1. CHAPTER 3 THE MOLECULES OF CELLS

2. Carbon: The Organic Element Compounds that are synthesized by cells and contain carbon are organic So what is inorganic? Why are carbon compounds so prevalent?

3. 4 valence electron configuration completes shell by sharing 4 the 4 electron orbitals are shaped like teardrops this forms a 3-D tetrahedron C

4. Hydrocarbons organic molecules consisting of only hydrogen and carbon The molecules’ chain of carbon atoms is called the carbon skeleton Ex: methane, ethane, propane Isomer – compounds with the same molecular formula but different structure

5. Functional Groups - Attachments replace one or more of the H on the C skeleton 1. Hydroxyl Group H bonded to O (-OH or HO-) Polar Known as alcohols

6. Carbonyl Group C double bonded to O (-CO) C=O Compounds are called aldehydes when –CO is at the end of the chain Compounds are called ketones when –CO is in the middle (Chain must have at least 3 carbons when finished)

7. Carboxyl Group O double bonded to C which is also bonded to a hydroxyl group,…forms carboxylic acids -COOH

8. Amino Group N bonded with 2 H (-NH 2 ) Forms compounds called amines The amino group acts like a base

9. Amino acid combines an amino group with a carboxyl group Amino Acids

10. Phosphate Group P bonded w/4 oxygen atoms (-OPO 3 ) *Used in energy transfer (ATP)

12. Macromolecules Polymer – a large molecule consisting of similar or identical subunits strung together Monomers - subunits

13. Making a Polymer Dehydration synthesis – monomers linked together by the removal of water One monomer loses a hydroxyl (-OH), the other loses a hydrogen (H) One H 2 O molecule must be removed for every link in the chain of monomers

14. Breaking a Polymer Hydrolysis – the reverse of dehydration synthesis (adding water) It breaks the molecule by using H 2 O Hydrolysis break a bond while adding water break a bond while adding water

15. Carbohydrates

16. Monosaccharides Simple sugars with a molecular formula in multiples of CH 2 O ex:C 6 H 12 O 6 Carbons in the chain each have an –OH group bonded to them; except one which is bonded to form a carbonyl group

17. sugar is either an aldehyde or a ketone depending on the location of the carbonyl group (p. 37 Fig B) monosaccharides are major nutrients for cells Are these properly identified?

18. Disaccharides double sugars (2 monomers) 2 monosaccharides joined by glycosidic linkage – 1 monomer gives up a H from a hydroxyl group and the other gives up an entire hydroxyl group bond formed by dehydration synthesis ex: p. 38

19. Polysaccharides --contain a few hundred to a few thousand monosaccharides linked together Storage polysaccharides – are hydrolyzed as needed to provide sugar for the cell

20. 2 Storage Types Starch – in plants – consists of many glucose molecules Glycogen – in animals – stored in the livers and muscles

21. 2 Structural Types - serve as building materials for structures protecting cells Cellulose – the major component of the tough walls enclosing plant cells (fiber for humans) - enzymes that digest starch are unable to hydrolyzed the linkages here (exception: cows & termites)

22. Chitin – structural polysaccharides are used by arthropods to build their exoskeletons

23. Lipids (hydrophobic – water fearing)

24. Fats - large molecules composed of glycerol and fatty acids Glycerol – an alcohol w/3 carbons, each w/a hydroxyl group Fatty acids – have long carbon chains (p. 79) What are the two kinds of fats?

25. Fatty Acids -One end has a –COOH head -Other end is a long hydrocarbon tail -Insoluble in water -Can be linked to glycerol by dehydration synthesis -Ester linkage bond

26. -triglyceride can be made this way – 3 fatty acids and a gylcerol -vary in length and # & location of double bonds Triglyceride-unsaturated

27. Saturated – no double bonds in the tail of the molecule (animal fats – solid at room temperature), causes plaque build up in arteries Transfats – unsaturated fat that has been converted to saturated by adding hydrogen

28. Unsaturated – have one or more double bonds in the tail (plant fats – liquid at room temperature) Major function of fats is energy storage (more than twice as much as sugar) Stored in adipose cells Cells shrink and swell

29. Phospholipid Structurally related to fats in structure, but only have 2 fatty acids Third carbon of glycerol is joined to a phosphate group (p. 79) The major component of cell membranes (phospholipid bilayer)

30. Waxes Have one fatty acid linked to an alcohol & are more hydrophobic than fats Used as water-resistant coatings on surfaces of fruits, leaves, and insects

31. Steroids Are lipids w/ a carbon skeleton consisting of 4 fused rings Cholesterol – precursor from which most other steroids are made Are all steroids bad? No! Cancer treatments, poison ivy

32. Anabolic Steroids – synthetic variants of testosterone, indiscriminate usage can cause liver damage, cancer, infertility, aggressive behavior and reduced sex drive Natural Synthetic

33. Proteins -structural, storage, enzyme (biological catalyst) -Made up of amino acids

34. Amino Acids (aa) --Building blocks of proteins --There are 20 amino acids that make trillions of different proteins --Consist of an asymmetric carbon bonded to 4 different covalent partners

35. C (alpha carbon) bonds to a H, a carboxyl group, an amino group, and a variable group (chemical group) called the R group or side chain

36. Polypeptide Chains= many aa’s joined by peptide bonds --2 amino acids can be joined by dehydration synthesis forming a peptide bond (p. 43)

37. Protein Conformation A protein consists of one or more polypeptide chains twisted in a 3-D shape or conformation When a cell makes a polypeptide, the chain folds spontaneously into its conformation

38. Primary – is the protein’s unique sequence of aa’s (one aa change in hemoglobin causes sickle cell) Secondary – describes how the primary structure is folded into it’s conformation (looks like spring coils or pleated folds) *this results from H bonding between peptides Levels of Protein Structure

39. Tertiary – describes additional, less regular contortions of the molecule (its 3-D shape) -caused by hydrophobic interactions, H bonds, ionic bonds, etc. -Disulfide bridges reinforce conformation

40. Quaternary – results from the relationship (bonding interactions) between subunits – each polypeptide chain is a subunit

41. Denaturation What is this? What causes denaturation?

42. Nucleic Acids Polynucleotides – another name for nucleic acid, phosphodiester linkages (phosphate and sugar) join monomers RNA and DNA are made up of monomers called nucleotides – contains 3 parts: nitrogenous base, a sugar, & a phosphate group (sugar-phosphate backbone)

43. RNA & DNA Ribonucleic acid Has the sugar ribose (pentose=5-C) Adenine, Guanine, Uracil, Cytosine Deoxyribonucleic acid Has the sugar deoxyribose (pentose=5-C) Adenine, Guanine, Thymine, Cytosine

44. Who all played a part in discovering the double helix? -consists of 2 polynucleotide chains that spiral -Genes are specific stretches of DNA that program the aa sequences (primary structure) of proteins -Watson, Crick, Franklin, Wilkins

45. Watson CrickFranklin Wilkins

46. How do base pairings ALWAYS occur? Adenine – Thymine Guanine - Cytosine