Unit 12Biochemistry
Carbohydrates
Tro's Introductory Chemistry, Chapter 19 3
Carbohydrates
• carbon, hydrogen & oxygen
• also known as sugars, starches, cellulose, dextrins & gums
• Produced through photosynthesis by plants
• Identified by the number of carbon atoms
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Types of Carbohydrates The types of carbohydrates are
• monosaccharides, the simplest carbohydrates
• disaccharides, which consist of two monosaccharides
• polysaccharides, which contain many monosaccharides
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Monosaccharides Monosaccharides are carbohydrates with
• three to six carbon atoms
• a carbonyl group (aldehyde or ketone)
• several hydroxyl groups
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Some Important Monosaccharides
Glucose (C6H12O6) is
• an aldohexose
• found in fruits, vegetables, corn syrup, and honey
• found in disaccharides
• the monosaccharide in polymers of starch, cellulose, and glycogen
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Blood Glucose LevelIn the human body,
• glucose has a normal blood level of 70 to 90 mg/dL
• a glucose tolerance test measures blood glucose for several hours after ingesting glucose
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Some Important Monosaccharides
Fructose is
• a ketohexose with the formula C6H12O6
• the sweetest monosaccharide
• found in fruit juices and honey
• converted to glucose in the body
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Cyclic Structure for Glucose
STEP 1 Turn the open-chain structure
clockwise 90°.
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Cyclic Structure for Glucose (continued)
STEP 2 Fold the carbon chain into a hexagon and bond the O on carbon 5 to the carbonyl group.
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Cyclic Structure for Glucose (continued)
STEP 3 Draw the new –OH on C1 down to give the form or up to give the form.
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Solution
Lipids
Tro's Introductory Chemistry, Chapter 19 14
Lipids• chemicals of the cell that are insoluble in water,
but soluble in nonpolar solvents• fatty acids, fats, oils, phospholipids, glycolipids,
some vitamins, steroids and waxes• structural components of cell membrane
because they don’t dissolve in water
• long-term energy storage• insulation
Tro's Introductory Chemistry, Chapter 19 15
Fatty Acids• carboxylic acid (head) with a very long
hydrocarbon side-chain (tail)• saturated fatty acids contain no C=C double bonds
in the hydrocarbon side-chain• unsaturated fatty acids have C=C double bonds
monounsaturated have 1 C=C polyunsaturated have more than 1 C=C
CH3 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 C
O
OH
HeadTail
Tro's Introductory Chemistry, Chapter 19 16
Fats & Oils: Triglycerides• fats are solid at room temperature,
oils are liquids• trigylcerides are triesters of
glycerol with fatty acids the bonds that join glycerol to the
fatty acids are called ester linkages• triglycerides differ in
Length of the fatty acid side-chains (12 to 20 C)
Glycerol
CH2
CH2
CH2
OH
OH
OH
CH2
CH2
CH2
O
O
O
C
C
C
O
O
O
CH2
CH2
CH2
CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2
CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2
CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2
CH3
CH3
CH3
ester linkage
Tro's Introductory Chemistry, Chapter 19 17
Steroids• characterized by 4 linked carbon
rings• mostly hydrocarbon-like
dissolve in animal fat• mostly have hormonal effects• serum cholesterol levels linked to
heart disease and strokelevels depend on diet, exercise,
emotional stress, genetics, etc.• cholesterol synthesized in the liver
from saturated fats
Proteins
Tro's Introductory Chemistry, Chapter 19 19
Amino Acids• main difference between amino acids is the side
chainR group
• some R groups are polar, others are nonpolar• some polar R groups are acidic, others are basic• some R groups contain O, others N and others S• some R groups are rings, other are chains • the differences in the R groups give the amino
acids their different properties
Tro's Introductory Chemistry, Chapter 19 20
Types of Proteins
• tertiary structure determines the type of protein• globular
folds into a fairly compact, spherical shapewater solublemobile
• fibrous long coils aligned in stacks like pipeswater insolubleprovide strength to tissues
Common Functions of Proteins
• Structure – bone, skin, cartilage, tendons, nails, hair
• Movement – muscles
• Protection – antibodies, blood clotting
• Catalysis – emzymes
• Transport – oxygen (hemoglobin)
• Energy – extract energy from food
Tro's Introductory Chemistry, Chapter 19 21
Nucleic Acids
Tro's Introductory Chemistry, Chapter 19 23
Nucleic Acids• carry genetic information• Every cell has a complete copy• RNA molar mass = 20K to 40K amu
i.e BIG polymers
Tro's Introductory Chemistry, Chapter 19 24
DNA• deoxyribonucleic acid• sugar is deoxyribose• one of the following amine
basesadenine (A)guanine (G)cytosine (C) thymine (T)
• 2 DNA strands wound together in double helix