Game about protein translation

Here it is the link to a game about protein translation that has a quiz at the end.

http://www.zerobio.com/drag_oa/protein/overview.htm

Tattoos - DNA

The DNA is consideted the molecule of life and, apparently, also brings to life some tattoos ... :)

Metabolic map on the regulation of protein translation

http://www.biocarta.com/genes/Metabolism.asp

Video about glycogenolysis

Here is a video about glycogen breakdown.

Scientific jokes (2)

A bear walks on a river and it dissolves in the water. Why?
Because it is a polar bear.

Cartoon about cloning

Will the future look like this???

Music about gluconeogenesis

Kevin Ahern (www.davincipress.com/metabmelodies.html) is a professor at the Oregon State University who have created several musics about biochemistry for his students. Here is the lyrics of the music about gluconeogenesis (based on the song Supercalifragilisticexpialidocious) and the link for the download of the .mp3 file.

http://www.mediafire.com/?8rwy9fzwg2ou9rm

When cells have lots of ATP and NADH too

They strive to store this energy as sugar yes they do

Inside of mitochondria they start with pyruvate
(slow) Carboxylating it to make oxaloacetate

Oh gluconeogenesis is so exhilarating

Memorizing it can really be exasperating

Liver cells require it so there’s no need for debating

Gluconeogenesis is so exhilarating

Oxaloacetate has got to turn to PEP

Employing energy that comes from breaking GTP

From there it goes to make a couple phosphoglycerates

(slow) Exploiting ee-nolase and mutase’ catalytic traits

Oh gluconeogenesis is liver’s specialty

Producing sugar for the body most admirably

Six ATPs per glucose is the needed energy*

Gluconeogenesis is liver’s specialty

Oh glucose, glucose joy to me

Glucose, glucose joy to me

Converting phosphoglycerate to 1,3BPG

Requires a phosphate that includes A-T-P energy

Reduction with electrons gives us all an N-A-D

(slow) G3P’s isomerized to make D-H-A-P

Oh gluconeogenesis is anabolic bliss

Reversing seven mechanisms of glycolysis

To do well on the final students have to learn all this

Gluconeogenesis is anabolic bliss

Oh, glucose, glucose factory

Glucose, glucose factory

The aldolase reaction puts together pieces so

A fructose molecule is made with two phosphates in tow

And one of these gets cleaved off by a fructose phosphatase

(slow) F2,6BP's acting blocking path-a-waysAnd

Oh gluconeogenesis a pathway to revere

That makes a ton of glucose when it kicks into high gear

The cell's a masterminding metabolic engineer

Gluconeogenesis a pathway to revere

Oh glucose, glucose jubilee

Glucose, glucose jubilee

From F6P to G6P, that is the final phase

The enzyme catalyzing it is an isomerase

Then G6P drops phosphate and a glucose it becomes

(slow) Inside the tiny endoplasmic-al reticulumsUnless

Oh gluconeogenesis is not so very hard

I know that on the final we will not be caught off guard

'Cause our professor lets us use a filled out index card

Gluconeogenesis is not so very hard

*Actually, you need two NADHs too, but that wouldn't fit the rhyme

Oh, glucose, glucose come to be

Glucose, glucose come to be

Lactic fermentation

This reaction is clearly favored in the forward direction. In situations of hypoxia (intense muscular effort, for example), or absence of mitochondria, the cell is unable to regenerate NAD+ from NADH through the respiratory chain. It does so using the conversion of pyruvate to lactate, which consumes NADH and releases NAD+ release. It should be noted that the NAD+ is essential for glycolysis to continue to occur, thereby to obtain energy through the catabolism of sugars. Each molecule of pyruvate converted to lactate regenerates a molecule of NAD+. The lactate formed is sent through the bloodstream to the liver where it is converted to glucose in gluconeogenesis. The question that arises is: "So if you can recycle lactate, converting it back into glucose, why is the liver that has to do this and not the muscle, since it is the muscle that produces lactate? If so, the muscle could use directly the product of fermentation to restore the levels of metabolic fuel." In fact, at a first glance it may make sense to think in this way. However, the synthesis of glucose through gluconeogenesis is very expensive, in terms of energy, so that after an intense physical effort, it did not make sense that the muscle has to spend additional energy to synthesize glucose. Thus, the recovery of an intense effort includes not only the restoration of ATP levels in muscle but also an extra consumption of oxygen in the liver, necessary for the synthesis of ATP to be used in gluconeogenesis from lactate. In other words, after muscular efforts, is the liver that has to use lactate, allowing a faster and more efficient muscle recovery. This process is called the Cori cycle.

Dring anaerobic work the concentration of lactate in the muscle fibers can increase about 30 times and it is a commonplace to say that it is this accumulation of lactate ion which causes fatigue. However, the experimental evidence shows that although the concentration of lactate is directly related to the degree of fatigue it does not interfere with the the muscle contractile activity. Fatigue, muscle pain and cramping experienced after an intense physical effort are the result of an acidification caused by lactic acid in muscle (the pH can drop from 7 to 6.5 !!!). The pKa of lactic acid is about 4, which causes that at the cell pH (≈ 7) or plasma (≈ 7.4) occurs the dissociation of lactic acid to lactate + H+. This accumulation of H+ will interfere with the contractile capacity of muscle fibers and will also invade the synaptic cleft. Thus, the inability of the neuromuscular junction in relaying the nerve impulses to muscle fibers is due probably to a lower release of the chemical transmitter acetylcholine by nerve endings, due to acidification of the interstitial fluid and alteration of protein structures (acetylcholine receptors) by the action of H+. This system provides energy for physical activities that result in fatigue after about 60-120 seconds. It is therefore the primary metabolic process associated with activities such as running up to 400-800 m, swimming events of 100-200m, and also provides energy for high intensity moments in football, basketball, volleyball, tennis, among others. The common denominator of these activities is the support of high-intensity efforts lasting 1-2 minutes. Even the best trained athletes are unable to sprint for more than a minute. A highly competitive athlete needs about 30 minutes to recover from a 100m sprint. Some lactobacilli and streptococcus ferment lactose to lactic acid in milk. The ionization of lactic acid lowers the pH and causes denaturation of the casein (main milk protein) and other milk proteins. When this denaturation is controlled, and occurs in the right conditions, you get the yogurt or cheese.

 

In short, the fermentation is not used to get energy under anaerobic conditions (this misconception is very common ...). It serves to regenerate NAD+ so that glycolysis can continue to occur in the absence of O2, as glycolysis is the process that will produce ATP!

Main bibliographic sources:

- Quintas A, Freire AP, Halpern MJ, Bioquímica - Organização Molecular da Vida, Lidel

- Nelson DL, Cox MM, Lehninger - Principles of Biochemistry, WH Freeman Publishers