Question 1

Q1: Can you list 10 recombinant proteins which are used in medical practice? Find out where they are used as therapeutics (use the internet).

Accepted Answer

Ten recombinant proteins used in medical practice and their therapeutic uses are: 1.  Human Insulin (Humulin): Used for the treatment of diabetes mellitus to control blood sugar levels. 2.  Human Growth Hormone (Somatotropin): Used to treat pituitary dwarfism in children and growth hormone deficienc...

Question 2

Q10: Describe briefly the following: (a) Origin of replication (b) Bioreactors (c) Downstream processing

Accepted Answer

(a) Origin of replication (ori): This is a specific DNA sequence in a genome (on a chromosome or plasmid) from which DNA replication initiates. For a piece of foreign DNA to be replicated and multiplied in a host cell, it must be linked to an 'ori' sequence. The origin of replication also controls t...

Question 3

Q11: Explain briefly (a) PCR (b) Restriction enzymes and DNA (c) Chitinase

Accepted Answer

(a) PCR (Polymerase Chain Reaction): PCR is a laboratory technique used to amplify a specific segment of DNA, creating millions to billions of copies in vitro. The process involves a cycle of three steps:     1.  Denaturation: The double-stranded DNA is heated (typically to $94-96^{\circ}	ext{C}$)...

Question 4

Q12: Discuss with your teacher and find out how to distinguish between (a) Plasmid DNA and Chromosomal DNA (b) RNA and DNA (c) Exonuclease and Endonuclease

Accepted Answer

(a) Plasmid DNA vs. Chromosomal DNA | Feature          | Plasmid DNA                                                              | Chromosomal DNA                                                              | | ---------------- | --------------------------------------------------------------------...

Question 5

Q2: Make a chart (with diagrammatic representation) showing a restriction enzyme, the substrate DNA on which it acts, the site at which it cuts DNA and th...

Accepted Answer

Here is a chart for the restriction enzyme EcoRI, as described in the chapter: | Feature                 | Description...

Question 6

Q3: From what you have learnt, can you tell whether enzymes are bigger or DNA is bigger in molecular size? How did you know?

Accepted Answer

DNA molecules are significantly bigger than enzyme molecules in molecular size. Reasoning: 1.  Composition and Structure: DNA is a macromolecule composed of millions or even billions of nucleotide pairs that make up a chromosome. Enzymes are proteins, which are polymers of amino acids, typically con...

Question 7

Q4: What would be the molar concentration of human DNA in a human cell? Consult your teacher.

Accepted Answer

Calculating the precise molar concentration of DNA in a human cell is complex and depends on several assumptions. Here is an estimation based on typical values: 1.  Amount of DNA: A diploid human cell contains approximately $6.4 	imes 10^9$ base pairs (bp). 2.  Molar Mass of a Base Pair: The averag...

Question 8

Q5: Do eukaryotic cells have restriction endonucleases? Justify your answer.

Accepted Answer

No, eukaryotic cells do not have restriction endonucleases. Justification: 1.  Origin and Function: As stated in the chapter, restriction endonucleases were isolated from prokaryotic organisms like bacteria (e.g., Escherichia coli). In bacteria, these enzymes are part of a defense mechanism called t...

Question 9

Q6: Besides better aeration and mixing properties, what other advantages do stirred tank bioreactors have over shake flasks?

Accepted Answer

Besides better aeration and mixing, stirred-tank bioreactors have several advantages over simple shake flasks for large-scale production: 1.  Process Control: Bioreactors are equipped with automated control systems to monitor and maintain optimal growth conditions. This includes sensors and regulato...

Question 10

Q7: Collect 5 examples of palindromic DNA sequences by consulting your teacher. Better try to create a palindromic sequence by following base-pair rules.

Accepted Answer

A palindromic DNA sequence is a sequence of base pairs that reads the same on the two strands when the orientation of reading ($5' ightarrow 3'$) is kept the same. Here are 5 examples, which are recognition sites for common restriction enzymes: 1.  EcoRI:     $5'—	ext{GAATTC}—3'$     $3'—	ext{CT...

Question 11

Q8: Can you recall meiosis and indicate at what stage a recombinant DNA is made?

Accepted Answer

Yes, in the context of natural genetic recombination during meiosis, recombinant DNA is formed during Prophase I. Specifically, this occurs in the pachytene stage of Prophase I. During this stage, homologous chromosomes are paired up (a structure called a bivalent). Non-sister chromatids of these ho...

Question 12

Q9: Can you think and answer how a reporter enzyme can be used to monitor transformation of host cells by foreign DNA in addition to a selectable marker?

Accepted Answer

A reporter enzyme can be used to differentiate between recombinant and non-recombinant cells through a process called insertional inactivation, often referred to as blue-white screening. This method works in addition to a selectable marker that selects for transformants. Here is how it works: 1.  Ve...

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