Macromolecules (Learning Objectives)

Transcription

1 Macromolecules (Learning Objectives) Recognize the role of water in synthesis and breakdown of polymers Name &recognize the monomer and the chemical bond that holds the polymeric structure of all biomolecules (where that applies). Which group of biomolecules are distinctly hydrophobic and lack a uniform monomer? Identify the function of monomers and polymers of each group with specific examples: Carbohydrates: Recognize common mono-, di-, and polysaccharides (note the structural and functional differences). Lipids: Name the three groups of lipids, their structure and function. Proteins: Name the generic monomer of proteins and identify the reason each of the 20 monomers provides any protein with structural and functional properties. What are the levels of protein structure? Name the chemical bond(s) involved with maintaining each level. What determines the function of a protein and how can a protein lose its activity? What does denaturation mean? Nucleic Acids: Name the generic monomer and its components. Learn the monomers that are found in DNA & RNA. Contrast the chemical bonds that hold the polymeric structure of nucleic acids that holding the two strands of poly-nucleotides together in DNA. Which chemical bond can be broken by physical means i.e by heat?

2 Role of Water in Polymer Synthesis and Breakdown a. Synthesis of polymers Short polymer Dehydration synthesis removes a water molecule, forming a new bond Unlinked monomer Longer polymer Dehydration reaction in the synthesis of a polymer b. Release of monomers Hydrolysis adds a water molecule, breaking a bond Hydrolysis of a polymer

3 Example of nutritional information on packaged macaroni and cheese Single Serving Serving Size 1 cup (228g) Calories 250 %DV Calories from Fat 110 Total Fat 12g 18% Trans Fat 1.5g Saturated Fat 3g 15% Cholesterol 30mg 10% Sodium 470mg 20% Total Carbohydrate 31g 10% Dietary Fiber 0g 0% Sugars 5g Protein Vitamin A 4% Vitamin C 2% Calcium 20% Iron 4% 5g

4 Food consists of simple and complex biomolecules Four Groups 1. Carbohydrates: simple sugars & complex carbs 2. Lipids: triglycerides, phospholipids, steroids 3. Protein 4. Nucleic acids: DNA & RNA Vitamins (other organic molecules) Minerals- chemical elements

5 Four groups of biologic polymers in living tissues N/A Only three are made of monomers Names of the monomer of each of the three polymers

6 Structures and Functions of Carbohydrates: Monosaccharides and Polysaccharides

7 Summary of Carbohydrate Functions Monomers Polymers Monosaccharides Polysaccharides Source of Storage of energycellular energy short term (animals) long term (plants) Source of carbon Structural - skeleton for the cell Plant cell wall Animal exoskeleton

8 Triose sugars (C 3 H 6 O 3 ) Pentose sugars (C 5 H 10 O 5 ) Hexose sugars (C 5 H 12 O 6 ) Functions 1. Cellular fuel Glyceraldehyde 2. Carbon skeletons, raw material for other molecules Dihydroxyacetone Ribose Glucose Galactose Ribulose Fructose Monosaccharides

9 Linear and ring forms Abbreviated ring structure Linear structure that form rings in aqueous solutions

10 Monosaccharides - Chemical Structure: - Monomers vary in carbon chain length - Functional groups: hydroxyl and carbonyl (aldehyde and ketone) groups - Water solubility: - Linear and ring forms

11 Common Disaccharides

12 Common Plant Polysaccharides (glucose polymers): Energy storage and structural roles

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14 Cellulose is a structural polysaccharide, a major component of the tough wall of plant cells.

15 Common Animal Polysaccharide (glucose polymers): energy storage

16 Common Animal Polysaccharide (glucose polymers): structural role Exoskeleton of arthropods Cell wall of fungus Fiber for humans!

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18 Lipids - Diverse Hydrophobic Molecules - Contain long hydrocarbon chains: saturated and unsaturated - Three major groups of lipids with different functions 1. Simple fats (glycerides)- long term energy storage 2. Phospholipids- make up cell membranes 3. Steroids- regulation

19 A simple fat is made of glycerol and fatty acids.

20 A triglyceride has three fatty acids joined to glycerol by an ester linkage, creating a triacylglycerol. The same or different fatty acid may be present

21 Fatty acids may vary in: - length of hydrocarbon chain (number of carbons). - number and locations of double bonds. Saturated fatty acids - have no carbon-carbon double bonds. - solid at room temperature.

22 Unsaturated fatty acid are kinked because they contain a double bond

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24 Common Fatty acids

25 Polyunsaturated fatty acids Chemical structure of docosahexaenoic acid, or DHA (22:6n-3), and eicosapentaenoic acid, or EPA (20:5n-3). Enhanced by Neuroinformation difference between omega 3, 6, and 9.

26 Polyunsaturated fatty acids Key omega-3 and omega-6 fatty acids - found primarily in oily cold-water fish such as tuna, salmon, and mackerel. - Fresh seaweed - Plant sources: Leafy greens, nuts, seeds Omega-9 are not essential in humans

27 Phospholipids - two fatty acids attached to glycerol and a phosphate group at the third position. - Important component of cell membrane

28 In the presence of water, phospholipids form micelles or bilayers.

29 Steroids have a carbon skeleton consisting of four fused carbon rings. Include cholesterol and other regulatory hormones

30 Proteins carry out most of the functions of the cell 1. Storage 2. Structural 3. Transport 4. Enzymes 5. Hormones 6. Receptors 7. Contractile

31 Proteins 20 monomers, amino acids. peptide bonds, polypeptides complex three-dimensional shape or conformation. may consist of one or more polypeptides

32 Essential Amino acids du/biochemistry/problem _sets/aa/aa.html Discovering Nutrition - Google Books Result by Paul M. Insel, R. Elaine Turner, Don Ross Medical pages

33 R The physical and chemical characteristics of the R group determine the unique characteristics of a particular amino acid.

34 Amino acid have enantiomers: 19 of the 20 amino acids have an asymmetric carbon surrounded by four different groups or atoms L & D forms L-Alanine D-Alanine

35 R groups are either Non-polar Polar Charged: acidic or basic

36 Complementary food combinations Essential amino acids Corn Methionine Valine (Histidine) Threonine Phenylalanine Leucine Isoleucine Tryptophan Lysine Beans and other legumes

37 Peptide bonds link the amino acids of the polypeptide

38 Protein structure catalase (7cat) or lysozyme (1hsw) 1. Primary structure- unique sequence of its amino acids. 2. Secondary structure- alpha helix or a pleated sheet. 3. Tertiary structure, the three dimensional shape or conformation. 4. Quaternary structure arises when two or more polypeptides join to form a protein.

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41 Chemical bonds that hold the tertiary structure of a protein forming among R groups: Relatively weak bonds - hydrogen bonds - ionic bonds - hydrophobic interactions - van der Waals interactions Strong bonds disulfide bridges covalent bonds that form between the sulfhydryl groups (SH) of cysteine monomers, stabilize the structure.

42 The folding of a protein: can occur spontaneously for some aided by other protein complexes, chaperonins Polypeptide Correctly folded protein Steps of Chaperonin Action: An unfolded polypeptide enters the cylinder from one end. The cap attaches, causing the cylinder to change shape in such a way that it creates a hydrophilic environment for the folding of the polypeptide. The cap comes off, and the properly folded protein is released.

43 The function of any protein is an emergent property resulting from its specific order of its amino acids.

44 Quarternary structure results from the aggregation of two or more polypeptide subunits. Collagen is a fibrous protein of three polypeptides that are supercoiled like a rope. Hemoglobin is a globular protein with two copies of two kinds of polypeptides.

45 A slight change in primary structure can affect a protein s conformation and therefore its function. Sickle-Cell disease

46 Physical and chemical conditions affecting the bonds folding the structure of a protein can change its conformation (ph, salt concentration, temperature), or denature it. Functionally active Functionally inactive

47 Nucleic Acids - Informational Polymers 1. Polymers of nucleotides. 2. Direct the activities and functions within a single cell. 2. Store and transmit hereditary information.

48 Two major types of nucleic acids: ribonucleic acid (RNA) deoxyribonucleic acid (DNA)

49 Nucleotide Structure Each nucleotide consists of three parts: a nitrogen base- A, T, G, C a pentose sugar- ribose (RNA) & deoxyribose (DNA) a phosphate group

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55 The DNA double helix The sugar-phosphate backbones of the two polynucleotides are on the outside of the helix. nitrogenous bases connect the polynucleotide chains with hydrogen bonds.

56 Base-pairing rule of nucleotides in nucleic acids H-bonds form between A & T A & U G & C The two strands of DNA are complementary