Sam (13) asked “What are the building blocks of cells? And does it vary for each cell?”

Up-dated  24/10/2019

Thank you for your question Sam. As usual I put it to a member of my team. Lets see what they say and then, maybe, I can add to it.

Thank you for that team. Cells are obviously very, very important. We, and all, living things are all made up of them. But what about the cells themselves …what are they made of ? A little research shows that all cells contain  proteins, lipids, carbohydrates and nucleic acids. Let’s look at the role of each of these groups of compounds.

Proteins are all important (they are made of things called amino acids BUT enough of that). Proteins have important roles in cells. They provide the cell with energy, they fight infections they help move other components  around the cell.

Lipids are basically fats and therefore are a source of energy. The proteins will access the lipids to help them in their tasks and the Carbohydrates are another source of energy

Nucleic acids are better known as amino acids that make up  RNA and DNA structures. These are probably the most important, ………no I am wrong, the nucleic acid component of the cell needs all the other components to survive. They will not last long if left alone. The nucleic acids are the messengers of the cells. In simple terms they have, in their structure , the message that enables the construction of a living thing (animal, plant) from the activity of the rest of the cell. You could say they are the managers.

A little addition ……. what is an amino acid? Firstly as an acid it contains the -COOH group of atoms. CH3COOH is a familiar acid

Shown here in its structural form

known as acetic acid (vinegar).

Amino acids basically contain NH2 groups instead of CH3 . One of the simplest is glycine.

Proteins also (in some cases) act as catalysts (something that enables a reaction to occur. In these situations they are called enzymes.

I really hope this is helpful. Thanks for the question.

Ella (10) asks “Was there ever any life form on Venus?”

Many thanks for the question Ella. At the present time there is no evidence that there has been any form of life on the planet Venus. Venus is quite close to the Sun, it is the second planet. Because of it’s closeness to the Sun it is a very hot planet.

It would be brilliant if we did find evidence of life on the other planets of our solar system. It would be evidence that at one time life on Earth was not alone in our Universe. If that was the case we could assume that life could exist on other planets in our Universe.

The planet that is closest to the Earth is Mars. At one stage during its existence Mars had a lot of water on its surface. As life on our Earth originated in it’s oceans any life on Mars might have started in its oceans.

I’ll let my friends continue the conversation.

There are plans to build a new Space Station that will allow humans to go to Mars. Meanwhile there are several mechanical ‘rover’ devices on the surface of Mars which at this very moment are looking for evidence wether life, did once, exist on Mars.

Luisa 9 asks “How did the first humans appear?”

Thank you Luisa for your second question.  Here are my friends thoughts about how humans appeared.

Thanks team, Luisa let me add some more details.

My friends are correct, it is thought that the first life appeared millions of years ago. The life that formed was not at all like the animals and plants that we see around today. It was very, very small. So small that we would have needed a microscope to see it.  Over the next thousands of years that life changed (we say it evolved) and it reproduced. Sometimes when it reproduced mistakes were made and bigger forms of life were formed. Eventually a mistake in the reproduction led to the first plant (a moss) being formed.

Over the next thousands of years further mistakes were made and  the first animal was born. From then onwards the evolution of animals and plants continued…….UNTIL …..again many thousands of years ago the first apes evolved. The apes continued to have babies and further mistakes were made …… the baby apes walked upright, their brains were bigger, they had less hair, all small changes but over thousands of years small changes can become big changes. The result was that humans were formed and you, me and everybody else are the result.

Things haven’t stopped ….changes (evolution) continues …..we might be very different in many thousands of years time.

Hope this helps. Not happy about something, then ask another question.

Hayley (11) asks “Were unicorns ever real????”

Thanks for the question Hayley. My friends are back from their holiday so I asked them ….this is their answer.

The fact that there are no fossils does not mean that unicorns never existed. If you look at how modern humans evolved (changed) from apes there are a lot of gaps in our understanding, which could be linked to fossils that have not yet been found.

Where fossils have been found we can get lots and lots of information from them especially from the age of the rock in which they are found. This is to do with something called radioactive decay. This allows the fossils to be placed fairly accurately on the ‘evolution table’.

Evolution is the change in the inherited characteristics of  populations of living things over successive generations. Evolutionary processes give rise to diversity at every level of the population. For example a pair of monkeys might give birth to an albino (white) baby. If that baby, when it is older, gives birth to an albino baby, we could call that an evolutionary change which might, in a few thousand years create a whole population of albino monkeys.

I have two immediate thoughts about unicorns. Firstly they are completely made up and secondly they are a brief part of an evolutionary  story that didn’t survive. For example an animal (horse, deer, goat or other animal) was born with one horn by some biological accident, it lived but it’s children were ‘normal’ so the trait ended.

I prefer the mythical, made up model. I would like your thoughts.

 

Destiny (10) asks “Did/are unicorns real?”

Destiny, thanks for this second question. Interestingly it has connections to your previous question about evolution.

I asked my friends about unicorns.

The fact that there are no fossils does not mean that unicorns never existed. If you look at how modern humans evolved from apes there are a lot of gaps in our understanding, which could be linked to fossils that have not yet been found.

Where fossils have been found we can get lots and lots of information from them especially from the age of the rock in which they are found. This is to do with something called radioactive decay. This allows the fossils to be placed fairly accurately on the ‘evolution table’.

I have two immediate thoughts about unicorns. Firstly they are completely made up and secondly they are a brief part of an evolutionary story that didn’t survive. For example an animal (horse, deer, goat or other animal) was born with one horn by some biological accident, it lived but it’s children were ‘normal’ so the trait ended.

I prefer the mythical, made up model. I would like your thoughts.

“Did humans evolve from monkeys?!?!” asks Destiny (10)

A great question Destiny and a difficult one to answer. You use the word ‘evolve’ in your question. I think we should spend the first part of a possible answer looking at that word – ‘evolve’. I thought I would ask my friends about this. Let’s see what they come up with ….

It was Darwin, a famous scientist, who proposed that all living things over time are slowly evolving. So another thing we have to think about is time. 

Life on our planet is thought to have been created four and a half billion years ago. That is 4,500,000,000 years ago. That give a lot of time for something to happen (evolve)  gradually.

Scientist think that ALL living things on our planet started 4.0 billion years ago with the formation of the first micro-organism that could reproduce itself. It was no bigger than a pinhead.

Below is a crude timeline which illustrates  how different life forms evolved (developed) over those millions and millions of years from that pinhead.


So Destiny, we have evolved from the primates but the primates evolved from other living things, and it started 4.0 billion years ago from that pinhead

I think the crucial factor in understanding this in the time span …which is unbelievable to us who live for such a short part of the story.

Unhappy about this, then please write a comment or ask another question.

(rewritten June 5th 2018 )

What happens to your eyes when you die? asks Olivia (12)

You did suggest Olivia that the eyeball might explode when a person died.  This is very unlikely. Look at the eye image below and try to identify the muscles in the eye. they will be attached to the two things that are constantly changing in the eye.

There are muscles attached to the lens and the iris.

When you die, your muscles relax. This causes the iris muscle contracts when this happens the eye is said to dilate ….like the image below

This is probably what your eye would look like  when you are asleep. Thanks for the question.

“How do people survive in the jungle?” asks Lachlan (8)

Thank you team, for your comments.

You are right Homo Sapiens survived because of their hunting and gathering skills.They were better at it than their fellow humans  Homo Neanderthal and the other human groups (Homo erectus, Homo ergaster, Homo rudolfensis …..)

Some clever people have found, that we still have hunting and gathering skills in our blood. So there you are, we will/might be able to cope in a jungle environment.

Revised 11/11/17 – added other homo species.

Jessie (13) asked “Why do humans age until 100 years old in average and not further?”

The Hydra are a group of invertebrates (animals that do not have backbones) that look like tiny tubes with tentacles protruding off one end. They grow only about 0.4 inches (10 millimeters) long and eat even tinier aquatic animals AND they seem to be immortal, they can live forever without aging.

So why can’t we? There are several reasons. One of them is the inability of our cells to continually divide. The cells of bacteria seem to be able to divide, and form two daughter cells endlessly. Our cells only seem to be able to divide about 60 times …. so after that time the part of the body that the cells support begins to degenerate (die).

The cell dividing and subsequent regenerating is controlled by our DNA. It tells the body what to do. Over the years our DNA becomes damaged by a variety of things and the instructions for regeneration are lost.

However the hydra survives so maybe that will be a route for researchers to find some answers to the problems we face.