing intensity, environmental conditions, and the delivery method of food (fresh, frozen, canned) can affect nutrient retention.

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What is baking, and how does it affect nutrients?

Uses dry heat, often in an oven, to bake food like bread or cookies. It can cause a loss of heat-sensitive vitamins like thiamin and vitamin C, but has minimal effect on fat-soluble vitamins.

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How does microwaving affect nutrients?

Involves high-frequency waves for rapid heating. It retains vitamins like thiamin and riboflavin, and has minimal effect on minerals.

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What is frying, and how does it affect nutrients?

Cooking food in hot oil or fat. It leads to a loss of water-soluble vitamins, but retains fat-soluble vitamins.

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How does grilling affect nutrients?

Utilizes direct high heat, often on a grill. It can cause moderate loss of water-soluble vitamins, but minerals are generally preserved.

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What is boiling, and how does it affect nutrients?

Boiling involves submerging food in boiling water. It leads to significant loss of water-soluble vitamins due to leaching, but minerals are relatively stable.

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What is steaming, and how does it affect nutrients?

Uses steam to cook food, preserving most nutrients.

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What is blanching, and how does it affect nutrients?

A quick submersion of food in boiling water followed by immediate cooling. It helps reduce nutrient loss by minimizing cooking time.

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What is pasteurization, and how does it affect nutrients?

A mild heat treatment to kill pathogens while preserving most of the nutritional quality.

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What is Basal Metabolic Rate (BMR)?

The minimum amount of energy needed for basic bodily functions like breathing, heartbeat, and cell processes while at rest.

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What is the Glycemic Index (GI)?

It's a ranking of carbohydrates based on how quickly they raise blood glucose levels after eating, compared to a reference food like glucose or white bread.

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What are the three categories of Glycemic Index (GI)?

Low GI foods (≤55) cause a slow and gradual increase in blood sugar, medium GI foods (56-69) cause a moderate increase, and high GI foods (≥70) cause a rapid spike in blood sugar.

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What is Energy Balance?

It means the number of calories consumed equals the number of calories burned, maintaining body weight.

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What is Positive Energy Balance?

This happens when more calories are consumed than expended, leading to weight gain.

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What is Negative Energy Balance?

This happens when fewer calories are consumed than expended, resulting in weight loss.

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What is the Basal Metabolic Rate (BMR) as a component of total daily energy expenditure?

This is energy needed for vital body functions at rest (~60-75% of your total daily energy expenditure).

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What is the Thermic Effect of Food (TEF)?

This is energy required for digesting, absorbing, and metabolizing food (~10% of your total daily energy expenditure).

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What is Physical Activity Level (PAL)?

This is energy spent on physical activity, including exercise and daily movement (varies widely).

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What is Non-Exercise Activity Thermogenesis (NEAT)?

This is the energy expended through non-exercise activities like fidgeting or maintaining posture.

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What are the roles of Insulin and Glucagon in energy balance?

Insulin regulates glucose uptake and storage, while glucagon promotes glucose release when blood sugar is low.

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What are the roles of Leptin and Ghrelin in energy balance?

Leptin signals satiety (fullness) and suppresses appetite, while ghrelin stimulates hunger and increases food intake.

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What is Obesity? What are its risks?

Prolonged positive energy balance leads to it, increasing risks for type 2 diabetes, cardiovascular disease, hypertension, and joint issues.

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What is Underweight and Malnutrition? What are its risks?

Chronic negative energy balance causes it, leading to risks like weakened immune system, muscle wasting, and nutrient deficiencies.

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What is Metabolic Syndrome? What are its health risks?

This is a cluster of conditions including insulin resistance, high blood pressure, and abnormal cholesterol levels linked to an energy imbalance.

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Pyruvate Oxidation

The process of converting pyruvate into acetyl-CoA, producing NADH and releasing carbon dioxide.

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Krebs Cycle

A cyclic series of reactions that produce ATP, NADH, and FADH₂ from acetyl-CoA, taking place in the mitochondrial matrix.

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Electron Transport Chain

A series of protein complexes in the inner mitochondrial membrane that use electrons from NADH and FADH₂ to generate ATP.

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Hypermetabolism

An increased metabolic rate causing excessive calorie burning, often seen in trauma, burns, or hyperthyroidism.

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Hypometabolism

A decreased metabolic rate causing reduced energy expenditure, associated with conditions like hypothyroidism or malnutrition.

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Insulin Resistance

Cells fail to respond to insulin, leading to high blood sugar levels. This can be caused by factors like obesity, sedentary lifestyle, or genetics.

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Metabolism

The sum of all chemical reactions in the body that convert food into energy and building materials.

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Anabolism

The process of building complex molecules from simpler ones, requiring energy (e.g., muscle growth).

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Catabolism

The breakdown of complex molecules into simpler ones, releasing energy (e.g., digestion).

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ATP

The primary energy carrier in the cell.

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Study Notes

Digestion, Absorption, Metabolism, and Energy Balance

  • Digestion is the conversion of ingested nutrients into absorbable forms by mechanical and chemical processes.
  • Feeding stages include ingestion, mechanical and chemical digestion, absorption, assimilation, respiration and excretion/egestion.
  • Mechanical digestion involves chewing, stomach churning, while chemical digestion uses enzymes.
  • Carbohydrates are broken down by amylase into simple sugars.
  • Proteins are broken down by proteases (e.g., pepsin, trypsin).
  • Fats are broken down by lipases into fatty acids and glycerol, aided by bile.

Food Processing and Nutrient Retention

  • Food processing alters raw ingredients for consumption and safety.
  • Processing improves quality (taste, color, texture) and increases convenience.
  • Processing methods include mechanical (e.g., grinding), thermal (e.g., baking), chemical (e.g., additives), and biological (e.g., fermentation).

Impact of Processing on Nutrient Content

  • Heat processing affects nutrient retention depending on the technique, food type and the chemical stability of the nutrient.
  • Factors influencing nutrient loss during processing include chemical stability of nutrients, extent of processing, environmental conditions, and food form.

Heat Processing Techniques and Nutrient Effects

  • Baking (dry heat) leads to loss of some water-soluble vitamins, minimal effect on fat-soluble vitamins.
  • Microwaving retains some vitamins and minerals.
  • Frying loses water-soluble vitamins while preserving fat-soluble ones.
  • Grilling results in moderate loss of water-soluble vitamins with sustained minerals.
  • Boiling leads to significant loss of water-soluble vitamins.
  • Steaming retains most nutrients.
  • Blanching limits nutrient loss with brief heating.
  • Pasteurization kills pathogens while largely preserving nutrients.

Mechanical Food Processing Techniques

  • Grinding reduces food particle size and increases surface area and cooking speed, but heat generated might cause slight nutrient losses, minerals and fiber are mostly retained unless refined.
  • Chopping breaks food into pieces for even cooking, preserving composition and minimal losses unless oxidation damages ingredients (e.g., vitamin C degradation in fruit).
  • Blending liquefies/purees food into a smooth mixture, potentially affecting texture and color, might degrade sensitive materials but increases the bioavailability of certain nutrients.

Chemical Food Processing Techniques

  • Chemical additives (e.g., preservatives, antioxidants, flavor enhancers, color additives, sweeteners, emulsifiers, thickeners/stabilizers, pH control agents) are used to improve food quality, safety, or characteristics.

Common Chemical Processing Methods

  • Curing/Salting draws out moisture for preservation, retaining protein and minerals but increasing sodium content.
  • Pickling uses acids (e.g., vinegar) for flavor and preservation, preserves minerals and fat-soluble vitamins but might reduce water-soluble ones like vitamin C.
  • Emulsification combines liquids (e.g., oil-water mixtures), maintaining intact nutrient content but increasing calorie count.
  • Hydrogenation (converting unsaturated fats to solid fats, e.g. margarine) creates unhealthy trans fats and raises cholesterol.
  • Acidification lowers pH to inhibit bacterial growth but may slightly degrade water-soluble vitamins.

Biological Food Processing Techniques

  • Fermentation uses microorganisms to convert sugars, enhancing B-vitamin availability but maintains minerals and fat-soluble types.

Energy Balance

  • Energy balance is achieved when calories consumed equal those expended, crucial for weight management.
  • Positive energy balance results in weight gain, while negative balance leads to weight loss.
  • Total Daily Energy Expenditure (TDEE) encompasses BMR, Thermic Effect of Food (TEF), PAL, and NEAT.

Factors Affecting Basal Metabolic Rate (BMR)

  • BMR is the minimum amount of energy required for essential bodily functions.
  • Age, gender, body composition, genetics, hormones, and environmental temperature influence BMR.

Glycemic Index (GI)

  • GI is a ranking of carbohydrates based on how quickly they increase blood glucose compared to a reference food.
  • GI categories include low (≤55), medium (56-69), and high (≥70).
  • GI is calculated through blood-glucose response measurements.

Detailed Breakdown of Key Metabolic Processes

  • Glycolysis breaks glucose into pyruvate, producing ATP and NADH (anaerobic).
  • Pyruvate oxidation converts pyruvate to acetyl-CoA, producing NADH and CO2 (aerobic).
  • Krebs Cycle (Citric Acid Cycle) produces ATP, NADH, and FADH2 from acetyl-CoA (aerobic).
  • Electron Transport Chain uses electrons from NADH and FADH2 to generate ATP through oxidative phosphorylation (aerobic).

Energy Balance and Metabolic Disorders

  • Hypermetabolism is increased metabolic rate leading to weight loss, while hypometabolism is decreased metabolic rate leading to weight gain.
  • Insulin resistance links high blood sugars with obesity, and can increase risks associated with metabolic diseases.
  • Eating disorders (Anorexia, Bulimia, Binge-eating) are related to disrupted energy balance and metabolism.

Key Nutritional Terms

  • Macronutrients (carbohydrates, proteins, fats) are required in larger amounts, while micronutrients (vitamins and minerals) are needed in smaller quantities.
  • Metabolism consists of chemical reactions converting food to energy and building blocks.
  • Absorption is the process of moving nutrients into the bloodstream or lymphatic system.
    • Glycolysis is glucose breakdown into energy (ATP).
  • BMR is the fundamental energy consumption rate at rest.

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Description

This quiz explores the fundamentals of digestion, absorption, metabolism, and energy balance. It also delves into food processing methods and their impact on nutrient retention. Understand how nutrients are broken down and the effects of food processing on dietary quality.

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