What are we made of? The unit of life

Last week I was chatting about the basic constituents of the body – quite literally what we’re made of, the elements and the working up of all the systems that join together. This week is a look at the controller of all that stuff – the thing that makes it all happen from our single fused-cell origins to the fully-formed trillions of cells we are today. Our deoxyribonucleic acid (DNA) sits protected in the nucleus of our cells and controls everything we are and everything the cell is and does. I’m sure describing DNA has been done a million times over, so I just want to make it a bit more understandable and tell you how amazing it actually is!

Below you’ll see what DNA actually looks like. It’s only when cells are ready to divide that it’s all coiled up tight into the chromosomes we’re used to seeing – it’s been twisted so much it’s called supercoiled.

dna structure 1

It’s made of things called nucleic acids, attached to a backbone of sugars and phosphates. The nucleic acids are the letters of the genetic code, called Adenine, Thymine, Cytosine and Guanine. In one strand of DNA, there are all these letters and they match the other strand since A only binds with T and C only binds to G, the bits just chemically match up and they seem to like each other!  See the image below, it shows you the chemistry of it all.

Chemical-structure-of-DNA

So great, there’s a big coiled bunch of chemicals held together in strands by this backbone. Crick and Watson theorized this shape it forms – the double helix. Now the fun comes with what all these letters do. When a bunch of letters together do something specific it’s called a gene; it “codes” for proteins. Basically, every three letters correspond to a specific building block – an amino acid. This means joining amino acids together in this specific order makes unique proteins. These fold up in unique ways too to eventually form proteins. It’s proteins that carry messages, give structure, virtually everything that makes cells and the body functional. Humans have about 20,000 genes that all encode proteins, which is a lot, but not really considering how many different functions cells have with all their unique components.

Cells can’t function properly if they don’t have DNA to make and control all the bits to keep it going. This is why there’s a security system in place to make sure that when it comes to making copies of itself, it’s only done if DNA is intact, without any changes being made to any of the letters – these are called mutations. So when the cycle comes round and it’s cell multiplying time, the DNA all condenses into the chromosomes we’re used to seeing. If there are any mutations it stops and will try repair it; if it can’t, it goes through a programmed cell death (apoptosis). If maverick cells ignore this, cells keep dividing until masses form – known as tumors, then certain criteria define it as cancerous.

So it’s pretty amazing stuff this DNA. It’s also true that we share most of it with our friends the chimpanzee. But there are a lot of “conserved sequences” which is why animal models are so useful in experimentation – if they make the same proteins as us, we can see the effects of its mutation or absence by following it around and seeing where it works and what it does. By tagging the proteins the sequence makes with something radioactive or fluorescent it can be tracked to see what’s going on. It’s been revolutionary in understanding countless mutations that can cause diseases and disorders.

Have a look below for the background of genetics and a summary of what DNA is and does. Meanwhile, since it’s summertime, go get some strawberries… and keep a few to extract some DNA for yourself! All you need is some salt, washing up liquid and ice cold rubbing alcohol/vodka. Look here for the instructions!

https://visual.ly/track.php?q=https://visual.ly/community/infographic/science/history-genetics&slug=communityinfographicsciencehistory-genetics From Visually.

What are we made of? The Basics

I’m not very philosophical, so strictly scientifically – what are we?  It’s a complex thing the body, tiny but important parts all together making a pretty robust organism. There are a few different ways to look at this, it depends on how microscopic you want to go: systems, organs, tissues, cells, molecules, atoms.  You could go smaller but it’s too small for me – quantum mechanics governs that stuff.

You could get roughly 160 billion helium atoms side-by-side in a centimeter but there’s a relatively huge gap between the middle (nucleus) and the electrons whizzing round the outside of the atom.   If the Earth was an atom, the nucleus would be a football stadium. All the space adds up, so we are mostly empty space, but so is everything else!  The atoms that make us are a little bigger than helium, but not hugely…

periodic table

Oxygen ~65%     Part of water (H2O) that’s in every cell in the main fluid of the body.

Carbon ~18.5%     It’s in every carbohydrate, protein, fat, all the organic chemicals in the body.

Hydrogen ~9.5%     The other part of water, and in your organic chemicals too, not very big or heavy, but very important.

Nitrogen ~3.3%     It’s in all your proteins, the amino acids that make them have it and the nucleic acids your DNA is made of.

Calcium ~1.5%     Bones and teeth: we all know how important they are! Also used in signaling to make muscles contract.

Phosphorous ~1%     The major player in energy is something called ATP, the P being phosphorus, so very important! It’s in bones too.

There’s a lot more, like sodium, potassium, and magnesium that help electrical signals in the body, that’s those “electrolytes” you may have seen in sports drinks. There’s probably hundreds of elements inside you, including arsenic and uranium! But the top four make up over 95% of your body weight, so there aren’t much of the others but we need them!

Thinking bigger, we get cells. Cells are amazing: they’re the functional units that make us, the building blocks. We have trillions of them and they’re all specialized.

Cells of the same type grouping together give us tissues; like muscle, nerve and connective tissue.  For example, muscle cells are built to contract, nerve cells are built to pass along electrical charges.  A big tissue is epithelial, made from tightly packed cells forming sheets – barriers to separate bits.

Organs are when you’ve got tissues working together for something specific. The biggest is the skin. Skin is pretty amazing, it has plenty of functions with all the kind of sensors it has.  The liver is the biggest internal organ and it too is amazingly complex with hundreds of vital functions.

Systems of the body are made of a group of organs like the digestive system from mouth, stomach, with a lot of intestines. There’s the respiratory system, cardiovascular, endocrine, immune, skeletal, muscular, lymphatic, reproductive, urinary, nervous… it’s a complex thing the body. This is a good site to learn more about all the different systems and their bits!

The Human Body

There we have the basics of the body, taken down to the littlest bits. Not that you’d put a price on a life, and the body is hugely complex, but if you could sell all the elements – I thought it’d be maybe £100, but a few years ago, the Royal Society of Chemistry ran a competition to guess the value of Benedict Cumberbatch and he went for around £96,500. So who knows your value, you could be worth millions! But let’s just not sell our elements, I mean I’m quite happy with mine?

Sun’s out!

Get outside! It’s here! Quick before you miss it! There’s not been a huge number of warm sunny days but hopefully plenty to come. If you’re stuck at home this summer, you need to make sure you get outside as much as you can to get some warmth, a golden tan and some vitamin D. “Tan” is one of those words now used secondary to its original meaning as the verb, with the tanning of animal skins et cetera; so after the era when being pale and staying inside was popular, from the 1930s getting a tan was cool. Thenceforth the sun was our friend. Until a few years later when official advice was given about the damage the sun can do, increasing the likelihood of skin cancer. But let’s not get ahead of ourselves, we’ll start simple…

What is tanning?

Tanning is the process of darkening the skin colour by exposure to UV light. It involves a wee group of molecules called melanins. There are different kinds of melanins responsible for your skin colour and other coloured bits of you, like your eyes, hair, and lips. The lack of one kind of melanin with age results in those grey hairs and albinism is a condition where there’s no melanin present. Melanin is made by cells called melanocytes and then cells in the skin grab it and it sits around the nucleus to protect the DNA within from damage by radiation like UV from the sun. This explains why people living closer to the equator have darker skin as they are exposed to more UV than me, in Edinburgh, looking like a ghost! (And no, that’s not me confirming my belief in the supernatural – ghosts aren’t real…)

I won’t get too genetics involving melanin, mostly because I don’t like genetics; but a mutation has caused my eyes to be blue – lots of melanin = brown, less = green, little = blue. It’s more complicated than that but I don’t really know much more – like I say, I don’t like genetics.

504_Melanocytes
The epidermis – the top, outermost section of the skin.  Melanin is released from melanocytes at the bottom in little pods (vesicles) moving up the keratinocyte cells.  There’s far more melanin in darker-skinned people.

So tanning is all about melanin which is there to protect you; it’s a fine balance as I’ve experienced, you don’t want to be scarlet, accelerate aging or worse, be exposed to too much and maybe get cancer. For those not up on what cancer is: normal cells have a process of dying when they can’t function properly, like if DNA gets mutated (changed), and it’s stopped from making copies of itself by checkpoints. Cancer cells ignore this and keep going and dividing: they are your own cells but the code of the DNA has been changed – it won’t do its job! That’s why melanin surrounds the nucleus of the cell, stopping it being attacked. It sort of makes sense that if you’re pale and expose yourself to more UV light, you won’t have enough melanin to protect you properly.

Protecting yourself by covering up with your classy hat and sunnies works, then you’ll probably be slathering on that white coloured sun lotion. Sunscreens scatter and absorb UV light to different degrees, measured by how much longer than usual it’ll stop you being burnt. This is what that SPF (sun protection factor) indicates, so 15 SPF would protect you 15 times longer that without it. It won’t block 100% of UV light and with you moving about, sweating and diluting it, that’s why you’ll have that weird patch of burnt skin! So keep your lotion topped up, and look here for all the best advice on how to protect yourself in the sun.

The infographic below explains how sunscreens work, with the chemicals involved; also it defines the differences between specific forms of UV radiation.

Chemistry-of-Sunscreen.png

If you’re a bit pale and are tempted to get some fake tan.  This stuff wasn’t really a thing until the 1960s.  The effects of the chemical in it called DHA (dihydroxyacetone) have been known since the 1920s.  Its discovery for tanning was completely accidental in the 1950s when Eva Wittgenstein was trying to treat children with a glycogen storage disease when it spilled and stained the skin.  After research on this, the first tanning lotion was sold in the 1960s.  It works the same as the Maillard reaction which happens when meat browns when it’s baked/roasted. That doesn’t mean your arm will be nice and tender after, it only the top layers that naturally fall off that are affected, meaning you’ll have to top it up when the cells go and the tan fades. Have a look below to see the process involved.

Chemistry-of-Fake-Tan-2015-1

The ultimate consequence of being unprotected in the sun for too long is skin cancer. Cancer is a scary word, but the most common type of skin cancer is the most easily treated because it doesn’t like to spread. Melanoma is far less common but is harder to treat, it loves to spread (metastasise) and ignores a lot of treatments.  But even when I was writing this post, a new breakthrough was made by researchers in finding a way to make melanoma respond to treatments better.  So although there are aggressive cancers, there is research giving results every year that provides new targets for drug treatment that is taken advantage of; unfortunately, to ensure efficacy and safety it’s usually years before something is available for treatment.  There are some cases though, where there’s a similar drug that can help which does save lives.  You can find information about skin cancers more here and see the lovely image below which gives a nice summary of everything you need to know! Enjoy the sun but be careful – don’t look like a lobster!

Skin Cancer: UV Rays on the Rise

The science of gin

Time for a drink? Maybe today’s one of those rare occasions where it’s not raining, perhaps it’s actually warm and the yellow thing in the sky makes an appearance. If it’s a pleasant evening then gin is what you need to match it. Gin and tonic maybe? Gin has had a huge renaissance just in the past five years; in Scotland alone there’s been a few brands gaining huge support and many more being set up. One of the main reasons for its popularity for producers is its relative simplicity and speed in making; many whisky distillers have chosen to make gin whilst they’re waiting at least three years for their batch to be ready. If you’ve ever been to a gin distillery you’ll have heard the history of gin, and it is quite interesting; the word itself coming from the dutch “geniver”. Living in Edinburgh it has also been interesting to learn about the local history of gin.

 

5pm-gin-guide-map-scotland.png
All the different gins across Scotland – there’s quite a few!

To start making your gin, you need some neutral grain spirit. It’s the basic, tasteless, odourless highly pure alcohol used for making spirits like vodka and gin. They come from grain crops that are fermented. Next, you’ll need some botanicals: legally you’ll need juniper berries. It’s the most important and defining ingredient. They grow wild in Scotland but are protected; they’re often imported from other countries like Greece and various places in Europe, southwest Asia, and North America. Juniper is part of the pine family and that’s what it tastes like. It’s been used for hundreds of years for medicinal properties: diuretic, antiseptic, stomachic, antimicrobial, anti-inflammatory, and antirheumatic. They all come from an oil inside; specifically there’s terpinen-4-ol that makes your kidneys filter more, which will make you need the toilet more often (diuretic); there’s amentoflavone that’s found in a few other plants and has a number of properties like antimalarial and anticancer, as well as inhibiting enzymes that metabolise some drugs (in the liver). If you get cold sores a lot, chemicals called desoxypodophyllotoxins might inhibit the virus that causes them (herpes simplex virus) – so drink up! Or just use a normal cream that definitely works… Other parts of the berry – the resins are tars – can be used for topical treatments for things like psoriasis. A really useful little berry then. Find out more about Juniper

Other botanicals add depth of flavour, bind flavours together and add special characteristics. Coriander, angelica, citrus peel and orris root are common ones used. There are a few different ways to infuse the botanical flavours into the gin, the infographic below describes them. You’ll probably add a bit water at some point soon to help everything mix properly. It’s heated and the first to be cooled, the “heads”, aren’t pure and aren’t collected. The product will be about 80% pure, once the product falls under about 60% again it’s not collected. After it all, there will just be the water and what’s left of your botanicals. The stuff that’s not collected for the final product can be scrubbed and the pure alcohol recovered to use again. Your final gin will be roughly 40% ABV (alcohol by volume) if you’re going for Navy Strength, closer to 60% ABV. There’s a bit more to it than that but that’s basically it.

 

The-Chemistry-of-Gin.png
The molecules important in all gins

A good tonic water will complement your gin nicely; the quinine gives a bitter taste and balances it all nicely. Then once you’ve got your bottling and PR sorted, you can go ahead and sell your gin! To get your “perfect serve” you’ll need to match whatever botanicals you have with the contents of good quality tonic, then a garnish of fruit or herb that will complement it too. It really makes all the difference. So you can say it’s for medical reasons, or just because it’s just really refreshing, either way, have a gin. If you want a proper review of any gins, head over to Juniper Daze – Steph’s even got a gin of the month going on!

Ginfographic-2016