Organic Compounds: Carbohydrates

Transcription

1 Organic Compounds: Carbohydrates Carbohydrates include sugars and starches Contain the elements C,H,O (H & O ratio like water, 2 H s to 1O), ex. glucose C 6 H 12 O 6 Word means hydrated carbon Classified according to size: monosaccharides, disaccharides, or polysaccharides Monosaccharides (common name = simple sugars) Means one sugar, single chain or single-ring structures containing 3 to 7 carbon atoms Important to body: glucose, fructose, galactose, ribose, deoxyribose Pentose - 5C monosaccharide Ribose, Deoxyribose nucleic acids and DNA Hexose - 6C monosaccaride glucose universal cell fuel, blood sugar fructose converted to glucose galactose converted to glucose

2 Organic Compounds: Carbohydrates Disaccharides double sugars, formed when two simple sugars are joined by a simple synthesis reaction, called dehydration synthesis sucrose = glucose + fructose cane sugar (requires protein enzyme, sucrase, to decompose to simple sugars) maltose = glucose + glucose malt sugar (requires protein enzyme, maltase, to decompose to simple sugars) lactose = in milk glucose + galactose (requires protein enzyme, lactase, to decompose to simple sugars) All double sugars are too large to pass through cell membrane, must be broken down to be absorbed by process hydrolysis water added to bond, bond breaks, then simple sugar is released

3 Organic Compounds: Carbohydrates Polysaccharides many sugars are long, branching chains of linked simple sugars Because they are large, insoluble molecules, ideal for storage, also lack sweetness of simple & double sugars Glycogen- storage polysaccharide found in animal tissues (liver & muscles) Starch storage polysaccharide formed by plants (potatoes & carrots) Cellulose (made of a different isomer of glucose, betaringed glucose, and cannot be digested by humans) Carbohydrate Functions: ready, easily used source of energy for cells to make ATP part of structure of DNA and RNA (pentose sugars - ribose and deoxyribose) recognition sites on cell membrane surfaces

4 Organic Compounds: Lipids Lipids organic molecules that contain: C, H, O Carbon & Hydrogen far outnumber the Oxygen atoms ex. C 57 H 110 O 6 - tristearin Most are insoluble in water, but will dissolve in other lipids and in other solvent such as acetone and alcohol Presence of P & N in some of the lipids Triglycerides (Neutral Fats) composed of two types of building blocks: fatty acids & glycerol Synthesis involves attachment of 3 fatty acids to a single glycerol molecule-results in an E shaped molecule that resembles the tines of a fork Maybe solid-typical of animal fats or liquid- plant oils Animal oils tend to be saturated, plant oils are unsaturated saturated fats- all carbons single bonds unsaturated fats- carbons have some double and triple bonds Most abundant & concentrated source of energy-when oxidized yield large amounts of energy Stored chiefly in fat deposits beneath skin & around organs, where help insulate body and protect deep tissues

5 Triglycerides

6 Organic Compounds: Lipids Phospholipids- similar to neutral, but differ in that a phosphorus group is attached & takes place of one of fatty acid chains Phosphorus portion the head contains an electrical charge gives special chemical properties and polarity Consists of a polar head attracts & interacts with water & ions but the nonpolar tail does not interact Found in cell membranes and allows cells to be selective about what may enter or leave Steroids flat molecules formed of 4 interlocking rings, look different than other 2 lipids, but act similar (C,H and lipid soluble) Examples - cholesterol, vitamin D, hormones, bile salts Cholesterol from food & in cell membranes, abundant in brain, provides raw material to produce vitamin D, some hormones, & bile salts

7 Phospholipids

8 Steroids

9 Organic Compounds: Proteins Proteins- a nitrogenous substance made up of amino acids Contains C,H,O,N & sometimes S Account for over 50% of the organic material in the body, and most varied in their functions of all the organic molecules amino acids are the building blocks of proteins, about 20 types Have 3 components: -COOH (carboxyl) group allow them to act as acids -NH 2 (amine) group gives basic properties R-group what is different for each that makes them chemically unique Amino acids joined in chains to form complex protein molecules that contain from 50 to thousands of amino acids Polypeptide fewer than 50 amino acids Each amino acid is distinct, sequence in which they are bound produce proteins that vary widely in both structure and function

10 Classifying Proteins Fibrous Proteins- are strand like, are also called structural proteins Appear most often in body structures, important in binding structures together and in providing strength to certain body tissues, very stable Ex. - Collagen found in bones, cartilage, and tendons-most abundant protein in body ex. Keratin found in hair, nails, and makes the skin tough

11 Classifying Proteins Globular Proteins mobile, spherical molecules that play critical roles in many biological processes, they do things rather than just form structures, are also called functional proteins, not stable Some are antibodies (provide immunity), hormones (regulate growth & development), enzymes (catalysts for chemical reactions) Hydrogen bonds are critically important in maintaining structure, but are fragile & easily broken by heat and ph changes When the 3 dimensional structure is destroyed, called denatured proteins, no longer can perform their roles (function depends on structure) active sites are structure on their surface that fit or interact with other molecules, ex. hemoglobin- has pepsin, that is inactivate by blood ph becoming to alkaline

12 Classifying Proteins Enzymes- are functional proteins that act as biological catalysts Catalyst- substance that increases the rate of a chemical reaction without be consumed or changed itself change the energy of activation for a chemical reaction Enzymes usually end in ase Enzymes are often produced in a inactive form and must be activated before can function, in some a cases are inactivated immediately after function(blood clotting)

13 Proteins Support structural proteins (e.g., keratin, collagen) Enzymes speed up chemical reactions Transport cell membranes channels, transporters in blood (e.g., Hemoglobin) Defense antibodies of the immune system Hormones cell signaling (e.g., insulin) Motion contractile proteins (e.g., actin, myosin)

14 Organic Compounds: Nucleic Acids Nucleic acids make up genes, composed of carbon, oxygen, hydrogen, nitrogen, and phosphorous atoms Largest biological molecules in the body Their building blocks, the nucleotide, are very complex 3 components: 1)nitrogen containing base, 2) pentose (5 carbon sugar), & 3) phosphate group 5 types of Nitrogen bases: 1)adenine(A), 2) guanine (G), 3) cytosine (C), 4) thymine(t), & 5) uracil (U) Two major kinds of nucleic acid: 1. deoxyribonucleic acid (DNA) & 2. ribonucleic acid (RNA)

15 Nucleotide Structure

16 Nucleic Acids: DNA Is the genetic material found in the nucleus Replicate itself exactly before cell divides Provides instructions for building every cell in the body Long double chain of nucleotides Bases are A,G,T,C Sugar deoxyribose Double stranded helix shape-chains held together by hydrogen bonds between bases (spiral staircase) Complementary base pairs A binds with T, and G binds with C

17 DNA

18 Nucleic Acids: RNA Located outside nucleus and can be considered the molecular slave of DNA Caries out the orders from the DNA for protein synthesis Consists of single nucleotide strands Bases A,G, C, and U instead of T Sugar is ribose 3 types of RNA: 1) messenger RNA, 2) ribosomal RNA, & 3) transfer RNA, each w/specific role in carrying out DNA s instructions Messenger RNA carries info. For building protein from DNA genes to ribosomes Transfer RNA ferries/caries amino acids to the ribosomes Ribosomal RNA forms part of the ribosomes, where it oversees the translation of the message & the binding together of amino acids to from proteins

19 ATP Adenosine Triphosphate (ATP) provides a form of chemical energy that is useable by all body cells w/out ATP, molecules cannot be made or broken down, cells cannot maintain their boundaries, all life processed would stop Glucose is most important fuel, but none of its chemical energy contained in its bonds can be used directly Energy released as glucose instead is catabolized (captured) and stored in the bond of ATP molecules as small packets of energy Structurally it is a modified nucleotide, consists of an adenine base, ribose sugar, & 3 phosphate groups When the high energy phosphate bonds are broken by hydrolysis, energy that can be used immediately by the cell is liberated ATP be compared to a tightly coiled spring that is ready to uncoil w/tremendous energy when the catch is released

20 How ATP Drives Cellular Work

21 THE BIG PICTURE Chemistry is essential for life