I remember the Krebs Cycle

•April 13, 2013 • Leave a Comment

On JM’s blog there is a saying  “Can I Keep Selling Sex For Money, Officer?‘ which helps us with the steps to the TCA or Krebs Cycle. I  found that it was very funny yet meaningful i actually remembered the names of the molecules because of this saying.

 

tca-steps

 

 

By remembering these steps it wouldnt take more than a few seconds to relate it to a question on an exam. So memorize it, it will come in handy!

 

Science Forever,

Latisha.

 

 

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Published Paper #1

•April 13, 2013 • Leave a Comment

The paper that i reviewed was entitled “Stress boosts Alzheimer’s proteins in the brain” by Roxanne Khamsi.

http://www.newscientist.com/article/dn10305-stress-boosts-alzheimers-proteins-in-the-brain.html

An experiment was conducted where a 4 month old mice was placed in a confined space and left for 3 days, causing its stress level to rise being in such a small space. Attached to the mice’s head was a micro-dialysis probe which extracted brain fluid to be analyzed. After the 3 days period the mice had 42% more brain proteins. The protein amyloid beta peptide was of special interest to David Holtzman at Washington University in St Louis, Missouri, Us. The research he conducted gave evidence that the protin is  linked to Alzheimers’ disease. Previous researchers has linked higher levels of amyloid beta peptide as an increased risk of dementia in humans (which is a deterioration of intellectual abilities that would cause interference to the social and occupational aspects in an individual’s life. He suggested that one of the most common causes of Alzhemiers’ disease is the lost of a spouse. This would result in higher stress levels that often boost the production of amyloid beta peptide.

This article didn’t give much information on the topic or explained how this protein causes this disease. The writer gave a vague description of the disease and did not show the structure of the protein leaving readers with many questions, for example:

  • What does the structure of  amyloid beta peptide look like?
  • Where is it situated?
  • How does it affect brain activity?
  • What damage does it cause to result in the Alzheimers’ disease?
  • Can this effect be prevented or maybe reversed?

I don’t see the writer as reliable because much more research had to be done because a lot of questions arose rather than being answered.

Published Paper # 2

•April 13, 2013 • Leave a Comment

I saw this article entitled ” Red meat boosts gut bugs that raise heart disease risk” by Rebecca Summers and found it really interesting.

http://www.newscientist.com/article/dn23352-red-meat-boosts-gut-bugs-that-raise-heart-disease-risk.html

Basically this article highlighted that red meat contain high amounts of carnitine. It is said that this substance can increase the risk of atherosclerosis, a thickening of the artery walls by the build up of plaque. An experiment was conducted by Stanley Hazen at the Cleveland Clinic Lerner Research Institute in Ohio where mice was feed food high in carnitine and they developed atherosclerosis. Another set of mice with suppressed gut flora was fed the same food, but they saw no increase in atherosclerosis.

Some bacteria in the gut use carnitine as a source of energy, when they break it down they convert it into trimethylamine (TMA). This substance is converted into trimethylamine-N-oxide(TMAO) by the liver and excreted in urine. High levels of carnitine causes a higher level of one bacteria which causes an increase volume of TMAO. This would cause the bacteria to keep feeding on this substance multiplying rapidly.

The increase of  TMAO volumes will increase the uptake of “bad” cholesterol and and which will not easily be destroyed by macrophages – white blood cells – in artery walls. This results in a build-up of plaque that leads to atherosclerosis.

Carnitine is also beneficial to the body,it transports fuel into mitochondria (power house of the cell). The body makes all the carnitine it requires so the intake of  large amounts of red meat will have  no significant benefit. Some may say that the increase amount of carnitine increase your energy level but in most cases it is quite the opposite and lead to cardiovascular disease.

This paper waas well written gave sufficient evidence and explanation on the topic discussed. People may be influenced to check their diet and start eating more healthily.

Krebs Cycle

•April 13, 2013 • Leave a Comment

The video that i reviewed was by an user on youtube.

http://www.youtube.com/watch?v=juM2ROSLWfw

This video started with a revision session of Glycolysis.

Things that we learnt before:

  • Glycolysis is the splitting of Glucose (a 6 Carbon Sugar) into 2 Pyruvate molecules (2 3-Carbon molecules).
  • It occurs in the cytosol of cells, he stated that Glycolysis takes place in the cytoplasm of the cell which is not true.
  • It produces a net gain of 2 Atp and 2 NADH moleules.

In the video he told us that Glycolysis take place in the presence or absence of Oxygen (Aerobic or Anaerobic conditions).

New Material

  • The Krebs Cycle is also known as the Citric Acid Cycle (substance found in orange juice).
  • It takes place in the inner space of Mitochondria  (Power House of cells).
  • Mitochondria has a double membrane outer and inner.
  • The inner membrane of the mitochondria is called the ‘Crista’ (plural Cristae).
  • Therefore it has 2 compartments
  1. The outer compartment.
  2. The Matrix.
  • A combination of Acetyl CoA (2 Carbon molecule) and Oxaloacetic Acid( 4 Carbon molecule)  to form Citric Acid (6 Carbon molecule) is what enters the Krebs Cycle.
  • All reactions are catalyzed by enzymes.
  • Carbons are lost via Co2 gas.
  • The Purpose of the Krebs Cycle is to generate ATP, NADH, FADH2 etc.
  • NADH and FADH2 produced here will go into the ETC (Electron Transport Chain) to generate much more ATP than in the Glycolysis Pathway and the Krebs Cycle.

Net Gain:

  • 14 Atps
  • 10 NADHs
  • 2 FADH2s
  • 6 CO2

Below is a detailed picture of the Krebs Cycle.

krebs_02

Joke

What did the Guy Prokaryote say to the girl Prokaryote???

Don’t worry babe I dont have Krebs.

Science Forever,

Latisha.

What can you do for my life?(Glycolysis)

•April 11, 2013 • Leave a Comment

Glycolysis is the pathway where a glucose sugar is split into 2 pyruvate sugars. This pathway is said to be the ancestor of all metabolic pathways where it occurs in the cytosol of humans, plants, bacteria or even yeast cells. The many function of Glyolysis is to generate ATP (energy) and NADPH. It is composed of 2 major stages;

  • Energy Investment Phase (Preparator Phase)
  • Energy Generation Phase (Payoff Phase)

Biological catalysts are used in the 10 steps. These enzymes as you all know speeds up the reaction. They are made up of proteins where in extreme heat will become denatured where their 3D shape will unravel hindering the pathway.

The 10 steps of Glycolysis is layed out in the picture below, the enzymes used at each step is in bold black.

preview008

In the first stage of Glycolysis there are two irreversible steps they are;

  • Step1 where glucose is converted to Glucose-6- Phosphate with the help of Hexokinase. This is a Phosphorylation reaction where a Phosphate group is added to Glucose.

This reaction is done so that Glucose can be trapped in the cell also making it reactive which would promote this reaction.

Hexreaction

Mg2+ is the Co-factor used in this reaction, now a co-factor is a non-protein molecule which forms a complex with some enzymes and is necessary  for their activity. It may be a metal ion or a co-enzyme.

Enzymes

  • Step 3 where Fructose-6- Phosphate is converted to Fructose-1,6-Bisphosphate with the help of Phosphofuctokinase 1.

Phosphofructokinase 1 is the most regulated enzyme in this Pathway. Why is the product called (Bis) and not Di? Easy, this is a Phosphorylation reaction meaning that a Phosphate group is added to a Carbon, but wait! it is already has a Phosphate group attached to its structure (view image below), this new Phosphate is not attached to the same Carbon as his padner before. Thats why its Bis and not Diphosphate.

pfk&fbp

In Stage 2 of Glycolysis there is only 1 irreversible step, this is step 10. Here Phosphoenolpyruvate (PEP) is converted to Pyruvate!!!!!!!!!!!! with the help of the enzyme Pyruvate Kinase. Now this reaction is the most energetically favourable reaction in the entire Glycolysis Pathway because the molecule PEP is extremely energetic. For every 1 PEP molecule 1 ATP molecule is produced and there are 2 PEP molecules so 2 ATP molecules are produced at this step.

pykin

Glycolysis is a very important Pathway without it we wouldnt be able to do basic activities like get up!!!!!!!

Joke

If Glycolysis is tearing Glucose apart, what does analysis mean?????

Science Forever,

Latisha.

Wordle: Fun, easy way to remember Key Points!

•April 11, 2013 • Leave a Comment

This is my wordle on the  Topic: Carbohydrates

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Minute Super-Speeders(Enzymes): Part1

•March 17, 2013 • Leave a Comment

Ok down to business. I called this post Minute Super- speeders because enzymes are minute(very small), Super because (they take on big roles of catalyzing reactions) and they are speeders because (welll they speed up the reactions). It is save to say that without our Minute Super-speeder friends, life will cease to exist!!!!!!!(according to JM).

Proper Definition: An enzyme is a biological catalyst (protein or RNA molecules) which speeds up a chemical reaction, because it creates an alternative pathway with a lower activation energy.

.Image

Now enzymes comprises of  2 important parts.

  1. Substrate- the molecule that binds to the enzyme.
  2. Enzyme itself- this contains the Active site (the binding site) where the substrate binds to the enzyme via Hydrogen bonds.

Saw this vid and i thought it was sooooo cute!!!!!!!!

Now the things that make these molecules sooooo fascinating are:

  1. These molecules are specific, meaning that they have a specific complementary shaped active site to the substrate coming in. Say for instance I tried using my key for my house to open the door for your house it wouldn’t work because the lock on your door is different from that of my door.

Lock-and-key_model

2.   Enzymes speed up reactions, meaning that the time a reaction will take with an enzyme will be less than the time taken without an enzyme. It is said that without enzymes some biological reactions can take up to 2.5 million years to occur.

wile_e_coyote_and_road_runner_wallpaper-29519

Say for instance the reaction without an enzyme is Wile.E Coyote and the reaction with an enzyme is Roadrunner. Now for you would don’t know the cartoon Wile.E Coyote never catches Roadrunner because Roadrunner is so much faster than Coyote. This is the basis in the enzyme world. The reaction with the enzyme is so much faster than the reaction without the enzyme.

For example Maltase is the enzyme used to convert Maltose into 2 Glucose molecules.

enzyme

Glucose can enter the Glycolysis Pathway via addition of a Phosphate group (Phosphorylation) with the help of the enzyme Hexokinase, which converts it into Glucose-6-Phosphate. This molecule will then undergo various other reactions with the help of different enzymes until the end product of pyruvate.

NswlCT1_L-bh_PexMwVnhg_m

3. Enzymes have the ability to take part in the reaction but remain unchanged in the end!

Joke via Facebook

If I were an enzyme I would be DNA helicase so I could unzip your genes.

Science Forever,

Latisha.