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+ Structure and Function of Large Biological Molecules.

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Presentation on theme: "+ Structure and Function of Large Biological Molecules."— Presentation transcript:

1 + Structure and Function of Large Biological Molecules

2 + Macromolecules 4 main types: carbohydrates, lipids, proteins, nucleic acids Large molecules typically made of smaller subunits Carbs, Nucleic acids, proteins = Polymers – built from monomers

3 + Synthesizing and Decomposing Macromolecules: Dehydration Synthesis: “adding” monomers together to form a polymer. Removal of an H 2 O molecule covalently bonds the monomers. Hydrolysis: Breaking down of polymers into smaller subunits using water. The H bonding to one monomer and the OH bonding to the other. Both processes use enzymes!

4 + Sugars and sugar chains – the fuel and building materials of life Carbohydrates

5 + Monosaccharides: Simple Sugars Sugar units have empirical formula: CH 2 O C chains range from 3-7 Enantiomers – different sugars! 5-6 C typically are aromatic!

6 + Glucose is Life C1 and C5 bond to form ring Glucose is a primary cellular fuel source for respiration Glucose is also used as a building block for many other macromolecules Can be stored for later use as di- and polysaccharides 2 forms of the rings α and β http://pslc.ws/macrog/kidsmac/toon_glu.htm http://pslc.ws/macrog/kidsmac/toon_glu.htm

7 + α -glucose and β -glucose

8 + Disaccharides Through Dehydration Synthesis 2 monosaccharides bonded Glycosidic linkage formed by dehydration synthesis Disaccharides: maltose, sucrose, lactose Linkages are named by the carbons that bond Maltose is a 1-4 glycosidic linkage Sucrose is a 1-2 glycosidic linkage

9 + Types of Glycosidic Linkages 1–4 glycosidic linkage 1–2 glycosidic linkage Maltose Sucrose

10 + Polysaccharides – huge chains of monosaccharides Each monomer is added through dehydration synthesis Huge chains are good for storage and even structure Function of the poly- determined by type of linkage and sugar monomers

11 + Storage Polysaccharides Plants create starch for storage Glucose monomers = stored energy Stored in plastids Formed by 1-4 glycosidic linkages

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13 + Storage Polysaccharides Animals synthesize glycogen Glucose monomers – high branched Stored in liver and muscle

14 + Structural Polysaccharides  Cellulose – major component of cell walls  Most abundant organic molecule on earth  Glucose monomers – different linkages!  Different forms of glucose but same 1- 4 linkage!

15 + Cellulose: Tough Cell Walls… Why? Cellulose is straight chains and never branched Form parallel chains Different enzymes to digest! Fiber Chitin = exoskeletons

16 + Hydrophobic, diverse molecules Lipids

17 + Lipid Basics: Hydrophobic energy chains Lipids are diverse in function but similar in their hydrophobicity Typically have large regions that are hydrocarbon chains

18 + Building Blocks of Fats Fatty acid chains Glycerol

19 + Triacylglycerol (TAGs) AKA Triglycerides Ester linkage! Dehydration Synthesis! x3

20 + Saturated and Unsaturated Fats Naturally occurring fatty acids have cis double bonds

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22 + Cis vs Trans Fats

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24 + Figure 5.12 Choline Phosphate Glycerol Fatty acids Hydrophilic head Hydrophobic tails (c) Phospholipid symbol (b) Space-filling model (a) Structural formula Hydrophilic head Hydrophobic tails

25 + Figure 5.13 Hydrophilic head Hydrophobic tail WATER

26 + Steroids Steroids have 4 carbon ring structures Can be hormones or cholesterol

27 + Multiple units, multiple uses Proteins

28 + Functions of Protein Proteins account for ~50% of the dry mass of most cells Proteins act as catalysts, play roles in defense, storage, transport, and cellular communication Greatest diversity in structure and function

29 + Figure 5.15-a Enzymatic proteins Defensive proteins Storage proteins Transport proteins Enzyme Virus Antibodies Bacterium Ovalbumin Amino acids for embryo Transport protein Cell membrane Function: Selective acceleration of chemical reactions Example: Digestive enzymes catalyze the hydrolysis of bonds in food molecules. Function: Protection against disease Example: Antibodies inactivate and help destroy viruses and bacteria. Function: Storage of amino acidsFunction: Transport of substances Examples: Casein, the protein of milk, is the major source of amino acids for baby mammals. Plants have storage proteins in their seeds. Ovalbumin is the protein of egg white, used as an amino acid source for the developing embryo. Examples: Hemoglobin, the iron-containing protein of vertebrate blood, transports oxygen from the lungs to other parts of the body. Other proteins transport molecules across cell membranes.

30 + Figure 5.15-b Hormonal proteins Function: Coordination of an organism’s activities Example: Insulin, a hormone secreted by the pancreas, causes other tissues to take up glucose, thus regulating blood sugar concentration High blood sugar Normal blood sugar Insulin secreted Signaling molecules Receptor protein Muscle tissue Actin Myosin 100  m 60  m Collagen Connective tissue Receptor proteins Function: Response of cell to chemical stimuli Example: Receptors built into the membrane of a nerve cell detect signaling molecules released by other nerve cells. Contractile and motor proteins Function: Movement Examples: Motor proteins are responsible for the undulations of cilia and flagella. Actin and myosin proteins are responsible for the contraction of muscles. Structural proteins Function: Support Examples: Keratin is the protein of hair, horns, feathers, and other skin appendages. Insects and spiders use silk fibers to make their cocoons and webs, respectively. Collagen and elastin proteins provide a fibrous framework in animal connective tissues.

31 + Protein Building Blocks - Peptides All proteins are made of 20 different amino acids Amino end Carboxyl end R = functional group α CARBON

32 + Proteins are Polypeptides Polymers of peptides are made through the formation of peptide bond Carboxyl end of one AA bonds to the amino end of adjacent AA Dehydration reaction to form peptide bond N terminus (+) and C terminus (-)

33 + Figure 5.16 Nonpolar side chains; hydrophobic Side chain (R group) Glycine (Gly or G) Alanine (Ala or A) Valine (Val or V) Leucine (Leu or L) Isoleucine ( I le or I ) Methionine (Met or M) Phenylalanine (Phe or F) Tryptophan (Trp or W) Proline (Pro or P) Polar side chains; hydrophilic 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 side chains; hydrophilic Acidic (negatively charged) Basic (positively charged) Aspartic acid (Asp or D) Glutamic acid (Glu or E) Lysine (Lys or K) Arginine (Arg or R) Histidine (His or H)

34 + Figure 5.16a Nonpolar side chains; hydrophobic Side chain Glycine (Gly or G) Alanine (Ala or A) Valine (Val or V) Leucine (Leu or L) Isoleucine ( I le or I ) Methionine (Met or M) Phenylalanine (Phe or F) Tryptophan (Trp or W) Proline (Pro or P)

35 + Figure 5.16b Polar side chains; hydrophilic Serine (Ser or S) Threonine (Thr or T) Cysteine (Cys or C) Tyrosine (Tyr or Y) Asparagine (Asn or N) Glutamine (Gln or Q)

36 + Figure 5.16c Electrically charged side chains; hydrophilic Acidic (negatively charged) Basic (positively charged) Aspartic acid (Asp or D) Glutamic acid (Glu or E) Lysine (Lys or K) Arginine (Arg or R) Histidine (His or H)

37 + Figure 5.17 Peptide bond New peptide bond forming Side chains Back- bone Amino end (N-terminus) Peptide bond Carboxyl end (C-terminus) Dehydration synthesis Side chains vary in their charge, polarity, length

38 + Protein – Structure Dictates Function 3D structure of each protein is unique Structure dictates function Structure is determined due to 4 levels of folding Most fundamental level of folding is sequence of AA

39 + Figure 5.19 Antibody protein Protein from flu virus

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41 Primary Structure AA Sequence Sequence of AA Read in order from N to C Dictates secondary, tertiary, quaternary levels

42 + Secondary Structure Regions of a peptide chain that are coiled or folded into patterns Regulated by H bonding of atoms in the peptide backbone α -Helix β -sheets

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44 + Tertiary Structure Overall shape of a protein Stabilized by R groups and how they interact Hydrophobic Interactions Disulfide Bridges

45 Quaternary Structure The interaction of multiple polypeptide chains Forms a functional protein Separate peptide chains

46 + Chaperonins: Protein Folders

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48 + Protein Structure in a Cell Folding is spontaneous Other proteins aid in this process Denaturation – unraveling/misfolding of a protein

49 + Blueprints of life Nucleic Acids

50 + Nucleotides Monomers of nucleotides 2 types: DNA and RNA Deoxyribonucleic acid Ribonucleic acid

51 + DNA to RNA to Protein Genetic material Inherited Codes for all genes DNA  RNA  Protein

52 + Nucleotides Types 2 Types of sugars Ribose Deoxyribose 2 Categories of N bases Purines (Pure As Gold) A and G Pyrimidines C, T, U

53 + Polynucleotides – Nucleic Acids Nucleotides are linked by a phosphodiester bond Adjacent sugars are linked from 5’ end to first sugar to 3’ of next sugar N Bases point inwards and provide “sequence” of DNA

54 + Structure of DNA Double helix Sugar- phosphates are antiparallel Bases pair 1 purine to 1 pyrimidine


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