The activity of retinoblastoma protein (Rb) is regulated primarily by phosphorylation at various serine/threonine residues. Specific patterns of pRb phosphorylation generate pRb conformational variants that mediate distinct protein-protein interactions. In an experimental cell system with a mutation in the Rb gene that encodes alanine rather than serine, which is phosphorylated in the wild-type Rb, you observe that the cell is unable to enter into the cell cycle. What this observation suggest and how do you design an experiment to substantiate your suggestion?

Adjust the isotonicity of the prescription written below using White – Vincent method and calculate the final quantity of NaCl for the isotonic solution that you have found.

Rx
Ciprofloxacin HCl 0,5 %       E = 0.23
Sodium sulphide 0.1 %       E = 0.31
Chlorbutanol 0.10 g     E = 0.10
Water   for injection       q.s. 15mL

explain the mechanism of how light is actually absorbed by atoms. thn explain the 4 possible fates of such absorbed energy. where does it go?

Imagine a human protein containing 27 repeats of a simple domain arranged in tandem. In contrast a homolog found in bacteria contain only one domain. what is the minimum number of duplication events that can account for the evolution of this protein since our divergence from bacteria? write down the number

What would be the result of an experiment if the primers had a melting temperature of 50 degress celcius if they orignally had a melting temperature greater than or equal to 78 degrees celcius?

There are many Firmicutes and Proteobacteria that are associated with food spoilage and foodborne illness. Several methods used to prevent foodborne illness and food spoilage during beer brewing and other food processing are presented.

• List a few species of Firmicutes and Proteobacteria and the issues that they cause that are associated with a) Food spoilage (min. 3 species) and b) foodborne illness (min. 3 species)

• How are these organisms controlled during food processing?

Conversion of pyruvate to glucose by reversal of glycolysis has a ?Go’ of +84 kJ/mol, whereas gluconeogenesis occurs with a ?Go’ of ?38 kJ/mol. Where does the energy come from that drives gluconeogenesis? Show the three enzyme reactions where this energy is consumed.

Write explanatory notes on the importance of the six principles by which
biosynthetic pathways are organized.

Genetics:

Using molecular hybridization:

fully explain the technique and discuss one application of that technique used in scientific research.

Describe the role of metabolic channeling and compartmentation in regulation of
metabolism.

The vertebrate limb bud is an ideal model system for exploring the genetic regulation of development.

(A) In the context of limb development, define the abbreviation "ZPA". What is the major morphogen that is secretes? 2 marks

(B)  (i) What axis is patterned by the ZPA in limb development? Describe ONE experiment demonstrating the function of the ZPA.  4 marks

(ii) In THREE dot points, describe how this morphogen patterns structures in the autopod. 3 marks

C) In FOUR dot points, describe the intracellular signalling pathway that is activated by the main ZPA morphogen.  4 marks

D) A change in this morphogen underlies limb loss in snakes. At the genetic level, what is this change and what is the resulting change to the morphogen?  2 marks

Discuss the different ways in which microorganisms degrade and utilize lipids,
carbohydrates, protein and amino acids.