From the given options, the following sidovery involving DNA happened first: C) Griffith learned that a chemical changed harmless cells into harmful cells.
The British medical officer named Frederick Griffith discovered DNA in 1928 while conducting experiments using Streptococcus pneumoniae bacteria and mice.
<span>He concluded that the living R bacteria had been transformed into pathogenic S bacteria by an unknown, heritable substance from the dead S cells that allowed the R cells to make capsules.</span>
Answer:
c.
Explanation:
They work by killing the bacteria or slowing down its growth, they achieve this by attacking places like the wall or coating the surrounding bacteria.
Answer:
The C. elegans embryo is a powerful model system for studying the mechanics of metazoan cell division. Its primary advantage is that the architecture of the syncytial gonad makes it possible to use RNAi to generate oocytes whose cytoplasm is reproducibly (typically >95%) depleted of targeted essential gene products via a process that does not depend exclusively on intrinsic protein turnover. The depleted oocytes can then be analyzed as they attempt their first mitotic division following fertilization. Here we outline the characteristics that contribute to the usefulness of the C. elegans embryo for cell division studies. We provide a timeline for the first embryonic mitosis and highlight some of its key features. We also summarize some of the recent discoveries made using this system, particularly in the areas of nuclear envelope assembly/ dissassembly, centrosome dynamics, formation of the mitotic spindle, kinetochore assembly, chromosome segregation, and cytokinesis.
1. The C. elegans embryo as a system to study cell division
The C. elegans embryo is a powerful model system for studying the mechanics of metazoan cell division. Its primary advantage is that the syncytial gonad makes it possible to use RNA interference (RNAi) to generate oocytes whose cytoplasm is reproducibly (>95%) depleted of targeted essential gene products. Introduction of dsRNA rapidly catalyzes the destruction of the corresponding mRNA in many different systems. However, depletion of pre-existing protein is generally a slow process that depends on the half-life of the targeted protein. In contrast, in the C. elegans gonad, the protein present when the dsRNA is introduced is depleted by the continual packaging of maternal cytoplasm into oocytes (Figure 1). Since depletion relies on the rate of embryo production instead of protein half-life, the kinetics tend to be similar for different targets. By 36-48 hours after introduction of the dsRNA, newly formed oocytes are typically >95% depleted of the target protein.
Explanation:
Answer: to predict the probability of offspring genotypes
Explanation: Punnett squares are developed to predict the probability of offspring genotype. Punnett square is a square shaped diagram used for predicting the possible genotypes of a cross between two organisms. Punnett square is named after Reginald C. Punnett, who invented the approach. In punnett squares, the genotypes of the parents are written on the top and left hand side of the square while the possible genotypes of their offsprings are written in the boxes.
