Answer:
(c) Inherited a mutation in a gene required for mismatch repair
Explanation:
Gene mutations are occasional changes that occur in genes, that is, the procedure by which a gene undergoes a structural change. Mutations involve the addition, deletion or substitution of one or a few nucleotides of the DNA strand. Mutation provides the emergence of new forms of a gene and, consequently, is responsible for gene variability.
It is common for several members of the same family to have the same genetic mutations, as the gene affected by the mutation may condition a trait that DNA cannot repair. An example of this is the family shown in the question above, where several people were diagnosed with the same type of cancer while still young. What probably happened in this family was that people diagnosed with cancer inherited a mutation in a gene needed to repair incompatibility.
Crossing over, or recombination is the exchange of chromosome segments between non sister chromatids in meiosis. Crossing over creates new combinations of genes in the gametes that are not found in either parent, contributing to genetic diversity.
Answer:
A. If the aerobic pathway—cellular respiration—cannot meet the energy demand, then the anaerobic pathway—lactic acid fermentation—starts up, resulting in lactic acid buildup and "oxygen debt."
C. After about 90 seconds of intense exercise, the muscles become depleted of oxygen, and anaerobic respiration can no longer function to produce ATP, resulting in "oxygen debt."
Explanation:
There are two sources of carbohydrates in the human's body for energy (ATP) production. 1) Creatine phosphate and 2) Glycogen. Creatine phosphate metabolizes easily and yields ATP quickly. Whereas glycogen is stored form of carbohydrate which yields energy more slowly. Therefore, initially, our bodies use creatine phosphate and then shift to glycogen. Within 60-90 seconds, the creatinine phosphate in the body is mostly utilized and then energy is produced by the use of glycogen in aerobic pathway. During areobic pathway, oxygen supply is sufficient and per cycle, it produces 32 molecules of ATP. However, when oxygen supply is limited or absent, the body will metabolize glycogen to lactic acid via fermentation and produce only 2 molecules of ATP.
Now consider the example: Kenny hikes all day at a steady pace therefore the supply of oxygen is sufficient for aerobic cellular respiration for ATP production. In this scenario, the oxygen debt is minimal and Kenny relies on aerobic respiration pathway to obtain energy. On the other hand, Janelle runs fast (100 meters in 13.5 seconds) and her cellular respiration would be on the compense of aerobic pathway initially which will be shifted to anaerobic pathway after the supply of oxygen is reduced/minimum. Janelle will heavily rely on the anaerobic pathway because running fast needs energy which cannot be provided via aerobic pathway easily. Therefore, Janelle's body will produce lactic acid and suffer from oxygen debt.
Answer:
Explanation:
The normal form of the prion protein PrP (shown here) is found on the surface of nerve cells, but when it changes into its misfolded form, it aggregates into long fibrils that clog up the normal functioning of the brain.
