Please answer the following questions in a 200-word response minimum. Try your best to reference the text I will message you privately for how to access the text book.
1. Our DNA is subject to mutations on a daily basis. Why do most mutations that occur in the genome of organisms escape detection and not elicit a deleterious effect? Why does the child of someone with cancer not necessarily develop cancer?
2. How would you explain variations in chromosome number and gene arrangement that result in inheritable disorders?
3. Mutagenic activity, as detected by the Ames/ Salmonella test system can be used to discriminate whether an environmental effect is mutagenic or carcinogenic. How would you distinguish between a mutagen and a carcinogen?
4. It is very important in the process of Mitosis that each new daughter cell receive a complete copy of the parent cell's DNA. If there is just one base left out this is called a mutation, and mutations can be helpful, harmful or neutral. However, you do not want that mutation being passed down to the offspring, if it is harmful. Therefore it is important to have each cell possess a complete unchanged copy of the original DNA so that you can protect the original blueprint. Do you know of any mutations that are "good"? Why are they good?
5. This is a simple question: If genetic mutations are common and occur naturally, why does everyone not develop cancer?
6. Why do you think gene regulation is more complex in a multicellular organism versus a single-celled organism? Why is it harder to study gene regulation in eukaryotes?
Please participate (respond) to the classmate's answers with POSITIVE notable and educational input. (200 word minimum Reponses)
1. Elizabeth: Mutations occur for a number of reasons. They may be spontaneous or induced. Thankfully, these mutations are typically halted by the DNA repair systems. Actions such as proofreading can lead to catching 99% of errors. When an error is found, the operation is reversed to fix the error. Another repair system is mismatch repair. This occurs when the incorrect base is paired. The error is exposed, taken out, and then replaced with the correct base.
An offspring of a parent with cancer may or may not have a higher chance of developing cancer. Some cancers can be inherited, such as breast & ovarian, when certain risk factors are present. Having several close relatives with same cancer, relatives who developed the cancer at a very young age, or having a family member who had more than 1 primary cancer are all factors that could increase risk.
Despite risk factors only about 2-3% of cancers are associated with inherited genes. More often cancers are caused by lifestyle choices, such as smoking, and environmental circumstances, such as exposure to carcinogens.
2. Anthony: Our DNA is subject to mutations on a daily basis. Why do most mutations that occur in the genome of organisms escape detection and not elicit a deleterious effect? Why does the child of someone with cancer not necessarily develop cancer?
Mutations are changes in the genetic material that are passed on to the next generation. They can be caused by a number of factors, and may or may not have a noticeable effect on a cell or on an organism. DNA repair systems are in place within the cell that detect and repair changes in the nucleotide sequence prior to cell division. These repair mechanisms prevent the alteration in DNA sequence from being passed along to the next generation of cells. However, some mutations go undetected or unrepaired and are passed along to the next generation of cells. If these mutations affect the function of critical genes, particularly those involved in the regulation of cell division, they may result in cancer. Men and women who carry a germline mutation have a 50% chance of passing it on to their children. Germline mutations can be passed on from generation to generation.
Canadian Cancer Society . (n.d.). Cancer Cell Development. In Canadian Cancer Society . Retrieved August 31, 2016, from https://www.cancer.ca/en/cancer-information/cancer-101/what-is-cancer/cancer-cell-development/?region=on.