Advertisements

Category Archives: 2.2 Food and Digestion

New TEDEd Lesson

I have just uploaded a new video and TEDEd lesson on the digestive system which I have been putting together for a while. I am also planning on updating my older video resources to bring them more up to date.

Screen Shot 2014-12-18 at 11.17.47

 

I will be posting a Christmas Special video in the next few days so subscribe on YouTube to see it first.

Advertisements

Would you eat this burger?

Today in London the first ever lab-grown hamburger was cooked and eaten. Would you eat meat grown in a lab? Before you answer the question you should know more about how the burger was made and more importantly, why?

How the burger was made?
It was made by Professor Mark Post from Maastricht University in Holland using using stem cells taken from a dead cow. These are muscle specific stem cells that are then provided with nutrients so that they can divide over and over again by mitosis. The cells naturally come together to form small fibres called myotubes. These are electrically stimulated to make them contract and relax, this builds the muscle fibres just like going to the gym. They are then combined with fat grown in a lab and a few other additives such as beetroot for colour and then pressed into a burger. Therefore only a few cells are needed to make a whole burger, and potentially tons of meat.

Watch the video below to learn more about stem cells.

Why was the burger made?

  • We currently have a huge demand for meat in the world. The increase of the middle classes in countries such as India and China has further increased demand for meat and also the cost. Artificial meat could therefore provide a cheaper alternative to real meat.
  • The population is increasing at an exponential rate. Current methods of producing meat will not be sustainable in the future and so artificial meat may be a good solution as it can be grown using 99% less land. Using less land for animals means more can be used to grow crops such as fruit and vegetables which are healthy and much needed as the population continues to grow.
  • Current methods of meat production are very bad for the environment. A lot of energy is used to farm meat, from producing the feed to housing and slaughtering the livestock. However the major issue is methane. Ruminants such as sheep and cattle release a lot of methane due to their digestive system. Methane is a greenhouse gas which is 25 times more powerful than carbon dioxide. This is contributing hugely to global warming and consequently climate change. In contrast, lab-grown beef uses 45% less less energy and produces 96% less greenhouse gases (Source: Environmental Science and Technology Journal).
  • Another issue is animal welfare. Many vegetarians and vegans have taken the life choice not to eat meat because they disagree with how animals are treated in the production of meat. Meat grown in the lab avoids the need to grow animals and slaughter them in the way we do now. Only one cow would be needed to make thousands and thousands of burgers.

Watch this video to see a nice summary of these issues.

What are the problems with lab-grown meat?

  • It costs about £250,000 to make lab-grown beef. However in the future when the cost of the technology involved becomes cheaper it could be economically viable to make meat on a mass scale. The question is will it ever be cheap enough to actually be used by the countries where it may be needed the most?
  • The taste of the meat may not be as good. At this afternoon’s tasting Austrian food researcher Ms Ruetzler said: “It’s close to meat, it’s not that juicy, the consistency is perfect”. It’s therefore expected that other additives will need to be used to make the meat taste better and also make it more healthy then regular meat.
  • Perhaps we should be focussing on managing our current issues with food such as food wastage – at the moment we throw away a 6th of all food!
  • The thought of growing food in a lab this way can be off-putting to people.

So now you know the details, have you made up your mind? If you’re still not sure watch this TED talk by Prof Mark Post and see if he can convince you.

Please comment below with your opinions on this amazing scientific development.

Photo credit: David Parry/PA

New IGCSE Quizlets available

I know a lot of recent visitors to the website have enjoyed using Quizlet to help with their revision. For anyone who hasn’t used Quizlet before you can learn what it is, and how to use it, by clicking here. There are now two new quizes available to help you revise Food and Digestion, just click on the links below to access them:

IGCSE Biology – Nutrition and Biochemistry

IGCSE Biology – Digestion and Enzymes

For anyone studying this topic I’d recommend watching Hank Green’s YouTube video below. He will take you on a crash course through the bowels of the human digestive system and explain why it’s all about surface area!

Hank’s YouTube channel is a great resource for anyone studying Biology, it has 40 different videos covering topics such as photosynthesis, meiosis, natural selection and ecology. Why don’t you check it out!

Need help with revision?

Over the next month I will be posting various resources to help you revise for your exams. This will include hints, tips, videos, summaries, tests and planners. Once they have been posted you will also be able to find them on the relevant pages.

IGCSE Biology Revision

OCR AS Biology Revision

OCR A2 Biology Revision

The first resource, available to download now, is a revision tracker. It can be used for any subject but is particularly useful when revising for a factual subject such as Biology. Every time you complete a test or a past paper question, you should write down anything you get wrong on the tracker. This will allow you to keep a note of your weakest topics and help you to focus your revision in the weeks leading up to your exam or test.

I have also posted an IGCSE revision quiz for the whole of Section B: Human Physiology. The quiz takes about 30 minutes to complete and I’d recommend doing it several times as it’s a really effective way to improve your factual recall. I wrote the the quiz using the Edexcel textbook so all the answers can be found there.

Please write in the comments below if you’ve found these helpful, or if there are any other revision resources that you’d like me to create.

%d bloggers like this: