Eicosanoids

Eicosanoids are derived from omega 3 and 6 fatty acids and are involved in many aspects of inflammation and immunity. There are four types: leukotrienes, prostaglandins, prostacyclins and thromboxanes. This link provides an easy to follow overview of the derivation and function of different eicosanoids.

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Phosphodiester bond

Phosphodiester bond

Phosphodiester bonds join the 5′-hydroxyl group of the deoxypentose of one nucleotide to the 3′-hydroxyl group of the deoxypentose of another nucleotide through a phosphate group.

Reference: Champe, Pamela C. and Richard A. Harvey. 1994. Lippincott’s Illustrated Reviews : Biochemistry. Philadelphia. J.B. Lippincott and Company

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Video Review 1: Origin of Life and Endosymbiotic Theory

As the title suggests an explanation is given for the origin of life and the endosymbiotic theory. Oparin’s (1924) hypothesis alluded to the spontaneous generation of life via chemical and physical processes. In 1953 Miller and Urey performed an experiment to support Oparin’s hypothesis; they formulated organic compounds from water vapour and other gases. In fact , amino acids were formed as a result of natural forces acting on inorganic molecules in the experiment. In the 1960s Lynn Margulis formulated the endosymbiotic theory which postulates that eukaryotic cells arose from symbiotic relationships between prokaryotic cells.

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BIOCHEMICAL WARFARE

Perhaps a bit mundane, but I have always been fascinated by the history, development and implications of war. As despicable as war is, our modern lives have been shaped by it: all technological advancements were done in the name of war, it is by the trickle down effect we, the public, have come to have access to such things as the internet or cellphones or even cars!! It is no coincidence that the militaries of the major powers of the world are at least a generation ahead in technological terms from the rest of society. As such, I thought I would share this, it is an excellent read summarizing the history of biochemical warfare and its devastating effects. It is sad when such science is put to gruesome use and regrettably, the use of biochemistry in formulating these deadly compounds has had a prominent role in the way warfare is carried out, and hence, the shaping of world history.

http://www.questia.com/library/history/military-history/weapons/biochemical-warfare

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Exam #2

 

Select the correct multiple answer using one of the keys A, B, C, D or E as follows:

A. 1, 2 and 3 are correct

B. 1 and 3 are correct

C. 2 and 4 are correct

D. only 4 is correct

E. all are correct          

 

1)     During vigorous exercise there is :

1.       Decreased levels of fructose-2,6-bisphosphate

2.       Conversion of pyruvate to lactate

3.       Increased gluconeogenesis

4.       Elevated NAD/NADH+ ratio

2)     Which of the following are epimers?

1.       Glucose and galactose

2.       Fructose and sucrose

3.       Mannose and glucose

4.       Amylose and amylopectin

3)     Which of the following amino acid have aromatic R groups?

1. Phenylalanine

2. Tyrosine

3. Tryptophan

4. Arginine

        4)  Non-competitive inhibiton:

                1. Decreases apparent Vmax

                2. Increases Km

                3. Has no effect on Km

                4. Inhibitors bind to same site as substrate

     5)  The irreversible reactions of the glycolytic pathway are:

                1. glucose to glucose-6-phosphate

                2. fructose-6-phosphate to fructose-1,6-bisphosphate

                3. phosphoenolpyruvate to pyruvate

                4. glyceraldehyde-3-phosphate to dihydroxyacetone phosphate

 

6) Where does the Krebs’ cycle take place?

                1. Nucleus

                2. Golgi apparatus

                3. Peroxisomes

                4. Mitochondria

7) Disulfide bridges may be found in:

                1. histidine

                2. lysine

                3.cysteine

                4. cysteine

8) Alternative fates of pyruvate are:

                1.aggregation in adipose tissue 

2. reduction of pyruvate to ethanol

                3. excreted in the urine

                4. carboxylation of pyruvate to oxaloacetate

9) Examples of substrate level phosphorylation is/are:

                1. formation of 1,3-bisphosphoglycerate

                2. reduction of pyruvate to lactate

                3. conversion of phosphoenolpyruvate to pyruvate

                4. formation of fructose-1,6- bisphosphate

10) The human cell DOES NOT possess

                1. mitochondria

                2. lysosomes

                3. rough ER

                4. cell wall

 

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Electron Transport Chain

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The electron transport chain relies on the creation of a proton gradient across a membrane via electron transfer between an electron donor and electron acceptor. The proton gradient is coupled to the production of chemical energy usable by the host(usually in the form of ATP).In eukaryotes it occurs in the mitochondria and is the site of oxidative phosphorylation. This pathway is also the mechanism by which plants harness the sun’s energy.

Reference : Champe, Pamela C. and Richard A. Harvey. 1994. Lippincott’s Ilustrated Reviews : Biochemistry. Philadelphia. J.B. Lippincott and Company.

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TCA Cycle

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Also known as the tricarboxylic cycle and Krebs’ cycle, organism use this pathway to yield energy via the oxidation of acetate (in the form of acetyl CoA), that is produced as a result of the catabolism of carbohydrates, proteins and fats. The cycle provides several precursory compounds as well as intermediates of other biological reactions.

Reference : Champe, Pamela C. and Richard A. Harvey.1994. Lippincott’s Ilustrated Reviews:Biochemistry. Philadelphia. J.B. Lippincott and Company

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