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:
Gene knockout is a technique used to determine the function of a gene that has already been sequenced, which is achieved by analyzing the phenotype of the individual carrying the knockout mutation(s). Moreover, gene sequencing is a technique used to determine the sequence of a given gene, which allows to determine how gene variants (polymorphisms) may be associated with the phenotypes of the target trait.
Explanation:
In genetics, gene knockout is a technique used to trigger mutations in a (already) sequenced gene in order to inactive its function and observe the resulting phenotype for a particular trait. This approach that starts with the inactivation of a given gene and ends with the phenotype is known as reverse-genetics. On the other hand, gene sequencing can be defined as the methodologies/techniques/tools used to determine the nucleotide base pair sequence of a particular gene. The gene knockout technique involves knowing a priori the gene sequence in order to obtain a gene knockout (gene KO). The combination of the information obtained from these techniques can be used to determine how variation (genetic variation) affects the expression of a phenotypic trait.
If we talk about mathematics and the science behind geography, east and west are directions that may represent infinitely. The reason why quantity exist is to measure and create scales on how far an object is from the origin or the point of locus.
These directions can be compared to a line in math which is an endless and limitless progress of points connected without a direction however, incorporating a specific direction could still represent a endless point of west; an endless point to east. Conclusively both are infinite and long unless determined and specified by a continouous measure.
