Fats, proteins, carbohydrates, DNA, and other biomolecules are discussed in the slides. Fats can be broken down into fatty acids and glycerol by hydrolysis using enzymes. Proteins are made of amino acids linked together through peptide bonds. DNA carries genetic information in its double-helix structure and is made of nucleotides containing nitrogen bases, phosphate groups and sugars. The slides describe the structures, functions and importance of these biomolecules.

1. Section 8.1 Carbohydrates, Fats, and Proteins
Slide 1 of 35
Fats
Section 4.4 F A T S
vvv
Like
Unlike
C
H
O
Carbohydrate
Carbohydrate
Oxygen << Hydrogen
Example:
Tristearin (beef
fat)  C57H110O6
The proportion of the elements that make up fats are not fixed.
There is no general formula for fats.

2. Section 8.1 Carbohydrates, Fats, and Proteins
Slide 2 of 35
Fats
•Fats are commonly used as a store of energy, esp. by
animals.
•Fats can be broken down into fatty acids and glycerol by
hydrolysis.
•Enzyme is involved.
Section 4.4 F A T S
vvvvvv
Enzyme

3. Section 8.1 Carbohydrates, Fats, and Proteins
Slide 3 of 35
Sources of Fats
Section 4.4 F A T S
vvvvvv

4. Section 8.1 Carbohydrates, Fats, and Proteins
Slide 4 of 35
•Soluble in organic solvent such as chloroform and ethanol.
•Examples:
• Fats
• Waxes
• Steroids
Lipids
Section 4.4 F A T S
vvv

5. Section 8.1 Carbohydrates, Fats, and Proteins
Slide 5 of 35
Saturated VS Unsaturated Fats
Section 4.4 F A T S
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6. Section 8.1 Carbohydrates, Fats, and Proteins
Slide 6 of 35
•Too much polysaturated fat and cholesterol in your diet
can lead to coronary heart disease.
•Unsaturated fats are thought to reduce the cholesterol
level in the blood. Hence, unsaturated fats should replace
animal fats in the diet as often as possible.
•Unsaturated fats may be converted into trans fats during
food production.
•Trans fats are produced by cooking at very high heat.
•Trans fats are bad  Increase coronary heart disease
Section 4.4 F A T S
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Saturated VS Unsaturated Fats

7. Section 8.1 Carbohydrates, Fats, and Proteins
Slide 7 of 35
Fats + Ethanol & Water  a cloudy white emulsion
Section 4.4 F A T S
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How Can We Identify Fats?

8. Section 8.1 Carbohydrates, Fats, and Proteins
Slide 8 of 35
•A source and store of energy
•An isulating material that prevents excessive heat loss.
•Eg: seals have blubber beneath the skin to reduce loss
of body heat.
•A solvent for fat-soluble vitamins and many other vital
substances.
•Eg: hormones.
•An essential part of protoplasm, especially in cell
membranes.
•A way to reduce water loss from the skin surface.
Sweating glands produce oily substance  reduces the
rate of evaporation of water.
Section 4.4 F A T S
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What Are the Function of Fats?

9. Section 8.1 Carbohydrates, Fats, and Proteins
Slide 9 of 35
•Organic molecules made up of the elements Carbon,
Hydrogen, Oxygen, and Nitrogen.
Section 4.5 P R O T E I N S
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Proteins
C
H O
N
PROTEIN
S
•Protein are always present in protoplasm.
•Their molecules are the largest and most complicated of all
the food substances

10. Section 8.1 Carbohydrates, Fats, and Proteins
Slide 10 of 35
•Simpler compounds: amino acids.
•Amino acids are made up of:
 Amino group (─NH2)
 Acidic group (─COOH)
 Side chain (R)
•R: sulfur, acidic groups, amino groups, and/or hydroxyl
groups (─OH) in place of one or more hydrogen atoms.
vvv
Section 4.5 P R O T E I N S
Amino Acids Are the Building Blocks of Proteins

11. Section 8.1 Carbohydrates, Fats, and Proteins
Slide 11 of 35
Section 4.5 P R O T E I N S
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20 Different Kinds of Amino Acids
•They differ because of their different R groups.

12. Section 8.1 Carbohydrates, Fats, and Proteins
Slide 12 of 35
Section 4.5 P R O T E I N S
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Polypeptides
•Condensation reaction:
•Peptide bond is formed.
1 amino acid + 1 amino acid  polypeptide

13. Section 8.1 Carbohydrates, Fats, and Proteins
Slide 13 of 35
Section 4.5 P R O T E I N S
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Polypeptides
Amino acids  Polypeptides  Proteins

14. Section 8.1 Carbohydrates, Fats, and Proteins
Slide 14 of 35
Section 4.5 P R O T E I N S
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Why Must Proteins be Broken Down?
•Enzymes take place!
•During digestion.
•Protein is hydrolysed into short polypeptides, which are in
turn hydrolysed into amino acids.
Protein  Polypeptides  amino acids
Enzyme Enzyme

15. Section 8.1 Carbohydrates, Fats, and Proteins
Slide 15 of 35
Section 4.5 P R O T E I N S
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Different Squence of Amino Acids
•There are only about 20 different naturally occurring
amino acids.
•However, each protein molecule has hundreds, or even
thousands, of them joined together in a unique sequence.
•This gives each protein its own individual properties.

16. Section 8.1 Carbohydrates, Fats, and Proteins
Slide 16 of 35
Section 4.5 P R O T E I N S
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•The long chains of amino acids fold to give each type of
protein molecule a specific shape. Proteins act as:
 Structural components of tissues (such as muscles)
 Hormones (such as insulin)
 Antibodies (part of the body's immune system)
 Biological catalysts (enzymes)
•The particular shape that a protein molecule has allows
other molecules to fit into it. This is particularly important
for antibodies and enzymes.
Different Proteins

17. Section 8.1 Carbohydrates, Fats, and Proteins
Slide 17 of 35
Section 4.5 P R O T E I N S
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Different Squence of Amino Acids
•Proteins are made from long chains of smaller molecules
called amino acids.
•These long chains are folded into particular shapes.
•This is important in relation to how antibodies and
enzymes work.
•Enzymes are biological catalysts.
•There are optimum temperatures and pH values at which
their activity is greatest.
•Enzymes are also proteins.
•If the shape of an enzyme changes, it may no longer work
(it is said to have been 'denatured').

18. Section 8.1 Carbohydrates, Fats, and Proteins
Slide 18 of 35
Section 4.5 P R O T E I N S
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•Enzymes are biological catalysts - substances that
increase the rate of chemical reactions without being
used up.
•Enzymes are proteins folded into complex shapes that
allow smaller molecules to fit into them. The place where
these substrate molecules fit is called the active site.
•If the shape of the enzyme changes, its active site may no
longer work. We say the enzyme has been 'denatured'.
How Enzymes Work

19. Section 8.1 Carbohydrates, Fats, and Proteins
Slide 19 of 35
•Biuret solution: blue solution made up of sodium
hydroxide and copper (II) sulfate.
•Violet (deep purple) occurs when proteins are present.
Section 4.5 P R O T E I N S
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How Can We Identify Proteins?

20. Section 8.1 Carbohydrates, Fats, and Proteins
Slide 20 of 35
Section 4.5 P R O T E I N S
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Where Are Proteins Found?

21. Section 8.1 Carbohydrates, Fats, and Proteins
Slide 21 of 35
•Synthesis of new protoplasm, for growth and repair of
worn-out body cells
•Synthesis of enzymes and some hormones
•Formation of antibodies to combat diseases.s
Section 4.5 P R O T E I N S
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Where Are the Functions of Proteins?
Deficiency?
•Need: 50─100 g protein/day
•Kwashiorkor:
 Swollen stomachs
 Skin cracks and becomes scaly

22. Section 8.1 Carbohydrates, Fats, and Proteins
Slide 22 of 35
Section 4.6 D N A
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Deoxyribonucleic Acid
•Almost all the
cells in our
body contain
DNA inside
their nuclei.
•±2 m of DNA
can be found in
each cell
nucleus.
•Carries genetic information.

23. Section 8.1 Carbohydrates, Fats, and Proteins
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Section 4.6 D N A
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Deoxyribonucleic Acid
•A small segment of DNA
carries a gene that stores
information used to make a
single polypeptide.
•Polypeptides are used to make
proteins  proteins are
responsible for determining
the characteristics of an
organism.

24. Section 8.1 Carbohydrates, Fats, and Proteins
Slide 24 of 35
Section 4.6 D N A
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Deoxyribonucleic Acid
•Each DNA molecule contists of two strands twisted
around each other (double helix).
•A helix: coiled structure like a corkscrew or spring.

25. Section 8.1 Carbohydrates, Fats, and Proteins
Slide 25 of 35
Section 4.6 D N A
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Basic Units of Deoxyribonucleic Acid
•Each nucleotide is made up of:
 A sugar
 A phospate group
 A nitrogen-containing base

26. Section 8.1 Carbohydrates, Fats, and Proteins
Slide 26 of 35
Section 4.6 D N A
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A Nitrogen-Containing Base
• Adenine (A)
• Cytosine (C)
• Guanine (G)
• Thymine (T)
•Complementary bases are joined by hydrogen bonds.

27. Section 8.1 Carbohydrates, Fats, and Proteins
Slide 27 of 35
Section 4.6 D N A
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Types of Nucleotides

28. Section 8.1 Carbohydrates, Fats, and Proteins
Slide 28 of 35
Section 4.6 D N A
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Deoxyribonucleic Acid
•Nucleotides can be joined together to form long chains called
polynucleotides.
•Each gene is made up of a sequence of nucleotides.
•The sequence of nucleotides (bases) can vary.
•This results in many different genes.
•The DNA molecule is made up of two anti-parallel
polynucleotide chains.
•Anti-parallel: because the two chains run in opposite
directions.
•The bases of one chain are bonded to those of the opposite
chain according to the rule of base pairing.