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STEM Students answer Children’s Questions #2

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When visiting schools and museums our Street Scientists often get asked a variety of questions from curious children. Here are the answers to some of our favourite questions!

This week, we’re focusing on Biology questions around DNA and genetics.

First of all we should really explain what DNA is. It stands for Deoxyribose Nucleic Acid. It is essentially the building blocks of life. All living things, plants, animals and you are made of DNA. It is a big, long code that tells your body how to make you. You inherit your DNA partly from your mother and partly from your father – that’s why we often look similar to our families.

Do twins have the same DNA?

-asked by Lucy, 11, from Burnside Primary School

Well it really depends on what kind of twins you have. Monozygotic twins (the scientific name for identical twins) do have the exact same DNA as each other because both individuals developed from the same fertilized egg. Dizygotic twins, (non-identical twins), don’t have the same DNA since the individuals are formed from two different eggs that are fertilised at the same time, this is also how twins can be born one boy and one girl.
– JC, Medical Student

How is DNA created?

-asked by Nicole, 11, from Burnside Primary School

DNA is created as a double helix (imagine a twisted ladder shape) of two complementary strands, which mean the strands are matched up to each other. These DNA strands are made of chemical building blocks called nucleotides. We can think of this building blocks as ladders. Each building blocks are made of three parts: a phosphate group, a sugar group and one of four types of nitrogen bases. To form a strand of DNA, nucleotides are linked into chains (one side of the ladder formed), with the phosphate and sugar groups alternating. They are formed like a spiral ladder, where the phosphate and the sugar molecules are the sides and the nitrogen bases act as the rungs. The base from one strand is then connected to complementary base of another DNA strand. So, even though the molecules are very long, a DNA is compact and coiled, which enables it to fit inside packaging we call chromosomes. In humans, we have 23 pairs of chromosomes inside the nucleus of our cells. These contains information and instructions needed for us to develop, grow and reproduce.
– Aurelia, Dental student

How many genes are in a body?

-asked by Kian, 9, from Hylton Castle Primary School

Every cell in your body has a nucleus with the DNA containing all of your genes. Each gene has the special code to make one of the proteins used to build the body. If you stretched out all the genes in the DNA of one cell it would be 2 metres long, and each person has 37 trillion cells! The DNA is very tightly coiled into 23 pairs of chromosomes, one of each pair comes from your mum and the other from your dad. This is why you and your siblings have some features from each of your parents. Scientists say we all have 25,000 genes that decide everything from your skin colour to your height. Everyone has different genes, apart from identical twins, meaning we are all unique and there is no one exactly like you in the entire world!
– Ailie, Evolution and Human Behaviour Masters Student

Is it possible to make a dinosaur come back to life using similar DNA?

-asked by Noah, 11, from Burnside Primary School

A great question, I definitely hope so, but we would have to be careful we don’t want a Jurassic park situation! Some people might say the most similar thing to a dinosaur nowadays would be a reptile, but dinosaurs were more likely warm blooded, unlike reptiles. The most related live group of animals to dinosaurs are birds, did you know chickens are thought to be distantly descended from a T-rex? However, birds aren’t very dinosaur like. Say we wanted to bring a diplodocus back to life, our best bet would be to try and find some source of DNA for example blood in the body of mosquito trapped in amber (like in jurassic park!) and splice (which is like fusing or attaching) it to a similar animal’s DNA.

Scientists have been working on a way to bring Mammoths back, using DNA from dead mammoths which were frozen in ice! They are splicing this DNA to elephant DNA to try and create a hybrid mammoth/elephant hybrid. It might be easier to bring a smaller dinosaur back, like a Compsognathus (a turkey sized dinosaur which was thought to eat small lizards and insects) by forming a hybrid with the most closely related animal today. Whilst scientist haven’t made mammoths de-extinct yet, they have managed to do it briefly with Pyrenean Ibex (a sort of mountain goat with big horns although sadly this didn’t live very long) so perhaps in the future there is hope yet for dinosaurs and mammoths to return, I certainly hope so!
– James, Biology and Psychology Student

Jurassic Park via Giphy.com

STEM Students Answer Children’s Questions #1

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When visiting schools and museums our Street Scientists often get asked a variety of questions from curious children. Here are the answers to some of our favourite questions!

This week, we’re focusing on questions around Earth Science and other planets.

If the Earth is the right distance away for it to be not too hot, not too cold, how come the north and south pole are cold?

– asked by a student from Blaydon West Primary School

As the Earth goes around the Sun it spins on its own axis. The equator is the closest bit to the sun during the day so it heats up, and stays relatively warm during the night as the atmosphere is good at retaining heat. The poles however are always the furthest part away from the Sun hence never warm up and are thus are the coldest parts of the Earth.
– Leo, Mechanical Engineering Student

How do we get seasons?

– asked by a student from Blaydon West Primary School

The Earth’s axis of rotation is tilted by 23.5 degrees and so some bits of the Earth’s surface are slightly closer to the Sun than the other bits. So in the Summer, the Northern Hemisphere is angled towards the Sun; in the Winter it is angled away from the Sun.
– Leo, Mechanical Engineering Student

What are the rings of a planet made of?

– asked by a student from Mortimer Primary School

There are rings around all of the planets known as gas giants; Saturn, Jupiter, Uranus and Neptune. These rings are made up of asteroid and ice particles. Only the rings around Saturn can be seen from Earth as they contain more ice which reflects the sunlight more. The rings around most of the gas giants (Jupiter, Uranus and Neptune) were formed from the impact of asteroids and meteorites which threw dust out into orbit. Whereas Saturn’s rings were formed by the impact of an icy moon causing a lot of bigger chunks of debris to be thrown into orbit. Although the debris is pushing away from the planet the gravity pulls this debris towards the planet enough to keep it in orbit.
– Jade, Earth Science student

How do you make a planet?

– asked by a student from Bede Burn Primary School

All matter was formed in a huge explosion called the Big Bang over 13 billion years ago. There are two main theories about the formation of planets, but they are both driven by a force called gravity which is the force that keeps us on the ground and causes objects to fall when dropped. Gravity causes the material formed in the big bang to come together forming asteroids and eventually planets. As these asteroids crash into each other they release a lot of heat that causes them to melt. This melting allows the heavier, denser elements to sink to the centre of the planet and the lighter elements rise further up. This separation forms the layers within the planets.
– Jade, Earth Science student

Have any more questions you’d like to ask our experts? Write them in the comments below!