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assignment 1A MCQ's...

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ASSIGNMENT

GROUP 80 ASHHURST, JAMES (Group Leader)

12884704

FIELD, HARRY

13226410

HALLISSY, TIMOTHY

13200896

HIGGINS, JACKSON

13200062

Question 1 Direction of Migration

The images above depict a stylised version of a migrating band of chromosomal DNA. Which of these images depicts a migrating band containing different length DNA fragment molecules? (note direction of migration) A)

a only

B)

b only

C)

c only

D)

d only

E)

a and c

Question 2 In Molecular Biology, the alcohols Ethanol and Isopropanol are used in the process of precipitating chromosomal DNA. This is achieved by lowering the dielectric constant of water, breaking H-bonds and allowing DNA molecules to clump together. Ethanol has a higher dielectric constant than IPA and is used in a ratio of 2.5:1, whereas isopropanol only needs to be used in a 1:1 ratio meaning that isopropanol is a more efficient precipitating agent. Why might this be the case?

A) Isopropanol is more soluble than Ethanol (due to one extra methylene group) making it more effective B) Isopropanol is less soluble than Ethanol (due to one extra methylene group) making it more effective C) Ethanol also has an aromatic ring, preventing it from being as miscible in an aqueous environment D) The polar solubility effect is greater between isopropanol and water E) The H-bonding propensity between Ethanol and DNA is higher than isopropanol making it less effective

Question 3

Above pictured is a Sodium Dodecyl Sulphate molecule (SDS). SDS consists of a long aliphatic chain with a charged polar head. SDS causes bacterial cell lysis by the destruction of cell membranes through which process… A) Using its polar end to interrupt polar and ionic bonds between lipids in the membrane B) Replacing current H bonds between the membrane and water surrounding the cell, lipids are then surrounded in a micelle and the membrane is destroyed C) Aliphatic chain binds with membrane lipids pulling them apart, disrupting the cell membrane D) SDS polar heads disrupt H bonding between cell membrane lipids and surrounding water, allowing for aliphatic chains to pull apart lipids. E) Polar heads disrupt the electrostatic interactions in the cell membrane allowing the aliphatic chains to penetrate the membrane causing lysis.

Question 4

The image above shows the four major macromolecular types of a bacterial cell. It also shows the process of amplification of plasmid DNA. In DNA or RNA isolation procedures, there are major aspects which must be considered, which of the following should NOT be considered when performing isolation procedures: A) How to maximise the yield of plasmid DNA by antibiotic amplification. B) How to isolate and purify just the nucleic acid of interest. C) How to maximise the yield of plasmid DNA by addition of proteins. D) How to remove cellular debris during the isolation procedure. E) How to remove unwanted macromolecules, such as proteins and lipids....