Biochemistry Answers

how does nitric acid lead to mistakes during DNA replication

What is the role of LDH in alcohol metabolism in the liver?

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The laboratory of your PhD supervisor has developed a DNA aptamer that that has been designed to bind the epidermal growth factor receptor (EGFR). Preliminary evidence indicates that the aptamer binds and prevents epidermal growth factor from binding, but a bivalent form of the aptamer (two aptamers linked together) acts as an EGFR agonist. You have access to the human glioma cell line U87 that overexpresses EGFR, and a null-mutant of the same cell line that carries a non-functional EGFR. Describe a series of experiments, and indicate potential results where applicable, to investigate the following.

(a) Changes in proliferative index when treated with the aptamers

(b) Changes in mRNA expression of target genes for EGFR

(c)   Changes in the phosphoprotein content of cells

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Review the protein-protein interactions and signalling networks that account for the action of PI3Kinase in relaying pro-survival signals and in preparing cells to grow.

A recently discovered plant extracted is thought to have therapeutic utility for treating stroke patients as it may inhibit neuronal cell death in the region of tissue with reduced blood flow by inhibiting apoptosis. A rat model of stroke exists in which a temporary reduction in blood flow (ischaemia) to one hemisphere of brain can be induced. Describe a series of experiments you would undertake to investigate if the drug is able to reduce post-ischaemic cell death and to determine if active Akt is induced following an ischaemic event.

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You have discovered a novel compound that you think may functions as a Wnt mimetic and modulate the activity of mesenchymal stem cells. You have access to human primary mesenchymal stem cells and the equipment typically found in a cell and molecular biology research laboratory. Describe a series of experiments, and indicate potential results where applicable, to investigate the following.

(a) Changes in proliferative index or induction of apoptosis

(b) Changes in mRNA expression of Wnt regulated genes

(c)   Changes in the cellular distribution of Wnt regulated proteins

(d) Changes in the phosphoprotein content of cells

• What are the two cycles related to carbohydrate metabolism that may undergo a Futile cycle?
• What is the end goal for a Futile Cycle?

Draw the structure of lac operon and its action when the following conditions are prevailing in the media: increased glucose, low glucose, higher c-AMP, low c-AMP, higher glucose, and high c-AMP, low glucose and High c-AMP, Higher glucose and higher allolactose?

—Estimate the net charge of a Glu–Tyr dipeptide at pH 6.0.