A gene mutation changes an AT base pair to a GC base pair. This causes a gene to
ID: 10278 • Letter: A
Question
A gene mutation changes an AT base pair to a GC base pair. This causes a gene to encode a truncated protein that is nonfunctional at higher than 37oC. A person who carries this mutation cannot survive for more than one day with a fever above 39oC. Give a genetic term that describes this type of mutation.What are the two general types of cancers?
Why would a mutation in Brca1 tend to leave an individual susceptible to cancer?
Explain how xeroderma pigmentosum can be caused by mutations in so many different genes.
What are two characteristics of early-onset familial breast cancer?
What is the most common mutagen that we find in our environment?
Explanation / Answer
Give a genetic term that describes this type of mutation.
Since this mutation produces a different protein, it can be called a missense mutation. It can also be called a "loss of function" mutation since it cuts off the function of the protein abnormally.
What are the two general types of cancers?
Benign and malignant or you could say benign and metastatic. This is a broad question so not sure precisely what you needed. I'd suggest adding the definitions of each word into your answer.
fyi, the term "tumor" describes any unusual growth. That growth can be considered benign or malignant, but technically only the malignant tumor is considered "cancer." Cancers which have infiltrated the lymphatic system have cells which leave their place of origin, travel somewhere else, and set up shop to form a new growth. These are called metastatic (aka metastasis).
Why would a mutation in Brca1 tend to leave an individual susceptible to cancer?
Brca1 (aka "braka 1") is a gene which prevents/suppresses mitosis from occurring inappropriately. For example, if the cell replicates its DNA with errors, a tumor suppressor gene will prevent further progression to mitosis.
Normally, you have 2 Brca1 genes so that if one is knocked out by a random mutation, the 2nd one will make enough protein to do the job. But if one Brca1 gene is already knocked out, then a 2nd mutation is a big problem. Since Brca1 has been implicated in breast cancer, this makes the individual with the 'knockout' (usually females) more vulnerable to breast cancer than most people.
Explain how xeroderma pigmentosum can be caused by mutations in so many different genes.
This disease is cool! (sorry I'm morbid) I saw someone with xeroderma the other day. Just like the pics. Many genes affect excess growth/mitosis in skin, so that mutations in any of them will cause tumor production. Normally, DNA repair mechanisms fix this to avoid problems. In xeroderma, the DNA repair mechanism is mutated/non functional, so any mutation becomes difficult to fix. The cell accumulates mutations and tumors begin to occur. This is caused by inevitable exposure to sunlight, for example.
What are two characteristics of early-onset familial breast cancer?
(1) early onset which gets earlier and earlier in successive generations (e.g. grandmother to mother to daughter) (2) increased association with one or more of several genetic mutations such as Brca1.
What is the most common mutagen that we find in our environment?
Depending on where you live and your personal perspective, pick any of these: UV radiation in sunlight, toxic chemicals in water, McDonalds, homework, a nearby nuclear power plant. The answer your teacher is probably looking for is sunlight.
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