The document details methods for controlling microbial growth through physical (e.g., heat, filtration) and chemical (e.g., detergents, heavy metals) means. It explains gene regulation mechanisms including inducible and repressible operons, and outlines the processes of genetic transfer among bacteria: transformation, transduction, and conjugation. Additionally, it lists pharmaceutical products derived from recombinant DNA in E. coli, S. cerevisiae, and mammalian cell culture.

1. Differentiate between physical and chemical methods used to control microbial growth; and
give 5 examples of each (Chapter 7). Describe pre-translational control through an inducible
operon, a repressible operon, positive regulation and epigenetic control and describe post-
transcriptional control (Chapter 8). Describe the three mechanisms whereby genes are
transferred from one bacterium to another (Chapter 8). Describe a typical genetic modification
procedure (Chapter 9). Identify 8 different pharmaceutical products of rDNA produced by E.
coli (Chapter 9) Identify 5 different pharmaceutical products of rDNA produced by S. cerevisiae
(yeast) (Chapter 9). Identify 7 different pharmaceutical products of rDNA produced by
mammalian cell culture (Chapter 9).
Solution
Q.NO I
Methods used to manage the growth of microbial growth could be placed into two broad
categories, physical and chemical. Physical methods either exclude microbes, or reduce their
numbers in a remedy, or at first glance of a fomite Examples for physical methods: heat, drying
or desiccation, filtration and radiation. Chemical methods involve the application of specific
chemical agents which inhibit growth or kill microbes on fomites or the outer lining of skin. The
choice of a suitable technique is essential, since many physical and chemical agents can cause
damage to the cells and tissues of the individual along with the microbe. Examples : detergents,
solvents, oxidizing agents and heavy metals.
Q.No III
Positive transcriptional control requires an activator protein to stimulate transcription at the
operon. In negative control, a repressor protein inhibits or turns off transcription at the operon.
An inducible operon normally is not transcribed. It needs an inducer molecule to stimulate
transcription either by inactivating a repressor protein in a negative inducible operon or by
stimulating the activator protein in a confident inducible operon. Transcription normally occurs
in a repressible operon. In a repressible operon, transcription is turned off either by the repressor
becoming active in a negative repressible operon or by the activator becoming inactive in a
confident repressible operon.
Q.No IV
Genetic transfer is the mechanism by which DNA is transferred from a donar to a recipient. Once
donar DNA is inside the recipient, crossing over can occur. The result is just a recombinant cell
that's a genome different from either the donar or the recipient. In bacteria genetic transfer can
happen three ways:
Transformation - horizontal gene transfer' ', where exogenous genetic material passes from

2. bacterium to another.
Transduction - DNA is transferred from one bacterium to another with a virus. Additionally it
refers to the method whereby foreign DNA is introduced into another cell using a viral vector.
Conjugation - is the transfer of genetic material between bacterial cells by direct cell-to-cell
contact or with a bridge-like connection between two cells. It is just a mechanism of horizontal
gene transfer as are transformation and transduction although those two other mechanisms do not
involve cell-to-cell contact.
Q.No V
1. Vector, such as for instance a plasmid, is isolated
2. DNA containing gene of interest fem an alternative species is cleaved by a chemical into
fragments
3. Desired gene is selected and inserted into plasmid
4. Plasmid is taken on with a cell, such as for instance a bacterium
5. Cells with gene of interest are cloned with either of two goals in mind
6. Create and harvest copies of a gene and create and harvest protein products of a gene.
Q.NO VI
E. coli is employed as cell factory for production of another 30% of the biopharmaceuticals
whereas 20% are being made by S. Cerevisiae. The important pharmaceutical items are:
Antibiotics, blood factors, hormones, growth factors, enzymes, vaccines, monoclonal antibodies,
drugs and cytokines.
Q.No VII
The features of using yeast S. cerevisiae as a cell factory for the production of
biopharmaceuticals are that eukaryal model system enables production and proper folding of
several human proteins. Furthermore, the proteins could be secreted to the extracellular medium
and this facilitates subsequent purification. The important pharmaceutical items are: Human
protein replacements, hepatitis vaccines, insulin, therapeutic agents for human diseases and
human serum albumin.
Q.No VIII
Monoclonal antibody products developed through mammalian cell culture are : Reopro,
Zenapax, Remicade, Synagis, Zevalin, Humira and Avastin.