Weissenhorn+DeLong,+J.

Regulation of the Cell Cylce;Tumors Johanna Weissenhorn DeLong Biology 12 Post Number 1

__ What are Tumors? __ Tumors are a large or small mass of cancer cells that can be harmful to organisms. They are essentially divided into 2 different categories benign, which is when the tumor stays in its original site and then malignant, which is when it spreads to other cells throughout the body. Unfortunately, this is the kind in which many many people around the world are suffering dearly from. It is unnormal cell growth and development where the billions of cells in our body divide and multiply without stopping.



__ How do They form? __ All cancer begins with our cells and because our bodies are made up of so many, cancer will start with one and then it will quickly spread to another. These specific cells lack the mechanisms to stop this development and do not properly respond to them. If they do suddenly stop, this is just at a random point. Our genes, make sure that our cells grow and reproduce in a certain organized fashion, they are encoded with directions on how to keep our body working healthily. When these genes change up their codes, this is called a mutation. For cancer cells, their mutation is that their reproduction cannot be controlled. Which means, they are lacking these mechanisms for stopping. Cancer cells are then spread by invading neighboring tissue cells that spread through lymph and blood vessels to other parts of the human body. With that being said, a small percentage of these cancer cells will survive, and then establish a new tumor somewhere else in the body.

CHECK OUT THIS NEAT VIDEO FOR FURTHER EXPLANATION! []

__ What specifically causes these mutations? __ Mutations can happen for several different reasons. Most commonly DNA fails to copy accurately during the reproduction phase. When a cell divides during mitosis, it makes a perfect exact replica of it's DNA and sometimes! This supposed to be "exact replica" has a slight DNA change which is a mutation. Another factor creating a mutation, is how external factors can affect our cells too. Simple mutations can be caused by exposure to certain chemicals or even radiation. Substances like this are unnatural and cause the DNA is break down. When the cell then commences to repair the DNA, it might not be able to re replicate it exactly how it was, and therefore it is now changed.



__ Cures? __ __Benign-__These tumors usually can be removed fairly easily with surgery depending on their location and size. Because these tumors can not spread, they are much easier to deal with. __Malignant-__ Most common treatments include chemotherapy, in which the condition is treated with chemicals. The focus of this treatment is to target rapidly diving cells. Unfortunately, this includes the patients healthy cells as well, making this battle very difficult. The other treatment that can be used, is radiation therapy. This allows for a beam of subatomic particles to damage the DNA, it specifically targets the tumor.



__ References: __
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 * [|http://www.webmd.com/a-to-z-guides/benign-tumors-causes-treatments#1]
 * Our notes From the Cell Regulation Section.

__ Further Reading For Interested Minds, here are some Websites to check out: __
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 * [|http://www.cancer.ca/en/cancer-information/cancer-101/what-is-cancer/the-cell-cycle/?region=o]

Evolution; What is Natural Selection Johanna Weissenhorn DeLong Biology 12 Post Number 2

__ What is Natural Selection? __ Natural selection is the process in which organisms will better adapt to their environment and try to survive and produce more offspring. It is the theory of organisms adapting to better suit environmental pressures, climate change and also dangerous predators.The theory of Natural Selection was first fully discovered by Charles Darwin and is now believed to be the one of the only processes that brings about evolution. The process of natural selection has 4 major components. The four components include: 1.) Variation- organisms all vary with physical appearance and behaviors 2.) Inheritance- all organisms have traits passed down from their parents 3.) Population Growth- Every population generally has a surplus of offspring and the environment cannot always support them all, creating mortality rates 4.) Differential survival and reproduction- Individuals with traits that can benefit them in their environment will create more suitable offspring them individuals with traits that will not benefit.



In this photo of natural selection exhibited it shows that the smaller neck giraffes could not reach the food necessary for them to survive, therefore natural selection played it's part in changing the length of their necks for better chances of survival.

CHECK OUT THIS NEAT VIDEO FOR FURTHER EXPLANATION!

@https://www.youtube.com/watch?v=X-CL4Mywfkc

The species of birds Darwin was observing during his voyage in 1835.

__ How did Charles Darwin discovered Natural Selection? __ Charles Darwin, an English naturalist was born in 1809. Always interested in life, he made many observations and theories upon the subject of evolution. After a voyage in the Galapagos islands during the year 1835, he realized that many of the same species of birds, varied on behaviors and physical attributes depending on which island offered what for food, climate and overall environment. This being said, he observed how some birds would catch food a certain way, whereas on another island, the birds would use another method. These ideas led him to the one major theory of evolution today, which is natural selection.



__ How does natural selection work? __ Natural selection is simply one of the mechanisms which creates evolution of ALL organisms. When a change is needed to save or adapt a species or individuals in trouble, this is when natural selection does it's work. Natural selection primarily selects "better" genotypes and phenotypes then others. It is a slow process but creates healthier and better suited organisms to recreate. It works by basically eliminating physical characteristics and behaviors which are not helping the animal. For example above, the giraffes neck. All giraffes from then on, now have longer necks due to their adaptation which was needed. In order for basic survival, the organisms must be able to reproduce and feed, and take care of their offspring. Natural selection wants only this, to evolve organisms to their best potential of survival.

__ 3 Types of Natural Selection: __ There are different modes of natural selection, but in general their basic theory is the same. 1.) Stabilizing Selection: This favors the more common phenotypes, and eliminates extremes. 2.) Directional Selection: Only one extreme variant is favored. This can be caused by changing climate or environmental conditions. 3.) Diversifying Selection: Environmental conditions favor both variants.



__ References: __
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 * Our notes from Evolution Unit.

__ Further Reading For Interested Minds, here are some Websites to check out: __ > >
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Genetics; Genetic Disorders Johanna Weissenhorn DeLong Biology 12 Post Number 3

__ What is a genetic Disorder? __ Genetic disorders are diseases that are caused by an abnormality in a persons DNA. This disorder causes illness's by either a natural mutation or due to environmental factors such as smoking, exposure to radiation and certain chemicals. These illness's are simply a change as small as a single base mutation or maybe even in just one little gene.Some disorders are inherited and some are just acquired changes developed later on in life. Sometimes causing deathly situations, genetic disorders can be life-changing and very hard to maintain.

These mutations causing a genetic disorder happen inside the genes.

__ How is it inherited? __ Genetic diseases that affect the population are generally __recessive__. Meaning, the chances of inheriting one, are smaller then if it were dominant. Dominant traits are far more popular and over powering then recessive genes,making it far more harder to inherit diseases and any recessive traits. For example, brown eyes are dominant to blue. Still possible for a child to have blue eyes, but there chances are more slim if one parent has brown and the other blue. Meaning, blue is recessive like genetic disorders. In this case, a normally functioning gene will override the abnormal one unless two abnormal genes are present. If parents both have abnormal recessive genes (carriers of a disease), there are chances they could potentially pass it down to their child or their child will then be a carrier too. Whereas if someone is a carrier of a __dominant__ genetic disease, then the child will have a 50% chance of developing this disease as well.



__ How are they developed later on? __ Genetic diseases cannot only be inherited but later on caused by a mutation. Mutations are caused by a limiting amount of factors but all have one common problem, the DNA has been altered. Because an organisms DNA was altered, this causes problems to the body creating a genetic disorder (a disease within your genetic code). This can affect everything. Mutations, environmental factors and damage to the structure of chromosomes are what causes genetic disorders to develop on later in life.



__ Mono-genetic(a single change in the DNA's code) disorders include: __
 * Cystic fibrosis
 * Sickle cell anemia
 * Marfan syndrome
 * Huntington's disease
 * Hemochromatosis

__ CHECK OUT THIS NEAT VIDEO FOR FURTHER EXPLANATION! __ @https://www.youtube.com/watch?v=4p1ZihXb29U



__ References: __
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__ Further Reading For Interested Minds, here are some Websites to check out: __
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