The Structure and Function of Macromolecules: Carbohydrates, Lipids, Proteins & Nucleic Acids.

Transcription

1 The Structure and Function of Macromolecules: Carbohydrates, Lipids, Proteins & Nucleic Acids.

2 Biological Compounds Carbohydrates Lipids Proteins Nucleic Acids

3 Introduction Cells join smaller organic molecules together to form larger molecules. Or, cells and their organelles are made up of smaller building blocks called macromolecules. These larger molecules, macromolecules, may be composed of thousands of atoms and weigh over 100,000 daltons. The four major classes of Organic Compounds or macromolecules are: carbohydrates, lipids, proteins, and nucleic acids. Essential to maintaining life processes: cell function, storage, energy, homeostasis and genetic information.

4 Macromolecules of life Found in all living things Building blocks of all cells Made up of the atoms: Carbon, oxygen, hydrogen, Nitrogen, Phosphorus, and Sulfur There are 4 1. Carbohydrates C, H, & O. 2. Lipids C, H, & O. 3. Proteins C, H, O, N, & S. 4. Nucleic Acids C, H, O, N, & P.

5 Macromolecule, Monomers & Polymers Biological molecules(macromolecules) are large molecules composed of thousands of covalently bonded atoms or, polymers, constructed from the covalent binding of smaller molecules (smaller subunits) called a macromolecule is called a monomer. Monomers are the simple building blocks that when polymerized yield a macromolecule.

6 Diversity of polymers e Diversity of Diversity of P 1. Most macromolecules are polymers. 2. An immense variety of polymers can be built from a small set of monomers. 3. Macromolecules vary among cells of an organism, vary more within a species, and vary even more between species. 4. Each cell has thousands of different macromolecules

7 1. Most macromolecules are polymers Three of the four classes of macromolecules form chainlike molecules called polymers (greek poly = many, mer = parts). Polymers consist of many similar or identical building blocks linked by covalent bonds. The repeated units are small molecules called monomers (mono = one). Some monomers have other functions of their own.

8 Monomers & Polymers Polymer: Large molecule consisting of many identical or similar building blocks linked by bonds Monomer: Subunits that serve as building blocks for polymers Monomer: one basic unit or subunit Polymer: a chain of many basic units

9 Monomer Polymer

10 Making & Breaking Polymers The chemical mechanisms that cells use to make and break polymers are similar for all classes of macromolecules.

11 Monomers are connected by covalent bonds via a condensation reaction or dehydration reaction. A. Making Polymers One monomer provides a hydroxyl group and the other provides a hydrogen and together these form water. This process requires energy and is aided by enzymes.

12 Monomers H HO H HO H 2 O Polymer

13 H 2 O

14 B -Breaking Down Polymers The covalent bonds connecting monomers in a polymer are disassembled by hydrolysis. In hydrolysis as the covalent bond is broken a hydrogen atom and hydroxyl group from a split water molecule attaches where the covalent bond used to be. Hydrolysis reactions dominate the digestive process, guided by specific enzymes.

15 Monomers H 2 O H HO

16 C12H22O11 + H2O C6H12O6 + C6H12O6

17 Hydrolysis 17

18 2. An immense variety of polymers can be built from a small set of monomers. 3-Each cell has thousands of different macromolecules. 4-This diversity comes from various combinations of the common monomers and other rarer ones.

19 What you need to know? 1. Names of the 4 macromolecules 2. Structure- monomers and polymers of each 3. Function- what are they used for? 4. Food sources- what foods will you find these in? 5. Indicator Tests- what tests do we use to find out if a food contains them?

20 Carbohydrates

21 Carbohydrates: Structure Carbohydrates are made up of Monomer (basic unit): simple sugars (or monosaccharides) Ex.: glucose Polymer (chain of units): complex carbohydrates (or polysaccharides) Ex.: starch, cellulose, chitin, glycogen Disaccharid e: 2 simple sugars bonded together

22 Carbohydrates: Structure Basic units: sugars Contain a hydroxyl (OH) group Contain atoms of carbon, hydrogen, and oxygen. Carbohydrates have the general formula Cn(H2O)n, that the ratio of the atoms is 1 C : 2 H : 1 O Provide energy to the cells. Dissolve in water (hydrophilic) Fiber is a carbohydrate that prevents constipation Foods: breads, cereals, vegetables, fruits, & seeds Extra glucose is converted into glycogen in the liver

23 Carbohydrates: Functions There are 3 main roles (Functions) : 1. Source of stored energy. 2. Transport stored energy. 3. Carbon skeletons that can be rearranged to form new molecules. 4. Energy Metabolism 5. Structural Components 6. Cell-to-Cell Contacts and Recognition 7. Elimination of wastes (fiber) Carbohydrates include sugars and the polymers of sugars The simplest carbohydrates are monosaccharides,or single sugars. Carbohydrate macromolecules are polysaccharides, polymers composed of many sugar building blocks

24 Types of Carbohydrates (Structure) Carbohydrates are classified according to size into 4 kinds 1. Monosaccharaides : simple sugars One sugar (monomer). 2. Disaccharides : two simple sugars linked by covalent bonds. 3. Oligosaccharides : three to 20 monosaccharides. 4. Polysaccharides : hundreds or thousands of monosaccharides Ex.: starch, cellulose, chitin, glycogen

25 Chemical Formulas C 6 H 12 O 6 C 6 H 12 O 6 From corn syrup

26 Chemical Formulas C 5 H 10 O 5 C 5 H 10 O 4 deoxyribose

27 Lactose glucose + galactose Maltose Sucrose glucose + glucose glucose + fructose

28 glycogen

29 Starch vs. Cellulose Corn starch Potato starch

30 Carbohydrates: Food Sources Simple carbs. (simple sugars) are found in most candy and sweet drinks, fruit, vegetables, and milk. They are quickly digested and give a short burst of energy. Complex carbs. (like starches) are found in pasta, bread, potatoes, legumes & corn. They take longer to digest, and provide energy longer.

31 Carbohydrates: Indicator Tests Simple Sugars: Benedict s solution Blue solution turns orange/green/brown Complex Carbs: Lugol s solution/iodine Turns from orange-red-brown to black-purple

32 Lipids

33 Lipids are the one class of large biological molecules that do not form polymers. The unifying feature of lipids is having little or no affinity for water Lipids are hydrophobic because they consist mostly of hydrocarbons, which form nonpolar covalent bonds. The most biologically important lipids are fats, phospholipids, and steroids Main types of Lipids : 1. Fats (Triglycerides : Fats & Oils). 2. Phospholipids. 3. Steroids.

34 Lipids are made up of Lipids: Structure Monomer (basic unit): fatty acids Polymer (chain of units): lipids Specific examples: triglycerides, phospholipids.

35 Monomers in Lipids Lipids

36 1) Triglycerides Fats & Oils Triglycerides 1. Predominate form of fat in foods and major storage form of fat in the body. 2. Structure composed of 3 fatty acids + glycerol. Fatty Acids Organic acid (chain of carbons with hydrogens attached) that has an acid group at one end & a methyl group at the other end.

37 Fatty Acids & Triglycerides glycerol + 3 fatty acids triglyceride + H 2 O

38 Fatty Acids Fatty Acids carbon chains, vary in: 1. Length affects-absorption 2. Saturation chemical structure; affects, cooking & storage properties and health

39 Fatty Acids Saturation Saturated fatty acid carbon chains filled with hydrogen atoms (no C=C double bonds). 1. Saturated fat triglyceride containing 3 saturated fatty acids, such as animal fats (butter, lard) & tropical oils(palm, coconut). 2. Appear solid at room temperature. Unsaturated fatty acid carbon chains lack some hydrogens (>1 C=C double bond):- 1. Monounsaturated fat triglyceride containing fatty acids with 1 double bond; i.e. canola & olive oil. 2. Polyunsaturated fat- triglycerides containing a high % of fatty acids with >2 double bonds; i.e. corn, safflower, soybean, sunflower oils and fish. 3. Appear liquid at room temperature.

40 Saturated & Unsaturated Fats Saturated & Unsaturated Fats

41 Oleic acid 18-carbon, monounsaturated Linoleic acid 18-carbon, polyunsaturated

42 Phospholipids Phospholipids similar to triglycerides in structure except only 2 fatty acids + choline Phospholipids in foods: Lecithin, egg yolks, soybeans, wheat germ, peanuts. 1.Functions: part of cell membranes and acts as an emulsifier (helps keep fats in solution). 2. Not a dietary essential; made by the liver.

43 Lecithin

44 Phospholipids

45 Found in cell membranes Head is the phosphate group. Hydrophilic Tails are the fatty acids. Hydrophobic Phospholipids

46 Dissolves in water (hydrophilic) Structure of a Lipid Does not dissolve in water (hydrophobic)

47 Sterols or Steroids Important part of: 1. Sex hormones testosterone. 2. Vitamin D. 3. Bile (aids fat digestion). 4. Adrenal hormones cortisol. 5. Cholesterol in foods and made by the liver; dietary sources include egg yolks, liver, meats, dairy products.

48 Sterols Structure consists of carbon rings

49 Functions of Fats In the body, fats provide: 1. Energy 9 kcals/gm A. Supplies 60% of body s energy needs at rest B. Stored as adipose tissue 2. Insulation & protection. 3. Cell membrane constituents. In foods, fats: 1. Provide energy (9 kcal/gm) 2. Contribute flavor, aroma, and tenderness 3. Provide satiety 4. Carry fat-soluble vitamins (A,D,E & K) 5. Provide a source of essential fatty acids

50 Lipids: Food Sources As you might have guessed, fatty foods contain lipids. Lipids are found in meat and fish, oils, avacados, eggs & nuts.

51 Lipids: Indicator Test Paper Bag Test: Smear substance onto paper bag If see-thru, it contains lipids

52 Proteins

53 Proteins Proteins are the building materials for the body. Hair, skin, muscles, and organs are made mostly of proteins. Composed of carbon, hydrogen, nitrogen, and oxygen Contain amine (NH 2 ) and carboxyl (COOH) groups

54 Proteins are made up of Monomer (basic unit): amino acids 20 different kinds!* Proteins: Structure Polymer (chain of units): protein More specifically- polypeptides Amino acids linked by peptide bonds dipeptide

55 20 Amino Acids: Some of these are polar & hydrophilic, others are non-polar and hydrophobic. Proteins can contain both kinds. Proteins: Structure

56 Proteins: Structure Proteins have complex structures. The shape of a protein determines its function! The levels of protein structure are: Primary structure: polypeptide chain Secondary structure: polypeptides in coils or sheets Tertiary structure: coils or sheets form a tangle Quaternary structure: more than one tangle combine to make a very complex protein!

57 Proteins: Structure

58 Proteins: Structure

59 Function of Proteins 1. The building blocks of proteins are amino acids (monomers). 2. Serve as enzymes which control rate of reactions and regulate cell processes. 3. Amino acids are connected by a special type of bond called a peptide bond. 4. A protein contains one or more polypeptide chains. 5. Amino acid chains are called polypeptides.

60 Amino Acids Function of Proteins

61 Types of Proteins There are two types of proteins fibrous and globular. Fibrous protein (found in skin, tendons, bones, and muscles) does not dissolve in water (hydrophobic). Globular protein (found in enzymes, some hormones, and hemoglobin) can dissolve in water (hydrophilic).

62 Proteins: Food Sources Proteins are found in meat, fish, legumes, nuts, milk, eggs, grains and soy products. There are 6 amino acids that our bodies cannot make- we can only get these from food.

63 Proteins: Indicator Test Biuret s Solution: Turns from blue to purple if protein is present

64 Nucleic Acids

65 Nucleic Acids: Structure Nucleic Acids are made up of Monomers (basic unit): nucleotides Polymers (chain of units): DNA or RNA

66 Nucleic Acids: Function Stores and carries genetic information

67 Nucleic Acids: Food Sources We get nucleic acid components from vitamins and minerals in our diet. These in turn, come from fruits, vegetables, grains, meats, & almost anything else you can think of with some nutritional value (no junk food!).

68 Nucleic Acids: Indicator Test You will not be using an indicator test for these but in case you re wondering Dische diphenylamine test Turns from clear-light blue to dark blue if nucleic acids are present

69 Digestion Products