The endosymbiotic theory stated
that the mitochondria of eukaryotic cells are actually prokaryotic bacteria
which were once engulfed by prehistoric eukaryotic cells as a result of
evolution.
Therefore to answer this
question, here are some characteristics:
1 Both mitochondria and prokaryotic cells contain their own
DNA.
2 Neither of the two have
true nuclei, but they do have a space in which their DNA is enclosed.
3 Mitochondria and prokaryotic cells have similar
transcriptional machinery, which means that they have the same process of
making RNA from DNA.
<span>4 Mitochondria
contain their own genome, and the formation of their genome in most organisms
is circular similar to prokaryotes.</span>
Eukaryotes contain linear chromosomes and therefore require telomerase to prevent loss of the ends of the chromosomes
Answer:
Which type of selection tends to increase genetic variation? A. Disruptive selection B. Directional selection C. Stabilizing selection
The Answer is option A (Disruptive selection)
Explanation:
Selection can either shift the mean value of a trait, reduce the trait's variation, or increase its variation.
Genetic variation which allows natural selection to increase or decrease frequency of alleles already in the population is a source of phenotypic variation as it refers to differences in all the hereditary information of members of the same species.
Disruptive Selection is important in maintaining variation and initiating speciation as it Increases Variation by favoring alleles corresponding to more extreme phenotypes. But for it to occur, the mean phenotype has to experience the lowest fitness. Disruptive selection affects the frequency distributions of alleles and genotypes within a population.
Disruptive selection is based on the variance of a trait in a population as it increases genetic variance by equalizing the frequencies of existing alleles at polymorphic loci (a genetic loci with two or more alleles). Disruptive selection maintains and may even increase variation in natural populations by favoring extreme phenotypes, individuals with extreme values for a trait have greater reproductive success than individuals with intermediate values.
Answer: Option A
Explanation:
An endosperm is defined as the tissue which are produced inside the seeds during fertilization. As the endosperm surrounds the embryo, it acts as the food storage for the embryo and provide nutrition.
During embryo development , endosperms supports enlargement of cotyledons which helps in storage function and stores fats and starch and provide nourishment to the embryo.
for example cereal crops or grains are primarily endosperm which stores fat and starch and are edible fruits.
Hence, the correct option is A, endosperm can be a cotyledon which functions as a source of food for embryo.
