BiochemistryBiochemistry

SOL BIO 3 b,c

BIO 3 b, cOBJECTIVE:

• TSW investigate and understand the chemical and biochemical principles essential for life.

Key concepts include-

• b) the structure and function of macromolecules

• c) the nature of enzymes.

• Most life processes are a series of chemical reactions influenced by environmental and genetic factors.

Metabolism

• the sum of all biochemical processes

2 Metabolic Processes

• Anabolism- the building up of complex molecules

•Catabolism- the breaking down of complex molecules

• Most cells function best within a Most cells function best within a narrow range of temperature and pH.narrow range of temperature and pH.

•At very low temperatures, At very low temperatures, reaction rates are too slow. reaction rates are too slow.

•High temperatures or extremes of High temperatures or extremes of pH can irreversibly change the pH can irreversibly change the structure of proteins and alter their structure of proteins and alter their function.function.

–The main components of a living cell are:

•Carbon•Hydrogen•Nitrogen•Oxygen

-Phosphorus-Sulfur

• Inside every cell is a concentrated mixture of thousands of different macromolecules forming a variety of specialized structures that carry out cell functions, such as:

– energy production– transport– waste disposal– synthesis (creation) of new molecules– storage of genetic material.

Organic CompoundsOrganic Compounds

• CompoundsCompounds that contain CARBONCARBON are called organicorganic.

• MacromoleculesMacromolecules are large organic organic moleculesmolecules.

Carbon (C)Carbon (C)• CarbonCarbon has 4 electrons4 electrons in outer shell

• CarbonCarbon can form covalent bondscovalent bonds with as many as 4 4 other atoms (elements)

• Usually with H, O, N, or CH, O, N, or C

• Example:Example: CC66HH1212OO66 (sugar) (sugar)

MacromoleculesMacromolecules• Large organic molecules.Large organic molecules.• Also called POLYMERSPOLYMERS.• Made up of smaller “building blocks” called

MONOMERSMONOMERS.• Examples:Examples:

1. Carbohydrates1. Carbohydrates2. Lipids2. Lipids3. Nucleic acids (DNA and RNA)3. Nucleic acids (DNA and RNA)4. Proteins4. Proteins

1. Carbohydrates1. Carbohydrates

• Small sugar moleculesSmall sugar molecules to large sugar large sugar moleculesmolecules.

• Examples:Examples:

A.A. monosaccharidemonosaccharide

B.B. disaccharidedisaccharide

C.C. polysaccharidepolysaccharide

1. Carbohydrates1. CarbohydratesA.A. monosaccharide: one sugar unitmonosaccharide: one sugar unit

• Examples:Examples: glucose (glucose (C6H12O6 blood sugar)

deoxyribosedeoxyribose

riboseribose

galactose (milk sugar)galactose (milk sugar)

fructose (honey)fructose (honey)glucoseglucose

B. disaccharide: two sugar unitB. disaccharide: two sugar unit

• Example:Example: sucrose = glucose + fructosesucrose = glucose + fructose

fructosefructoseglucoseglucose

C.C. polysaccharide: many sugar unitspolysaccharide: many sugar units

• Examples:Examples: starch (bread, potatoes)starch (bread, potatoes)

glycogen (beef muscle)glycogen (beef muscle)

cellulose (lettuce, corn)cellulose (lettuce, corn)

chitin (exoskeletons)chitin (exoskeletons)

glucoseglucoseglucoseglucose

glucoseglucoseglucoseglucose

glucoseglucoseglucoseglucose

glucoseglucoseglucoseglucose

cellulosecellulose

• The primary functions of carbohydrate macromolecules are to:– provide and store energy.

2. Lipids2. Lipids• General term for compounds which are not not

soluble in watersoluble in water.

• Lipids are soluble in hydrophobic are soluble in hydrophobic solventssolvents.

• Remember:Remember: “stores the most energy”“stores the most energy”

2. Lipids2. Lipids• Examples:Examples: 1. Fats1. Fats

2. Phospholipids2. Phospholipids

3. Oils3. Oils

4. Waxes4. Waxes

5. Steroid hormones5. Steroid hormones

6. Triglycerides6. Triglycerides

• 5 functions of lipids:5 functions of lipids:1.1. Long term energy storage Long term energy storage (fat)(fat)2.2. Protection against heat loss Protection against heat loss (insulation)(insulation)3.3. Protection against water loss & Protection against water loss & germs germs (oils & waxes)(oils & waxes)4.4. Chemical messengers Chemical messengers

(hormones & steroids)(hormones & steroids)5.5. Major component of membranes Major component of membranes

(phospholipids)(phospholipids)

• Triglycerides: Triglycerides: composed of 1 glycerol1 glycerol and 3 3 fatty acidsfatty acids.

H

H-C----O

H-C----O

H-C----O

H

glycerol

O

C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3

=

fatty acids

O

C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3

=

O

C-CH2-CH2-CH2-CH =CH-CH2 -CH

2 -CH2 -CH

2 -CH3

=

• There are two kinds of fatty acidsfatty acids you may see on food labels:

1.1. Saturated fatty acids:Saturated fatty acids: no double bonds no double bonds (bad)(bad)

2.2. Unsaturated fatty acids:Unsaturated fatty acids: double bonds double bonds (good)(good)

O

C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3

=

saturatedsaturated

O

C-CH2-CH2-CH2-CH =CH-CH2 -CH

2 -CH2 -CH

2 -CH3

=

unsaturated

3. Nucleic acids3. Nucleic acids

• Nucleic acids (DNA and RNA) control cell Nucleic acids (DNA and RNA) control cell activities by controlling protein synthesisactivities by controlling protein synthesis

3. Nucleic acids3. Nucleic acids

• Two types:Two types:1. deoxyribonucleic acid (DNA-double 1. deoxyribonucleic acid (DNA-double helix)helix)2. ribonucleic acid (RNA-single strand)2. ribonucleic acid (RNA-single strand)

• Nucleic acidsNucleic acidsare composed of long chains of

nucleotidesnucleotides

3. Nucleic acids3. Nucleic acids• Nucleotides:Nucleotides:

Backbone:Backbone:phosphate groupphosphate groupsugar (5-carbon)sugar (5-carbon)

nitrogenous bases:nitrogenous bases:adenine (A)adenine (A)thymine (T) - uracil (U) thymine (T) - uracil (U) RNARNAcytosine (C)cytosine (C)guanine (G)guanine (G)

Nitrogenous Base pairs:

• DNA: A-T RNA: A-U

G-C G-C

NucleotideNucleotide

OO=P-O O

PhosphatePhosphate GroupGroup

NNitrogenous baseNitrogenous base (A, G, C, or T)(A, G, C, or T)

CH2

O

C1C4

C3 C2

5

SugarSugar(deoxyribose)(deoxyribose)

DNA - double helixDNA - double helix

P

P

P

O

O

O

1

23

4

5

5

3

3

5

P

P

PO

O

O

1

2 3

4

5

5

3

5

3

G C

T A

4. Proteins (Polypeptides)4. Proteins (Polypeptides)• Amino acids (the building blocks of

protein)

• 2 kinds of amino acids

- essential & non-essential amino acids

- Essential amino acids cannot be synthesized by our body & need to be obtained through our diet

• 7 functions of proteins:7 functions of proteins:

1.1. Storage:Storage: albumin (egg white)albumin (egg white)

2.2. Transport: Transport: hemoglobinhemoglobin

3.3. Regulatory:Regulatory: hormoneshormones

4.4. Movement:Movement: musclesmuscles

5.5. Structural:Structural: membranes, hair, membranes, hair, nailsnails

6.6. Enzymes:Enzymes: cellular reactionscellular reactions

7. Defense:7. Defense: antibodiesantibodies

• A protein’s structure depends on its A protein’s structure depends on its specific jobspecific job

• The sequence of amino acids and The sequence of amino acids and the shape of the chain are a the shape of the chain are a consequence of attractions between consequence of attractions between the chain’s parts.the chain’s parts.

• Four levels of protein structure:Four levels of protein structure:

A.A. Primary Structure (1°)Primary Structure (1°)

B.B. Secondary Structure (2°)Secondary Structure (2°)

C.C. Tertiary Structure (3°)Tertiary Structure (3°)

D.D. Quaternary Structure (4°)Quaternary Structure (4°)

A. Primary Structure (1°)

• Amino acids bonded together by peptide bonds.peptide bonds.

aa1 aa2 aa3 aa4 aa5 aa6

Peptide Bonds

Amino Acids (aa)

B.B. Secondary Structure (2°)Secondary Structure (2°)

• 3-dimensional folding arrangement of a primary structureprimary structure into coilscoils and pleatspleats held together by hydrogen bondshydrogen bonds.

B.B. Secondary Structure (2°)Secondary Structure (2°)

Two examples:Two examples:

Alpha HelixAlpha Helix

Beta Pleated SheetBeta Pleated Sheet

Hydrogen BondsHydrogen Bonds

Alpha Helix

Beta Pleated Sheets

C.C. Tertiary Structure (3°)Tertiary Structure (3°)

• Secondary structuresSecondary structures bendbend and foldfold into a more complex 3-D arrangementmore complex 3-D arrangement.

• Called a “subunit”.“subunit”.

C.C. Tertiary Structure (3°)Tertiary Structure (3°)

Alpha HelixAlpha Helix

Beta Pleated SheetBeta Pleated Sheet

D.D. Quaternary Structure (4°)Quaternary Structure (4°)• Composed of 2 or more “subunits”.• Example: enzymes (hemoglobin)enzymes (hemoglobin)

3° subunits3° subunits

Subunits

Enzymes: Enzymes: Special Proteins