Nutrition and Metabolism Quiz
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Questions and Answers

What type of lipoprotein is beneficial for transporting cholesterol to the liver for disposal?

  • HDL (correct)
  • VLDL
  • Chylomicron
  • LDL

Which type of fats are considered healthier and can reduce the risk of heart disease?

  • Trans fats
  • Monounsaturated and polyunsaturated fats (correct)
  • Hydrogenated fats
  • Saturated fats

Essential fatty acids (EFAs) must be obtained through the diet because:

  • The body can produce them in sufficient quantities.
  • The body cannot synthesize them. (correct)
  • They are not necessary for survival.
  • They are primarily found in carbohydrates.

What occurs during the process of dehydration between two monosaccharides?

<p>They release water and form a covalent bond. (D)</p> Signup and view all the answers

Which configuration is typical for the double bonds found in natural vegetable oils?

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

What is metabolism primarily responsible for in living organisms?

<p>Supporting life through chemical reactions (A)</p> Signup and view all the answers

Which of the following macronutrients provides the highest amount of energy per gram?

<p>Fats and oils (C)</p> Signup and view all the answers

What happens to energy when macronutrients are consumed in excess?

<p>It is stored as body fat or glycogen (B)</p> Signup and view all the answers

What is the thermic effect of food (TEF)?

<p>Energy expended in digesting and metabolizing food (B)</p> Signup and view all the answers

Which type of metabolism involves energy used to keep essential bodily functions operating?

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

Which macronutrient classification includes vitamins and minerals?

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

What is a consequence of the thermic effect of food after eating a large meal?

<p>Drowsiness due to blood diversion (C)</p> Signup and view all the answers

What is the caloric value of carbohydrates per gram?

<p>4 Cal/g (B)</p> Signup and view all the answers

How is basal metabolism measured?

<p>At rest after fasting for 12 hours (B)</p> Signup and view all the answers

What is the primary role of food in the human body?

<p>To provide chemical energy (D)</p> Signup and view all the answers

What is the relationship between calories and kilocalories?

<p>1 kcal = 1000 calories (B)</p> Signup and view all the answers

What unit is commonly used to measure energy in terms of heat?

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

Which statement correctly describes calorimetry?

<p>The technique for measuring heat in chemical processes (D)</p> Signup and view all the answers

How many joules are equivalent to 1 calorie?

<p>4.2 Joules (A)</p> Signup and view all the answers

If a 100-watt light bulb is triggered for one hour, how much energy is consumed in joules?

<p>360,000 Joules (A)</p> Signup and view all the answers

In what way does metabolism relate to the energy obtained from food?

<p>It breaks down food to release energy (C)</p> Signup and view all the answers

What is the estimated calorie consumption for a healthy adult at rest?

<p>1 Calorie per hour per kg (A)</p> Signup and view all the answers

Which of the following is NOT a function of fats and oils?

<p>Transport of oxygen (D)</p> Signup and view all the answers

What characterizes a saturated fatty acid?

<p>Has no carbon-carbon double bonds (B)</p> Signup and view all the answers

What impact does body stress have on calorie consumption?

<p>Increases calorie consumption (B)</p> Signup and view all the answers

Which aspect of fatty acids varies among different types?

<p>Number of carbon atoms (D)</p> Signup and view all the answers

What is a characteristic of fats and oils in food?

<p>Not soluble in water (C)</p> Signup and view all the answers

Which of the following statements about fatty acids is true?

<p>Fatty acids have a hydrocarbon side chain (C)</p> Signup and view all the answers

What is a potential benefit of fats in the body?

<p>Protection against heat loss (C)</p> Signup and view all the answers

What is true about the properties of fats in relation to flavor?

<p>Fats and oils are flavorless on their own (A)</p> Signup and view all the answers

What is considered a long-chain fatty acid primarily composed of?

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

What is stearic acid primarily composed of?

<p>One hydrocarbon chain and one carboxylic group (D)</p> Signup and view all the answers

Which statement correctly describes unsaturated fatty acids?

<p>They possess one or more carbon-carbon double bonds. (C)</p> Signup and view all the answers

What characterizes a triglyceride with a low melting temperature?

<p>Short side chains and low saturation (A)</p> Signup and view all the answers

Which type of fatty acid would most likely have a linear orientation in its structure?

<p>Saturated fatty acid (C)</p> Signup and view all the answers

What does a higher iodine number indicate about a triglyceride?

<p>It is more unsaturated. (A)</p> Signup and view all the answers

How do unsaturated side chains affect the melting point of triglycerides?

<p>They decrease the melting point due to irregularities in their structure. (D)</p> Signup and view all the answers

Which of the following fats exists as a solid at room temperature?

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

What role does cholesterol play in the body?

<p>It aids in digestion and hormone production. (D)</p> Signup and view all the answers

What type of fatty acid is oleic acid?

<p>Monounsaturated fatty acid (D)</p> Signup and view all the answers

Which of the following factors contributes to a higher melting point of triglycerides?

<p>Linear orientation and high degree of saturation (C)</p> Signup and view all the answers

What is the primary function of nutrients in food within the human body?

<p>To supply chemical energy for work and sustain life (C)</p> Signup and view all the answers

If 1 calorie is equivalent to how many joules?

<p>4.2 joules (A)</p> Signup and view all the answers

What measurement technique is used to quantify the amount of heat absorbed or released in a chemical reaction?

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

How many calories are there in a kilocalorie?

<p>1000 calories (D)</p> Signup and view all the answers

Which of the following statements is correct regarding watts and joules?

<p>1 watt is equal to 1 joule per 1 second (B)</p> Signup and view all the answers

What is the primary difference between macronutrients and micronutrients?

<p>Macronutrients are needed in large amounts, while micronutrients are required in small quantities. (C)</p> Signup and view all the answers

Which of the following statements correctly describes basal metabolism?

<p>It supports essential bodily functions while at rest after fasting. (B)</p> Signup and view all the answers

What is the caloric value of fats and oils per gram?

<p>9 Cal/g (D)</p> Signup and view all the answers

Which process primarily contributes to the thermic effect of food (TEF)?

<p>Digestion and metabolism of food (C)</p> Signup and view all the answers

What is a potential consequence of consuming an excess of macronutrients?

<p>Long-term storage of energy as body fat. (B)</p> Signup and view all the answers

What is the primary function of fats in the body?

<p>Serving as energy storage and insulation (D)</p> Signup and view all the answers

Which statement correctly describes the structure of saturated fatty acids?

<p>They have no carbon-carbon double bonds. (B)</p> Signup and view all the answers

Which of the following factors does NOT affect the nature of fatty acids?

<p>The type of organisms consuming it (B)</p> Signup and view all the answers

What happens to calorie consumption during periods of body stress like illness or pregnancy?

<p>Calorie consumption increases. (D)</p> Signup and view all the answers

What is a common misconception about fats and oils?

<p>They serve as a major source of vitamins. (A)</p> Signup and view all the answers

What is the primary structural characteristic of triglycerides that influences their melting point?

<p>Length and saturation of the fatty acid side chains (D)</p> Signup and view all the answers

Which fatty acid is a common component of chocolate and makes up a significant portion of its fatty acid content?

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

What effect does the number of double bonds in a fatty acid have on its structure?

<p>Causes a bent orientation (C)</p> Signup and view all the answers

What does a higher iodine number signify regarding a triglyceride?

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

How do saturated fatty acids affect the melting point of triglycerides?

<p>Higher melting point due to strong associations (C)</p> Signup and view all the answers

What is true about unsaturated side chains in triglycerides?

<p>They promote weaker molecular associations. (D)</p> Signup and view all the answers

What type of triglyceride is likely to remain liquid at room temperature?

<p>Unsaturated with short side chains (A)</p> Signup and view all the answers

Which aspect of fatty acids primarily affects the physical properties like melting point?

<p>The degree of saturation and carbon chain length (D)</p> Signup and view all the answers

What is a characteristic of triglycerides that results in a higher melting temperature?

<p>They have saturated side chains that are linear. (C)</p> Signup and view all the answers

Which type of carbohydrate is digested and absorbed quickly, leading to rapid changes in blood sugar levels?

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

What structural feature prevents our bodies from digesting cellulose?

<p>It has a β-glycosidic linkage (B)</p> Signup and view all the answers

What is the primary function of glycogen in animal cells?

<p>To provide quick energy (A)</p> Signup and view all the answers

What happens to adults with a deficiency of lactase regarding lactose digestion?

<p>They experience fermentation of unabsorbed lactose (B)</p> Signup and view all the answers

Which level of protein structure involves the unique sequence of amino acids?

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

What characterizes polar basic amino acids?

<p>Two amino groups and one carboxyl group (D)</p> Signup and view all the answers

What structural formation follows the act of two amino acids forming a peptide bond?

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

In which type of protein structure do peptide chains fold into globular forms?

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

What occurs during protein denaturation?

<p>Protein structure unravels (B)</p> Signup and view all the answers

What type of amino acid possesses a hydrophobic side chain?

<p>Non-polar amino acid (B)</p> Signup and view all the answers

What is primarily responsible for the structural strength of fibrous proteins?

<p>Parallel arrangement of protein molecules (B)</p> Signup and view all the answers

What is the function of lactase in the digestive system?

<p>To hydrolyze lactose into glucose and galactose (C)</p> Signup and view all the answers

What type of bond is formed between amino acids during the formation of peptides?

<p>Peptide bond (C)</p> Signup and view all the answers

What is the primary effect of high levels of cholesterol in the body?

<p>Formation of fat deposits in arteries (D)</p> Signup and view all the answers

How do HDL and LDL differ in terms of their effects on the arteries?

<p>HDL removes cholesterol; LDL deposits cholesterol (C)</p> Signup and view all the answers

Which type of fatty acids are linked to an increased risk of heart disease?

<p>Trans-fatty acids (C)</p> Signup and view all the answers

Essential fatty acids (EFAs) are important because they need to be...

<p>Obtained from the diet (B)</p> Signup and view all the answers

What occurs during the process of hydrolysis in carbohydrates?

<p>Disaccharides split into monosaccharides (A)</p> Signup and view all the answers

Which of the following describes a triglyceride that is rich in polyunsaturated fatty acids?

<p>Lower melting point (A)</p> Signup and view all the answers

What is the typical configuration of double bonds in natural vegetable oils?

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

Carbohydrates are primarily composed of which three elements?

<p>Carbon, hydrogen, and oxygen (B)</p> Signup and view all the answers

Which statement about glycosidic linkage is true?

<p>It connects two monosaccharides (A)</p> Signup and view all the answers

What is the typical hydrogen to oxygen ratio in carbohydrates?

<p>2:1 (C)</p> Signup and view all the answers

Trans-fatty acids are generally produced through which process?

<p>Catalytic hydrogenation of vegetable oil (D)</p> Signup and view all the answers

Which food component is associated with a high glycemic index?

<p>High-carbohydrate foods (A)</p> Signup and view all the answers

What type of fatty acid is typically found in salmon and flaxseed?

<p>Omega-3 fatty acid (C)</p> Signup and view all the answers

Which type of carbohydrate is the simplest form, consisting of single sugar molecules?

<p>Monosaccharides (C)</p> Signup and view all the answers

Flashcards

Calorie

The amount of energy needed to raise the temperature of 1 gram of water by 1 degree Celsius.

Kilocalorie

A unit of energy equal to 1000 calories.

Metabolism

The complex chemical processes that occur in the body to maintain life, including the breakdown of food for energy.

What is the relationship between calories and joules?

1 calorie is equivalent to 4.2 joules.

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What is calorimetry?

The technique used to measure the amount of heat.

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How does food provide energy for the body?

Food contains nutrients that are broken down through metabolism, releasing chemical energy that powers bodily functions.

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What is the role of energy in our bodies?

Energy from food allows us to do work and sustain life processes like breathing, muscle movement, and brain activity.

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Macronutrients

Major food components providing energy and building blocks for the body. Includes fats, oils, carbohydrates, and proteins.

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Micronutrients

Essential nutrients needed in small quantities, like vitamins and minerals.

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Energy In

The energy we consume from food, measured in Calories (Cal). Fats and oils provide 9 Cal/g, carbohydrates 4 Cal/g, proteins 4 Cal/g, and alcohol 7 Cal/g.

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Energy Out

The energy we use throughout the day, including exercise, metabolism, and keeping our bodies functioning. Two main forms: Thermic Effect of Food (TEF) and Basal Metabolism.

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Thermic Effect of Food (TEF)

The energy expended during digestion and metabolism of food. This is why you might feel warmer after meals.

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Basal Metabolism

The energy needed to keep vital organs functioning at rest, like heart beating, lungs breathing, and brain activity.

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Energy Stored

Excess macronutrients are converted for storage. Long-term storage is as body fat, while short-term storage is as glycogen.

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Energy In = Energy Out

To maintain a healthy weight, the energy we consume from food should balance the energy we expend.

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Atherosclerosis

A condition where fat deposits build up on the inner lining of arteries, reducing blood flow and increasing the risk of high blood pressure and heart disease.

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Cholesterol

A hydrophobic molecule essential for cell membranes and hormone production. It is classified as a steroid due to its four-ring structure.

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Lipoproteins

Packages of cholesterol wrapped in proteins and triglycerides to transport them through the bloodstream. Classified as HDL (high-density lipoprotein) and LDL (low-density lipoprotein).

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HDL vs. LDL

HDL is beneficial, removing cholesterol deposits from artery walls and transporting them to the liver for disposal. LDL deposits cholesterol on artery walls, contributing to atherosclerosis.

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Essential Fatty Acids

Unsaturated fatty acids that the body cannot produce and must be obtained through diet. Examples include omega-3 fatty acids found in fatty fish, walnuts, and flaxseeds.

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Resting Metabolic Rate (RMR)

The number of calories your body burns at rest, typically measured after a 12-hour fast.

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RMR & Body Weight

A healthy adult burns approximately 1 calorie per hour for every kilogram of body weight at rest.

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Factors Affecting RMR

Stressors like illness, pregnancy, or increased activity can increase your resting metabolic rate.

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Fats & Oils in the Body

Fats and oils serve multiple functions, including energy storage, insulation, and organ protection.

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Fat Solubility

Fats and oils are highly soluble in other fats, meaning they mix well together.

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Fatty Acids

Fatty acids are long chains of carbon and hydrogen atoms with a carboxylic acid group at one end.

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Variation in Fatty Acid Chains

Fatty acid chains can vary in length (number of carbons) and the presence of double bonds between carbon atoms.

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Saturated Fatty Acid

A saturated fatty acid has no carbon-carbon double bonds, meaning it's fully saturated with hydrogen atoms.

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Unsaturated Fatty Acid

An unsaturated fatty acid has at least one carbon-carbon double bond, meaning it's not fully saturated with hydrogen atoms.

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Chocolate's Fat Content

Chocolate's smooth, creamy texture is largely due to the presence of saturated fatty acids.

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Stearic acid

A saturated fatty acid found in chocolate, making up about one-third of its fatty acid content.

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Oleic acid

A monounsaturated fatty acid abundant in avocados, almonds, and olive oil, contributing to their healthy fats.

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Triglyceride

A molecule composed of a glycerol backbone attached to three fatty acid chains, forming the building block of fats and oils.

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What determines the melting point of fats and oils?

The length of the fatty acid chains and the degree of saturation determine the melting point. Longer chains and higher saturation lead to higher melting points, resulting in a solid fat at room temperature. Shorter chains and lower saturation lead to lower melting points, resulting in a liquid oil.

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Iodine number

A measure of the degree of unsaturation in a fat or oil. It indicates how many grams of iodine can add to 100 grams of triglycerides.

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How does the structure of a fatty acid affect its properties?

The length of the fatty acid chain and the degree of saturation influence its properties. Longer chains and more saturation lead to a more rigid, linear structure with higher melting points. Shorter chains and lower saturation result in a more flexible, bent structure with lower melting points.

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What is the difference between fats and oils?

Fats and oils are both triglycerides, but fats are solid at room temperature due to their high melting point, generally caused by longer fatty acid chains and higher saturation. Oils are liquid at room temperature due to their low melting point, generally caused by shorter fatty acid chains and lower saturation.

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Why are fats and oils important in our diet?

Fats and oils are essential for energy, cell structure, hormone production, and vitamin absorption. They provide a concentrated source of energy and help transport essential nutrients.

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What fuels our body?

Food provides chemical energy through nutrients, powering life processes like movement and thinking. This is like gasoline for a car, providing energy for the engine to drive.

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What is metabolism?

Metabolism is a complex set of chemical reactions in our bodies that break down food for energy and build important body components. It's like a factory that transforms food into energy and building blocks for the body.

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What is a calorie?

A calorie is a unit of energy that measures the amount of heat needed to raise the temperature of 1 gram of water by 1 degree Celsius.

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What are watts and joules?

Watts measure power (energy per unit time) and joules measure energy. They are related to calories, which also measure energy. 1 calorie is equal to 4.2 joules.

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What is resting metabolic rate?

The number of calories your body burns at rest, typically measured after a 12-hour fast.

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How many calories does a healthy adult burn at rest?

Approximately 1 calorie per hour for every kilogram of body weight.

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What factors can increase RMR?

Stressors like illness, pregnancy, or increased activity can increase your resting metabolic rate.

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What are saturated fatty acids?

Fatty acids with no carbon-carbon double bonds.

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What is the difference between saturated and unsaturated fatty acids?

Saturated fatty acids have no double bonds, while unsaturated fatty acids have at least one double bond between carbon atoms.

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What are triglycerides?

Triglycerides are molecules made up of a glycerol backbone attached to three fatty acid chains. They are the building blocks of fats and oils.

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What are fat and oil mixtures like?

Fats and oils in our diet are complex mixtures of triglycerides with different side chains (long, short, saturated, unsaturated).

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Why is cholesterol important?

Cholesterol is crucial for cell membranes, hormone production, and vitamin D synthesis. Our body needs cholesterol for healthy functioning.

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What are lipoproteins?

Lipoproteins are packages of cholesterol, triglycerides, and proteins that transport them through the bloodstream.

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What makes a fatty acid saturated or unsaturated?

A saturated fatty acid has no carbon-carbon double bonds, meaning it's fully saturated with hydrogen atoms. An unsaturated fatty acid has at least one carbon-carbon double bond, meaning it's not fully saturated with hydrogen atoms.

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What is the relationship between fat saturation and melting point?

Longer chains and more saturation lead to a more rigid, linear structure with higher melting points. Shorter chains and lower saturation result in a more flexible, bent structure with lower melting points.

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How does cholesterol get transported through the blood?

Cholesterol is wrapped in proteins and triglycerides to form lipoproteins (HDL and LDL) that help transport it through the bloodstream.

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What is the role of HDL and LDL in the body?

HDL is 'good' cholesterol that removes cholesterol deposits from arteries and transports them to the liver for disposal. LDL is 'bad' cholesterol that deposits cholesterol on artery walls, contributing to atherosclerosis.

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What are essential fatty acids and why are they important?

Essential fatty acids are unsaturated fatty acids that the body cannot produce and must be obtained through diet. They are important for cell structure, hormone production, and other vital functions.

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How can we reduce our risk of atherosclerosis?

Maintaining a healthy diet low in saturated and trans fats, exercising regularly, and managing stress can help reduce the risk of atherosclerosis.

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What are some examples of foods rich in essential fatty acids?

Fatty fish (salmon, tuna, mackerel), walnuts, flaxseeds, and chia seeds are good sources of omega-3 fatty acids, an important type of essential fatty acid.

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What is the role of hydrogenation in vegetable oils?

Hydrogenation is a process that adds hydrogen atoms to vegetable oils, converting them into semi-solids and extending their shelf life. However, it can create trans-fatty acids, which are unhealthy.

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What are carbohydrates?

Carbohydrates are organic compounds made up of carbon, hydrogen, and oxygen. They are essential for energy production in the body.

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What are the types of carbohydrates?

There are 2 main types: simple carbohydrates (sugars) and complex carbohydrates (starches).

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What is the difference between starch and cellulose?

Starch is a digestible complex carbohydrate that provides energy, while cellulose is an indigestible fiber that helps with digestion.

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Why can we digest starch but not cellulose?

Our bodies have enzymes that can break down the alpha-linkages in starch but not the beta-linkages in cellulose.

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What is glycogen?

Glycogen is a complex carbohydrate stored in the liver and muscles for quick energy release.

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What is lactose?

Lactose is a sugar found in milk. It requires the enzyme lactase to be broken down.

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What is lactase deficiency?

Lactase deficiency occurs when the body doesn't produce enough lactase to digest lactose, leading to digestive problems.

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What are proteins?

Proteins are polymers of amino acids that serve various functions in the body, including building muscles and tissues.

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What are amino acids?

Amino acids are the building blocks of proteins, containing an amino group, a carboxyl group, and a side chain.

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What are the four types of amino acids?

Amino acids are categorized into four groups: non-polar, polar neutral, polar acidic, and polar basic, based on their side chain polarity.

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What are the four levels of protein structure?

Proteins have four levels of structure: primary, secondary, tertiary, and quaternary, each increasing in complexity.

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What is primary protein structure?

The primary structure of a protein is the linear sequence of amino acids linked by peptide bonds.

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What is secondary protein structure?

The secondary structure of a protein refers to its local folding patterns, such as alpha-helices and beta-sheets.

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What is tertiary protein structure?

The tertiary structure of a protein is its overall three-dimensional shape, formed by interactions between side chains of amino acids.

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What is quaternary protein structure?

The quaternary structure of a protein involves the association of multiple polypeptide chains to form a functional complex.

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What is the difference between fibrous and globular proteins?

Fibrous proteins are long and thin, providing strength and structure, while globular proteins are compact and spherical, often involved in biological processes.

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What is protein denaturation?

Protein denaturation is the disruption of a protein's native three-dimensional structure, often leading to a loss of function.

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Study Notes

UGEB2380: The Chemistry of Life (2024-25)

  • Course code: UGEB2380
  • Academic year: 2024-25
  • Instructor: Dr. Sam CK HAU (Department of Chemistry)

Energy of Foods

  • Food is the chemical fuel for the human body, analogous to gasoline for a motor vehicle.
  • It provides energy for various bodily functions.
  • Food and drinks are integral parts of cultures and social interactions.
  • Different types of fats, including trans fats, saturated fats, and omega-3s, are discussed.
  • Various types of foods (e.g., fats, oils, carbohydrates, proteins, alcohol) are part of the chemical fuel.

Energy, Heat, and Work

  • Nutrients in food supply chemical energy for bodily functions.
  • Metabolism is a complex process that sustains life.
  • Energy is the capacity to do work and is typically measured in terms of its heat equivalent.
  • A calorie is a common unit for quantifying heat or energy.
  • 1000 calories = 1 kilocalorie (kcal) = 1 Calorie (Cal)
  • Calorimetry is the technique used to measure the amount of heat.
  • The human body converts food into useful energy and physical components through metabolic processes.

Watts, Joules, and Calories

  • 1 watt = 1 joule/second
  • 1 joule = 0.24 calories
  • 1 calorie = 4.2 joules
  • Example calculation: A 275-Calorie candy bar provides enough energy to power a 100-watt light bulb for approximately 192 minutes.

The Human Body

  • Metabolism encompasses all chemical reactions in a living organism to support life.
  • Food is converted into energy and the physical substances needed by the body.
  • An example chemical reaction is the breakdown of sucrose (sugar) in the presence of oxygen to produce carbon dioxide, water, and energy.
  • The rate of metabolism is slower than combustion, and occurs under milder conditions.

Nutrients

  • Macronutrients are the major components of food that provide energy and building materials.
  • Examples: fats, oils, carbohydrates, and proteins.
  • Micronutrients are needed in smaller quantities and include vitamins and minerals.

Energy In and Out

  • Energy intake: Calories from fats (9 Cal/g), carbohydrates (4 Cal/g), proteins (4 Cal/g), alcohol (7 Cal/g).
  • Energy expenditure: Exercise, thermic effect of food (TEF), and basal metabolism (BMR).
  • Maintaining weight: Calories eaten equals calories burned.
  • Weight loss: Calories eaten are less than calories burned.
  • Weight gain: Calories eaten exceed calories burned.
  • Energy storage: Excess macronutrients are stored as energy (body fat) for long-term use or glycogen for short-term storage.

Thermic Effect of Food (TEF)

  • Energy used to digest and metabolize food.
  • A physiological response after a meal.
  • The amount varies depending on the type of food with the approximate breakdown being protein (20-30%), carbohydrates (6-8%), and fats (3-5%).

Basal Metabolism

  • Energy used to sustain basic life functions (e.g., heart beat, breathing).
  • Measured after 12 hours of fasting and rest to exclude exercise-related energy expenditure.
  • Dependent on body weight and other factors such as illness and pregnancy.

Fats and Oils

  • Fats and oils serve as energy storage, insulation, and cushioning for organs.
  • Different types of fats have varying degrees of saturation (e.g., saturated or unsaturated).
  • Fatty acids are an important component of fats and oils composed of a hydrocarbon chain with a carboxyl group at one end.
  • Fats and oils are complex mixtures of triglycerides.

Saturated and Unsaturated Fatty Acids

  • Saturated fatty acid: A fatty acid without carbon-carbon double bonds.
  • Unsaturated fatty acid: A fatty acid with one or more carbon-carbon double bonds.

Fats and Oils: Composition

  • Natural fats are complex mixtures of triglycerides with different lengths and degrees of fatty acid saturation.
  • Classification of triglycerides includes saturated, monounsaturated, and polyunsaturated categories depending on the type and number of fatty acids present.
  • Examples of fats include coconut oil, butter, palm oil, lard, corn oil, olive oil, etc. Various forms of fats and oils are used in the culinary process.

Fats and Oils: Extent of Unsaturation

  • Iodine number is a measure to determine the extent of unsaturation in fats and oils.
  • Higher iodine number implies higher unsaturation and vice versa.
  • The iodine number can be used to quantify the degree of unsaturation.

Fat, Cholesterol, and Heart Disease

  • Cholesterol is critical for hormone and vitamin D production, but high levels are linked to atherosclerosis.
  • Atherosclerosis is the buildup of fats in artery walls reducing blood flow.
  • Lipoproteins, including high-density lipoprotein (HDL) and low-density lipoprotein (LDL), are involved in cholesterol transport and affect heart health.
  • Cholesterol is needed by the body for various functions but high levels can lead to health problems.

Fats, Cholesterol, and Heart Disease: Transport

  • Lipoproteins, specifically HDL and LDL, are involved in the transport of cholesterol through blood.
  • HDLs (high-density lipoproteins) are considered "good" cholesterol, while LDLs (low-density lipoproteins) are considered "bad" cholesterol.

Fats and Oils in Our Diet

  • Unsaturated fats are generally healthier than saturated ones and promote heart health.
  • Trans fats, a byproduct of hydrogenation of vegetable oils at high temperatures, are potentially harmful.
  • Essential fatty acids (EFAs) are needed by the body but cannot be synthesized and hence must come from the diet
  • Types of EFAs discussed include omega-3 fatty acids

Carbohydrates

  • Carbohydrates are macronutrients and a major source of energy in living organisms.
  • They are made up of three main elements: carbon, hydrogen and oxygen.
  • The ratio of hydrogen to oxygen is approximately 2:1, similar to water (H₂O).
  • Various types of carbohydrates are discussed in the course.

Types of Carbohydrates

  • Monosaccharides (e.g., glucose, fructose, galactose) are the simplest carbohydrates.
  • Disaccharides (e.g., sucrose, lactose, maltose) are formed by the linking of two monosaccharides.
  • Poly-saccharides are formed by the linking of multiple (many) monosaccharides. .

Carbohydrates and Diet

  • High glycemic-index foods, rich in carbohydrates, tend to cause rapid increases in blood sugar levels and are associated with health issues like diabetes and obesity.
  • Lower glycemic-index foods digest and absorb slowly, leading to more stable blood sugar levels (e.g. whole grains, fruits).
  • Enzyme sucrase helps break down complex sugars in the gut.
  • Starch is a digestible carbohydrate, while cellulose is a dietary fiber not digestible by humans.
  • Glycogen serves as a quick energy source in animals.
  • Various types of carbohydrates and their functions are discussed.

Carbohydrates and Diet: Lactose

  • Lactose is a disaccharide found in milk.
  • Lactase is the enzyme that breaks down lactose into glucose and galactose.
  • Individuals lacking lactase experience lactose intolerance.

Proteins

  • Proteins are crucial to the structure and function of life.
  • They are composed of amino acids.
  • Genes carry the instructions (blueprints) for protein synthesis. .

Amino Acids

  • There are 20 standard amino acids that are the building blocks of proteins..
  • Types of amino acids include: Non-polar, Polar neutral, Polar acidic, Polar basic

Structures of Proteins

  • Primary structure: The amino acid sequence.
  • Secondary structure: Alpha-helices and beta-sheets.
  • Tertiary structure: Complex three-dimensional shape.
  • Quaternary structure: Complex formed from two or more tertiary structures.

Fibrous and Globular Proteins

  • Fibrous proteins have elongated shapes and are often strong, structural proteins—e.g. collagen, keratin.
  • Globular proteins have folded, spherical shapes, and are involved in metabolic processes—e.g., enzymes, antibodies.
  • Different protein structures perform specific functions in the body.

Protein Denaturation

  • Denaturation is the disruption of the secondary and tertiary structures of a protein, often caused by heat or other factors.
  • Denaturation is often irreversible.
  • Cooking an egg is an example of protein denaturation.

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UGEB2380 The Chemistry of Life Lecture Notes - PDF

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Test your knowledge on nutrition and metabolism with this quiz. Explore essential concepts such as lipoproteins, healthy fats, macronutrients, and the metabolic processes in living organisms. Understand how energy is derived from food and the role of various nutrients in health.

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