Search This Blog
Sunday, November 13, 2011
Monday, July 19, 2010
genetic diseases
Saturday, July 17, 2010
Works cited
http://ghr.nim.nih.gov/handbook/basics/dna
http://www.en.wikipedia.org/
http://www.dna.gove/
http://blc.arizona.edu/molecular_graphics/DNA-structures/DNA_tutorial.html
http://nobelprize.org/educational/medicine/dna_double_helix/readmore.html
www.slidshare.net/minty/process_of_dna_replication
www.biology.arizona.edu/cell_bio/tutorials/meiosis/
www.phschool.com/science/biology_placemain.html
http://www.cancer.org/
www.uic.edu/classes/bms/bms655/lesson15.html
http://dwb.unl.edu/teacher/NSF/c10/c10links/www.middlebury.edu/~ch0337/ho/fh.html
http://www.learn.genetics.utah.edu/
cancer myths and truths
1. cell phones cause cancer: cell phones do emit radio waves, but these radio waves are like the radio waves emitted by a television. Cell phones do not cause brain tumors.
2. One of the most popular myths about cancer among woman is that antipersiprants and deoderants cause breast cancer. There is not evidance from recent studies can conclude that wearing them causes breast cancer.
3. cancer causes hairloss. Cancer its self does not cause hairloss, but effects from cancer treatment can cause hairloss.
4. certain types of cancers are contagious. This is not true, you cannot develop cancer from another person. Though some disease such as HIV are contagious and can lead to some types of cancer.
5. If a parent has cancer, they will pass it on to their offspring. This is totally NOT true. Cancer is caused by mutations in the genes, like was dicussed previously. Cancer is usually not hereditary.
6. Only women get breast cancer. This is a common myth that is not true. 1500 men are diagnosed with breast cancer every year and every year 500 of those men die from breast cancer. Breast cancer in men is not as common as in women, but they can still develop breast cancer.
7. hair dye causes cancer. There is no evidance to prove that using hair dye causes cancer.
8. drinking water with flouride in it causes cancer. Half of Americans drink water with flouride in it, there are no creditable evidance that drinking water with flouride causes cancer.
9. coral calcium can cure cancer. coral calcium is a dietary supplement made from marine coral. This is not true, coral calcium cannot cure cancer and legal action has been taking against those saying it can.
Here are some truths about cancer:
1. eating grilled meats cause cancer. grilling meat causes a chemical called heterocyclicamines, to be created, this can be harmful. This chemical is found in higher qualities when meat is well done or burnt. It is recommended that you limit grilled meat and avoid eating the burnt parts
2. magnetic field exposure causes cancer. Some say that being around powerlines causes cancer. While many test have proved this to be inconclusive, still the National Institute of Environmental Health Sciences suggests distancing yourself from these kinds of things.
causes of cancer
growing older - we cannot avoid growing older, but most of the diagnosis of cancer are those who are over the age of 65, though children and those younger the 65 develop cancer.
tobacco - tobacco use is avoidable, every year around 180,000 people die from cancer related to tobacco use. Just being around tobacco smoke, such as secondhand smoke increases the risk. Those who smoke are at a higher risk of cancer of the: lung, larynx, mouth, kidney, throat, stomach and cervix. Those who use smokeless tobacco are at a higher risk of developing cancer of the mouth.
sunlight - sunlight from uv rays also increases the risks of cancer. uv rays come from sun, sunlamps and tanning booths. This can cause skin cancer. Though we cannot completely avoid uv rays, unless we never go outside, but we can help lower our risk by using sunscreen and wearing a hat.
ionizing radiation - ionizing radiation comes from radon gas and more commonly x-rays. The x-rays that the doctor gives you, produce only a small amount of ionizing radiation, which is not enough for a person to develop cancer.
some viruses and bacteria - the human papillomavirus (hpv) increase the risk of developing cervical cancer, hepatitis B and C viruses increase the risk of liver cancer, Human Immunodeficiency virus (HIV) are at a greater risk for lymphoma and a rare cancer called kaposi's sacroma and those with the epstein - barr virus are at greater risk for kaposi's sacroma.
Family history of cancer - Most cancers occur because of mutations in genes that happen over time and are passed on. Cancer to run in a family is usual, though some times such as: breast cancer, ovary, prostate and colon cancers sometimes run in families. Usually several cases of the same cancer in the same family is just a matter of chance. Just because your family has a history of a certian cancer, does not mean that you will develop the cancer.
Alcohol - having more then two drinks a day may increase the risk of developing cancers of the: mouth, throat, larynx, liver and breast. Risks are higher with those who both drink alcohol and use tobacco.
poor diet, lack of physical activity and being overweight - those who eat diet that is high in fat have increased risk for cancers of the colon, uterus and prostate. Those who do not get regular physical activity and/or are overweight have an increase risk for cancers of the breast, colon, kidneys and uterus. Risks can be decreased by eating a healthy diet that includes foods that are high in fiber, vitamins and minerals but eating whole-grain breads and cereals, eating enough fruits and vegatables everyday and limiting the amout of high fat foods (butter, whole milk, fried foods etc.). Also getting a moderate amount of physical activity for 30 minutes 5 times a week, will help to reduce body weight and keep you healthier.
As you see most of these risk factors can be avoided. Avoiding these things, or if you can't avoided them reducing your exposure to them will decrease your risks of developing cancer now or in the future.
Thursday, July 15, 2010
Stem cells
Tuesday, July 13, 2010
inheritance and pedigree analysis
genetics and inheritance
Above is his experiment. Mendel started by crossing a round yellow pea plant (YY) and a wrinkly green pea plant (yy). All of the first generation ended offspring ended up being round and yellow. Mendel then took the first generation offspring and crossed them. What Mendel found was that most of the second generation plants were yellow and around, but a few where wrinkly and green. Mendel continued to do this until he noticed that there was always a 3:1 ration of yellow to green and round to wrinkly.
From this experience Mendel not only was able to better understand inheritance but he was also able to figure out about Dominant and recessive genes. the yellow round plants were Dominant while the wrinkly green plants where recessive. the first generation offsprings had an equal chance to receive either the dominant or recessive trait. One parent passed on the dominant trait while the other passed on the recessive trait, but since one trait was dominant it was the only trait shown.
An organism with two dominant traits are called homozygous dominant, (homo means same). An organism with two recessive traits are known as homozygous recessive and an organism with one dominant trait and one recessive trait are known as heterozygous (heter means different).
In some cases though, both traits can be shown, or neither trait could be shown. This is known at incomplete dominance or co - dominance.
Incomplete dominance - incomplete dominance is when two organism like flowers are crossed (breed) and the offspring ends up having a mixture of both of the parents traits. The picture to the left starts with a homozygous recessive white flower crossed with a homozygous dominant red flower. The first generation ends up all being heterozygous pink flowers. When the two heterozygous pink flowers are crossed the result is a 1:2:1 ratio. 1 homozygous recessive, 2 heterozygous and 1 homozygous dominant traits are inherited by the second generation offspring.
Co-Dominance - results when neither of the traits completely dominants the other trait. So instead of having a dominant and a recessive trait, both traits are equally dominant. The picture the the right is the result of a white flower crossed with a red flower. All of the first generation flowers result in patches of red and white.
How do you know which traits are dominant? Here is a list of dominant vs. recessive traits. Compare your traits with you parent's traits and you can find out which parent you inherited which trait from.
Dominant Recessive
Brown eyes any other color eyes
curly hair staight hair
widows peak normal hairline
dimples & freckles no dimples & freckles
double jointed normal joints
These are just a few, there are many more, but this it just to give you an idea.
Monday, July 12, 2010
Genes, proteins and traits
Friday, July 2, 2010
Meiosis
Meiosis is cell division, which is how genes are inherited from parent to offspring, through sexual reproduction. Every Person has 46 chromosomes in their body. Half of your chromosomes come from your mother and half from you father. These are found in the gamates, which means they are in either the egg of a female or the sperm of a male. When the egg is fertilized, it becomes diploid, meaning is has two sets of chromosomes. Meiosis goes through two processes, each containing different phases. In meiosis I the parent cell divides to two identical daughter cells. In meiosis I there are 4 phases: prophase, metaphase, anaphase and telophase.
Prophase I: the Chrosomes are duplicated during interphase I, before Prophase I. During prophase the duplicated homologous ( same) pairs of chromosomes go through crossing - over. This is just when the chromosome pairs, also known as sister chromatids, cross - over each other and exchange parts of the chromosome parts. This allows for varieties in genes. Prophase takes the longest time out of all of the other phases. Also during prophase the nucleolus disappears and the meiotic spindles start to form on opposite poles of the cell.
Metaphase I: During Metaphase I the homologous pairs of chromosome line up on the metaphase plate, in random orders. The the spindle fibers come down from the poles and attach to the homologous chromosomes.
Anaphase I: In anaphase I the spindle fibers pull the chromosomes to opposite sides of the cell. the tetrads stay connected at the centromere. They are not yet seperated, this takes place during anaphase II.
Telophase I: During Telophase I the chromosome pairs are on two different sides of the cell, which makes two daughter cells that are each haploid ( 23 chromosomes ) and each contain two sets of chromatids. the spindle disappears and cytokinesis starts. In cytokinesis a cleavage furrow forms, which makes the cells into two seperate cells. . This concludes meiosis I and meiosis II proceeds, starting with Prophase II.
Meiosis II: Meiosis II takes the two daughter cells and divides them into four daughter cells. This process starts with Prophase II.
Prophase II: The centrioles duplicate. No new chromosomes are replicated during meiosis II. the nuclear envelope disappairs and the spindles form.
Anaphase II: the centromeres split and the to sister chromatids move to opposite sides of the poles, these are now seperate chromosomes.
Friday, June 25, 2010
DNA Replication
Thursday, June 24, 2010
DNA Structure
DNA is constructed by a phosphate backbone, which are held together by phosodiester bonds. DNA starts with a phosphate attached to a deoxyribose sugar, which is attached to one for the four base pairs. DNA is double stranded, which forms a twist of the strands, which is called a double helix.