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Biotechnology
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From the greek words bios, meaning life, and technikos, meaning
involving human knowledge and skills
The controlled and deliberate manipulation of biological systems
whether living cells or cell components for the efficient
manufacture or processing of useful products
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It is the science for our century and it involves biology, chemistry,
physics, engineering computers and information technology to
develop new tools and products
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Can be traced back to human’s transition from hunter to gatherer to
farmer
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Humans discovered that food matures in a way that changes
it taste, content and makes it less perishable
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Examples of traditional biotechnology technique include:
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Selective Breeding
Hybridization
Fermentation

Selective breeding is a process used by humans to develop new organisms with desirable
characteristics
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Hybridization is the concept of mixing atomic orbitals into new hybrid orbitals suitable for the
pairing of electrons to form chemical bonds in valence bond theory
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Ex
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Bacteria perform fermentation converting carbohydrates into lactic acid
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 Rice, barley and wheat were among the first domesticated plants
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 Dog, sheep and goat are thought to be among the first animals that were domesticated
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Like many other food preservation processes, this allows the
nutritional and economic value of a food material (milk) to be
preserved in concentrated form
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Add Cultures
- The milk is heated and acidifies as the bacteria eat the lactose in the
milk
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Add Rennet
- This creates a protein matrix that coagulates the milk into a semisolid
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Cutting
- After we see the newly formed curd, we cut it to release the liquid
whey
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Stirring/Cooking
- To create texture, the curd is heated and stirred
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Draining
- Time to let your curd drain whey
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6
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Modern Biotechnology
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Mutagenesis

Refers to a number of techniques that involve the intentional
manipulation of genes, cells and living tissues in a predictable and
controlled manner to generate changes in the genetic makeup of an
organism or produce new tissue
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o Mutation may occur due to exposure to
natural mutagens such as UV light, to
industrial or environmental mutagens
such as benzene or asbestos
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Nucleoid
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DNA in the bacterial cell is generally confines to this central region
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Give the cytoplasm of bacteria a granular appearance in electron
micrographs
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Nutrients and reserves may be stored in the cytoplasm in the form
of glycogen, lipids, polyphosphate or sulphur or nitrogen
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Once the hazard is removed, the spore germinates to
create a new population
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This lipid bilayer is found in gram negative bacteria and is the source
of lipopolysaccharide (LPD) in these bacteria
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Composed of peptidoglycan (polysaccharide + protein), the cell wall
maintains the overall the shape of a bacterial cell
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Mycoplasma is bacteria that have no cell wall and
therefore have no definite shape
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In the space are enzymes and other proteins that help
digest and move nutrients into the cell
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The other 2 bases, Cytosine and Thymine, have a single -ring
structure of a type called a Pyramidine
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Made up of genes
Its shape is a double helix

The Central Dogma in Molecular Biology
Concept 1: Overview of the Central Dogma
 The central dogma of molecular biology describes the two-step process, transcription
and translation by which the information in genes flow into proteins:
DNA → RNA → Protein
The Central Dogma

 Translation is a process by which the genetic code contained within an mRNA molecule
is decoded to produce the specific sequence of amino acids in a polypeptide chain
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 Transcription is the synthesis of an RNA copy of a segment of DNA-RNA is synthesized by
the enzyme RNA polymerase
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In a eukaryotic cell, transcription occurs in the
nucleus and translation occurs in the cytoplasm
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 Transcription and translation are spatially and temporally separated in eukaryotic cells;
that is, transcription occurs in the nucleus to produce a pre -mRNA molecule
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Concept 3: Different Genes for Different RNAs
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There are 4 types of RNA, each encoded by its own type of gene
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In any cell, only some of the genes are expressed, that is, transcribed into RNA
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 tRNA - Transfer RNA: brings amino acids to ribosomes during translation
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 sRNA- Small nuclear RNA: with proteins, forms complexes that are used in RNA
processing in eukaryotes
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 The promoter is a base-pair sequence that specifies where transcription begins
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Concept 5: The RNA Molecule
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RNA is structurally similar to DNA
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 In complementary base pairing A, T, G and C on the template DNA strand specify U, A, C
and G, respectively, on the RNA strand being synthesized
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Concept 8: mRNA in Prokaryotes
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The sequence of a prokaryotic protein-coding gene is collinear with the translated
mRNA; that is, the transcript of the gene is the molecule that is translated into the
polypeptide
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 Most eukaryotic protein-coding genes contain segments called introns which break up
the amino acid coding sequence into segments called exons
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 The pre-mRNA is processed in the nucleus to remove the introns and splice the exons
together into a translatable mRNA
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Concept 10: Pre-mRNA Processing (Splicing)
 Eukaryotic pre-mRNAs typically include introns
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The steps of pre-mRNA splicing (intron removal) are as follows:
 The intron loops out as snRNPs (small nuclear ribonucleoprotein particles, complexes of
snRNAs and proteins) bind to form the spliceosome
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 The resulting mature mRNA may then exit the nucleus and be translated in the
cytoplasm
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It has no roots
 They have an extensive tissue made of fine networks called
hyphae
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Each chromosome is made up of DNA tightly coiled many times around proteins called
histones that support its structure
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Most of what researchers know about chromosomes was learned by observing
chromosomes during cell division
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The short arm of the chromosome is labelled the p arm
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The location of the centromere on each chromosome gives the chromosome its
characteristic shape and can be used to help describe the location of specific genes
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It is relatively simple to demonstrate this
fact for eukaryotic nuclear chromosomes
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 Furthermore, if a mass of cells is ground up and its components fractionated, it becomes
clear that bulk of DNA can be isolated from the nuclear fraction and the remainder from
mitochondria and chloroplasts

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