QUESTION 3 QUESTION 5 QUESTION 1. Proteins and Nucleic Acids QUESTION 2 QUESTION 4. Carbon is such an important molecule for life because:

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1 QUESTION 1 You are sitting by a lake, you drop a leaf on the lake and notice that it floats on the top of the water, which of the following properties of water could help explain what you observe? A) It is more dense when liquid than when frozen. B) It can dissolve large quantities of solutes. C) It has a high specific heat. D) It has a strong surface tension. E) None of these can explain what you observe. QUESTION 2 The formation of large, repetitive organic molecules from small monomers is a reaction. A) dehydration synthesis B) reduction C) dehydrogenation D) hydrolysis QUESTION 3 Carbon is such an important molecule for life because: A)it can form chemical bonds with a maximum of four other atoms. B) it is part of the water molecule. C) it can hydrogen bond to so many molecules. D) it can be bonded ionically. E) it can form isomers. Glycogen is a polysaccharide used for energy storage by: A)monera B)fungi C)plants D)animals QUESTION 4 QUESTION 5 Which of the following solutions has the greatest concentration of hydrogen ions (H+)? A) gastric juice at ph 2 B) black coffee at ph 5 C) vinegar at ph 3 D) tomato juice at ph 4 E) household bleach at ph 12 Proteins and Nucleic Acids KEY WORDS: Protein Polypeptide Amino Acid Essential Amino Acid Denature 1, 2, 3, 4 Structure Nucleic Acid Nucleotide DNA RNA

2 Types of Proteins Storage Transport See Table 5.1 Structural Enzymes Hormones Proteins Subunit = amino acid Amino acids have three parts: Receptor Contractile Antibodies 1. Amino group 2. R group 3. Carboxyl group The 20 amino acids of proteins: nonpolar The 20 amino acids of proteins: polar and electrically charged Linking Amino Acids Making a polypeptide chain Dehydration synthesis: forms a covalent bond A Peptide Bond Creates a polypeptide

3 How are proteins able to do so many things? 20 different kinds amino acids - different R-groups Non-polar Polar Charged - O Carbohydrates: Glucose Hard to make more than one word Scrabble Analogy Proteins: 20 amino acids Glutamine E 1 Isoleucine Asparagine Serine Threonine Lysine Arginine I 1 N 1 S 1 T 1 K 5 R 1 Proteins Fold into Active Shape Protein function depends on shape Primary (1 ) Structure Sequence of amino acids in polypeptide Four Levels of Structure: Primary 1 Secondary 2 Tertiary 3 Quaternary 4 The primary structure of a protein Secondary (2 ) Structure Folds in part of amino acid chain: Hydrogen bonds β- pleated sheet α-helix

4 Tertiary (3 ) Structure 3D Packing of Polypeptides: More hydrogen bonds Examples of interactions contributing to the tertiary structure of a protein Quaternary (4 ) Structure Interactions between 2+ polypeptides The quaternary structure of proteins Review: the four levels of protein structure Conformation of a protein, the enzyme lysozyme

5 ph Heat A chaperonin in action What can cause proteins to denature? Chemicals Protein Folding and Disease Many diseases caused by incorrect protein folding Mad Cow Disease Alzheimers Cystic Fibrosis Parkinson s Disease Sickle Cell Anemia Arthritis Marfan Syndrome ALS (Lou Gehrig s Disease) Cancer Diabetes Insipidus Denatured Proteins Proteins can be unfolded = denatured Can affect the behavior of the protein Shape is critical for protein interactions EXAMPLE: Hemoglobin 4 Polypeptides Binds Iron Oxygen transport A single amino acid substitution in a protein causes sickle-cell disease

6 Sickled cells Diet: Essential Amino Acids 20 different amino acids All living things have protein 8 Essential Amino Acids can not be synthesized by our bodies - must be found in diet All 8 essential amino acids are present in animal protein and soy beans Essential Amino Acids QUESTION Which of the following is contains all 8 essential amino acids? 1. Wheat 2. Soy beans 3. Brown rice 4. Corn 5. None of these Lipoproteins & Glycoproteins LIPOPROTEINS -Lipid + Protein -Used for transport of fats throughout the body -Example: HDL and LDL Cholesterol GLYCOPROTEINS -Carbohydrate + Protein -Receptors on the surface of cells QUESTION The myoglobin protein, which carries oxygen in muscle cells, only has the first three levels of protein structure (it lacks a quaternary level). From this you can conclude that myglobin: a)is made of nucleic acids b)is made of only one polypeptide chain c)lacks hydrogen bonds d)is not helical or pleated e)is a fiber

7 NUCLEIC ACIDS Nucleic acids include RNA and DNA Polymers made up of repeating monomers called nucleotides. James Watson and Francis Crick Rosalind Franklin X-ray crystallography 5-Carbon Sugar (Pentose): RNA ribose, DNA deoxyribose NUCLEOTIDES 3 Main Components: Nucleotides: Important Energy Storage Molecules Adenosine Triphosphate (ATP): acts like cell s battery, providing energy for most activities. Phosphate Group Nitrogen-containing base

8 SIMILARITIES: 5-carbon sugar Phosphate group RNA and DNA DIFFERENCES: Nucleotides DNA: Adenine, Guanine, Cytosine, Thymine RNA: Adenine, Guanine, Cytosine, Uracil Sugar DNA: Deoxyribose RNA: Ribose Nucleic Acid Synthesis Nucleotides joined by dehydration synthesis Covalent bond forms between PHOSPHATE GROUP and SUGAR Structure of DNA The components of nucleic acids The DNA double helix and its replication

9 Polypeptide Sequence as Evidence for Evolutionary Relationships Nucleotides are to as are to proteins. Nucleic acids; amino acids Amino acids; polypeptides Glycosidic linkages; polypeptide linkages Genes; enzymes Polymers; polypeptides The structural level of a protein least affected by a disruption in hydrogen bonding is Primary Secondary Tertiary Quaternary All equally affected Which of the following is not a protein? Hemoglobin cholesterol An antibody An enzyme Insulin