Topic 3: Chapter 4
NutrientsNutrients –– Part 1Part 1
The needThe need
for foodfor food
++
CarbohydraCarbohydra
Chemicals and Reactions that
take place in the cell.
• Living organisms contains huge amount of
Macromolecules (large mole...
Anabolic & Catabolic
Reactions
• Anabolic reactions build up large molecules
from simple molecules.
• Catabolic reactions ...
Illustration of Anabolic &
Catabolic Reactions
H20 Nitrate Phosphate
Sunlight
CO2
Carbohydrates
(e.g. Glucose)
Photosynthe...
Illustration of Anabolic &
Catabolic Reactions
Nitrate Phosphate
Lipids
Carbohydrates
(e.g. Glucose)
Protein
Eat
Digestion...
Why do organisms need
food?
1) To provide energy for the vital activities of
the body via respiration.
 Physical movement...
Nutrients
• Chemical substances in food that nourish the body.
• They provide energy & raw materials needed by
the body.
(...
A(1): Carbohydrates
• Organic compounds made up of the
elements carbon (C), hydrogen (H) &
oxygen (O).
• The hydrogen & ox...
A(1): Functions of Carbohydrates
a) as a substrate for respiration
 provide energy for cell activities
a) to form support...
A(1): Sources of Carbohydrates
•Broken down quickly to provide
energy for the body
• Found naturally in food (Fruits,
Milk...
A(1): Groups of Carbohydrates
CarbohydratesCarbohydrates
Polysaccharides
(complex carbohydrates)
Polysaccharides
(complex ...
• Simple sugars, sweet
• Smallest basic unit.
• ALL with general formula C6H12O6.
- But differ in arrangement of atoms in
...
Disaccharides
(double sugars)
Disaccharides
(double sugars)
• Simple sugars, sweet
• Formed when 2 monosaccharides are
joi...
Condensation
• Chemical reaction in
which
• A water molecule is
needed
• to break up a complex
molecule into smaller
molec...
Condensation: Formation of
LactoseLactose
• occurs naturally in milk (milk sugar).
• broken down by the enzyme “lactase” d...
Condensation: Formation of
Maltas
e
Maltas
e
• Malt Sugar
• Important component in the process of fermenting
barley that c...
Condensation: Formation of
Sucros
e
Sucros
e
• occurs naturally in sugarcane (cane sugar), sweet
fruits, honey and certain...
Hydrolysis: Breaking down of
Sucros
e
Sucros
e
+
enzyme
glucose fructosesucrose water
+
• broken down by the enzyme “sucra...
Polysaccharides
(complex carbohydrates)
Polysaccharides
(complex carbohydrates)
• Consists of many monosaccharide
molecule...
starch
Polysaccharides
(complex carbohydrates)
Polysaccharides
(complex carbohydrates)
Starch
Starch
• Long straight or
br...
starch
Polysaccharides
(complex carbohydrates)
Polysaccharides
(complex carbohydrates)
Cellulose
Cellulose
• Long straight...
starch
Polysaccharides
(complex carbohydrates)
Polysaccharides
(complex carbohydrates)
Glycogen
Glycogen
• Highly branched...
Storage Glucose
• Starch
• Stored in leaves, tubers and roots
Plants
Animals
• Gycogen
• Stored mainly in liver and muscles
Glycogen and Starch
as storage materials
• Insoluble in water
 do not change the water potential in cells
• Large molecul...
Hydrolysis and Condensation
maltase maltase maltase maltase
Starch (in plants)Starch (in plants)
MaltoseMaltose
GlucoseGlu...
Food Test (1)Food Test (1)
Test for Starch – Iodine TestTest for Starch – Iodine Test
Procedure:
• Add 1-3 drops of iodine...
Food Test (2)Food Test (2)
Test for Reducing Sugars – Benedict’sTest for Reducing Sugars – Benedict’s
TestTest
Reducing Su...
Food Test (2)Food Test (2)
Test for Reducing Sugars – Benedict’sTest for Reducing Sugars – Benedict’s
TestTest
Results
Col...
Food Test (2)Food Test (2)
Test for Reducing Sugars – Benedict’sTest for Reducing Sugars – Benedict’s
TestTest
Results
Pos...
Topic 3: Chapter 4
NutrientsNutrients –– Part 2Part 2
FatFat
ss
LipidsLipids
SteroidsSteroids
ExamplesExamples
PhospholipidsPhospholipidsFatsFats
For storage
of energy
For storage
of ene...
A(2): FATS
• Organic compounds made up of the
elements carbon (C), hydrogen (H) & oxygen
(O).
• but unlike carbohydrates, ...
A(2): Composition of a Fat
Molecule
• A fat molecule is made up of four parts:
- 1 molecule of glycerol
- 3 fatty acid cha...
A(2): Breaking down fats
Hydrolysi
s
Hydrolysi
s
• The breaking down of 1 fat molecule involves the
addition of 3 water mo...
A(2): Forming fats
Condensatio
n
Condensatio
n
• Conversely, a fat molecule can be formed by
adding 3 fatty acid molecules...
A(2): Groups of Fats
FatsFats
Unsaturated FatsUnsaturated FatsSaturated FatsSaturated Fats
A(2):
• Found mostly in animals
• Fatty acids are straight
chains
• Most are solid at room
temperature (e.g butter)
• Chol...
• Found mostly in vegetables
(except Coconut and Palm Oil)
• Fatty acids are bent in some
places
• Most are liquid at room...
Saturated Fats Unsaturated Fats
 Butter
 Cheese
 Fatty Meats
 Coconut oil
 Palm oil
 Peanuts
 Walnuts
 Olives
 Co...
A(1): Functions Fats
a) as a source and store of energy
b) Insulating material (Prevents excessive heat
loss)
 e.g layer ...
Food Test (3)Food Test (3)
Test for Fats – Alcohol EmulsionTest for Fats – Alcohol Emulsion
TestTest
Procedure:
 Add 2 cm...
Food Test (3)Food Test (3)
Test for Fats – Alcohol EmulsionTest for Fats – Alcohol Emulsion
TestTest
Procedure:
 Cut the ...
Food Test (3)Food Test (3)
Test for Fats – Alcohol EmulsionTest for Fats – Alcohol Emulsion
TestTest
Results:
 A white em...
Topic 3: Chapter 4
NutrientsNutrients –– Part 3Part 3
ProteiProtei
nsns
Where are Proteins found in
our body?
A(3): Proteins
• Are very large complex organic moluecules
containing carbon (C), hydrogen (H), oxygen
(O) and nitrogen (N...
ProteinsProteins
Acidic Group
-COOH
Acidic Group
-COOH
Formed
from
Formed
from
R-Groups:
May contain:
Sulphur,
Acidic grou...
A(3): General Structure of an
amino acid
• A fat molecule is made up of four parts:
- 1 Amino Acid group (-NH2)
- 1 Acidic...
A(3): Why is there a need for so
many different R-groups?
• The R-Group determines the type of
amino acid formed.
• There ...
A(3): Synthesis of Proteins
• The bond between 2 amino acids is called: Peptide Bond
• Many amino acids link together by p...
amino acids polypeptides Protein molecule
A(3): Synthesis of Proteins
Primary / Secondary
Structure
Primary / Secondary
St...
Different proteins have a different
sequence of A.A
 A.A sequence determines the
bonds formed and the structure of
the p...
A(3): Digestion of Proteins
polypeptides
amino acids
protein
hydrolysis (digestion)
hydrolysis (digestion)
Protein molecul...
Animals Plants
 Milk
 Eggs
 Seafood
 Chicken
 Lean beef
 Nuts
 Soy bean
 Grains
 Vegetables
A(3): Sources of Prot...
A(1): Functions Proteins
a) Formation of new protoplasm
 for growth & repair of worn-out body parts/ cells
b) Synthesis o...
Food Test (4)Food Test (4)
Test for Proteins – Biuret TestTest for Proteins – Biuret Test
Procedure:
 Add 1 cm3
of sodium...
Food Test (4)Food Test (4)
Test for Proteins – Biuret TestTest for Proteins – Biuret Test
Results:
 A violet colouration ...
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Topic 3 chapter 4 part 1 nutrients - full

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Topic 3 chapter 4 part 1 nutrients - full

  1. 1. Topic 3: Chapter 4 NutrientsNutrients –– Part 1Part 1 The needThe need for foodfor food ++ CarbohydraCarbohydra
  2. 2. Chemicals and Reactions that take place in the cell. • Living organisms contains huge amount of Macromolecules (large molecules) • Chemical activities that take place in a cell is known as metabolism. • Metabolic reactions are categorized as anabolic reactions and catabolic reactions.
  3. 3. Anabolic & Catabolic Reactions • Anabolic reactions build up large molecules from simple molecules. • Catabolic reactions break down larger molecules into smaller molecules.
  4. 4. Illustration of Anabolic & Catabolic Reactions H20 Nitrate Phosphate Sunlight CO2 Carbohydrates (e.g. Glucose) Photosynthesis
  5. 5. Illustration of Anabolic & Catabolic Reactions Nitrate Phosphate Lipids Carbohydrates (e.g. Glucose) Protein Eat Digestion Absorption
  6. 6. Why do organisms need food? 1) To provide energy for the vital activities of the body via respiration.  Physical movement, Digestion, Excretion, etc. 2) To synthesize new protoplasm – for growth & repair, & for reproduction. 3) To maintain good health – prevent deficiency disease.  Vit. C, Calcium, etc.
  7. 7. Nutrients • Chemical substances in food that nourish the body. • They provide energy & raw materials needed by the body. (A) Organic Nutrients(A) Organic Nutrients (Contains Carbon)(Contains Carbon) (A) Organic Nutrients(A) Organic Nutrients (Contains Carbon)(Contains Carbon) (B) Inorganic Nutrients(B) Inorganic Nutrients (does not contain Carbon)(does not contain Carbon) (B) Inorganic Nutrients(B) Inorganic Nutrients (does not contain Carbon)(does not contain Carbon) 1)1) CarbohydratesCarbohydrates 2)2) FatsFats 3)3) ProteinsProteins 4)4) VitaminsVitamins 5)5) Dietary FibreDietary Fibre 1)1) WaterWater 2)2) Mineral SaltsMineral Salts
  8. 8. A(1): Carbohydrates • Organic compounds made up of the elements carbon (C), hydrogen (H) & oxygen (O). • The hydrogen & oxygen atoms are present in the ratio 2:1. • Generalized formula: CnH2mOm.
  9. 9. A(1): Functions of Carbohydrates a) as a substrate for respiration  provide energy for cell activities a) to form supporting structures  e.g. plant cell walls a) to be converted to other organic compounds such as amino acids and fats b) for the formation of nucleic acid  e.g. DNA a) to synthesize lubricants  e.g. mucus – Carbo + Protein) a) to produce the nectar in some flowers
  10. 10. A(1): Sources of Carbohydrates •Broken down quickly to provide energy for the body • Found naturally in food (Fruits, Milk, etc.) • Found in processed or refined food ( Candy, Syrup, etc.) •Lack Vitamins, Minerals & Fibres •Made of sugar molecules strung together in long complex chains • Majority of carbohydrates are from complex carbohydrates and naturally occurring sugars. •Provides Vitamins, Minerals & Fibres
  11. 11. A(1): Groups of Carbohydrates CarbohydratesCarbohydrates Polysaccharides (complex carbohydrates) Polysaccharides (complex carbohydrates) Disaccharides (double sugars) Disaccharides (double sugars) Monosaccharides (single sugars) Monosaccharides (single sugars) e.g. glucose fructose, galactose e.g. glucose fructose, galactose e.g. starch, glycogen, cellulose e.g. starch, glycogen, cellulose e.g. Sucrose, Maltose, Lactose e.g. Sucrose, Maltose, Lactose
  12. 12. • Simple sugars, sweet • Smallest basic unit. • ALL with general formula C6H12O6. - But differ in arrangement of atoms in molecules. Monosaccharides (single sugars) Monosaccharides (single sugars)
  13. 13. Disaccharides (double sugars) Disaccharides (double sugars) • Simple sugars, sweet • Formed when 2 monosaccharides are joined together by condensation. • ALL with general formula C12H22O11.
  14. 14. Condensation • Chemical reaction in which • A water molecule is needed • to break up a complex molecule into smaller molecules • Chemical reaction in which • A water molecule is needed • to break up a complex molecule into smaller molecules • Chemical reaction in which • 2 simple molecules are joined together to form a larger molecule • with the removal of water • Chemical reaction in which • 2 simple molecules are joined together to form a larger molecule • with the removal of water Hydrolysis
  15. 15. Condensation: Formation of LactoseLactose • occurs naturally in milk (milk sugar). • broken down by the enzyme “lactase” during digestion to yield glucose and galactose by hydrolysis • When milk sours, bacteria converts lactose to lactic acid
  16. 16. Condensation: Formation of Maltas e Maltas e • Malt Sugar • Important component in the process of fermenting barley that can be used for brewing beer. • broken down by the enzyme “maltase” during digestion to yield 2 glucose molecules by hydrolysis
  17. 17. Condensation: Formation of Sucros e Sucros e • occurs naturally in sugarcane (cane sugar), sweet fruits, honey and certain storage roots (e.g. carrots). • Not found in mammals
  18. 18. Hydrolysis: Breaking down of Sucros e Sucros e + enzyme glucose fructosesucrose water + • broken down by the enzyme “sucrase” / “invertase” during digestion to yield glucose and fructose by hydrolysis
  19. 19. Polysaccharides (complex carbohydrates) Polysaccharides (complex carbohydrates) • Consists of many monosaccharide molecules joined together by condensation. • Starch, Glucogen and Cellulose are complex carbohydrates which are made up of numerous glucose molecules condensed together.
  20. 20. starch Polysaccharides (complex carbohydrates) Polysaccharides (complex carbohydrates) Starch Starch • Long straight or branched chains of glucose molecules • Made and stored in plants but not in animals
  21. 21. starch Polysaccharides (complex carbohydrates) Polysaccharides (complex carbohydrates) Cellulose Cellulose • Long straight chains of glucose molecules • But different linkages from starch. • Main part of plant cell wall • Forms fibre in the diet of mammals
  22. 22. starch Polysaccharides (complex carbohydrates) Polysaccharides (complex carbohydrates) Glycogen Glycogen • Highly branched chains of glucose • Made and stored in animals and fungi but not in plants
  23. 23. Storage Glucose • Starch • Stored in leaves, tubers and roots Plants Animals • Gycogen • Stored mainly in liver and muscles
  24. 24. Glycogen and Starch as storage materials • Insoluble in water  do not change the water potential in cells • Large molecules  Unable to diffuse through cell membranes • Easily hydrolysed to glucose when needed  e.g for tissue respiration • Compact shapes which occupies less space.
  25. 25. Hydrolysis and Condensation maltase maltase maltase maltase Starch (in plants)Starch (in plants) MaltoseMaltose GlucoseGlucose Hydrolysis in the mouth Hydrolysis in the guts by enzyme maltase Condensation in the liver Glycogen (in animals)Glycogen (in animals) Consumed and undergoes Digestion Digestion Glucogenesis
  26. 26. Food Test (1)Food Test (1) Test for Starch – Iodine TestTest for Starch – Iodine Test Procedure: • Add 1-3 drops of iodine solution onto any substance. Results: • If starch is present, the iodine solution changes from yellowish brown to blue-black colour.
  27. 27. Food Test (2)Food Test (2) Test for Reducing Sugars – Benedict’sTest for Reducing Sugars – Benedict’s TestTest Reducing Sugars:Reducing Sugars: Glucose, Fructose, Maltose, Lactose Procedure:Procedure: 1. Add 2 cm3 of Benedict’s solution to equal volume of test solution. 2. Mix the solutions by shaking. 3. Heat the mixture in a boiling water- bath for 5 minutes. 4. Prepare a control using distilled water instead of the test solution Benedict’s solution
  28. 28. Food Test (2)Food Test (2) Test for Reducing Sugars – Benedict’sTest for Reducing Sugars – Benedict’s TestTest Results Colour change Amount of reducing sugar present blue to green mixture trace amount blue to yellow / orange precipitate moderate amount blue to brick-red precipitate large amount
  29. 29. Food Test (2)Food Test (2) Test for Reducing Sugars – Benedict’sTest for Reducing Sugars – Benedict’s TestTest Results Positive Benedict’s test Negative Benedict’s test Brick Red Precipitate Blue solution
  30. 30. Topic 3: Chapter 4 NutrientsNutrients –– Part 2Part 2 FatFat ss
  31. 31. LipidsLipids SteroidsSteroids ExamplesExamples PhospholipidsPhospholipidsFatsFats For storage of energy For storage of energy e.g. cholesterole.g. cholesterol Makes up the Plasma membrane Makes up the Plasma membrane
  32. 32. A(2): FATS • Organic compounds made up of the elements carbon (C), hydrogen (H) & oxygen (O). • but unlike carbohydrates, they contain much less oxygen in proportion to hydrogen. (E.g. Beef Fat: Tristearin – C57H110O6) • No General formula for fats
  33. 33. A(2): Composition of a Fat Molecule • A fat molecule is made up of four parts: - 1 molecule of glycerol - 3 fatty acid chains Glycerol Fatty Acids
  34. 34. A(2): Breaking down fats Hydrolysi s Hydrolysi s • The breaking down of 1 fat molecule involves the addition of 3 water molecules to form 1 glycerol and 3 fatty acid molecules IN THE PRESENCE OF AN ENZYME (Lipase)
  35. 35. A(2): Forming fats Condensatio n Condensatio n • Conversely, a fat molecule can be formed by adding 3 fatty acid molecules to 1 glycerol molecule, removing 3 molecules of water
  36. 36. A(2): Groups of Fats FatsFats Unsaturated FatsUnsaturated FatsSaturated FatsSaturated Fats
  37. 37. A(2): • Found mostly in animals • Fatty acids are straight chains • Most are solid at room temperature (e.g butter) • Cholesterol usually found with polysaturated fats  Increases risk of Coronary Heart Diseases & Gall stone formation Saturated FatsSaturated Fats
  38. 38. • Found mostly in vegetables (except Coconut and Palm Oil) • Fatty acids are bent in some places • Most are liquid at room temperature (e.g Olive Oil) • Fatty acid chains contains double bonds and are able to take in 1 or more pairs of H-atoms • Hydrogenation of unsaturated fats  Trans-fat A(1): Unsaturated FatsUnsaturated Fats
  39. 39. Saturated Fats Unsaturated Fats  Butter  Cheese  Fatty Meats  Coconut oil  Palm oil  Peanuts  Walnuts  Olives  Corn Oil  Soybean  Most fishes (e.g Salmon, mackerel, tuna, sardines) A(2): Sources of Fats
  40. 40. A(1): Functions Fats a) as a source and store of energy b) Insulating material (Prevents excessive heat loss)  e.g layer of blubber beneath the skin of whales a) Solvent for fat-soluble substances  some vitamins and vital substances (e.g hormones) d) Essential part of the protoplasm  e.g cell membrane (Phospholipds and cholesterol) e) A way to reduce water loss from the skin surface
  41. 41. Food Test (3)Food Test (3) Test for Fats – Alcohol EmulsionTest for Fats – Alcohol Emulsion TestTest Procedure:  Add 2 cm3 of ethanol to the test solution and shake the mixture thoroughly for 5 minutes. Observe for changes.  Add 2 cm3 of water to the mixture and shake the mixture. Observe for changes. Liquid Food
  42. 42. Food Test (3)Food Test (3) Test for Fats – Alcohol EmulsionTest for Fats – Alcohol Emulsion TestTest Procedure:  Cut the sample into small pieces and place them in a test tube.  Add 2cm3 of ethanol and shake thoroughly.  Allow the solid particles to settle. Decant the ethanol into another test tube containing 2cm3 of water. Make observations. Solid Food
  43. 43. Food Test (3)Food Test (3) Test for Fats – Alcohol EmulsionTest for Fats – Alcohol Emulsion TestTest Results:  A white emulsion is formed if fats is present white emulsio n
  44. 44. Topic 3: Chapter 4 NutrientsNutrients –– Part 3Part 3 ProteiProtei nsns
  45. 45. Where are Proteins found in our body?
  46. 46. A(3): Proteins • Are very large complex organic moluecules containing carbon (C), hydrogen (H), oxygen (O) and nitrogen (N). Sometimes, Sulfur (S) and Phosphorus (P) • E.g. Insulin: C254H317O75N65S6 • Made up of basic small units called amino acids
  47. 47. ProteinsProteins Acidic Group -COOH Acidic Group -COOH Formed from Formed from R-Groups: May contain: Sulphur, Acidic groups, amino groups, and/or Hydroxyl groups R-Groups: May contain: Sulphur, Acidic groups, amino groups, and/or Hydroxyl groups Amino Group -NH2 Amino Group -NH2 Amino Acids NH2-CHR-COOH Amino Acids NH2-CHR-COOH
  48. 48. A(3): General Structure of an amino acid • A fat molecule is made up of four parts: - 1 Amino Acid group (-NH2) - 1 Acidic Group (-COOH) - 1 Side Chain (denoted by R) Can be: •Sulfur (S) •Acidic groups (-COOH) •Amino groups (--NH2) and/or •Hydroxyl groups (-OH)
  49. 49. A(3): Why is there a need for so many different R-groups? • The R-Group determines the type of amino acid formed. • There are 20 naturally occuring amino acid: • Examples – • Leucine, Valine, Glutamine: • 8 Essential a.a: Cannot be synthesized by the body. Must be obtained through the diet • 12 Non-Essential a.a: Can be synthesized by the body
  50. 50. A(3): Synthesis of Proteins • The bond between 2 amino acids is called: Peptide Bond • Many amino acids link together by peptide bonds to form a polypeptide chain / peptone Condensatio n Condensatio n
  51. 51. amino acids polypeptides Protein molecule A(3): Synthesis of Proteins Primary / Secondary Structure Primary / Secondary Structure Tertiary Structure Tertiary Structure Amino acids are linked by peptide bonds to form polypeptide chains Amino acids are linked by peptide bonds to form polypeptide chains Polypeptide chains coil and fold around each other to form a 3-d structure held by weak H-bonds Polypeptide chains coil and fold around each other to form a 3-d structure held by weak H-bonds
  52. 52. Different proteins have a different sequence of A.A  A.A sequence determines the bonds formed and the structure of the protein.  Different proteins with different structures perform different functions. Weak H-bonds can be easily broken by: • Heat • Chemicals like Acid and Alkalis Protein loses its structure and function (is DENATURED) Different proteins have a different sequence of A.A  A.A sequence determines the bonds formed and the structure of the protein.  Different proteins with different structures perform different functions. Weak H-bonds can be easily broken by: • Heat • Chemicals like Acid and Alkalis Protein loses its structure and function (is DENATURED) Structure VS FunctionStructure VS Function
  53. 53. A(3): Digestion of Proteins polypeptides amino acids protein hydrolysis (digestion) hydrolysis (digestion) Protein molecules are too large to pass through the cell membranes Smaller and simpler A.A molecules are soluble in water and can pass through the cell membrane into the cells to synthesize new proteins
  54. 54. Animals Plants  Milk  Eggs  Seafood  Chicken  Lean beef  Nuts  Soy bean  Grains  Vegetables A(3): Sources of Proteins
  55. 55. A(1): Functions Proteins a) Formation of new protoplasm  for growth & repair of worn-out body parts/ cells b) Synthesis of enzymes and hormones  e.g digestive enzymes and insulin / sex and growth hormones b) Formation of antibodies to combat diseases d) Can be source of energy
  56. 56. Food Test (4)Food Test (4) Test for Proteins – Biuret TestTest for Proteins – Biuret Test Procedure:  Add 1 cm3 of sodium hydroxide solution to the 2 cm3 of test solution. Shake thoroughly.  Add 1% copper (II) sulphate solution, drop by drop, shaking after each drop. ALTERNATIVELY  Add 2cm3 of test solution to an equal volume of Biuret solution. Shake well and allow the mixture to stand for 5 minutes.
  57. 57. Food Test (4)Food Test (4) Test for Proteins – Biuret TestTest for Proteins – Biuret Test Results:  A violet colouration is formed if proteins is present positive test for protein positive test for protein

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