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C4 : NUTRIENTS Building block of life. 5094 Pure Syllabus (a) state the roles of water in living organisms. (b) list the chemical elements which make.

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Presentation on theme: "C4 : NUTRIENTS Building block of life. 5094 Pure Syllabus (a) state the roles of water in living organisms. (b) list the chemical elements which make."— Presentation transcript:

1 C4 : NUTRIENTS Building block of life

2 5094 Pure Syllabus (a) state the roles of water in living organisms. (b) list the chemical elements which make up: carbohydrates fats proteins (c) describe and carry out tests for: starch (iodine in potassium iodide solution) reducing sugars (Benedict’s solution) protein (biuret test) fats (ethanol emulsion) (d) state that large molecules are synthesised from smaller basic units: glycogen from glucose polypeptides and proteins from amino acids lipids such as fats from glycerol and fatty acids

3 Intro Why do we need food? Energy for daily activities (respiration) Repair or Replace damaged or worn-out tissues/cells Keep us healthy (prevent diseases) To Grow

4 Constituents of Food So what can we find in food? Dietary Fibre (vegetables like cellulose are not digested) Water Nutrients Carbohydrates Proteins Fats (lipids) Vitamins Mineral Salts

5 Roles of Water 70% of the Body is made up of WATER Lost of water by Breathing Urination Excretion of faeces Perspiration Extreme loss of water may affect the homeostasis of the body causing many vital processes unable to function and may lead to death.

6 Roles of Water Water is used as a solvent Dissolves a range of substances that are useful or waste products. Eg: glucose, amino acids, mineral salts, urea. Regulating body temperature Water enables the loss of heat from the body in the form of perspiration (Heat Capacity of water = 4.2 kJ/Kg°C) Prevent overheating of the body (fever) Supporting structure Shape of eye maintained by aqueous and vitreous humour which is largely made up of water. Amniotic fluid in the placenta protects the foetus from mechanical stress.

7 Water plays a role as lubricant Mucus in digestive and respiratory tract Synovial fluid in joints Carries sperms in seminal fluid Water as a site of many reactions Water is needed for transport of substances (diffusion & osmosis) Movement of water and mineral salts in the xylem Diffusion of carbon dioxide in the mesophyll layers in the leaf Water as a reactant in photosynthesis Water used for dispersal of fruits (coconut)

8 Carbohydrates

9 Nutrients Carbohydrates Made of elements Carbon (C), Hydrogen (H) and Oxygen (O) Good source of energy Eg : Rice, noodles, potato, starch, sugar Consist of 3 Groups Simple sugars (monosaccharides) Complex sugars (disaccharides) Polysaccharides

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11 Simple Sugars (Monosaccharide) Mono – single or one Eg : glucose, fructose, galactose

12 Complex Sugar ( Disaccharide) Di – two Made up of 2 simple sugars joined together Eg :

13 Formation of Disaccharides by Condensation (removal of water) Breakdown of Disaccharides by Hydrolysis (addition of water)

14 Polysaccharide Poly – many Made up of multiple simple sugars Eg : starch, glycogen

15 Different Forms of Polysaccharides Starch (Cell Sap) & Glycogen Many units of glucose Used as energy reserves in plants(starch) and animals(glycogen). Starch – long chains with few side branches Glycogen – many side branches Cellulose (Cell Wall) Multiple units of glucose Arranged differently thus more difficult to break Used as a structural support in leaves and plants Referred to as fibre

16 Starch vs Cellulose vs Glycogen

17 Function of Carbohydrates Simplest unit of Carbohydrate (Monosaccharides) provides energy for the human body It releases energy during aerobic respiration in the cell’s mitochondria. Glucose is the most common form of monosaccharide.

18 # JC Level

19 #Uni Level – Molecular BioChemistry

20 Test for Carbohydrates : Iodine Test Iodine test used to detect the presence of starch. Procedure Add a few drops of iodine solution onto the sample that is placed on a white glass tile. +ve – iodine turns blue black-ve – iodine remains brown

21 Test for Reducing Sugar : Benedict’s Test Some sugars act as a reducing agent and reduces Copper(II) Sulfate. These sugars are known as reducing sugar. Procedure Add 2cm 3 of Benedict’s solution to 2cm 3 of sample Shake & immerse test tube into beaker of boiling water for 2 mins +ve result Brick red precipitate Orange precipitate Green solution -ve result Remain blue solution

22 Sugar : Reducing & Non-reducing Reducing sugars Sugar that reduces Copper(II) Sulfate [Benedict’s Solution] Usually has an aldehyde group Eg: glucose, galactose, lactose Non-Reducing sugars Sugars that do not reduce Benedict’s Solution Eg: Sucrose

23 # Classification of Carbohydrates

24 5094 Pure Syllabus (a) state the roles of water in living organisms. (b) list the chemical elements which make up: carbohydrates fats proteins (c) describe and carry out tests for: starch (iodine in potassium iodide solution) reducing sugars (Benedict’s solution) protein (biuret test) fats (ethanol emulsion) (d) state that large molecules are synthesised from smaller basic units: glycogen from glucose polypeptides and proteins from amino acids lipids such as fats from glycerol and fatty acids

25 Proteins

26 Proteins are made up of carbon (C), nitrogen (N), oxygen (O) and hydrogen (H) Proteins are made up of simple units of amino acids Amino Acids  amino and carboxyl group 22 amino acids (9 essential amino acids) Structure : AA  polypeptides  Proteins AA are held by hydrogen bonds & sulfide bridges. Affected by heat and ph.

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29 Functions of Proteins Synthesis of new protoplasm for growth, repair and replacement. Synthesis of muscle, enzymes, hormones and antibodies. Deficiency of proteins may lead to Kwashiorkor

30 Test for Proteins : Biuret’s Test Test for presence of proteins Procedure Add 1cm 3 of sodium hydroxide to 1cm 3 of sample Shake thoroughly. Then add 1% copper(II) sulfate drop by drop. Observe colour change. +ve result Turns from blue to pink to violet. Intensity of colour depicts concentration of protein

31 5094 Pure Syllabus (a) state the roles of water in living organisms. (b) list the chemical elements which make up: carbohydrates fats proteins (c) describe and carry out tests for: starch (iodine in potassium iodide solution) reducing sugars (Benedict’s solution) protein (biuret test) fats (ethanol emulsion) (d) state that large molecules are synthesised from smaller basic units: glycogen from glucose polypeptides and proteins from amino acids lipids such as fats from glycerol and fatty acids

32 FATS

33 Fats & Oils Fats are made up of carbon (C), oxygen (O) and hydrogen (H). Fats produce twice amount of energy of carbohydrates. Fats broken down by hydrolysis to a Glycerol head and 3 Fatty acid tails.

34 Test for Fats Emulsion Test Add 2cm 3 of ethanol to the substance in a test tube Shake the test tube. Add 2cm 3 of water. +ve result White emulsion

35 Functions of Fat Provide a source & storage of energy Provides insulation to prevent excessive loss of heat. Solvent for fat-soluble substances (vitamins, minerals) Part of the cell membrane Reduce water loss from skin Prevent organs from physical injuries.

36 5094 Pure Syllabus (a) state the roles of water in living organisms. (b) list the chemical elements which make up: carbohydrates fats proteins (c) describe and carry out tests for: starch (iodine in potassium iodide solution) reducing sugars (Benedict’s solution) protein (biuret test) fats (ethanol emulsion) (d) state that large molecules are synthesised from smaller basic units: glycogen from glucose polypeptides and proteins from amino acids lipids such as fats from glycerol and fatty acids


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