Biology 1010C LSSC Dr. Joseph Silver

1. Biology 1010CLSSCDr. Joseph Silver

2. in this chapter we willlearn about the chemical building blocksof life

3. there are many facets of chemistryanalytical, quantitative, forensic, industrial,inorganic, and many morethe chemistry of life involves organic chemistrywhich isthe chemistry of carbon containing compounds

4. life on earth is based on theelement carbonyou are carbon based life forms

5. Carbon has 4 valence electronsin order to become stable a carbon atomcan give away 4 electronscan gain 4 electronsor can share 4 electrons

6. carbon compounds containingonlycarbon, and hydrogenare called hydrocarbons

8. when all the available valence electronsform single carbon to carbon bondsthe chemical is saturated (page 34)butif some carbon to carbon bonds aredouble or triple bondsthe compound is unsaturated (fig 3.27)

10. hydrocarbons (C and H) are non polarbutmany organic compounds containcarbon, hydrogen, oxygen,nitrogen, sulfur, and phosphorustheseare polar compounds

12. look at page 35 fig 3.2many organic compounds havea carbon and hydrogen backboneto which are added functional groupsfunctional groups provide specific chemical properties to the organic compounds

15. look at figure 3.8fructose and glucose and galactosehave the same chemical formulabut they are each differentthey are structural isomersthey have the same 6 carbons12 hydrogen6 oxygenbut they are arranged differently in the molecule

17. in living systems isomers can have different shapesthe correct shape is important becauseenzymes are very specific to theshape of the chemicals they interact withwhy is this important?

19. message to cell – membrane carries message to cytoplasm- series of chemical changes take place in cytoplasm - changes carry message to nucleus - in nucleus message cause 1 gene to unwind- DNA of gene makes a copy of the gene- the copy is known as messenger RNA (mRNA)-mRNA leaves the nucleus-mRNA stimulates RER to make a protein enzyme- enzyme tells cell what work to doat every step chemicals fit together like pieces of a puzzleif the pieces do not fit the process stops

20. some molecules exist as a single moleculethese are known as monomersbutmany biologically active molecules exist as long chains of monomersthese are polymers

21. look at figure3.5and learn the difference between a dehydration reaction and a hydrolysis reactionthese reactions are common inall living organisms

23. DEHYDRATIONwhen 2 molecule are joined togetherto form a larger compoundan H is removed from 1 reactantand an OH is removed from the 2nd reactantresulting inthe formation of a molecule of waterthe reactants were dehydrated (water was removed)

24. HYDROLYSISwhen a large molecule is being split by an enzymethenwater is split to H and OHthe H is added to one partand OH is added to the other partwater was split and added to the subunits

25. the next section deals with the chemistry and biological role ofsaccharides (sugars)proteins (amino acid polymers)lipids (fats and oils)and nucleic acids (DNA and RNAs)

26. most biologically active simple saccharides (sugars) have 3, 4, 5, and 6 carbonsbutthese monomers can be arrangedinto many complex polymer sugarssuch asstarch, glycogen, chitin, and cellulose made up of 100s or 1000s of sugars

27. 3 and 4 carbon sugars are important in energy production5 carbon sugars are important in DNA & RNAs6 carbon sugars as monomers – dimers – and polymersare important for energy, storage, and support

28. sugar is often transportedas a disaccharideglucose + glucose = glucoseglucose + fructose = sucroseglucose + galactose = lactose

30. in animals sugar is storedas a highly branched amylose complexcalled glycogenamylose is a complex form of glucosesee fig 3.10

32. in plants sugar is storedas an maltose complexwhich islinked together with many maltose moleculesto form starchone of the simplest starches is amylose

34. cellulose is a complex polymerof glucose where the side chainsof glucose are cross linkedin such a way that the most enzymeswhich digest starch cannotbreak down cellulosethuscellulose is a good structural materialproviding support for plants

36. chitin is a polymerized of glucosewhich links up with a protein componentto form a strong cross linked toughvery resistant materialwhichforms the exoskeleton of crustaceans and othersstep on a cockroach and listen to thebreaking of the bonds in chitin

37. proteins are very complexthey consist of a polymerized moleculemade up of 20 different amino acidsproteins can include as few as 3 amino acidsmost proteins are made up of 100s or 1000s of amino acidslinked together to formspecific shapes

39. proteins function-as enzymes-tell the cell what to do-defense-fight infection and disease-transport-oxygen, hormones, through membranes-support-hair, skin, bone, muscle-motion-muscles, tendons, ligaments, mitosis, meiosis-regulation-hormones, as enzymes, gene activation-storage-calcium, iron, oxygen

40. there are 20 naturally occurring amino acidssome are polar, and others nonpolarevery amino acid has a generalized structure asR(?) l H2N - C - COOHlHthere are 20 different Rs

41. the R(?) on the generalized amino acidare shown on page 47you will see that there are 20different functional groupswhich make each of theamino acids different

42. when amino acids link togetherit is a dehydration reactionwhen an amino acid is split from a proteinit is a hydrolysis reaction

44. when amino acids join together to form apolypeptide the molecule goes througha series of structural or shape changes

45. Look on page 49 to see the changesin shape as a protein is constructedthe molecule goes through a primary – secondary – tertiary structurethis folds the protein into the correct shape

47. why do we keep talking about shape?molecules cannot talk to each other!Butwhen they fit together like pieces of a puzzlethe new molecule is then able to fit into another moleculeeach linkage causes something to happenin the cell membrane, cytoplasm, or nucleuswhich results in the cell doing work needed by the cell, or body

48. proteins with the correct tertiary structurecan link up to form many complex proteinswith a quaternary shape

49. just as there are homeodomain proteinsfound in every living organismthere aresimilar sequences of amino acidsresulting in similar shapes in all living organismsthese areprotein motifsarecommon patterns found again and again in proteins

50. homeodomain proteins were discussed in chapter 1these arefunctional units of a proteinwhich have specific tasksand are ubiquitous