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:
Mutation is the source for new genetic variation: Genetic variation is brought about by random mutation. Without mutation, genetic variation cannot occur. Mutation is a change in the genetic code in DNA and can lead to a change in the protein that is coded for that segment of DNA.
Explanation:
Mutations are changes to an organism's DNA and are an important driver of diversity in populations. Species evolve because of the accumulation of mutations that occur over time. ... This mutation has introduce a new allele into the population that increases genetic variation and may be passed on to the next generation.
As for this problem, the most probable answer and the most likely answer for this one would be D. the effect of pesticides on organisms in the environment.
A toxicologist would only study about chemicals and their effect on organisms in the environment. Pesticides are chemicals made to combat organisms that aren't wanted particular parts of the environment such as crops and rice field. These pesticides don't just affect those organisms that are targeted, but even the users and other organisms that may have come in contact with pesticides.
Explanation:
The autonomic nervous system _____.
A. controls involuntary actions
The nervous system is subdivided into; the central nervous system (CNS), which includes the brain and spinal cord, within the vertebral column; and the peripheral nervous system, which includes nerves that branch into the rest of the body from the brain and spinal cord. Nervous tissue responds to electrical impulses, allowing for communication between different regions of the body.
The peripheral nervous system is further divided into the somatic nervous system responsible for carrying out sensory and motor information between the peripheral nervous system- including sensory organs like the eyes; and central nervous system; and the autonomic nervous system (ANS) which regulates involuntary bodily functions like heartbeat, breathing and blood flow. The ANS is mainly acts unconsciously and affects smooth muscle and internal organs. It is related to homeostasis- where the body maintains a constant internal balance in pH, temperature, blood pressure etc.
Learn more about the autonomic nervous system at brainly.com/question/10386413
Learn more about homeostasis at brainly.com/question/1601808
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Answer:
rock that forms when melted rock (magma, lava) cools and hardens
Explanation:
Igneous rock, or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rock is formed through the cooling and solidification of magma or lava. The magma can be derived from partial melts of existing rocks in either a planet's mantle or crust.
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