Ch. 4 post

Explain what active transports are and their role then differentiate them from facilitated difffusion

Chapter 4

There are many different types of membranes that are in the human body. First explain what a membrane is and then explain the difference between biological membranes and plasma membranes.

Cell as a city

Describe the cell as a city. Make sure to add as may of the roles of the organelles as you can and relate them to a role of a prominent member of the city.

Biological compounds

Compare and contrast the 4 main classes of biological compounds.

Characteristics of life

For your first comment, add a post that outlines the characteristics of life. Make sure to explain each one of them. Do not just write the list.

Down Syndrome and SCR

Mutations are a sudden departure from the parents in one or more characteristics. Mutations cause disorders by adding, deleting, or extending a gene strand. These disorders can be large or small depending on how much of the DNA is changed.
There are four types of inheritance patterns: autosomal dominant, autosomal recessive, x-linked recessive, and x-linked dominant. Autosomal dominant is when the inheritor has a 50/50 chance of receiving the mutated gene. This is because the carrier only has one copy of the mutant allele and one normal copy. Autosomal recessive is when the inheritor only has a 25% chance of inheriting the mutation because the disorder is only inheritable if there are two copies of it. If there is only one copy of the gene the inheritor is only a carrier of the gene but is not affected by it. X-linked recessive inheritance is a something that is more likely to infect a man because they only have one set of the gene they will automatically be affected by the mutation because they do not have an extra copy. X-linked recessive inheritance also can only be passed from male to female but from female to male and female. Females are very likely to not get a X-linked recessive disorder because they need to have two copies of it for the mutation to have an affect. X-linked dominant inheritance is more likely to affect the female because there is not transmission from father to son and automatic transmission from father to daughter. There is only a 50% chance of a mother passing it on also.
Down Syndrome is a genetic disorder that is caused by extra material added to the 21st chromosome. There are no environmental factors that can lead to the disorder of Down Syndrome. Recently they have found a shot that can be given to relieve some symptoms, but it has only been used on test mice. It is not yet known whether it will work on human beings. Not a whole lot of research has been happening with Down Syndrome lately; scientists believe that it is too complex of a disorder to have a cure be found. Down Syndrome causes a flat facial profile, squinty eyes, heart problems, low muscle tone, slower growth rate, and learning disabilities. Stem Cells are cells that haven’t committed to a specific type of cell yet. The hope for them is that if they replace them with other cells in the human body they will be able to heal and help different health problems. It is controversial because they use unborn babies as test subjects. That kid will never have a chance to live a life, and it was born for purely research purposes. It almost lowers the value of human life. I do not think that it should be legalized for the simple fact that it’s killing babies. All humans should have the right to live a normal life, and stem cell research can take that away. There is a chance that stem cell research could find a way to replace the missing chromosome from a down baby, but I don’t think it’s worth killing another one.

Alzheimer’s and Stem Cells

Genetic disorders are diseases caused by abnormalities in one’s DNA. These “abnormalities” can range from a small mutation in a single nucleotide to the addition or subtraction of entire chromosome pairs. One might imagine why the mutation of a single gene could cause an entire disorder like Sickle Cell Disease or Cystic Fibrosis. It is because each three gene pair is called a codon. These codons are used in protein synthesis to make a specific protein. Each codon “codes” for a specific amino acid. However, if one codon (possibly one gene) is mutated, the wrong amino acid(s) may be used in protein synthesis. Now the organism has a completely different protein with a completely different structure than what it originally needed. A genetic disorder is born.
We get our genetic information from our parents. This process of passing on genes is called “inheritance.” Each parent contributes half or the offspring’s total DNA. Genes can be described as dominant or recessive. Since the offspring receives a copy of each chromosome from its parent, the gene that ‘dominates’ can be observed. However, the offspring could be a carrier for the recessive gene. The pattern can be described by the pattern aa, AA, Aa, (aA).
Alzheimer’s Disease (AD) is the most common form of dementia. I decided to research this disorder because my mom has dementia. Alzheimer’s disease is characterized as an incurable, degenerative, and terminal and is generally attributed to those over 65. As of now, no medicines slow the progression of the disease. Only some slightly reduce its symptoms. Only a few hypotheses are in acceptance. One describes reduced synthesis of the neurotransmitter acetylcholine. Another postulated that amyloid beta deposits were the cause for AD. Support for this idea came from the location of the gene for the amyloid beta precursor protein on chromosome 21. Evidence also arose when a pattern was noticed in patients with Down Syndrome. They developed AD by age 40 and have an extra gene copy of chromosome 21.

Stem cell research is the controversial study of regenerative cells. A stem cell is characterized by its ability to renew itself through mitosis and differentiate into specialized cell types. There are two broad classifications for mammalian stem cells: Embryonic and Adult (embryonic are more researched because they are more medically valuable). Embryonic stem cells are found in multi-cellular embryos ant are known as totipotent (omnipotent) meaning that they could, at this point, differentiate into any type of mammalian cell with enough stimulation for that type. Most research today is being done on mouse embryonic stem (mES) cells. Some research, however, has been conducted on human embryonic stem (hES) cells. Here lies the controversy. Many people believe that human embryos (even those obtained from abortions) should not be used for such research as it is “inhumane.” I believe that embryonic stem cell research should only be conducted on aborted embryos if the parent(s) agree(s) to it. I believe that it is their choice. However, in no cases should an embryo be used in research without parental consent. Alzheimer’s disease could be affected by stem cell research, but it is hard to say at this point. Little is known about Alzheimer’s and stem cells. Hopefully advances in stem cell research and determining the cause for AD can be paired into a cure for AD or even a treatment of any kind.