Organic Compounds Biology I Honors Elements and Compounds

Organic Compounds Biology I Honors

Elements and Compounds in Living Things n n 90 elements NATURALLY occurring Only 11 are common in living things n MOST Common are: n n n Carbon Nitrogen Oxygen Hydrogen These 4 elements make up 96. 3% of the human body 20 elements are found in small (TRACE) amounts in living things

2 Main Groups of Chemical Compounds n n Organic Inorganic

Organic Compounds n n Contain carbon Also tend to be n n Large molecules (made up of lots of atoms) Complex Lots of carbon and hydrogen atoms bound covalently These are the primary compounds that make up the working structures of living things!

Inorganic Compounds n Generally do NOT contain carbon n n Also tend to be n n n CO 2 is an exception Small Simple While NOT the major building blocks of life, they are absolutely necessary for life n Think WATER and Carbon Dioxide!

What’s so special about CARBON? n It’s a great Tinker Toy! n n 4 outer (valence) electrons Can bind with 4 different atoms

What’s so special about CARBON? n Readily forms COVALENT bonds with other atoms that are strong and stable

What’s so special about CARBON? n n Can form chains of almost unlimited length by bonding with other carbon atoms These long chains can then FOLD to make many complex shapes

THE BOTTOM LINE about CARBON n It has HUGE potential for making a WIDE VARIETY of different types of molecules!

How to BUILD (and take apart) Organic Molecules n n Polymer – a large molecule made up of many smaller subunits Monomer – a small subunit (building block) that can be joined with other subunits to make a polymer

How to BUILD (and take apart) Organic Molecules n Polymerization – the process of building LARGE molecules by joining together many smaller subunits n n Provides a way for really large complex molecules to form from smaller ones Macromolecule – term for VERY large polymers

How to BUILD (and take apart) Organic Molecules n Dehydration Synthesis n n Process that MAKES polymers Two monomers are joined together by removing a molecule of water from between them n n Dehydration – lose water Synthesis – making or putting together

How to BUILD (and take apart) Organic Molecules n Hydrolysis n n Process in which polymers are broken apart Add back the water that was taken out Breaks polymer into monomer subunits Example: digestion

Bottom Line about Making Polymers n Small subunits link together to make large polymers n Dehydration reactions link them n n n Removal of water Creates covalent bonds between subunits To break apart polymers into subunits, you just add the water back n n Hydrolysis reaction Breaks covalent bonds between subunits

Bottom Line about Making Polymers n n Really LONG complex molecules can be made and broken down by these methods. Like linking and unlinking cars in a train.

FOUR MAJOR GROUPS of Organic Compounds n n Carbohydrates Lipids Proteins Nucleic Acids

Carbohydrates n Functions Quick ENERGY n Energy STORAGE in PLANTS n Energy STORAGE in ANIMALS n Structural compounds for SUPPORT n

GENERAL CARB STRUCTURE: Monomers and Polymers n Monomers Monosaccharides n Individual car in the train n n Polymers Polysaccharides n The whole train n

Monosaccharides n n Monomers of carbs are monosaccharides Simple/single sugars Basic formula CH 2 O Example: n n n GLUCOSE; C 6 H 12 O 6 Sugar made by plants in photosynthesis Others: galactose (milk sugar); fructose (fruit)

Why monosaccharides are important n Energy in them can be made QUICKLY available to living things n Energy is stored in the chemical bonds of the sugar molecules n In particular, bonds between CARBON and HYDROGEN atoms store lots of energy When these bonds are broken, energy is released n This energy is then available to use n n Cellular respiration converts this energy to a usable form!

Monosaccharide - Glucose n n Note that there are lots of these C-H bonds in a sugar molecule Each has lots of potential energy stored in it

Disaccharides n n n DOUBLE sugars Two monosaccharides joined Examples: n Sucrose (table sugar) n n Glucose + fructose Lactose (milk) n Galactose + glucose

Why are Disaccharides useful? n n Not quite so easily broken down as monosaccharides Can by used by plants / animals for safe temporary storage of sugars n Used in transport in plants n n Sugar not consumed on its way from leaves to roots Makes milk harder to digest in animals n n MOST adult animals cannot digest milk Keeps it for YOUNG ONLY

Polysaccharides n n Made by joining MANY monosaccharides Sugar (thus energy) is STORED in this form

TYPES of Polysaccharides n STARCH PLANTS store energy in this form n LOTS of GLUCOSE molecules linked in LONG CHAINS n Animals CANNOT store energy in this form, but they CAN digest and USE it! n

Starch

TYPES of Polysaccharides n GLYCOGEN Energy storage carbohydrate in ANIMALS n Found in the liver, mostly. n ALSO made of lots of glucose linked together n As you consume sugar, your liver converts it to glycogen and stores it. n n Through the day as you need energy, the liver breaks off sugars from the glycogen molecules for you to us

Glycogen

Cellulose n n n STRUCTURAL carbohydrate in PLANTS ALSO lots of glucose linked together CELL WALLS in plant cells SUPPORT and PROTECTION UNDIGESTABLE BY ANIMALS WOOD

Chitin n STRUCTURAL carbohydrate Cell walls of fungi Exoskeleton of arthropods

Lipids n n Waxes Oils Fats Steroids

Functions of Lipids n n Energy Storage animals and plants Insulation n n Keeps animals warm blubber

Functions of Lipids n Waterproofing n n Duck feathers are kept dry by a layer of oil Mammal fur (beaver, otter, etc. ), too.

Functions of Lipids n n n shockabsorption/protection of organs formation of membranes in cells and organelles make important compounds called steroids - cholesterol and hormones (estrogen and testosterone, for example)

Structure of Lipids n Glycerol + 3 fatty acids n n Glycerol is just a “connector” 3 fatty acids are the most important part

Why are Fatty Acids the “important part”? n n n fatty acids are LONG chains of carbon and hydrogen atoms remember: bonds between carbon and hydrogen atoms STORE ENERGY! So fats (with their 3 fatty acids) are PACKED with energy and are GREAT at energy storage

EFFICIENT energy storage n Because there are SO MANY C-H bonds in fatty acids, lipids are VERY efficient ways of storing energy. n n Fats produce more energy per gram than carbohydrates do! more efficient means better for animals lots of energy without much "baggage“ for animals that need to move.

Efficient energy storage n Some plants do use oils for energy storage n n Corn oil, peanut oil, etc. Efficiency is just not as important for plants since they don’t have to move around - so starch is still often the primary energy storage molecule for them

Saturated vs. Unsaturated Fats n n n saturated fat - when each carbon in a fatty acid shares a single covalent bond with as many hydrogen atoms as possible causes the fatty acids to be very straight fatty acids like this can pack very tightly together because they can pack tightly, saturated fats tend to be solid at room temperature butter and lard

Saturated Fat

Saturated vs. Unsaturated Fats n n n unsaturated fat - a fatty acid that has at least two carbons double bonded to each other instead of to hydrogen atoms - that is, the carbons are NOT bound to the maximum number of hydrogen atoms. causes the fatty acids to bend fatty acids like this cannot pack very tightly together because of this unsaturated fats tend to be liquid at room temperature n oils

Saturated vs. Nonsaturated Fats

Protein n Functions – MANY! Structural – build structures in organisms n muscle contraction n communication between cells n movement of cell parts n MOST IMORTANT: ENZYMES!!! n

Structure of Proteins n Monomers of Proteins are AMINO ACIDS n n n ALWAYS a carbon in the middle ALWAYS an H at the “top” ALWAYS an amino group on one side ALWAYS a carboxyl group on the other side R group is always there, but TYPE of R-group VARIES n n 20 different types All have different characteristics

Protein Structure n n A protein is a polymer of amino acids Amino acid monomers link together by covalent bonds called PEPTIDE BONDS. = Proteins are long chains of amino acids n n sometimes called polypeptides in reference to their peptide bonds. Peptide bonds are formed the same way as all bonds among the organic compounds we're discussing - DEHYDRATION reactions.

Making Proteins from Amino Acids

Enzymes n n Chemical reactions are what living things are all about. Most of the chemical reactions in your body, if left to themselves, would not happen quickly enough for you to survive. CATALYST - something that speeds up a chemical reaction Enzymes are proteins that act as catalysts for the chemical reactions in your body.

Enzymes n n Enzymes have unique shapes designed to fit the chemicals that they are to "speed up" (the SUBSTRATES of the REACTION) The region of the enzyme that FITS the substrate specifically is called the enzyme's ACTIVE SITE. n The substrate BINDS with the enzyme at the enzyme's ACTIVE SITE.

Enzymes n Enzymes can either: bring two (or more) reactants together more quickly and force them to react n stress bonds in a single substrate and cause it to break apart more easily n

Enzymes n n An enzyme itself is NOT CHANGED by the chemical reaction it catalyzes A single enzyme can repeat its catalytic activity with many, many substrate molecules - that is, it can be used over and over again.

Enzyme catalyzed reaction

Enzymes n ENZYMES ARE VERY SPECIFIC! If the shape of the enzyme's active site becomes damaged, it will be unable to bind with its substrate n Thus, it will be unable to function. n If an enzyme loses its shape it is said to be DENATURED. n enzymes can be denatured by HEAT n or by extremes in p. H. n

Nucleic Acids n Functions tell the cell how to function n transmit genetic information to offspring n

Nucleic Acids n Structure n Monomers of nucleic acids are nucleotides n n Sugar Phosphate Base Many nucleotides linked together give a nucleic acid - RNA and DNA are the two main examples