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Biology 20 Biochemistry.

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Presentation on theme: "Biology 20 Biochemistry."— Presentation transcript:

1 Biology 20 Biochemistry

2 Explain how the human digestive and respiratory system exchange energy and matter with the environment Describe the chemical nature of carbohydrates, lipids, and proteins and their enzymes.

3 Biochemistry Atom - The smallest particle of an element
Element - A substance consisting entirely of one type of atom, for instance, carbon, hydrogen or oxygen. Elements can combine into compounds to form other substances. Ion – an atom or group of atoms that have a charge Compound - A substance consisting of more than one atom or one type of element, e.g. carbon dioxide is a compound.

4 Biochemistry Covalent bond - Chemical bond formed by the sharing of one or more electron pairs between two atoms Ionic bond - Chemical bonding resulting from the transfer of one or more electrons from one atom or a group of atoms to another.

5 Biochemistry pH scale - scale is commonly used over a range 0 (acidic) to 14 (basic). Acid - Substances that have a pH of lower than 7 (neutral) that can dissolve in water. Base - Substances that have a pH of higher than 7 (neutral) that can dissolve in water. Buffer - Solution that resists change in pH;

6 Metabolism Metabolism: All the chemical reactions that occur within the cells. Monomer: Basic subunit used to build larger molecules. Eg. Amino acids Polymer: Molecules composed of many basic subunits bonded together Eg. Many amino acids bond together to form on protein.

7 Polymer: Protein Monomer: Amino acid

8 Chemistry Review Isomer - A chemical with the same number and types of atoms as another chemical, but possessing different properties.

9 Catabolic Reactants Complex chemicals broken down into smaller units
Eg. Breaking down food

10 Anabolic Reactions Small units combine to make larger molecules
Eg. Plants and photosynthesis


12 Dehydration Synthesis
The process by which larger molecules are formed by the removal of water from two smaller molecules. + H20

13 Hydrolysis The process by which a larger molecule is broken down into two smaller molecules. Water is taken up at the broken bond site. + H20

14 Chemistry Review Organic Compounds Inorganic Compounds
contain carbon atoms that are linked together Inorganic Compounds do not contain linked carbon atoms.

15 4 Types There are 4 major types of organic molecules important in biology. Carbohydrates monosaccharides, disaccharides, polysaccharides Lipids Triglycerides, Phospholipids, Waxes, Steroids Proteins Primary, Secondary, Tertiary, Quaternary Nucleic Acids DNA, RNA

16 Biochemistry Carbohydrates

17 Types of Carbohydrates
Monosaccharides Disaccharides Polysaccharides

18 Carbohydrates Characteristics Purpose
A Carbohydrate can be a single sugar or a polymer of many sugars. Carbohydrates contain CHO Carbon, Hydrogen, Oxygen Ratio of carbon, hydrogen, oxygen = 1:2:1 Purpose Source of energy for cellular respiration Structural material

19 Purposes of Carbohydrates
Structural Major structural component of cell organelles, membranes and cytoplasm Energy Produced by photosynthesis, carbohydrates are the major energy source for cells. Energy is released through cell respiration

20 Monosaccharides

21 Types of Monosaccharides
Single sugar = C6H12O6 Three common isomeres Glucose blood sugar Fructose fruit, honey, twice as sweet as glucose Galactose milk sugar, rarely found alone.

22 Types of Monosaccharides

23 Three Monosaccharides
Galactose Glucose Fructose

24 Three Monosaccharides

25 Disaccharides

26 Disaccharides Formed by the joining of 2 monosaccharides

27 Disaccharides

28 Dehydration Synthesis

29 Dehydration Synthesis

30 Disaccharides Formed by the joining of 2 monosaccharides
Process called DEHYDRATION SYNTHESIS The reverse process is called HYDROLYSIS

31 Disaccharides Three Common Isomers Sucrose Maltose Lactose
Glucose + Fructose sugar cane, table sugar Maltose Glucose + Glucose found in seeds of germinating plants Lactose Glucose + Galactose Found in milk Lactose Intolerance is common

32 Polysaccharides

33 Complex Carbohydrates

34 Important Polysaccharides
Structural Storage Starch Glycogen Cellulose Chitin Exoskeletons...

35 Polysaccharides Formed by the union of may monosaccharides by dehydration synthesis Types: Starch Multiple sub-units of glucose Storage form of energy in plants Glycogen Branched chains of glucose Storage of of glucose in animals liver and muscle cells High Blood Glucose -- Glycogen formed in the liver Low Blood Glucose -- Glycogen converted to glucose

36 Cellulose Structural material found in plant cell walls
glucose is linked together differently compared to starch and therefore only organisms with cellulase can digest it. Microbes in cow’s first stomach cleave the bonds with cellulase The cow regurgitates (vomits into his own mouth) chews again (gross!) swallows into second stomach (yummy) What is it good for?? Roughage -- retains water in feces = soft poo

37 Biochemistry Lipids

38 Lipids Structure Purpose Contains CHO
Ratio of H to O is greater than 2 to 1 Purpose Long Term Energy Storage 1 gram of lipids contains > twice the calories compared to carbohydrates or proteins Structural Material cell membranes cushion for organs carriers for vitamins raw material for synthesis of some hormones insulator

39 Classification of Lipids
Phospholipid Steroid Triglyceride

40 Types of Lipids Triglycerides Formed from 1 glycerol and 3 fatty acids
formed by dehydration synthesis

41 Classification of Lipids
Phospholipid Steroid Triglyceride

42 Triglyceride Formation

43 Triglyceride Formation


45 Types of Lipids Triglycerides Formed from 1 glycerol and 3 fatty acids
formed by dehydration synthesis 1) FAT usually from animals saturated fatty acids only contain single bonds Very Stable -- hard to break down solid or semi-solid at room temperature Example: Butter

46 Types of Lipids 2) Oil usually from plants
polyunsaturated fatty acids have some double bonds between carbon atoms more reactive than fats therefore more easily broken down liquid at room temperature Example: Canola oil


48 Types of Lipids Phospholipids
Have a phosphate molecule attached to a glycerol backbone

49 Classification of Lipids
Phospholipid Steroid Triglyceride

50 Types of Lipids Phospholipids Waxes
Have a phosphate molecule attached to a glycerol backbone Polarized molecule one side is relatively hydrophilic, other side hydrophobic Major component of membranes Waxes Very stable Insoluble in water valuable waterproof coatings for plant leaves, animal feathers and fur


52 Types of Lipids Steroids structure = four fused carbon rings

53 Classification of Lipids
Phospholipid Steroid Triglyceride

54 Types of Lipids Steroids structure = four fused carbon rings
Made from cholesterol

55 Biochemistry Proteins

56 Proteins After water, protein is the most abundant molecule in body
17% of body weight 1000’s of types: species specific and individual specific

57 Proteins Purpose 1) Cell Structure 2) Cell Function
Major part of muscle, skin, nerves … Required for the building, repair and maintenance of cell structure. 2) Cell Function Chemical messenger -- hormones Transport -- hemoglobin Movement -- contractile proteins Catalysis of cell reactions -- enzymes Defence against foreign substances -- antibodies

58 Protein Structure

59 Proteins Structure Terms Contains CHON
Carbon, Hydrogen, Oxygen, NITROGEN Terms Protein A large molecule made of one or more polypeptide chains folded and coiled into a specific shape. Polypeptide Chains polymers of amino acids arranged in a specific order and linked by peptide bonds

60 Proteins Peptide Bond Amino Acids
Covalent bond between adjacent amino acids Amino Acids The structural subunit of proteins 20 Different types 8 are “essential” Cannot be manufactured by the body Must be obtained from food Structure...

61 Amino Acid

62 Amino Acids


64 Levels of Protein Structure
Primary protein structure linear arrangement of amino acids in the polypeptide (like beads on a string) exact sequence of amino acids determines overall protein structure (analogy: different arrangements of letters spell out words with different meanings) all proteins have primary structure

65 Primary Protein Structure

66 Levels of Protein Structure
Secondary Protein Structure The coiling and folding of amino acid chains (polypeptides) coils are like springs folding produces sheet-like structure this type of structure is held together by hydrogen bonding between amino acids Some proteins have lots of secondary structure, some have none

67 Secondary Structure

68 Levels of Protein Structure
Tertiary Protein Structure The coiled and folded polypeptide is further twisted into n overall 3-D shape Shape held together by hydrogen bonds, covalent bonds, ionic bonds Refers to the polypeptide as a whole Polypeptides may have an overall shape (tertiary structure) that is either Globular (like a big blob), or Helical (like a long, coiled spring)

69 Tertiary Structure

70 Levels of Protein Structure
Quaternary Protein Structure arrangements of polypeptide subunits, when a protein is made up of more than one polypeptide Held together by hydrogen bonds, ionic bonds, covalent bonds Example: hemoglobin, many enzymes

71 Quaternary Structure

72 (a) The primary structure of a protein is the sequence of amino acids in the polypeptide strand.
(b) Hydrogen bonds that form with nearby amino acids coil and fold the polypeptide into α-helices and β-pleated sheets; these constitute the polypeptide’s secondary structure. (c) The polypeptide folds further to form its tertiary structure. These folds are stabilized by R-group interactions. (d) The clustering of two or more polypeptides in a tertiary structure generates the quaternary structure of a protein.

73 Protein Changes Denaturation Coagulation
Changes in the shape of the protein by physical or chemical factors such as heat, radiation or pH changes. Protein may uncoil or assume a new shape. Protein’s physical properties and biological properties are changed. Coagulation Permanent change in the shape of the protein e.g. boiling and cooling egg white

74 Biochemistry Vitamins and Minerals

75 Vitamins Characteristics: Organic molecules
Not used for energy construction Cannot be synthesized from food Needed in small amounts for bodily functions

76 Inorganic Molecules Minerals
building materials for cell structures and hormones -- calcium, iron, iodine coenzymes -- magnesium activates enzymes in protein synthesis regulating body’s acid-base balance -- potassium regulates the body’s water balance -- sodium

77 Inorganic Molecules Water Most abundant molecule in the body
60% of adult weight Functions: excellent solvent involved in chemical reactions hydrolysis maintains constant body temperature

78 Biochemistry Chemical Tests

79 Chemical Test Chemical tests are used to determine the presence of different types of organic molecules. Some important tests include: Benedicts Reagent Iodine Test Biuret Sudan IV Dye

80 Benedicts Reagent Tests for the presence of simple sugars
Negative test: After heating the benedict solution remains blue Positive test: After heating the blue benedict solution turns yellow  to orange.

81 Benedicts Test Negative Test: Blue Positive Test: Orange
No simple sugar is present Positive Test: Orange Simple sugar is present

82 Iodine Test Test for Starch
Negative Test: The iodine solution remains amber when no starch is present Positive Test: The iodine solution turns blue black when starch is present

83 Iodine Test for Starch Positive Test: Solution turns blue black
Starch is present Negative Test: Solution remains amber No starch in present

84 Biuret Test for Protein
Biuret solution is blue Negative Test: When added to a substance not containing protein, the solution remains blue Positive Test: When added to a substance containing protein, the substance turns purple

85 Biuret Test for Protein
Negative Test: Solution remains blue Positve Test: Solution turns violet

86 Sudan IV & translucence test
Test for fats If fat is present in the sample tested, a red or pink colour will result Translucence test The presence of fats can be detected by rubbing samples on a piece of unglazed paper

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