The use of the isotope 32P as a tracer element in the study of invasion and lysis of bacteria by viruses has shown that bacteriophage protein enters the bacteria.
Phosphorus-32 is a radioactive isotope of phosphorus, such that the nucleus of phosphorous-32 contains 15 protons and 17 neutrons, one more neutron than the most common isotope of phosphorous, phosphorous-31.
Answer:
In bryophytes, the sporophyte is minute and dependent on the relatively prominent and nutritionally independent gametophyte for resources. The moss gametophyte looks like a miniature herb, with tiny leaf-like photosynthetic organs. The gametophyte generation begins as a dormant spore, which germinates under appropriate conditions to produce filamentous and branching protonemal tissues. These form multicellular bud-like structures, each of which develops into a leafy shoot. The mature gametophytes produce male and female sexual organs, the antheridia and archegonia, respectively. The gametophyte is often sexually distinct, and plants are either male or female.
Each antheridium has an outer layer that encloses and protects thousands of motile sperm, which swim through available external water layer to the egg. Fertilization at the base of the cylindrical archegonium produces a diploid zygote which develops into an unbranched sporophyte. The sporophyte consists of a thin stalk attached to the gametophyte, and a capsule that encloses the sporophytic meiotic cells.
In recent years, the mosses Physcomitrella patens and Funaria hygrometrica have emerged as attractive model systems for studying gene function in non-vascular plants because of the relative ease of molecular manipulation by homologous recombination. Mutants affecting gametophyte development have been isolated and their analysis should provide insights into the molecular basis of gametophyte development in mosses.
Explanation:
Answer:
Sperm undergo more mitotic cellular divisions than egg and therefore have a higher risk of developing a spontaneous mutation.
Explanation:
As you have seen in the question above, lycanthropy is a mutation that is more likely to be established as the supply of male gametes comes from older men. This is because sperm undergo more mitotic cell divisions than eggs, and therefore are at greater risk of developing a spontaneous mutation.
In order for you to understand this, you need to know that eggs (which are female gametes) are produced at once in a woman's body. Thus, cell division is limited and therefore the opportunity for spontaneous mutations to occur is also limited. However, men produce sperm from adolescence to death, creating the need for countless cell divisions, which can develop genetic errors that create spontaneous mutations in gametes.
