Basic biochemistry: A Biotechnology Perspective.

The unit of all life is the cell.

Single-cllled organisms: Bacteria and protozoa

Multicelled organisms: All plants and animals

Hierarchy of cellular life:Cells -->Tissues -->Organs -->Organisms -->Populations

Tissues are composed of specialized cells types”Examples: Blood, muscle, nerve, adiposeOrgans are systems composed of several tissues, andhave specific functions:Examples: Heart, kidney, liver, brain

PROTONS

NUTRIENTS

ATP

ADP + P

RIBOSOMES

MEMBRANE

CELL WALL

DNA

Small molecules of life

What are the elements of living molecules?

CHONPS – biogenic elements: carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfurCompose ~ 99 percent of the organic matter in living cells.

How do biogenic elements produce the small molecules of life?Biogenic elements by themselves cannot be part of life, but instead are present as five kinds of molecular compounds.

1. Hydrocarbon derivatives (fatty compounds such as fat, plant oils, phospholipids, sterols2. Carbohydrates (sugars, starches, cellulose)3. Amino acids4. Nucleotides5. Metabolic intermediates

The Four Molecules of LifeHydrocarbons HC Octane = C8H18

(Lipids)

Carbohydrates CHO Glucose = C6H12O6

(Sugars)

Amino acids CHON(S) Glycine = C2H5O2N

(Proteins)

Nucleotides CHONP AMP = C10H14N5O7P

(DNA,RNA)

Why are hydrocarbons important in life processes and biotechnology?

Life is based on carbon, yet carbon by itself only forms graphite, diamonds and soot. But if carbon bonds to hydrogen, molecules called hydrocarbons are formed:

Example: Octane = C8H18 = H3C-CH2-CH2-CH2-CH2-CH2-CH2-CH3

Hydrocarbon derivatives include fatty acids and sterols.

Example of a fatty acid:

Fatty acids are a major energy source for the heart and other muscle tissues.Fatty acids (as triglyceride, or “fat”) provide energy storage capacity for animals and plants.

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Example of a sterol: cholesterol.

Cholesterol is also a component of most cell membranes.

Cholesterol is used to synthesize steroid hormones such as estrogen, testosterone, and cortisone.

Why is cholesterol important in biotechnology?

In heart disease cholesterol accumulates in coronaryarteries to form atherosclerotic plaques. This process can be inhibited by drugs that lower the levels of cholesterol circulating in the blood.

All cells are bounded by a cell membrane.

The cell membrane maintains larger molecules of life in an enclosed volume so that they can interact.

Cell membranes also provide a selective permeability barrier that allows certain molecules such as nutrients into the cell, but excludes others.

Membrane surface receptors permit the cell to communicate with other cells.

Membrane receptors are important sites of drug action.

Membranes are composed of amphiphilic molecules called lipids. Amphiphiles are organic molecules having both a hydrophobic non-polar portion (hydrocarbon chains) and a hydrophilic polar head group.

Phospholipid and cholesterol are biological amphiphiles that assemble into the lipid bilayers of all biomembranes.

LIPID VESICLES

WATERHYDROCARBON CHAINS

Why are membranes important in biotechnology?

Cell boundary – certain kinds of pharmaceutical agents must cross the membrane to enter the cell and produce an effect.

Drug receptors are present on the membrane surface. Many drugs bind to membrane receptors to produce a desired effect.

What is a carbohydrate?

A carbohydrate typically contains carbon, hydrogen and oxygen in the ratio C:H2O, from which the name is derived.

Example: glucose – C6H12O6

Carbohydrates are sources of energy for most tissues, particularly the brain.

Carbohydrates are also used in cellular structures. For instance, cellulose is a polymer of glucose.

Why are carbohydrates important in biotechnology?

A major health problem is diabetes, one form of which occurs when the hormone insulin cannot be produced by specialized cells in the pancreas. Insulin activates the transport of glucose across cell membranes. In its absence, glucose cannot cross cell membranes and accumulates in the blood, often leading to serious circulatory problems. The synthesis of insulin to treat diabetes is a multibillion dollar industry.

All life uses polymers for structure and function.

What are monomers and polymers?

o o o o o o o o-o-o-o-o-o-o-o-o-o-oMonomers PolymerLike loose beads Beads on a string

Ethylene, propylene and styrene are common monomers

Polyethylene, polypropylene and polystyrene, are polymers – common plastics in industry.

Two biological polymers are fundamental to all life: proteins and nucleic acids

Monomers PolymersAmino acids Peptides and proteins

Nucleotides Nucleic acids (DNA, RNA)

What is an amino acid?

Twenty different kinds of amino acids are used by living organisms to produce proteins

An amino acid is a molecule containing an amine (-NH2) an acid (-COOH) and a third chemical group (-R) that defines the amino acid. In glycine, the simplest amino acid, R is –H, or a hydrogen atom. In alanine, R = -CH3. The R groups give specific properties to each amino acid, and to the proteins composed of amino acids.

R |

Structure of an amino acid: H2N – C – COOH H

Why are amino acids important in biotechnology?Amino acids are used by the body to producehormones and neurotransmitters that are essential in regulating physiological functions.

Thyroxin regulates metabolic rate, and insulin regulates blood sugar levels. Thyroxin is synthesized from the amino acid tyrosine, and insulin is a small protein composed of 52 amino acids. Both hormonesare produced commercially by pharmaceutical companies.

Examples of neurotransmitters include the amino acids glycine, aspartic acid, glutamic acid, and gamma amino butyric acid (GABA). Norepinephrine and epinephrine are synthesized from the amino acid tyrosine, and serotonin is synthesized from the amino acid tryptophan. Many toxins and psychoactive drugs affect the way that neurotransmitters modulate the nervous system.

What is a nucleotide?

Structure: Base-sugar-phosphate

In DNA, the sugar is deoxyribose, and in RNA it is ribose.

Bases of DNA are adenine, thymine, guanine and cytosine (ATGC)

Bases of RNA are adenine, uracil, guanine and cytosine (AUGC)

Nucleotides are linked in polymers called nucleic acids (DNA, RNA)

Base – sugar – phosphate

Base – sugar – phosphate

Base – sugar – phosphate

Base – sugar – phosphate

Why are nucleotides important in biotechnology?

Besides their role as monomers in nucleic acids, some nucleotides are also important regulatory agents. For instance, the nucleotide ATP is used by cells to produce cyclic AMP (cAMP) which controls many cell functions such as the response of heart cells to adrenaline. Understanding the regulatory function of nucleotides leads to the development of pharmaceutical agents that can modify physiological functions.

Example: beta blockers are used to treat hypertension (high blood pressure). This drug inhibits the effect of adrenaline on heart tissue by blocking the beta receptorsfor adrenaline on heart cells.

Cells grow by linking monomers into polymers.

EnzymesMonomers Polymers

Energy

RibosomesAmino acids Proteins

Energy

PolymerasesNucleotides DNA, RNA

Energy

Why is it important to understand cell growth processes?

Certain infective agents can grow in the body and produce disease:

Bacterial diseases:

“Strep throat” and scarlet fever produced by streptococcus.Staphylococcus (“staph”) infections Food poisoning (E. coli, Salmonella)Bacterial meningitisLeprosyTuberculosisPlagueAnthraxTyphoid feverDiphtheriaSyphilis

Most bacterial species are not pathogens. In fact, bacteria areessential to the biosphere, and in their absence advanced life wouldnot be possible on the Earth.

However, a few bacteria have become pathogens. Bacterial infections occur when pathogenic bacteria invade the body and begin to grow in the extracellular space.

Pharmaceutical agents called antibiotics can interrupt bacterial growth processes. Examples of antibiotics: penicillin, streptomycin, tetracycline, vancomycin – all inhibit polymer synthesis pathway in bacteria, but not in eukaryotic cells. This fundamentally important advance in biotechnology has led to a vast improvement in human health over the past 80 years.

Viruses cannot be treated by antibiotics, since they infect cells directly and grow within the cell, using cellular biosynthetic machinery to reproduce.