The Chemistry of Life Part Two
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Transcript of The Chemistry of Life Part Two
The Chemistry of Life
Part Two
ProteinsElements• C, H, O, N, STypes• 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.
Functions1. Part of the cell membrane (for transport, etc.)2. Provide support and shape to cells3. Hormones to send chemical messages4. Speed chemical reactions (as enzymes)5. Energy supply
ProteinsMonomerAmino acids act as monomers in protein synthesis. There are 20 standard amino acids.PolymerAmino acids are added together. Because water is a byproduct, this is called dehydration synthesis or condensation.
Amino Group
Carboxylic Acid Group
Side Chain
Peptide BondA molecule of water is removed from two
amino acids to form a peptide bond
…
Amino Acids (six of twenty)
Glycine Alanine Valine
Leucine Methionine Isoleucine
Twenty Standa
rd Amino Acids
A small protein (polypeptide)
Nucleic AcidsElements• C, H, O, N, PTypes• DNA
(deoxyribonucleic acid)• RNA (ribonucleic acid)
Functions1. Stores genetic
blueprint as DNA2. RNA is used as the
blueprint for proteins
base pairsAdenine Thymine
Guanine Cytosine
Sugar phosphate backbone
Nucleic AcidsMonomerNucleotides are monomers made of 3 parts: phosphate, sugar, nitrogenous base. The sugar is ribose in RNA and deoxyribose in DNA.PolymerNucleic 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 – phosphateS – sugar
(deoxyribose)A – AdenineT – ThymineC – CytosineG – 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 – 101. 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 – 2011. 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 – 2C O H P S N
carbohydrateslipidsproteinsnucleic acids
x 1.
x x x x x (x) (x) x x x (x) x x x x x x Monomers Polymers
carbohydrates
lipidsproteinsnucleic acids
fructose, glucose
2. cellulose, chitin
glycogen, starch, polysaccharide
fatty acid, glycerol triglycerideamino acids
nucleotidepolypeptideDNA, RNA
Answers: 4
O
NH2
SHO
NH
OHCH3O
NH
O
NH
CH3O
NH
CH3 CH3
OH
A) lipid B) carbohydrate
C) nucleic acid
E) lipidD) carbohydrate
F)protein
Answers: 3 – 53. Lipids (triglycerides and phospholipids)
are made from glycerol.4. A) lipid (triglyceride)
B) carbohydrate (disaccharide)C) nucleic acidD) 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: 66. a) proteins
b) lipidsc) lipidsd) carbohydratese) proteinsf) proteinsg) carbohydratesh) nucleic acidsi) nucleic acidsj) lipidsk) nucleic acids
Answers: 7 – 117. 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.11. 20 % A (same as T), 30% C, 30% G (all must
add to 100%; C and G must be the same).