Molecules of Life. ! The dynamics of the diversity of life is due to the proper functioning and interaction of the molecules in each cell.

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1 Molecules of Life! The dynamics of the diversity of life is due to the proper functioning and interaction of the molecules in each cell.! Inefficient molecules can cause cells or organisms to become inefficient.! For example, diary products can cause issues in some people. Why would this happen? 1

2 Molecules of Life! The diagram is an illustration of the 3-dimensional structure of the enzyme Lactase (a protein with enzymatic function).! The function of Lactase is to break down Lactose (above), a molecule made from 2 simple sugars.! Today, ~ 75 % of the world s population is lactose intolerant due to the formation of a bad enzyme in their intestinal wall. Molecules of Life! Recent research has shown that we humans acquired the capacity to digest milk products only ~ 7500 years ago.! Data indicate that this occurred in central europe, and from here spread through other human populations.! One of the reasons that lactose intolerance is still high in people of Asian, South American, and African descent. 2

3 entral role of arbon! The diversity of all life is related to the diversity of its chemistry, which in turn is all possible due to the variety in which ARBON can react and form molecules.! All life forms on planet earth are carbon based organisms.! arbon-based molecules are referred to as organic compounds.! arbon always creates covalent bonds with other carbons or other atoms to create simple to extreme complex structures. entral role of arbon! The reason is the fact that carbon always makes 4 covalent bonds! If we look back at the arbon atom, it has atomic number 6. This means 6 protons, and 6 electrons. 4 of those electrons are in the outer-shell. It likes to get 4 more to get a full outer shell! Sharing its 4 electrons with 4 other ones thus creates 4 pairs of shared electrons ( thus 4 covalent bonds). 3

4 entral role of arbon Formation of methane entral role of arbon Structural formula Ball-and-stick model Space-filling model 4

5 entral role of arbon Ethane Propane arbon skeletons can vary in length. By stringing carbons one after another, one creates carbon chains or carbon skeletons. Obviously, this can result in very large complexes. entral role of arbon Butane Isobutane Skeletons may be un-branched or branched. 1-Butene 2-Butene Skeletons may have double bonds, which can vary in location. 5

6 entral role of arbon! When a carbon chain only has carbons and hydrogens, we call it a YDRO-ARBON chain! The longer the hydrocarbon chain, the more hydrophobic it becomes. Thus not very soluble in water!! ydrocarbon chains are most often drawn in a simplified, skeletal manner. Start, end and intersection represent the carbon atoms, the hydrogens are not shown, but assumed present according to the rules known (that carbon can make 4 bonds and hydrogen can only makes one bond). entral role of arbon or Butane 1-Butene Ethane 6

7 Molecular formula Butane Isobutane Molecular formula tells us what atoms are in the molecule, but it does not tell us the organization The example above shows that both have the same molecular formula. That s why the chemical structure becomes important. Isomers Butane Isobutane Molecules with the same molecular formula but with a different chemical structure are called ISOMERS. 7

8 Isomers! The changes between Isomers can be very subtle and can be the difference between being a biological active or non-active molecule.! For example, if a group occurs on the left side or right side of a carbon, it becomes spatially different like for example L and D lactic acid. They are mirror images like your left and right hand. and thus not the same molecules. We humans make for example L-lactic acid we cannot metabolize D-lactic acid! L-Lactic acid D-Lactic acid Optical Isomers! Such differences in being mirror molecules such as L or D form are called Optical Isomers or Enantiomeres! For example : Bacteria can make D-Lactate in our body and we have no way of neutralizing it. (our enzymes only break down L- lactate).! In are cases, too much of D-lacate can affect the brain and has been reported to result in sleepiness, hallucinations, clumsiness, blurred vision, disorientation, dizziness, lethargy, excessive irritability,. Lactobacilli (bad guys) 8

9 Optical Isomers! Methamphetamine is another example, but with graver consequences.! The L-isomer is just a decongestant and has no stimulant activity. The D-form is known as speed/ice: it is a potent brain stimulant and highly addictive The face of a meth user Functional groups! Functional groups refer to the side chains on carbon chains! They are important because they convey functionality to the molecules by creating regions for chemical interaction with other molecules.! Many of the functional groups are polar because they can be ionized and thus provide a hydrophillic character to the molecule. The more such functional group a molecule has, the more it becomes waterloving (the exception is the methyl group). 9

10 Functional groups! There are six (6) important functional groups in the chemistry of life:! ydroxyl group! arbonyl group! arboxyl group! Amino group Functional groups! Phosphate group! Methyl group All groups provide some hydrophillic characteristic to a molecule except for the methyl groups (they are hydrophobic). 10

11 Functional groups Female lion Estradiol Testosterone! Just like subtle changes in isomer structures can have drastic effects, so does the presence of functional groups on certain molecules.! Look at the minor chemical differences of the functional groups on these steroid hormones! and think on what effects they have on the animal or human body. Male lion MacroMolecules of Life! ells can make a huge number of different carbon molecules AND make larger molecules by combining sets of small molecules (like playing with lego blocks)! Many of the molecules are very large! Those are called macromolecules or polymers! No matter what cell type, molecules of life can be put into 4 major classes :! carbohydrates, lipids, proteins, and nucleic acids 11

12 MacroMolecules of Life! ells make most of their large molecules by joining smaller organic molecules into chains called polymers! Those smaller organic building blocks called are called monomers! ells link monomers to form polymers using a dehydration reaction. ( a water molecule is removed and the two parts are joined via a covalent bond)! It requires a very specific enzyme to perform this reaction MacroMolecules of Life O O O Short polymer Unlinked monomer Dehydration reaction 2 O O O Longer polymer 12

13 MacroMolecules of Life! The breaking down of a large polymer into smaller building blocks (monomers) occurs via a hydrolysis reaction.! In this case, water is inserted (by means of another specific enzyme) between two monomers to break the covalent bond apart. 2 O O ydrolysis O O arboydrates! arbohydrates are the sugar molecules! The basic building blocks (monomers) of carbohydrates are the simple sugars; these are also called the mono-saccharides! A monosaccharide has a formula that is a multiple of 2 O (carbon with water a carbo-hydrate).! It usually contains hydroxyl groups and a carbonyl group, that make the molecule hydrophilic ( water soluble)! 13

14 arboydrates O O O O Glucose and fructose are examples of typical simple sugars (mono-saccharides). O O Both can be written as 6 12 O 6 O O Or 6 ( 2 O) 6 a multiple of 2 O O O O O Their chemical structure is different and thus they are isomers. Glucose Fructose Notice the many hydroxyl groups (-O) that provide a hydrophilic character to sugars. arboydrates Monosaccharides can also occur as ring structures 6 2 O O 2 O 5 O 4 1 O O O O O O 3 2 O O Structural formula Abbreviated structure O Simplified structure 14

15 arboydrates! Mono-saccharides are the main fuel molecules for cellular work the breakdown of sugars in cells releases energy.! That is why sugar drink work very well as quick pepme-up s energy bars are usually filled with sugars! People that can t eat orally get sugars supplied via IV s. (intra-venous bags)! The carbons from sugar breakdown can also be used to make fats and proteins. (but too many simple sugars in a meal will quickly be turned into fat..) arboydrates 2 O O 2 O O When two mono-saccharides join we get a di-saccharide. O O O Glucose O O 2 O O O Glucose O The example here shows two Glucose molecules linking up to form Maltose. 2 O O 2 O O Notice the dehydration synthesis aspect of this reaction. O O O O O Where do we find maltose? O Maltose O Sucrose, table sugar, is a different disaccharide made from glucose and fructose. 15

16 Di-saccharides What is the chemical formula for Sucrose or Lactose? arboydrates ow sweet are sugars? Sweetness all depends on how well the molecules trigger your sweet receptors on your tongue.. Lugduname ~300,000 times sweeter 16

17 arboydrates What s the deal with high fructose corn sugar (FS)? Many researchers claim that FS is the carbohydrate equivalent of crack cocaine. Researchers find that high-fructose corn syrup prompts considerably more weight gain! Rats with access to high-fructose corn syrup gained significantly more weight than those with access to table sugar, even when their overall caloric intake was the same. In addition to causing significant weight gain in lab animals, long-term consumption of high-fructose corn syrup also led to abnormal increases in body fat The normal molecule that regulates your appetite is glucose. Evidence indicates that fructose does not turn off your appetite but may stimulate it! arboydrates Wanna Supersize it? 17

18 arboydrates! When many monosaccharides link up we get a polysaccharide (a polymer of monosaccharides).! They Link together by dehydration reactions! Some polysaccharides are energy storage molecules Starch in plants Glycogen in animals! Some polysaccharides serve as structural compounds ellulose in plants hitin in exo-skeleton of insects/crustaceans arboydrates Starch granules in potato tuber cells STAR Glucose monomer Glycogen granules in muscle tissues GLYOGEN ellulose fibrils in a plant cell wall ellulose molecules ELLULOSE 18

19 ellulose in Plant Walls hitin in ExoSkeleton 19

20 hitin Technology! The nanofibers from chitin have appealing physical and biological features and have attracted intense attention due to their excellent biological properties related to biodegradability, biocompatibility, antibacterial activity, low immunogenicity and wound healing capacity.! These nanofibrous materials have tremendous potential to be used as drug delivery systems, tissue engineering scaffolds, wound dressing materials, antimicrobial agents, and biosensors. arboydrates! We can eat and digest starch (from plants) and glycogen (from animal muscle). They provide us with a sugar source glucose molecules.! ellulose makes up the cell walls of plants. The covalent bonds in cellulose are different then those in starch and glycogen. Same goes for chitin.! We cannot break those bonds in cellulose and chitin. ows and termites have micro-organisms in their gut to help with that process.! Thus grazing like cows will not get us any useful carbohydrate supply!! 20