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Biological Compounds.

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Presentation on theme: "Biological Compounds."— Presentation transcript:

1 Biological Compounds

2 Macronutrients ENERGY ‘BIG’ nutrients – these are complex ‘chemicals’
XS stored as FAT Broken down into glucose Stored as glycogen Carbohydrates Cellular respiration ENERGY Glucose + oxygen  water + carbon dioxide + ENERGY

3 Other macronutrients…
Lipids: ENERGY stored in body fat and found in membranes Proteins: growth and repair

4 Micronutrients The body only needs VERY SMALL amounts of these
Inorganic Ions:Calcium (Ca2+) for teeth, muscles, bones, blood clotting Sodium (Na+) for nerves, heartbeat, muscle contraction Magnesium (Mg2+) Iron (Fe2+) Phosphate (PO43-) Vitamins: complex organic substances water soluble (in blood) e.g. vit C fat soluble e.g. vit A

5 Vitamin C Vitamin C: connective tissue, bones, skin, teeth, endothelial cells deficiency can lead to scurvy can contribute to CVD

6 Water & fibre: (roughage)
holds water provides bulk for intestinal muscles to work on

7 Organic Molecules Carbohydrates

8 Carbon Chemistry! 2D version Long chain of C atoms
The very lazy scientist….

9 Branched chain carbon polymer
Carbon ring structures Buckminsterfullerine (‘Buckyball’)

10 Carbon Chemistry KEY FACTS
Organic molecules contain: Carbon, hydrogen, oxygen, (sulphur, nitrogen, phosphrous) One carbon atom can bond with four other atoms forming a TETRAHEDRAL shape The bits of the body that are not WATER are ORGANIC molecules Carbon can form long chains, branched chains or ring structures They can ‘fold-up’ to make three-dimensional structures

11 Carbohydrates (CHO’s)
Sugars: sucrose (white crystalline ‘sugar’) glucose (energy supplier – sports drinks) starch (flour, potatoes) Carbohydrates fall into four main groups: Monosaccharides (one ‘sugar-structure’) Disaccharides (two ‘sugar-structures’) Oligosaccharides (3-11 ‘sugar-structures’) Polysaccharides (over 11 ‘sugar-structures’)

12 Monosaccharides (‘simple’ sugars)
triose Monosaccharides (‘simple’ sugars) Just one sugar-structure Have an empirical formula of (CH2O)n ribose Triose – found in mitochondria Pentose – found in DNA or RNA Hexose – glucose galactose fructose glucose Empirical formula for hexoses is C6H12O6


14 Ribose & Deoxyribose C5H10O5

15 Glucose

Monosaccharides you need to know… SIDE CHAINS AFFECT THE WAY IN WHICH THE MOLECULE IS USED BY THE BODY all of the carbon atoms are numbered 1-6 α-glucose has a side chain at position 6 fructose has a side chain at position 1 and position 6

17 Disaccharides

18 Disaccharides These are 2 monosaccharides JOINED TOGETHER glucose + glucose makes MALTOSE glucose + fructose makes SUCROSE glucose + galactose makes LACTOSE Monosaccharides join together by CONDENSATION REACTION and the bond that joins them together is a GLYCOSIDIC BOND

19 Building a disaccharide

20 Disaccharide summary The three common disaccharides you need to know:
All of these are formed by CONDENSATION REACTION (the one you need to be able to draw and label is maltose!!!)

21 Challenge! See if you can draw the structure of Lactose
(that’s glucose + galactose)

22 Breaking apart disaccharides (and polysaccharides)

23 (break them up with hydrolysis)
Disaccharides – KEY FACTS Disaccharides are formed from two monosaccharides glucose + glucose makes MALTOSE glucose + fructose makes SUCROSE glucose + galactose makes LACTOSE The reaction that joins two monosaccharides is called a condensation reaction (break them up with hydrolysis) The bond formed between two monosaccharides is called a GLYCOSIDIC BOND – the number of the carbon atoms nearby that are joined gives the bond its name e.g. 1,4 glycosidic bond for maltose

24 Polysaccharides

25 What are they? Macromolecules Polymers
Made up of monosaccharide monomers Covalently bonded by Condensation Polymerisation

26 Common ones Starch Glycogen Cellulose Chitin All made from glucose
Different properties depend on which ISOMER and the type of GLYCOSIDIC bond

27 Polysaccharide Monomer Glycosidic Bond Molecule Shape 1,4
Starch α-glucose (amylose) 1,4 Unbranched wound into a helix (amylopectin) 1,4 with some 1,6 Tightly packed branched chain Glycogen 1,4 with more 1,6 than amylopectin Very branched compact molecule Cellulose β-glucose Unbranched straight chains

28 Starch Mixture of amylose (30%) and amylopectin (70%) Amylose:
unbranched chains 1,4 glycosidic bonds >300 glucose monomers, helical shape coils have 6 monomers/turn held together by hydrogen bonds

29 Starch Amylopectin: Glucose monomers 1,4 glycosidic bonded chains
Branches in chains due to 1,6 glycosidic bonds Branches every residues Molecule several 1000 monomers, very branched and coiled compactly

30 Starch Functions as storage in plants:
Compact Insoluble No osmotic effects Doesn’t interfere in cell reactions Easily hydrolysed to sugars when required Build up into grains in structures called amyloplasts in plant cytoplasm

31 Polysaccharides Complex carbohydrates – many monosaccharides joined together by glycosidic bonds In plants strings of α-glucose joined by glycosidic bonds form starch, which is made up of amylose & amylopectin Amylase breaks the glycosidic bonds from the ends of amylose, and amylopectin (branched) which releases energy

32 Glycogen Polymer of α-glucose with 1,4 and 1,6 glycosidic bonds
Very similar to amylopectin but it branches more often, every 8 – 12 residues. Very compact Energy storage in animals –liver and muscle cells Cytoplasm of bacteria Well suited to its role Compact Rapidly hydrolysed to sugars when needed Page 6 of molecules handout Question pack

33 Cellulose Polymer of β-glucose
1,4 glycosidic bonds forming straight unbranched chains 1000’s of monomers Major constituent of the plant cell wall


35 Hydrogen bonding can occur between -OH groups on adjacent chains holding it together

36 Cellulose cont. Up to 2000 chains can be held together
form microfibril giving high tensile strength

37 Cellulose cont. Microfibrils embedded in a matrix (like a cement) making it a composite material Few organisms can break it down (digest) using enzyme cellulase A few prokaryotes and fungi can

38 What is cellulose called in the field of nutrition?
fibre Can mammals break down cellulose? Ruminant mammals have bacteria in gut to do it

39 Anaerobic bacteria in caecum and appendix

40 Chitin Chitin is used structurally HOMEWORK – find out more!
Hand in a ‘fact sheet’ on Chitin Maximum of one side

41 Polysaccharides – key facts
Complex carbohydrates – many monosaccharides joined together by glycosidic bonds They often fold-up on themselves to become more complex or are branched The body/plants uses polysaccharides as storage – these molecules can be broken down into smaller components Breaking glycisidic bonds is referred to as HYDROLYSIS and releases a lot of ENERGY Polysaccharides are INSOLUBLE so do not interfere with other chemical functions of the cell and have little impast on osmosis Starch is a polysaccharide found in plants Glycogen is a polysaccharide found in animals

42 Lipids Fats, Oils and Waxes

43 Soluble in organic solvents (eg acetone, ether)
Organic compounds Insoluble in water Soluble in organic solvents (eg acetone, ether) Relatively small (compared to polysaccharides) Tend to form together into globules Due to not being soluble

44 Naturally occurring fats and oils are esters
Formed by condensation reactions between glycerol (an alcohol) and fatty acids + Fatty acid Ester Glycerol + 3 H2O

45 each can undergo condensation reaction with a fatty acid.
H – C – C – C – H H OH Glycerol C3H8O3 3 hydroxyl groups each can undergo condensation reaction with a fatty acid. Produces an ester called a triglyceride (triacylglycerol)

46 Fatty Acid Long non-polar Hydrocarbon chain Polar carboxyl (COOH) end

47 Condensation Reaction

48 Triglycerides Triglycerides containing saturated fatty acids have a high melting point and tend to be found in warm-blooded animals. At room temperature thay are solids (fats), e.g. butter, lard. Triglycerides containing unsaturated fatty acids have a low melting point and tend to be found in cold-blooded animals and plants. At room temperature they are liquids (oils), e.g. fish oil, vegetable oils.

49 Triglycerides They are used for storage, insulation and protection in fatty tissue (or adipose tissue) found under the skin (sub-cutaneous) or surrounding organs. They yield more energy per unit mass than other compounds so are good for energy storage. Water released in oxidisation called metabolic water, important to organisms in dry climates Carbohydrates can be mobilised more quickly, and glycogen is stored in muscles and liver for immediate energy requirements.

50 Phospholipids Like lipids, are esters of glycerol and fatty acids. BUT, one of the fatty acid chains is replaced by a polar phosphate group

51 Phospholipid

52 Phospholipids Polar (phosphate) group is soluble in water The fatty acid chains are not So at air-water or oil-water interfaces, phospholipids orientate so the polar head is in the water. Important constituent in cell membranes.

53 Fats and health. Saturated or unsaturated? Which is best?
What are the risks of the wrong type? How much is too much? Who says? What’s BMI? Question Pack

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