1. If we compare the lengths, the good answer would be the neurons.
The body of the neuron measures from 5 to 120 μm. The size of a neuron (or rather an axon) varies from a fraction of a micron to two meters (the equivalent from the brain to the toe).
2. The particularity of neurons is that it does not divide, but survive for a very long time.
Neurons do not usually die before the death of the entire organism. However, many types of trauma and pathology can shorten the duration of their existence. Neurons that disappear and are rarely replaced (or not) because there are few stem cells that can differentiate into neurons in the mature nervous system. Like most cells, neurons can die in two different ways: necrosis or apoptosis.
Answer:
The correct option is D. When Harry asks “What is different with this plant that does not grow very well compared with the other house plants?”
Explanation:
A scientific method can be described as a method on the basis of which all scientific theories or researches are made. A scientific method begins with a question. A hypothesis is made in response to the question. To test the hypothesis, experimentation is done. And finally a hypothesis is considered true or false on the basis of experiments made.
In the question above, Harry's problem is described in the question which he makes. And then he derives a possible hypothesis for his question.
they tend to close the stomata to prevent water loss
Answer:
In reproductive or sexual cells
Explanation:
There are two principal types of cells in the organism: Somatic diploid cells (2n) that reproduce by the process of mitosis, and germ cells that are diploid reproductive cells in charge of gamete production. These germ cells suffer both mitosis (to form more sexual cells) and meiosis (giving place to haploid gametes: sperm and egg cells, through the gametogenesis process). Both somatic cells and germinal cells will end their cycle becoming two daughter cells with the same genetic dotation.
Gametes from each parent will merge in the process of fecundation, during which a new diploid cell called a zygote emerges through fertilization. The zygote is a complete cell from the structural point of view that suffers successive mitosis to form the new organism.
Any cell in the organism might suffer mutation.
- If the mutation occurs in the somatic cells, it will produce a population of identical mutated cells in that organism. However, this mutation in these cells is not inheritable. By definition, mutations in somatic cells do not inherit because these cells do not produce progeny.
- If the mutation occurs in the germinal line, in the germ cells, or the sexual cells, this <u>mutation will pass to the offspring</u>. The organism with mutated germinal cells might express a normal phenotype, but this mutation will be detected in the progeny.
Ans.
Gene regulation or regulation of gene expression involves mechanisms, used by the cells to enhance or reduce the expression of specific genes to make proteins or RNA. Gene regulation occurs at transcriptional level and post-transcriptional level, which involves regulation at translational level or protein level.
Regulation at translational level or protein level is also important as regulation at transcriptional level. Translational regulation controls formation of proteins from mRNA molecules and includes non-coding mRNAs and repressor proteins. It is important for cell growth, differentiation and cellular response to stress and provides an immediate adjustment of gene expression by directly regulating the protein concentration.
Regulation at protein level involves regulation of active protein. It includes regulation by various small molecules, post-translational modifications (such as phosphorylation), and proteolysis. Regulation only at transcriptional level is not sufficient to provide proper gene regulation and leads to various drawbacks, such as Fragile X Syndrome (due to defect in a protein).
Thus, 'gene regulation is important both at transcriptional level and at post-transcriptional level (during translation or protein level).'
