Reflection of the week 12

“Parting is such sweet sorrow that I shall say farewell til it be morrow”

 

The time has finally come and I am sad and a bit nostalgic. When we started back in January, I was a bit uneasy and hesitant about this blogging thing. Now, I am very disappointed that we have completed this task.

 

Reflecting on the past semester, I had a blast. There were some trials and tribulations and days when I did not fancy Biochem at all. However, these were overshadowed by the exciting, invigorating, challenging activities that Sir always had for us with every week. I could not ask for any more in a course. If I had a choice, I would have liked to continue blogging.

 

Biochemistry was an enjoyable and interesting course that had me obsessing about the topics and the various avenues to research as the weeks went on. Blogging allowed for consolidation of all the course materials, applications of concepts as well as fostering continuous studying. Sir was very cunning indeed in assigning us this activity. I also developed another unintended skill while undertaking this blogging task, Becoming more tech savvy! Trying to maintain captivating blog postings forced me to learn how to use application, search through sites and format documents to uphold the aesthetic appeal of my blog page.

 

Additionally, I am truly grateful to have Mr Matthew as a lecturer. In all of my University life, I have met very few teachers that have employed effective methods of relating the course material to the student body. his techniques are adaptable, encouraging and promote a high standard of learning by us, his students. He has taken a seemingly difficult course and showed us that once you put the work in, we can accomplish success. Sir has encouraged me to persist in studies and work and eventually everything will fall in place.

 

Therefore, I want to thank him for always assisting us when we were stuck on assignments, encouraging us when we were fed up, stimulating our minds when we were bored and entertain us when we were unmotivated.

 

I am looking forward to new and better things. Moreover, I hope that my experiences in Biochemistry are repeated in other avenues of my academic career and hopefully, I can continue to have fun while learning.

 

Before I go, I want to send warm thanks and praise to all my followers and commenters to my blog. It has been much appreciated to see your approvals and admiration for the information that I presented. I hope that I did not disappoint and I look forward to your support and love in the future. Thank you, thank you, and thank you.

 

Well, that is all folks. Until we meet again. It has been a trill and I could not anticipate having enjoyed this experience any more than I did. So keep good, study hard and live right…….

 

So long, farewell, auf weidersehen, goodbye,

Adieu, adieu, adieu, to you and you and you.

Good-bye, good-bye, good-bye!!!!

Reflection of the week 11

Hello there Biochem people.

Week 11!!!! Can you believe it?

We have reached the penultimate week for the blog and I must say that I am saddened and disappointed. I am not sure how time flew by so quickly but I must say that this journey was not as painful as anticipated. I believe that Sir has done what I did not think was possible, MAKE ME ENJOY BIOCHEM.

I will not lie to you, it has been a lot of work this semester, but I did have fun and the activities were very intriguing, kept me on my toes, and interested. Nevertheless, all things must come to an end and I am extremely excited to close this chapter and look forward to bigger and better things. However, that is not until next week and let us cross that bridge when we get to it. For now, I am going to focus on the week that was.

 

Week 11 was marked by the BIG EVENT. The one that we have been anticipating for weeks, the one that we thought would never come… the Mock Exam!!!!

 

Now this exam was not bad at all. The questions were fair and tested across all the topics. I was definitely prepared for worse, but I was pleasantly surprised by the ease to which I was able to answer the questions. There was only one drawback to this exam and I believe that most of us share the same sentiments, that we just needed a five minutes extra to finish that exam. In the local parlance, ‘sir put goat mouth on us’.

Why I say that? You might ask. Well because, he kept mentioning it in class that the biggest hurdle that we would face was the fact that our knowledge will not translate to the exam answers due to our inability to think quick enough and then actually finish the exam.

 

Well, I hate to say it, but he was right. I am not too disappointed though since I take it as a learning experience and know exactly what strategy to employ for the final. So, I am not ruminating on the fact that I could have done better in the exam, had I finished. I am optimistic of the finals.

 

Week 11 did not have any other remarkable event since we were all consumed with the big exam. Therefore, on to the final week of lectures, blogs and lab reports. I am eagerly anticipating the end since it means that I have successfully completed an entire semester of Biochem without being worse for wear.

 

Thus, all the best for the final week and wishing you all the success in all your remaining projects. Keep good and talk again in a bit.

Reflection of the week 10

Hello again my Biochem people,

We have arrived at week 10, only three weeks and counting until end of term. I think that I am more excited than sad. This week has been rather calm even though next week brings with it our DREADED IN-COURSE MOCK EXAM and we should be reviewing all the weeks work. Maybe it was ‘the calm before the storm’. Week 10 was focussed on tutorials, class quizzes and TCA/ETC as well as the two online review quizzes.

A few comments on each of those items. Let me begin with the review quizzes. I was a bit hesitant to attempt these quizzes without having studied previously and recollect all the finer details of cells, carbs and proteins. Therefore, looked over my notes and studied for the day before attempting the quiz. I was slightly disappointed when I did the quiz and the questions were quite straightforward and simple. I felt that the quiz could have tested more in-depth understanding and application of knowledge on the material. On the glycolysis quiz, I was even more surprised that the questions were all the questions from the Glycolysis MCQ worksheet YouTube video that Sir put up for us to test our knowledge of the important aspects of glycolysis. I must say though, unlike the cells quiz, I was glad that the glycolysis quiz was based on information that I already knew. Moreover, do not get me wrong, I am by no means complaining. Nevertheless, I thought that these quizzes were meant as a refresher to aid in studying for the mock exam and therefore would be slightly more challenging. I must say though, that if this is a reflection on the type of questions being asked, I am not as nervous about next week’s mock exam.

Tutorial focussed on enzyme kinetics and glycolysis. Very enjoyable session, at least the most enjoyable thus far. Sir not only asked some tough questions that forced us to apply all the knowledge that we knew on glycolysis, he also guided us as to the most appropriate means of answering essay questions. This session was also a good review of the enzymes and assimilating all the information we have on enzymes and proteins into developing an appropriate answer for questions. This method, I believe was the ultimate goal for tutorials, for us to take all the information that we are learning and apply it not only to questions of specific subject matter, but also to related topics and real life situations.

As far as lectures are concerned, week 10 was very light. Even though it continued into TCA and ETC, there were little details and main focus was on the general overview of both processes. I believe that the focus was on getting ready for the mock exam. Those two quizzes in class were really helpful. It taught me two very important things: even though you know, the answer you need to write it down quickly and accurately and DOESN’T UNDERESTIMATE SIR WHEN HE SAYS BE PREPARED FOR A QUIZ AT ANY DAY. I must admit that I did browse over the information for class, but I was not as sharp as I wanted to be.

I wanted to talk a little about something that seems to be cropping up often and that is enzyme-inhibitor kinetics. Even though there were many examples in class, I feel it necessary to go over the basics in each category.

We will begin with inhibitors. Inhibitors are substances that alter the rate of reaction of an enzyme-catalysed reaction. There are two main classes of inhibitors: IRREVERSIBLE and REVERSIBLE.

Irreversible inhibitors: these are substances that bind to the active site of the enzyme and form a covalent bond between the R-groups of the active site and the R-groups of the inhibitor. As you know, during enzyme-substrate binding, the formation of a weak bond occurs to allow for easy dissociation and release of the products and substrate from the active sites of the enzyme. However, with irreversible inhibitors, there is the formation of a strong covalent bond that causes a decrease in the activity of the enzyme. This bonding prevents the substrate from binding since the active site is pre-occupied and the strong bonding of the inhibitor prevents the detaching and hence renders the enzyme inactive.

Irreversible inhibitors may also be called suicide substrates. Why you might ask? These substances are similar to the substrate of the particular enzyme i.e. substrate analogues. These analogues become highly reactive and activated by binding to the active site of the enzyme or near the active site and cause the formation of covalent bonds between the active site and the substrate analogue. This then inactivates the enzyme.

Most irreversible inhibitors are natural or synthetic toxins that exhibit competitive, irreversible inhibition. Examples of these may include:

–    

  Cyanide: now you are wondering where in world I would get cyanide from unless someone is blatantly trying to poison me. The answer is quite simple, bitter almonds may contain cyanide. Cyanide, reacts with metal ions in the enzyme structure such as iron, zinc and copper and form irreversible bonding that alters the action of the enzyme. Enzymes found in the electron transport chain are highly vulnerable to this and may cause decreased energy production.

–    

  Sarin: this is also called nerve gas and it binds to the serine residues found in the active sites of enzymes to form that covalent bond that renders the enzyme inactivated. The enzyme most vulnerable is acetylcholinesterase which is responsible for the breakdown of acetylcholine, a neurotransmitter, from the synaptic cleft of neurones. Acetylcholinesterase in effect regulates the action of acetylcholine by decreasing the activity on the postsynaptic membrane. However, if acetylcholinesterase is inhibited it allows for the prolonged action of acetylcholine on the postsynaptic neurones. Acetylcholine is responsible for motor activity in the body as well as wakefulness and learning. Therefore, increased activity of this neurotransmitter causes the constant contraction of muscles and thus may alter ability to breathe since respiratory muscles are hypertonic and unable to function properly. This may lead to the individual dying of asphyxia.

–     

Penicillin: this reacts on bacterial cell walls. Penicillin binds to the active site of the enzyme, glycopeptide transpeptidase. It forms a covalent bond with the serine residues present in the active site to render the enzyme inactive. Glycopeptide transpeptidase is responsible for the crosslinking of the peptidoglycan cell wall in gram-negative bacterial. Inactivation of the enzyme causes weakening of the bacterial cell wall and thus increases vulnerability to cell death. Weakened cell walls also decrease bacterial growth and thus reduce infections caused by bacteria.

There are many more examples of irreversible inhibitors, but the main idea is the loss of function of the enzyme leading to dire consequences for the organism.

Reversible inhibitors on the other hand form non-covalent bonding with the enzyme and therefore, this inhibition may be reversed or overcome. It is a temporary state. Reversible inhibition may be sub-classified into four main categories: competitive, non-competitive, uncompetitive and mixed inhibition.

Competitive inhibition: the substance or compound is similar to or closely resembles the substrate for the particular enzyme. The inhibitor competes with the substrate to bind to the active site of the enzyme. Once the inhibitor is bound to the active site, it forms a non-covalent bond with the active site and prevents the substrate from binding to the enzyme since the active site is already occupied. This leads to a decrease in the affinity of the enzyme to bind to the substrate. This decreased in affinity may show an increase in the Km value for the enzyme since with the increase in the concentration of the inhibitor, there is increased binding of the inhibitor to the active site of the enzyme due to out-competition of the inhibitor to the substrate.

However, this inhibition may be overcome by an increase in the substrate concentration. This increase in substrate concentration facilitates the out-competing of the substrate over the inhibitor and so the substrate will bind to the enzyme more than the inhibitor. Hence, the maximum velocity or rate of reaction of the enzyme is unaffected by this inhibition. Therefore, Vmax is unaffected.

This inhibition may be observed graphically via M-M curve and L-B plots.

M-M  curve showing the effect of competitive inhibition on an enzyme. There is an increase in Km and no effect on Vmax.

L-B plot for competitive inhibition.

A classic example of competitive inhibition is observed in the metabolism of ETHANOL and the drug, DISULFIRAM/ANTABUSE. Alcoholic beverages possess ethanol, which is metabolized in the liver by two enzymes. Firstly, ethanol is oxidized to acetaldehyde by the enzyme alcohol dehydrogenase in the cytosol and then rapidly to acetic acid by the aldehyde dehydrogenase in the mitochondria of hepatocytes. Therefore, there is little accumulation of acetaldehyde in the body. Acetaldehyde is responsible for the side effects or hangover effects felt by alcohol consumption such as nausea, vomiting, headaches and light-sensitivity. Hence, quick metabolism of this substance is necessary.

 

Disulfiram is a drug that is utilized by recovering alcoholics in order to aid in overcoming drinking habits. Disulfiram competes with acetaldehyde in the mitochondria for binding to the enzyme aldehyde dehydrogenase. When disulfiram binds to the active site of aldehyde dehydrogenase, it prevents acetaldehyde from binding and thereby causes an increased accumulation in the cells and lead to the severe side effects.

Ethanol may also be utilized as a treatment or antidote for methanol poisoning by similar mechanisms. Methanol may be oxidized to formaldehyde and formic acid, which are severely toxic to the cells of the body, especially the optic nerve, leading to blindness as well as respiratory and neurological effects. Ethanol may be administered since it competitively inhibits the action of alcohol dehydrogenase enzyme in the liver. When ethanol binds, it decreases the affinity of alcohol dehydrogenase for methanol and thus decreases the oxidation of methanol, since the products of methanol oxidation is toxic to cells rather than methanol itself.

Another type of reversible inhibition is non-competitive inhibition. With non-competitive inhibition, the inhibitor binds to the free enzyme at another site other than the active site of the enzyme or to the enzyme-substrate complex. It does not resemble the substrate and binding to these sites enable a change in conformation of the active site leading a decrease in the formation of products. Thus, by this inhibition, there is a decrease in the maximum velocity of the enzyme and hence a decrease in Vmax. However, it does not affect the substrate from binding to the active site of the enzyme rather the inhibitor prevents the formation of products by altering the interaction of the enzyme and substrate. Therefore, the affinity of the enzyme for the substrate is unaffected and Km is unchanged.

This may be illustrated by M-M curve and L-B plot.

M-M curve showing the effect of non-competitive inhibition. there is a decrease in the Vmax but Km is unchanged.

L-B plot illustrating the effect of non-competitive inhibition.

An example of non-competitive inhibition is ALANINE AND PYRUVATE KINASE. Alanine, the amino acid is formed from the transamination of pyruvate. When there are high amounts of alanine produced, it acts as a negative feedback onto the enzyme pyruvate kinase. As you know, pyruvate kinase catalyses the reaction that dephosphorylates phosphoenolpyruvate to pyruvate in the last step of glycolysis to yield ATP. Increased levels of alanine, causes increased binding of alanine to pyruvate kinase and in some cases to pyruvate kinase-phosphoenolpyruvate complex and prevents the formation of pyruvate. This leads to decrease in formation of pyruvate and regulation of amino acid production in times of plenty.

Uncompetitive inhibition is another class of reversible inhibition. The inhibitor binds ONLY to the enzyme-substrate complex in this process. Binding of the inhibitor prevents the formation of products by causing a change in the interaction between the enzyme and the substrate. Therefore, there is a decrease in the maximum velocity of the enzyme and the rate of reaction of the enzyme and so Vmax is reduced. Since the enzyme-substrate complex exists in equilibrium to the enzyme and substrate, when there is a shift in the equilibrium by binding of the inhibitor to the enzyme-substrate complex, there is a compensation effect. This means that there is increased binding of substrate to free enzyme active sites to attempt to recover the equilibrium by formation of more enzyme-substrate complexes. This gives the appearance of an increase in affinity of the enzyme for the substrate due to increased binding and complex formation. Hence, there is a decrease in the Km for that particular enzyme. Therefore, there is increased use of substrate than in a non-inhibited state. To note with uncompetitive inhibition, there is a proportional decrease in the Vmax and Km values of the enzyme. This means that both are decreased in proportional value due to the equilibrium compensation.

This may be observed graphically on M-M curves and L-B plots.

 

 

An example of uncompetitive inhibition involves the drugs, PROBENECID and ZIDOVUDINE. Probenecid is a drug that is utilized to treat chronic gout. Zidovudine is a potent HIV inhibitor that decreases levels of HIV in the blood by inhibiting the replication of HIV. Zidovudine is metabolized in the liver where it undergoes glucuronidation to become a glucuronide that is less reactive to the body. Thus, the liver decreases the activity of zidovudine. It was found however, that probenecid binds to the glucuronide enzyme-zidovudine complex in the liver to decrease the glucuronidation of zidovudine.

The last class of reversible inhibition is mixed inhibition. There is binding of the inhibitor to the free enzyme as well as the enzyme-substrate complex similar to non-competitive inhibition. This leads to a decrease in the rate of reaction of the enzyme and hence a decrease in Vmax, however, there may be a change in the affinity of the enzyme for the substrate and so there may be an increase or decrease in the Km value.

All right then folks, I hope that this information is easy to understand and helps with your studies.

Therefore, to conclude, Week 10 has come and gone and now we are in deep preparation mode for this exam on Wednesday. I am both scared and excited. This one is supposed to test our readiness for the final and give an assessment of the amount of work that we require to do. So all the best to my fellow Biochemians and happy studying.

Bye for now and keep up the struggle.

 


 

References

–      Biochemistry by Dr Jakubowski. Chapter 6- Transport and kinetics. Models of enzyme inhibition. 19th March, 2013.

http://employees.csbsju.edu/hjakubowski/classes/ch331/transkinetics/olinhibition.html

 

–      MyMCAT: start your prep now. Enzyme Inhibition. 11th July, 2010. http://www.mymcat.com/wiki/Enzyme_Inhibition#Competitive

 

–      ChemPages Netorials. Biomolecules: Enzymes. http://www.chem.wisc.edu/deptfiles/genchem/netorial/modules/biomolecules/modules/enzymes/enzyme4.htm

 

–      Pathway detail: Ethanol metabolism. http://flipper.diff.org/app/pathways/info/2980

 

–      Elmhurst College. Virtual Chembook. Enzyme Inhibitors. 2003. http://www.elmhurst.edu/~chm/vchembook/573inhibit.html

 

–      Enzyme Kinetics. http://www.uvm.edu/~mcase/courses/chem205/lecture13.pdf

 

–      Enzyme inhibition. http://www.pearsonhighered.com/mathews/ch11/c11ei.htm

 

–      Kokbiolab. Lecture 7: Enzyme Inhibition. http://www.google.tt/url?sa=t&rct=j&q=&esrc=s&source=web&cd=12&sqi=2&ved=0CIwBEBYwCw&url=http%3A%2F%2Fwww.kokbiolab.com%2Flib%2Fexe%2Ffetch.php%3Fmedia%3Dfnkok%3Alec7-inhibition.ppt&ei=_-xZUePjKdTi4AOiy4GgDw&usg=AFQjCNFr8Q66T9oJ6P9hQda0DnyrBsN09w&sig2=WOO_7GK9PpDG5biHJfe4hA

 

Reflection of the week 9

Hey there my lovely Biochem people,

Week 9, week 9, week 9!!!!!

All right, we are over the hill and almost to the finish line. We must conserve the energy in preparations to burn that midnight oil. I have mixed feelings now that we are nearing the end of the semester. I am somewhat glad that in a few short weeks, I will be enjoying vacation time but the Biochem topics are finally becoming more interesting and I just do not have enough time to delve deeper into the course material. However, alas, No complaints.

 

Week 9 was quite uneventful, yet very entertaining. This week was our last Biochem lab and fittingly enough, it was on Enzymes. This was by far the most stimulating and fascinating lab session since it involved numerous reactions and very colourful lab results. I wished that I took a picture; unfortunately, I could not take out my phone. However, this lab session proved to be an apt review of the entire topic of enzymes. It covered inhibition, reaction time and reaction rate as well as effects of temperature on enzymes. This facilitated practical application of all the theory we learnt thus far. It was easy and painless, a greater improvement to last ascorbic acid lab. I believe that I developed a mild case of tendonitis after all that swirling for the titration of ascorbic acid. My wrist still hurts a little. Nevertheless, enough about that since I am sure that I will have more to say on that issue in the coming weeks.

 

This week’s lecture highlights were on my very, special favourite topic, GLYCOLYSIS!!!! Yayyyyyyyy

We completed the glycolytic pathway and began to delve into the fates of pyruvate. Could you ask for better lectures? I was engrossed into the efficiency and efficacy of our cells to produce energy, conserve energy as well as replenish the materials necessary for the functioning of these energy pathways. I was very pleased and thoroughly enjoyed classes. If only all topics were like this.

 

However, I digress, I have decided not to discuss details of the highlights for this week in the reflection but rather focus on my thoughts of the week in general. I must say that Biochem is turning out to be not as bad as I thought. Unfortunately, I have been scorched by Biochem before and thus reserve the judgement until after finals. However, Mr Matthew has made the course tolerable by invigorating it with these new and innovative methods of learning and teaching. This very blog, that I now eagerly anticipate to post things on, was Sir’s brainchild. I was doing much of this stuff for the grades but gradually, I found myself engrossed and consumed by ideas and future posting topics. I also felt that this challenged my learning and studying methods and forced greater research and devotion to the subjects in order to bring a better understanding and increase the depth of knowledge and information that I was posting. This was a fantastic idea and I must say that through this medium, I am able to test my understanding of the topics.

 

Anyway, I just want to end by saying that this week has come and gone and I am pleased with the journey that we are on thus far. Even though, at some points the winding roads exhausted me, I have stuck with it and now I have seen the sunshine and daisies.

 

On a last note, I want to thank and acknowledge all the international visitors to my blog. I really appreciate the interest and I hope that the information is both informative and helpful. Thanks for the support.

 

Well that is all for now folks. Keep up the fight. Moreover, talk soon.

Reflection of the week 7

Hello Biochem people,

Week 7 was a whirlwind. I have barely any breathing time.

With four midterms, a week of enzyme lectures and two biochem assignments to hand in.I feel like my head is spinning and my laptop has become my bedmate for the week.

The upside was that we did not have any labs (*sigh of relief*). Okay, that is not such a good thing but with the hectic week, I was glad for the time off, even though, I spent it doing so many things.

 

 

But alas, I do not have any time for complaining and ruminating either. So now to this business.

This week was Enzymes… Nature’s hardest and most dedicated workers. These lectures were short and surprisingly easy to follow. Few important things to note are M-M curves and L-B plots.

These are not to be confused even though they convey similar information and may be used to ascertain rates of reaction of enzymes.

Therefore, it is prudent to break it down into simple and easily understandable terms.

M-M curves: These curves illustrate the relationship between reaction velocity of an enzyme and the substrate concentration. It is based on the M-M equation:

V0 = {Vmax [S]}/{Km + [S]}

V0 : this is the initial reaction velocity i.e. the reaction rate measured as soon as the enzyme and its substrate is mixed

Vmax : this is the maximal reaction velocity of the enzyme i.e. the fastest point at which the enzyme may react with the substrate to cause a product formation. This is altered by reversible inhibition methods.

[S] : the concentration of the substrate

Km: Also known as, Michaelis constant and represents the affinity of the enzyme for the particular substrate since it is characteristic of the particular enzyme and substrate. It is the result of the sum of the rate constant to convert the enzyme substrate complex back to enzyme and substrate (K-1) and the enzyme-substrate complex to product and enzyme (K2) divided by the rate constant to convert the enzyme and substrate into enzyme-substrate complex (K1). Increase in the Km means a decreased affinity of the enzyme for the substrate whilst a decrease in Km means an increase in the affinity of the enzyme for that substrate. Increased affinity means that only small concentrations of substrate is required to half saturate the enzyme i.e. only small concentration of substrate is required to reach ½ Vmax.

M-M curves may demonstrate the change in reaction velocity that occurs during inhibition of the enzyme activity. (Look out for that in a subsequent posting). However, these hyperbolic curves make it difficult to ascertain exact values for Km and Vmax. Hence, we require more specific means of evaluating the reaction velocity of the enzyme. This may be achieved by L-B plots.

L-B plots: these are similar to M-M curves in that they are able to give the relation between the reaction velocity of the enzyme and the substrate concentration. However, as you may have guessed, these plots are straight lines and not curves. They are also the inverse of the M-M curves in which 1/V0 is plotted against 1/[S]. This causes a linear relationship to be drawn from the data. One is better able to determine Vmax and Km from the graph since these are now direct points on the L-B plot. -1/Km is the point at which the straight line hits the x-axis of the x-intercept where the 1/ V0 = 0. Whereas, the 1/Vmax is the y-intercept or the point at which the straight line cuts the y-axis where the 1/[S] = 0. Therefore, one is able to easily ascertain these values.

L-B plots may also be utilized to demonstrate and determine the effect of inhibitors to the enzyme on the reaction velocity of the enzyme.

This is the basics and knowing these little points make understanding the effects of inhibition much simpler. Therefore, this was the biggest highlight from Week 7.

 

Just a few comments on the two assignments that we had to do on cells, carbs, amino acids and proteins. These assignments incorporated real world applications to all the course material. This was a very interesting and intriguing venture especially learning about bioluminescence in jellyfish and the properties of honey and gelatine.

However, although the tasks seemed simple, it took a very long time to research and then summarizes to avoid plagiarism. I felt that some of the enjoyment in doing these assignments was lost by the structuring and formatting of the actual material for submission.

I was frustrated at the end of the exercise and was more concerned with finishing the assignment on time and ensuring that the material was not similar to the research sources that I think that some of the assimilation and comprehension of the material was lost. This made be a little disheartened since prepping for these assignments, I was very enthusiastic to apply my knowledge to explaining mechanisms of actions and creating links in functioning of humans and other animals.

Nevertheless, we cannot complain because plagiarism is a serious issue and I would not be too pleased if some person just copies and pastes my hard work and use it as their own. And I cannot criticize the University for trying to foster more responsible research and critical evaluation of materials.

But I had really hoped that these assignments were more fun than they turned out to be. Anyway, I am hopeful that things will get better since the good news is that the term is almost over and this will only be a distant memory. So we have to just look at the horizon and remain focus on our goals.

Well, I think that I have spoken enough on this week. I am sorry for my ranting. But my hopes are high since the weeks to come are going to be more captivating and I will not remember the trials of this week.

Bye for now, beautiful people and look out for some more enzyme stuff to come.

Reflection of the week 8

Alrighty then my Biochem peeps,

Can you believe that we are in week 8 already?

It seems like time is just zooming by and I really hope that we could slow down the clock.

Nevertheless, I guess such is everything life and so we have to keep up the fight and keep wading through. Like I always say, have to tell yourself those positive lies to persevere.

I took a hiatus last week since I was so overwhelmed. Last week reminded me of finals week in Grenz, seven days of little sleep, lots of reading and gallons of Coke. I think I am still dealing with the after effects.

However, I am playing catch this week in terms of all my blogging commitments. Week eight highlights focus on the very exciting, intriguing and energetic, GLYCOLYSIS. Now this is probably my favourite topic in Biochemistry because it is probably the only item that is very straightforward. We have only reached the first step in the 10-enzyme pathway, but I feel as though we have revised the entire course work in this one stage.

So a little recap,

Glycolysis is the first stage of cellular respiration and is involved in the conversion of glucose into a three-carbon compound known as pyruvate. This process is essential for energy generation for the cell and facilitates the control of blood glucose levels by ensuring that there is a steady intake and utilization of glucose from the blood.

As you would know, I went into why high blood glucose levels are hazardous to our tissues and why it must be metabolized quickly and efficiently. (Check out the Highs and Lows of glucose on my blog).

Glycolysis is the most primitive energy producing reaction that occurs in bacteria, fungi and even us humans. It occurs in the absence or presence of oxygen. Glycolysis occurs in the cytosol of the cell and therefore can occur in both prokaryotes as well as eukaryotes since it does not require an organelle to occur.

 

Of importance, is the fact that erythrocytes or rbcs’ as I call them, depend solely on energy generated from glycolysis to carry out its functions. Now, I hope that you know that red blood cells do not possess organelles; hence, this process is ideal for them. You see rbcs’ transport oxygen via haemoglobin, which if you are still unsure, is the most important job in the body, so in order to become more efficient and effective in their duties, rbcs’ shed most of their organelles to make room for the haemoglobin. Hence, you might derive the fact that inability for glycolysis to occur, will lead to degeneration of function of rbcs’ leading to a little known ailment as anaemia.

Glycolysis involves 10 enzymes that catalyse three irreversible reactions and seven reversible reactions to yield two molecules of pyruvate (3C), four molecules of ATP (net ATP equals two), two molecules of NADH and two molecules of water. All of this results from one glucose molecule.

Now, ATP is a nucleotide that comprises of adenosine and three phosphate groups. These phosphate bonds have high chemical energy stored. This energy is released by the hydrolysis of the phosphate bonds to yield ADP. Therefore, production of one molecule of ATP stores high levels of energy, enough to adequately power the functions of the cell.

NADH is also a high-energy compound. It is the reduced form of NAD, which is a co-enzyme that is found in tissue. NADH is able to transport electrons to the electron transport chain in order to yield ATP or energy.

Pyruvate may move on to the Krebs cycle or TCA cycle as the hip people call it, in the mitochondria or to produce lactic acid if there is no oxygen present as in muscles as they undergo the Cori cycle.

TCA further metabolizes the pyruvate to yield more energy and produce electron transporters. NADH produced is then transported to the inner mitochondria through the electron transport chain to yield energy/ATP. The ATP produced may be utilized to facilitate the different functions of the cell that require energy such as contraction of actin and myosin fibres.

Well this is just an overview and as next week rolls around, I will go more in-depth with every stage of this glycolytic pathway. However, I am very interested and highly anticipating the fun and adventure that we will undertake as we meander through the energy pathways.

Thus, I hope that I have whetted your appetite and increased your thirst for more information on this topic. Stay tuned, keep keeping on and conquer that mountain with a smile on and determination in your spirit.

I know I am pushing ever forward, we will come out victorious.

Bye for now people.

Reflection of the week 5

 Hey Biochem people, so week 5 has come and gone and this week was Amino acids and proteins. We are now getting into the real ‘meat’ of this biochem thing.

Amino acids and proteins are THE most important biomolecule in my opinion. These molecules are found in just about every nook and cranny of the body. As you may realize that we, humans are nothing without these little molecules.

 I enjoyed this week of lectures since it is the topics that lay the foundation to just about every other biochemical reaction in the body. Amino acids and proteins for that matter are critical to the efficient and effective functioning of the body.

 

Proteins act as the gladiators of our body fighting and defending intruders such as antigens that infiltrate our blood and other bodily fluids and try to suppress our immune system.

These invaders may be microbial villains like bacteria, viruses and even foreign objects.

 

These knights in shining armour are none other than…

ANTIBODIES. Antibodies work with our armies of immune cells such as white blood cells to suppress the enemy and keep the immune system functioning at optimal level.

 

 

Proteins also aid in the moving and shaking of cells and the body by extension….literally!

Contractile proteins such as myosin and actin interact with each other to facilitate movement via contraction of these molecules. This is observed within the cell to enable cytoplasmic streaming as well as in myocytes (muscles) that facilitate movement of muscular tissue. Therefore, we could not shake our moneymakers without proteins.

 

Proteins make up the working force of the body. They are there diligently labouring to speed up or facilitate the biochemical reactions of our body. These catalysts ensure that all the requirements for metabolism and general functioning are carried out. And you must guess what this protein is… ENZYMES. These things are literally everywhere and in everything… like a macco. They aid in digestion, energy production and degradation, drug metabolism, clean up and recycling.

 

Now, proteins may also be the traffic police and mail carriers of the body. They can transmit messages as well as co-ordinate different bodily processes. These molecules are essential to managing certain reactions. Hormones such as insulin produced by the beta cell of the islet of Langerhans in the pancreas crucial to the regulation of glucose intake and metabolism, somatotropin aka a growth hormone is critical to stimulation of protein production such as creatinine to make muscles.

collagen

Proteins also form the backbone to many structures of the body including skin, bone, organs and ligaments and various appendages like hair and nails. These fibrous, insoluble structures provide support to numerous structures. Structural proteins include collagen, keratin and elastin. These proteins are found in hair and connective tissue. Therefore, being able to whip your hair back and forth or jumping up and down without your joints giving way and crumpling like a puppet is all thanks to proteins.

 

 

Proteins may also be the big trucks of the body acting as carrier molecules that transport important molecules throughout the cell as well as the body to the target destination to be used.  The famous ones such as Haemoglobin that transports just about the most important molecule, oxygen! to cells as well as cytochromes which are critical to electron transport in ETC in the inner mitochondria.

electron-transport

 

And this is just a few of the many, many functions of proteins in the body. Hence, I believe that proteins are VERY GOOD THINGS!!!

 Overall, I am excited for the rest of the term to delve into the exciting path of this Biochem course.

 Reference

About.com Biology. 2013. “Protein Function by Regina Bailey.” Accessed on March 14, 2013. http://biology.about.com/od/molecularbiology/a/aa101904a.htm