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Cloing

Ämne: Biologi, Engelska
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Human and animal cloning including stem cell research
Cells are the smallest building blocks of life. Every living organism on this earth that fulfil all the terms of “Mrs Gren/Nerg”, are definitely made out of cells. Cells have many functions with parts like nucleus, cytoplasm, cell membrane etc. Animal cells have nucleus, cytoplasm, vacuole and cell membrane but, lack the parts like chloroplasts and a cell wall that plant cells have for making glucose in the process photosynthesis and staying rigid.

How cells are built up – Mitosis

Eukaryotic cells are made by an asexual cell division process called mitosis. The process starts by the chromosome dividing in a cells nucleus. The chromosomes in a eukaryotic cell separate in its own cell nucleus and develops into two identical daughter cells with the same nucleus. The processes in a cell were dividing chromosomes in a cell nucleus occurs is called mitosis.

The process mitosis showed in a small diagram:
How a cells function – the important cell parts: The 5 main organelles of an animal cell:
Nucleus – Is the “brain” of a cell and is the control centre, the nucleus contains DNA (the genetic coding) and has all the genetic info for making a new cell.
Cell membrane – The “skin “of a cell, it controls what comes in and goes out of the cell, is the surrounding of the cell and it also recognizes other cells .
Mitochondria – Are the power stations of a cell and break down food and combine it with oxygen for making energy to the cell.
Vacuoles – The food storage of a cell, it stores food (energy) for the cell.
Cytoplasm – Is the jelly like substance “transportation network” of a cell, allows other parts of the cell to move around in the cell.

The most important part of a cell – for the topic stem cells included cloning I have chosen to write the essay about, is the nucleus. All the parts in your body contain exactly the same DNA (because of the nucleus in every cell) – that’s why cloning and making stem cells are possible.

The process of cloning and stem cells

The most important part is the nucleus because you take the nucleus for e.g. from any cell to clone yourself and take that cells nucleus and inject that to a surrogate woman’s empty egg cell which doesn’t contain any nucleus. This egg cell with your DNA in it, develops into stem cells in the other surrogate woman’s womb – you don’t let the stem cells develop into a baby with the same DNA as you and take the embryonic stem cells out which contains your DNA and use it for improving your health or, you let the embryonic stem cells develop into a clone of you.
There are two different types of stem cell research:
• Adult stem cells – When you take the stem cells from an adult and make new tissue from it but adult stem cells are not as flexible as embryonic stem cells unfortunately.
• Embryonic stem cells – When you take the stem cells from a pre-embryo. The same as therapeutic cloning.
There are three different types of cloning:
Cloning is making an exact copy of another animal, human etc.
• Embryo cloning – Twins or triplets can be made with this type of cloning because it duplicates the natures process and therefore twins and triplets are made.
• Adult DNA cloning (a.k.a. reproductive cloning) – A new exact copy of a mammal is made with this type of cloning. This type of cloning is used for helping animals that are less in numbers to increase so their species survive.
• Therapeutic cloning (a.k.a. biomedical cloning) – The first stages in therapeutic cloning is the same as the adult DNA cloning – but it changes because you take the (fertilised ovum) pre-embryo and take the stem cells to make new organs for transplant and new tissues for damaged tissues.

Interesting fact about cloning: Cloning happens natural in both animal and plants when identical twins are made. If the identical twins then look different, then that is caused by environmental variation.

Genetic heredity

The passing of characteristics and genes for e.g. eye colour are passed down from parents to their offspring. Some genes are recessive others are dominant. Because some genes are not dominant (recessive) – that’s why some offspring are mixtures. Allele is a different name for gene, but genes are called alleles when there are two different genes for e.g. Bb. Allele is also a specific type of gene for a specific characteristic, for ex bb for blond hair and Bb for black hair. An offspring which is a mixture has a dominant and a recessive allele from its parents then that individual is heterozygous. An offspring which is not a mixture, have the same type of alleles from both parents then that individual is homozygous.

Big letters represents dominant genes and small letters represent recessive genes.

Genotypes are the genes one person has and phenotypes are the physical characteristics we see on a person. You inherit characteristics from your both parents and you’re not identical to them; you’re a mixture between their genes and physical features. The chromosomes you get from your father and mother are called homologous pairs because they contain almost the same information for your body like e.g. eye colour, hair colour etc.
Punett squares help us to find the probability of how an offspring will look like by the alleles of two parents. Punett squares show the relation between the genotypes and the phenotypes. Punett squares appearance (to the right).

Sexual reproduction in animals

An offspring gets 23 chromosomes each from a male and a female gamete and have 46 chromosomes as a total. The process of when the haploid gametes the sperm (male gamete) and the ova (female gamete) join is called fertilisation. The fertilised egg is called the zygote, it implants itself into the lining of the uterus which is called implantation. When implantation has occurred, then the woman is classified as pregnant. This zygote grows into tiny balls of cells and it’s now called the embryo. The embryo grows more and becomes a foetus eventually. This foetus develops more until it’s ready to come out of its mother’s body.
The process of life span development simply starts when you are a baby (being conceived), and have developed from an organism to a full-term infant.

Importance of biological diversity

All organisms depend on each other to stay alive. In the nature there is an ecosystem humans included. This means that if one animal species dies, than other animals in that ecosystem will die. There are predators and preys. E.g. If the seals and fishes dies where the polar bear lives, then the polar bear will also die of starvation – because its food are the seals and the fishes which doesn’t exist anymore. If the polar bear the predator becomes extinct then its prey the seals and the fishes will increase in number because there is no predator hunting and eating them. It’s important with biological diversity because if every human and animals had the same DNA, it could cause problems for offspring’s so they were born with handicap, diseases etc

The main reason for stopping animal species becoming extinct is because the ecosystem can collapse if animal species becomes extinct, that’s why cloning is necessary. Scientists can now clone animal species that are not many in numbers so they increase in numbers however, this can also be seen in a negative way. Cloning one animal species too much can lead to animals with too much of the same DNA which can cause diseases between the animals because of the non variation in DNA.

The important for biological diversity are huge because you want to have variation in all the species so animals with diseases, handicap, disorders etc are less. Not enough spreading between the genes results often in handicap, diseases, disorders etc.

Arguments for and against cloning and stem cell research

There are many arguments for and against stem cell research and cloning. Ethical arguments are the one’s that I think have stopped the use of stem cells, the ethical arguments are making good statements for not using stem cells and the scientific arguments are making good statements for stem cells. One of the aesthetic arguments is that if a person have a disease you go and take a healthy cell from that person, clone that cell and then take the stem cells that converts into (any cell) healthy tissue and replace the damaged tissue or organ in that persons body. This person will be healthy because the infected part of his/her body is gone. But there are many ethical arguments against stem cell research; the strongest argument for not using stem cell research is that taking stem cells is a homicide because you are killing an embryo which many religious people can consider as a living thing – which it is but it doesn’t have a conscious yet – does anybody remember being an embryo? I don’t think an embryo is a human, it’s not really a human being yet – it’s not in that stage yet when the heart starts to beat. Many religious groups opposes stem cell research because you take the embryonic stem cells, and according to these religious groups a life starts just after sperm and ova have turned into a zygote (fertilised egg). Pro-lifers say that when the fertilisation happens a new human being has been made. The pro-lifers also says that it’s homicide to take stem cells from an embryo because you’re killing a life.

The scientific arguments for stem cell research is that it can actually help people who are really sick, have a disease, disorder and no waiting list for organs at hospitals because new organs are made with cloning. The scientific arguments, aesthetic arguments are for stem cell research and cloning while the religious arguments are against both of them because they think cloning and taking stem cells isn’t morally correct.

I believe that I can agree with all the arguments above, but I feel it’s more important to save a human life, helping a person with a disorder/disease and taking stem cells is not really killing a human being with a conscious. I am for stem cell research and cloning but if you abuse both technologies it will probably have serious effects on the nature, the society and individual.

Cloning history

First animal cloned

Dolly is the sheep that was the first animal to get cloned in 1996 and contributed to the improvement of our living conditions by increasing our knowledge for cloning. Because you could clone Dolly the sheep that’s why you can clone many other mammals like us humans, pandas, horses etc and help the pandas or the other animals from extinction. This type of “adult DNA cloning” was abused when Dolly died as a 6 year old sheep because they maid 277 attempts and Dolly was the only sheep that maid it to adulthood.

How Dolly the sheep was cloned.

Horse cloning

The seventh species cloned is the horse Promethea and was born in May 28th, 2003 and it also helped human increase their knowledge about cloning. Cloning was also abused here, because they tried several times to clone horses but Promethea was the only one that succeeded in birth. Cloning of mammals has resulted in helping animals that are less in numbers to increase.

All the cloning on animals so far has given us knowledge on cloning. Dolly the sheep the first animal to be cloned, gave us the knowledge about actually how to clone, the most important knowledge of this scientific approach. GM foods (genetically modified foods) which are related to biotechnology – can help the starvation in the third world which can multiply foods. But at the same time it can cause unknown health risks and allergy among mankind.

Conclusion:

Cloning and stem cells are both positive and negative. Cloning humans would increase the rate of the world’s population and therefore the earth’s resource management wouldn’t be enough for people. Stem cells would make people with sicknesses – make them healthy and therefore also increase the rate of earth’s population by making the sick people healthy. There are more children being born everyday and people’s death ages are increased. This simply means more children are being born than people are dying. The earth will probably be overpopulated without the help of cloning. Biotechnologies like stem cell research and cloning are really powerful technologies and abusing them can have many awful consequences. I have read about “eternity life” by the help of cloning cells in our body and stop the aging process. I don’t really believe we can do that, but with the rapid speed that technology is developing maybe that can happen in the next 20 or 30 years. If they find a way to make humans young with the help of cloning cells/stem cells, then I believe their will be abuse with it and will have more consequences than just cloning.

Making people young with a powerful tool as biotechnology would cost a lot of money and those who would have afford it would be young. Many people would stay young much longer and not die until they are really old. The consequences are the earth will be very overpopulated because of all healthy and young people – the resource management of the earth will run out eventually, because the aging cycle is broken (read: life cycle – from baby to death). More people will be homeless because of the lack of apartments in the world, rich and famous celebrities would abuse this technology and it will be abused on the black market. The advantages with cloning are that couples who can’t have a child – can have a child that has its half DNA and the disadvantages are the effects on the earth, pupils and ethics. Cloning can also increase the amount of animal species that can be extinct and preserve the species.
Anika Hossain

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