Short polymer. Dehydration removes a water molecule, forming a new bond. Longer polymer (a) Dehydration reaction in the synthesis of a polymer

Transcription

1 HO H HO H Short polymer Dehydration removes a water molecule, forming a new bond Unlinked monomer H 2 O HO H Longer polymer (a) Dehydration reaction in the synthesis of a polymer HO H Hydrolysis adds a water molecule, breaking a bond H 2 O HO H HO H (b) Hydrolysis of a polymer 1 Trioses (C 3 H 6 O 3 ) Pentoses (C 5 H 10 O 5 ) Hexoses (C 6 H 12 O 6 ) Ketoses Aldoses Glyceraldehyde Dihydroxyacetone Ribose Glucose Galactose Ribulose Fructose 2

2 (a) Linear and ring forms (b) Abbreviated ring structure glycosidic linkage Glucose Glucose (a) Dehydration reaction in the synthesis of maltose Maltose 1 2 glycosidic linkage Glucose Fructose Sucrose (b) Dehydration reaction in the synthesis of sucrose 4

3 Chloroplast Starch Mitochondria Glycogen granules 0.5 µm 1 µm Amylose Glycogen Amylopectin (a) Starch: a plant polysaccharide (b) Glycogen: an animal polysaccharide 5 (a) α and β glucose ring structures α Glucose β Glucose (b) Starch: 1 4 linkage of α glucose monomers (b) Cellulose: 1 4 linkage of β glucose monomers 6

4 Cell walls Cellulose microfibrils in a plant cell wall Microfibril 10 µm 0.5 µm Cellulose molecules β Glucose monomer 7 8

5 (a) The structure (b) Chitin forms the (c) of the chitin exoskeleton of monomer. arthropods. Chitin is used to make a strong and flexible surgical thread. 9 Fatty acid (palmitic acid) Glycerol (a) Dehydration reaction in the synthesis of a fat Ester linkage (b) Fat molecule (triacylglycerol) 10

6 Structural formula of a saturated fat molecule Stearic acid, a saturated fatty acid (a) Saturated fat Structural formula of an unsaturated fat molecule Oleic acid, an unsaturated fatty acid (b) Unsaturated fat cis double bond causes bending 11 Hydrophobic tails Hydrophilic head Choline Phosphate Glycerol Fatty acids Hydrophilic head Hydrophobic tails (a) Structural formula (b) Space-filling model (c) Phospholipid symbol 12

7 Hydrophilic head WATER Hydrophobic tail WATER 13 14

8 15 Substrate (sucrose) Glucose OH Fructose H O Enzyme (sucrase) H 2 O 16

9 α carbon Amino group Carboxyl group 17 Nonpolar Glycine (Gly or G) Alanine (Ala or A) Valine (Val or V) Leucine (Leu or L) Isoleucine (Ile or I) Methionine (Met or M) Phenylalanine (Phe or F) Trypotphan (Trp or W) Proline (Pro or P) Polar Serine (Ser or S) Threonine (Thr or T) Cysteine (Cys or C) Tyrosine (Tyr or Y) Asparagine (Asn or N) Glutamine (Gln or Q) Electrically charged Acidic Basic Aspartic acid (Asp or D) Glutamic acid (Glu or E) Lysine (Lys or K) Arginine (Arg or R) Histidine (His or H) 18

10 Peptide bond (a) Peptide bond Side chains Backbone (b) Amino end (N-terminus) Carboxyl end (C-terminus) 19 Groove Groove (a) A ribbon model of lysozyme (b) A space-filling model of lysozyme 20

11 Antibody protein Protein from flu virus 21 Primary Structure Secondary Structure Tertiary Structure Quaternary Structure β pleated sheet + H 3 N Amino end Examples of amino acid subunits α helix 22

12 Hydrophobic interactions and van der Waals interactions Hydrogen bond Polypeptide backbone Disulfide bridge Ionic bond 23 Polypeptide chain β Chains Iron Heme Collagen α Chains Hemoglobin 24

13 Primary structure Normal hemoglobin Val His Leu Thr Pro Glu Glu Primary structure Sickle-cell hemoglobin Val His Leu Thr Pro Val Glu Secondary and tertiary structures β subunit Secondary and tertiary structures Exposed hydrophobic region β subunit Quaternary structure Normal hemoglobin (top view) α β α β Quaternary structure Sickle-cell hemoglobin β α β α Function Molecules do not associate with one another; each carries oxygen. Function Molecules interact with one another and crystallize into a fiber; capacity to carry oxygen is greatly reduced. 10 µm 10 µm Red blood cell shape Normal red blood cells are full of individual hemoglobin moledules, each carrying oxygen. Red blood cell shape Fibers of abnormal hemoglobin deform red blood cell into sickle shape. 25 Denaturation Normal protein Renaturation Denatured protein 26

14 Cap Polypeptide Correctly folded protein Hollow cylinder Chaperonin (fully assembled) Steps of Chaperonin 2 The cap attaches, causing the 3 Action: cylinder to change shape in 1 An unfolded poly- such a way that it creates a peptide enters the hydrophilic environment for cylinder from one end. the folding of the polypeptide. The cap comes off, and the properly folded protein is released. 27 DNA 1 Synthesis of mrna in the nucleus mrna NUCLEUS CYTOPLASM 2 Movement of mrna into cytoplasm via nuclear pore mrna Ribosome 3 Synthesis of protein Polypeptide Amino acids 28

15 5ʹ C 5ʹ end Nitrogenous bases Pyrimidines 3ʹ C Nucleoside Nitrogenous base Cytosine (C) Thymine (T, in DNA) Uracil (U, in RNA) Purines 5ʹ C 3ʹ C Phosphate group (b) Nucleotide Sugar (pentose) Adenine (A) Guanine (G) 3ʹ end (a) Polynucleotide, or nucleic acid Sugars Deoxyribose (in DNA) Ribose (in RNA) (c) Nucleoside components: sugars 29 5' end 3' end Sugar-phosphate backbones Base pair (joined by hydrogen bonding) Old strands 3' end Nucleotide about to be added to a new strand 5' end New strands 3' end 5' end 5' end 3' end 30

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