The Chemistry of Life Part Two

Proteins Elements C, H, O, N, S Types All proteins are long chains of amino acids. Changes in amino acid order create enormous variation. * Even more complexity arises when proteins fold and combine with other proteins. Functions 1.Part of the cell membrane (for transport, etc.) 2.Provide support and shape to cells 3.Hormones to send chemical messages 4.Speed chemical reactions (as enzymes) 5.Energy supply

Proteins Monomer Amino acids act as monomers in protein synthesis. There are 20 standard amino acids. Polymer Amino acids are added together. Because water is a byproduct, this is called dehydration synthesis or condensation. Amino Group Carboxylic Acid Group Side Chain Peptide Bond A molecule of water is removed from two amino acids to form a peptide bond …

Amino Acids (six of twenty) GlycineAlanine Valine LeucineMethionineIsoleucine

Twenty Standard Amino Acids

A small protein (polypeptide)

Nucleic Acids Elements C, H, O, N, P Types DNA (deoxyribonucleic acid) RNA (ribonucleic acid) Functions 1.Stores genetic blueprint as DNA 2.RNA is used as the blueprint for proteins base pairs AdenineThymine GuanineCytosine Sugar phosphate backbone

Nucleic Acids Monomer Nucleotides are monomers made of 3 parts: phosphate, sugar, nitrogenous base. The sugar is ribose in RNA and deoxyribose in DNA. Polymer Nucleic acids form when many nucleotides join. Only certain pairings of bases occur: adenine (A) with thymine (T), cytosine (C) with guanine (G). In RNA, thymine is replaced with uracil (U). As with amino acids, different combinations of nucleotides allows for enormous variety. Phosphate group Sugar Nitrogenous base

Nucleic Acids P – phosphate S – sugar (deoxyribose) A – Adenine T – Thymine C – Cytosine G – Guanine To form a large DNA polymer, nucleotides join via dehydration synthesis Nucleotide Sugar- phosphate backbone base pairs Hydrogen bonds Sugar- phosphate backbone Base pair

Part Two Answers: 1 – 10 1.F – nucleic acids (& some lipids) have N (6) 2.T – proteins are used as an energy source (2) 3.T – “there are 20 standard amino acids” (3) 4.T – look at the six examples: one has S (4) 5.F – notice the general formula contains N (3) 6.F – proteins can range from a few amino acids to thousands. “A small protein” suggests that many proteins are larger (5) 7.T – amino acid monomers join to form protein polymers (3) 8.F – only DNA stores genetic information (6) 9.T – this is true for all monomers (3) 10. T – this is true for all monomers (8)

Part Two Answers: 11 – F – enzymes are proteins (2) 12.T – all nucleotides have a phosphate group, sugar, & base; the sugar in RNA is ribose (7) 13.F – adenine does not pair with cytosine (7) 14.T – adenine pairs with thymine (7,8) 15.F – most hormones are proteins (or lipids) (2) 16.F – although proteins and lipids are found in membranes, nucleic acids are not (6) 17.F – U (i.e. uracil) is only in RNA, not DNA (7) 18.T – the “backbone” is phosphate and sugar; the “steps” are the nitrogenous bases (6,8) 19.T – polymers form from many monomers (3...) 20.F – RNA = ribonucleic acid (6)

Answers: 1 – 2 COHPSN carbohydrates lipids proteins nucleic acids x 1. xx xxx(x) xxx x xxxxx MonomersPolymers carbohydrates lipids proteins nucleic acids fructose, glucose 2. cellulose, chitin glycogen, starch, polysaccharide fatty acid, glycerol triglyceride amino acids nucleotide polypeptide DNA, RNA

Answers: 4 A) lipid B) carbohydrate C) nucleic acid E) lipid D) carbohydrate F)protein

Answers: 3 – 5 3.Lipids (triglycerides and phospholipids) are made from glycerol. 4.A) lipid (triglyceride) B) carbohydrate (disaccharide) C) nucleic acid D) carbohydrate (monosaccharide) E) lipid (steroid) F) protein 5.Saturated fatty acids have only C-C single bonds (saturated with H), which means they are straight and more likely to form solid fats. Unsaturated fatty acids have at least one C=C double bond, are bent, and tend to form oils.

Answers: 6 6.a) proteins b) lipids c) lipids d) carbohydrates e) proteins f) proteins g) carbohydrates h) nucleic acids i) nucleic acids j) lipids k) nucleic acids

Answers: 7 – 11 7.A monosaccharide (e.g. glucose) is a single monomer, whereas a disaccharide (e.g. sucrose) contains two monomers. 8.A phosphate group, a sugar (deoxyribose or ribose), and a nitrogenous base (adenine, cytosine, guanine, thymine, or uracil). 9. A C A G G T C G T A A C | | | | | | | | | | | | T G T C C A G C A T T G 10.Yes, because A is always paired with T % A (same as T), 30% C, 30% G (all must add to 100%; C and G must be the same).