Monthly Archives: February 2013

Ninhydrin Starring in CSI!



Every family has their own special traditions. For my mummy and I, we enjoy curling up on the couch on a Friday evening to watch marathons of our favourite TV-shows. One such show is CSI, specifically CSI Miami. I love Horatio’s character the most! He’s just so badass.


If you’re an avid CSI fan such as me, you may have noticed that in the field of forensics, fingerprint work makes an appearance in every episode. Have you ever wondered what they use in forensics to develop fingerprints?






Ninhydrin has become the most common method used to reveal prints on porous surfaces. Nearly all forensics labs use ninhydrin for this purpose, and some seldom use anything other than ninhydrin. Ninhydrin is cheap, sensitive, and commercially available in disposable spray cans. The developed prints are a high-contrast purple that’s readily visible on most paper backgrounds.



Ok, so how does the ninhydrin work exactly?

Dusting the crime scene is the commonest, simplest and oldest latent print developing technique. A white powder composed of the chemical ninhydrin is used to develop latent prints (prints invisible to the eye). Latent prints are formed by sweat, either from the hands themselves or by unconscious contact between the fingers and the face or other parts of the body. Even the swiftest of criminals find it difficult to escape without leaving behind the trace of a single fingerprint. The traces of amino acids present in perspiration bind with the ninhydrin and the prints begin to appear in about an hour. In the pH range of 4-8, all α- amino acids react with ninhydrin; a powerful oxidizing agent to give a purple colored product (diketohydrin) termed Rhuemann’s purple.




Ninhydrin degrades amino acids into aldehydes, ammonia, and CO2 through a series of reactions; the net result is ninhydrin in a partially reduced form hydrindantin. Ninhydrin then condenses with ammonia and hydrindantin to produce an intensely blue or purple pigment, sometimes called Ruhemann’s purple.

ninhydrin reaction

In our last lecture, we made a clear distinction between the two tests : Biuret test and Ninhydrin test. Mr. Matthew (my lecturer) made a video that clearly differentiates between the two tests in a clear understandable manner so if you are having trouble understanding their differences, I urge you to watch the vid! It’s really helpful and not too long.

Apparently students mix up their uses all the time, and if my lecturer didn’t stress on this I’m 99.9% sure I would’ve been one of those careless students as well.The Biuret test is used to test for proteins while the Ninhydrin test is used to test for amino acids.  Don’t forget!!!!

Mr. Matthew also posed a question to us. Do all amino acids give that lovely purple colour when the ninhydrin test is performed? From his tone I knew there had to be some exception.

Here’s what I found:

The color produced when the ninhydrin test is performed varies slightly from amino acid to amino acid, probably because the unreacted acids complex with the pigment.

Proline and hydroxyproline give a yellow color.  Proline has aliphatic side chains with a distinctive cyclic sturcture. The secondary amino (imino) group of proline  residues is held in a rigid conformation that reduces the structural flexibility of polypeptide regions containing proline. Proline does not give the ninhydrin reaction as this reagent requires free alpha amino group (-NH2) but proline has an imino group (-NH).  For the amino acids which have a free -NH2 (amino) group, ninnydrin test is positive but is negative for proline because it only has -NH (imino) group.

I hope this post was helpful! Can you find any more amino acids that don’t give the purple colour when the ninhydrin test is performed?







Did You Know…?



Now that we are onto the topic of amino acids and proteins in my biochemistry course, I found it only appropriate to share some interesting facts about protein that I discovered . I’m sure at least one will interest you!

  • Proteins can have really weird names. For example, the protein Pikachurin is a retinal protein that was named after a Pokémon character Pikachu and the protein Sonic Hedgehog was named after Sonic the Hedgehog. There is also a blue protein that is named Ranasmurfin, after the Smurfs.

pikachu2 images images (1)

  • Protein is found in each of the trillions of cells in the human body. Life would not be possible without proteins. Water is the only other substance which is as abundant in the body. Approximately 18-20% of the body is protein by weight.

Inside Outside Puzzle Human Body inside

  • In 2010, 20-year-old athlete Ben Pearson tried to increase his protein intake to boost muscle development. However, no one knew he had a rare genetic disorder that prevented his body from breaking down protein.

AthlteThe increased protein intake increased ammonia levels in his blood that caused brain swelling and death. (Read more of his story here:

  • Hair is made up of a protein called keratin, which forms a helical shape. This protein has sulfur bonds, and the more sulfur links it has, the curlier a person’s hair will be. I guess my hair has A LOT of sulfur links!curly_by_jessicaxyl-d4q8gau
  • One of the smallest countries in the world, Luxembourg, is per capita the biggest meat eater. Luxembourgers eat on average about 300 pounds of meat annually per person. The U.S. comes in second with about 276 pounds of meat—mostly beef—per year. Austria is third with about 267 pounds of animal protein per person.


  • Cow used to be the global leader in meat eaten. The pig is now the most popular.


  • Without a protein called Albumin, the entire human body would swell.


  • Cataracts are caused by the denaturation of proteins in the lenses of the eyes.


  • Insects are more nutritious than many other common forms of protein. For example, 100 grams of top sirloin beef contain 29 grams of protein and 21 grams of fat. However, 100 grams of grasshopper contain 20 grams of protein and just 6 grams of fat.


  • A protein in semen acts on the female brain to prompt ovulation.


  • The human body has about 100,000 different types of protein. The body needs protein to grow, heal, and carry about nearly every chemical reaction in the body.


  • Protein deficiency can cause serious health problems. For example, children with a protein deficiency could develop a condition known as Kwashiorkor. The symptoms include a protruding belly, thin hair, overall weight loss, and discolored skin and hair. Left untreated, it can lead to stunted growth, mental impairments, and death


  • Middle- aged and elderly people have more extensive body breakdown than a younger person, which means they need more protein. However, as people enter middle age, hydrochloric acid, which helps digest protein in the stomach, drops to half its regular level. Because protein is crucial in cell regeneration, some researchers suggest that most of aging is due to this drop alone.


  • Eating too much protein can be dangerous for the body. For example, high levels of protein can stress the livers and kidneys because they have to work extra hard to dismantle and dispose of the extra protein. Excess protein can result in weight gain.


  • Proteins in the human body have many jobs. For example, a protein called rhodopsin in our eyes helps us see light. Hemoglobin in red cells carries oxygen from the lungs to the body’s cells and takes away their harmful waste product, carbon dioxide. A series of chemical reactions involving proteins makes the blood clot. Additionally, proteins give the body structure, help regulate body processes, defend against disease, maintain the body’s internal environment, and give us energy


  • While human meat is a good source of high-quality protein, cannibalism was not historically motivated by diet or starvation. Rather it was a symbolic gesture, usually as a way to commune with the gods.


Well, if you didn’t know any of these things..





Bombshell… “Bumshell”?



For many years I have been the unfortunate witness to the passing of pungent gas from a person whose name I shall not call, for they might slap me silly for posting this on the World Wide Web. These occurrences usually present themselves at birthday parties, Christmas limes or just our monthly trip to an ice-cream parlour.


When I was younger, I used to accuse this anonymous person of being lactose intolerant. I was young, I didn’t really know what this meant, I had only heard of the term occasionally in primary school when teachers would huddle around the teacher’s desk discussing their “old people” problems, you know, high blood pressure, menopause, the usual. Yes, I was a maco :D.

At the time I didn’t know all the science behind the term, only that the wind that would be passed would be quite unpleasant and accompanied by complaints about bloating and tummy aches from the anonymous. When I would make the accusations, that certain person would strongly agree with my diagnosis yet still the spoon of ice-cream and the slice of cheesecake would make no attempt to detour from her mouth. It was honestly like waiting for a volcano to erupt. Oh the joy.



This never fails to be my reaction:


In the last lecture, we discussed carbohydrates more in detail and along the way we talked about the science behind being lactose intolerant. I learnt a lot of new information and I plan to use it in a letter to convince the anonymous that maybe its about time that she switch to soya.

Here is how my letter will begin.

blog letter

Wish me luck!

Just had to include this, LOL!


Don’t forget to check out my lecturer’s vid below! Super informative 🙂




Stitches Made of Chitin…What?!!



Have you ever had stitches? I’ve never had them (thank God) which is really surprising considering how clumsy I am. Someone out there might relate:

When you trip down stairs in public


And you try to act like nothing happened


But then you realize someone saw it all



But I can imagine what it would feel like having needles sewn through my flesh, not a pretty thought.

I was watching one of my lecturer’s vids on Carbohydrates (check out his vid below), and he was talking about how one of the functions of carbohydrates is for structure. Now you may only have heard of cellulose since it’s probably the most popular, but chitin is a structural polysaccharide found in the exoskeletons of insects and crustaceans.

This sugar has various uses but the one that stuck out to me the most was when my lecturer said they were used for sutures.  I don’t know about you, but I had no idea what that meant. So I googled it.

Surgical suture is a medical device used to hold body tissues together after an injury or surgery Application generally involves the use of a needle with an attached length of thread. Basically surgical sutures are stitches.


You read the title right. Some dissolvable stitches are made of chitin. Do you know why? I’ll tell you. Not only is chitin strong and flexible but it also dissolves over time, thus allowing patients to avoid the painful removal of stitches. They dissolve? Is that safe for your body to absorb you might wonder.



The purpose of chitin is to provide support for organisms. The material allows the stability and rigidity, but it also allows flexibility. The body considers chitin a foreign substance so it reacts against it to remove it. An enzyme called chitanase is produced in our body to help breakdown chitin. Hydrolysis separates the individual chitin molecules from each other. One of the more important things that chitin, and its products, could be used for is in treating burn patients. Chitin has a remarkable compatibility with living tissue, and has been looked at for its ability to increase the healing of wounds. Chitin is also the subject of exciting medical experiments. It has been discovered that when applied to human wounds and surgical cloths, it accelerates the skin healing process. An acidic mixture of chitin, when applied to burns, also accelerates the healing process. Left on for a few days, it can heal a third-degree bun completely. It has been shown to support the immune system during certain kinds of illness-blocking procedures.

Wow. Just think about it. The same compound found in insects and crabs can be used to heal wounds, and it’s a carbohydrate!

Blows My Mind.


Check out the vid below if you would like to know more about carbohydrates, I promise you will learn a lot!






Endosymbiosis Theory: Fact or Fiction?


 endosymbiosis (1)

To be honest, this theory of endosymbiosis is not a new term I’ve come across. I’ve actually heard about this for a long time, especially in my first semester of UWI studying Biology. But I never really got it, it never clicked in my head, I was a lot like this actually


And now this semester it has come back to haunt me *insert horror music here*


So I decided it was time for me to get this concept fully understood in my head. Now, I’m a very simple person, I like to learn in simple ways. No complicated terms to mess me up, just saying things in layman’s terms. Thank God for this video I found that does just that! Take a look if you like cute, funny drawings and want to grasp the concept of the endosymbiotic theory in no time.


Cute vid right?

What does endosymbiosis mean? If you watched the vid I couldn’t explain it any better than he did. But who was little Jon and little Jim? Well, little Jon was a primitive aerobic bacteria that became engulfed by the host cell (big fat tony) and since their relationship proved to be beneficial to both of them, little Jon became mitochondria. Can you guess what little Jim, the photosynthetic bacteria, became? Chloroplast! That’s right.


Now, am I just supposed to accept this theory as fact? Where’s the evidence? How can I be sure this is true?

Let’s look at three main factors:

  1. DNA

bacteria (1)

Mitochondria and chloroplasts have striking similarities to the primitive bacteria cells. They have their own DNA, which is separate from the DNA found in the nucleus of the cell. And both organelles use their DNA to produce many proteins and enzymes required for their function. Also, the DNA in mitochondria and chloroplasts are circular, not linear as in eukaryotic cells.

       2. Membranes


A double membrane surrounds both mitochondria and chloroplasts, further evidence that each was ingested or engulfed by a primitive host.

3. Reproduction


The two organelles also reproduce like bacteria, replicating their own DNA and directing their own division. Scientists found that the asexual reproduction that occurs in our cells is pretty much similar to the binary fission that happens in the bacteria.

So after all of this, do I understand this theory? Yes, FINALLY!


The evidence is all there and cannot be denied.  I hope my post helps you understand this theory a little bit better!

What about you? Do you think the endosymbiotic theory is fact or fiction?




Photo Credit: