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:
The nervous system is comprised of two major subdivisions, the central nervous system (CNS) and the peripheral nervous system (PNS).
Explanation:
Answer:
- Organism A is most likely a herbivore
- Organism B is most likey a carnivore
Explanation:
Based on feeding habit, organisms, usually animals, can be classified into three categories namely: herbivores, carnivores and omnivores.
- Herbivores are those organisms that feed on vegetative matter i.e. plants while carnivores are those organisms that feed on flesh of other animals or organisms. Based on what they feed on, herbivores are adapted to possess blunt teeth (for chewing) like Organism A in this question while carnivores are adapted to possess sharp teeth (for tearing flesh) like Organism B.
Based on the above explanation, organism A is most likely a HERBIVORE while organisms B is most likely a CARNIVORE.
- Another notable point of difference between herbivores and carnivores, which is likely to differentiate organism A and B as well, is that herbivores possess digestive enzyme- amylase in their saliva while carnivores do not. Herbivores need AMYLASE to break down complex carbohydrate (starch) in the plants they feed on.
<span>Atoms that have filled outermost energy levels and do not participate in chemical bonding are called Inert Atoms. Remember this by thinking of the definition of Inert; meaning unable or not having the strength to move. So if it an atom has a filled outer level the electrons will be inert.
</span>
<span>When two or more elements bond together in specific proportions, "Compound" is formed.
Hope this helps!</span>
