Department of Chemistry CHEM1010 General Chemistry Instructor: Dr. Hong Zhang Foster Hall, Room 221...

Department of Chemistry

CHEM1010 General Chemistry

Instructor: Dr. Hong ZhangFoster Hall, Room 221

Tel: 931-6325

Email: [email protected]

CHEM1010/General Chemistry_________________________________________

Chapter 15. (L38)-Biochemistry• Today’s Outline

..A molecular view of life and biospherenatural world vs. industrial worldbiochemistry: a molecular view of life and biospherethe cell

..Carbohydrates: Warehouse of energysimple sugarspolysaccharides: starch and cellulose

..Fats and other lipids LipidsFatty acidsFats

Chapter 15. (L38)-Biochemistry

• A molecular view of life and biosphere

…Natural world vs. industrial world

-natural world: composed of molecules formed naturally under natural conditions (natural T, P, pH,

concentrations, environmental constrains, etc.)

the natural world results from long-time evolution and is a coherent system as a whole

-industrial world: composed of molecules made artificially under artificial conditions (any required T,

P, pH, concentrations, etc. ), many intervention of humankind


• A molecular view of life and biosphere …Life: the natural phenomenon and natural occurring or natural event…Biosphere: the natural world of life …Biochemistry: life and biosphere are composed of molecules, the molecular view of the natural living things…Life and biosphere: A polymer world…Monomers or basic molecular units of the life and biosphere…How these basic molecular units are built up to form the complex biosphere…Reductionism in biology and chemistry…Biochemistry is the chemistry of living things and life processes.


• The cell …The cell: the basic structural unit of all living things at the biological level

-In biology, all living things are reduced to cells. -Cells are complex factories or reactors in the

living bodies. They are taking inputs of nutrients and other resources, manufacturing biochemical products, rejecting wastes, and maintaining the biological activities of the living things. …Two kinds of cells: Plant cells and animal cells

-Plant cells have cell walls made of cellulose-Animal cells do not have cell walls


• The cell …The structure of the cell

Cells have a variety of interior structures and subunits that serve a variety of biological functions.

Major sub-cell units:-Cell nucleus: Containing the genetic

materials-Ribosomes: Proteins synthesis-Mitochondria: Energy production-Chloroplasts: In plants, energy conversion


• Energy in biological systems …Life is sustained by energy.

Energy maintains the order out of chaos.At equilibrium, there is no life. Life is a steady state, maintained by energy.

…Photosynthesis: The ultimate energy source for living things. …Photosynthesis: A highly efficient way of providing energy for living things out of solar energy


• Energy in biological systems …Photosynthesis

General chemical reaction of photosynthesis:

6CO2 + 6H2O C6H12O6 + 6O2

or 6CO2 + 6H2O C6(H2O)6 + 6O2

where: C6H12O6 is glucose as a representative chemical for photosynthesis products

Note: C6(H2O)6 can be written as {C(H2O)}6

so, the C-to-H2O ratio is 1:1.That’s why glucose and related sugar compounds or similar biochemical compounds are called carbohydrates.


• Energy in biological systems

…Metabolism: The entire series of coordinated chemical reactions that keep cells alive.

…Two types of metabolism:

-Catabolism: The degrading of molecules to provide energy

-Anabolism: The process of manufacturing, building up, and synthesizing the molecules of living systems


• Carbohydrates: The molecules storing bio-energy

…Carbohydrates are polyhydroxy aldehydes or ketones or compounds that can be hydrolyzed to form such compounds…Elemental composition of carbohydrates: C, H, and O.

…General molecular formula: Cx(H2O)y for simple sugar, glucose, x = y = 6

…Three general kinds of carbohydrates:-sugars-starches-cellulose


• Carbohydrates: Some simple sugars…Sugars are sweet-tasting carbohydrates

Two kinds: monosaccharidesdisaccharides

These monosaccharides cannot be further hydrolyzed.

…Three common monosaccharides:glucose (dextrose), as aldose (aldhyde)galactose (a component of lactose, sugar in milk),

also as aldose (aldehyde)fructose (fruit sugar), as ketose (ketones)


• Carbohydrates: Some simple sugars…Structures of monosaccharides

two kinds of structural forms:-open-chain structural form to show the aldehyde or ketone functional groups

(pp 435, Fig. 15.3)-cyclic structural form (pp. 436, Fig. 15.4)

…Basic structural components:-Main C chain or stem-OH groups-aldehyde functional groups-ketone functional groups


• Carbohydrates: Some simple sugars

…Carbohydrates: disaccharides, the sugars that can be hydrolyzed to form two simple monosaccharides

Examples of disaccharides:

Sucrose + H2O Glucose + Fructose

Lactose + H2O Glucose + Galactose

…Structural forms of disaacharides

pp. 437, Fig. 15.5


• Carbohydrates: Polysaccharides…Polysaccharides are composed of large molecules that yield many monosaccharide units on hydrolysis.

…Two basic kinds of polysacchrrides in plants:First knid: Starch, a polymer made of 100-6000 α-ring glucose monomers (α-linkage); starch chain is not quite linear -starch is for energy storage Second kind: Cellulose, a polymer made of 1800-3000 or more β-ring glucose monomers that has the β-linkage, relatively straight chain, fibrous material because of the alternative units-polymerization

-cellulose is for plant structural material or matrix


• Carbohydrates: Polysaccharides

…Polysaccharides in animals:

The animal starch is called glycogen.

Glycogen has branched chains of glucose units.

Glycogen in muscle and liver tissue is arranged in granules, clusters of small particles.


Quiz Time

Which of the following reactions is the photosynthesis reaction:

(a) CO2 + H2O H2CO3;

(b) C6H12O6 + 6O2 6CO2 + 6H2O;

(c) 6CO2 + 6H2O C6H12O6 + 6O2;

(d) CO + O2 CO2.


Quiz Time

Which of the following are the common monosaccharides: (a) milk;(b) pineapple juice; (c) fruit, starch, cellulose;(d) glucose, fructose, and galactose.


Quiz Time

The two kinds of polysaccharides in plants are: (a) glucose and fructose;(b) starch and celluloid; (c) glycogen and glycerol;(d) starch and cellulose.


Quiz Time

The starch in animals is:

(a) acetic acid;

(b) glycerol;

(c) glycogen;

(d) amylopectin.


• Lipids …A lipid is a cellular component that is soluble in organic solvents of low polarity such as hexane, diethyl ether, or carbon tetrachloride.

Lipids have common solubility properties. Lipids are insoluble in water. Lipids are not defined by functional groups.

…Lipids include fatty acids, fats, steroids such as cholesterol and sex hormones, fat-soluble vitamins, waxes, and other substances.


• Fatty acids

…Fatty acids are long-chain carboxylic acids.Natural fatty acids almost always have an even number of carbons.

Saturated fatty acids: Fatty acids without C-to-C double bonds

Unsatuated fatty acids: Fatty acids with C-to-C double bond(s)

-monounsaturated fatty acids: with only one –C=C– bond-polyunsaturated fatty acids: with more than one –C=C– bonds


• Fats

…A fat is an ester of fatty acids and the trihydroxy alcohol glycerol (Fig. 15.10 on pp.439)

Fats are also called triglycerides or triacylglycerols.

-Animal fats: Rich in saturated fatty acids, generally solids at room temperature

-Vegetable fats, called oils: Rich in unsaturated fatty acids, liquid at room temperature


• Iodine number and degree of unsaturation …Chlorine and bromine can readily add to C-to-C double bond:

| |>C=C< + Br -C-C-

| | Br Br

The iodine number is the number of grams of iodine that are consumed by 100 g of fat or oil. The higher the iodine number, the more unsaturation is.

Generally, animal fats have low iodine numbers while vegetable fats have high iodine numbers (see Table 15.2 on pp. 440)


• Iodine number and degree of unsaturation Typical iodine numbers for some fats and oilsFat or Oil Iodine No. Fat or Oil Iodine No. Coconut oil 8-10 Oliver oil 75-95Butter 25-40 Peanut oil 85-100Beef tallow 30-45 Cottonseed oil 100-117Palm oil 37-54 Corn oil 115-130Lard 45-70 Fish oils 120-180

Canola oil 125-135

Soybean oil 125-140Safflower oil 130-140Sunflower oil 130-145


Quiz Time

A lipid is: (a) an inorganic compound;(b) a carbohydrate substance; (c) a cellular component that is soluble in organic solvents of low polarity such as hexane, diethyl ether, or carbon tetrachloride;(d) none of above.


Quiz Time

Fatty acids are:

(a) long-chain aldehydes;

(b) short-chain carboxylic acids;

(c) long-chain carboxylic acids;

(d) long-chain alcohols.


Quiz Time

Saturated fatty acids have:

(a) C-to-C triple bonds only;

(b) C-to-C double bonds only;

(c) both C-to-C double and single bonds;

(d) C-to-C single bonds only.


Quiz Time

Unsaturated fatty acids have:

(a) C-to-C triple bonds only;

(b) C-to-C double bonds only;

(c) both C-to-C double and single bonds;

(d) C-to-C single bonds only.


Quiz Time

A fat is: (a) an alcohol;(b) a carboxylic acid; (c) an ester of fatty acids and the trihydroxy alcohol glycerol ;(d) none of above.


Quiz Time

Animal fats are: (a) generally rich in saturated alkanes;(b) generally rich in unsaturated fatty acids; (c) generally rich in saturated fatty acids;(d) none of above.


Quiz Time

Vegetable fats or oils are: (a) generally rich in saturated alkanes;(b) generally rich in unsaturated fatty acids; (c) generally rich in saturated fatty acids;(d) none of above.


Quiz Time

Fish oils are: (a) generally rich in saturated alkanes;(b) generally rich in unsaturated fatty acids; (c) generally rich in saturated fatty acids;(d) none of above.


Quiz Time

Coconut oil is: (a) generally rich in saturated alkanes;(b) generally rich in unsaturated fatty acids; (c) generally rich in saturated fatty acids;(d) none of above.

Department of Chemistry CHEM1010 General Chemistry Instructor: Dr. Hong Zhang Foster Hall, Room 221...

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Transcript of Department of Chemistry CHEM1010 General Chemistry Instructor: Dr. Hong Zhang Foster Hall, Room 221...