Answer:
B. Many active genes are found in euchromatin, because proteins involved in transcription can easily access these regions of DNA.
Explanation:
Euchromatin is the loosely coiled chromatin and is capable of undergoing the process of transcription. On the other hand, heterochromatin is the highly coiled and compacted chromatin present in its inactive state. Active genes are associated with more loosely packed chromatin, which is the euchromatin. This is due to the fact that the DNA in euchromatin is not tightly packed which in turn allows its interaction with a transcription factor. The tightly packed DNA of heterochromatin cannot interact with proteins requires for gene expression.
The optical microscope, also referred to as a light microscope, is a type of microscope that commonly uses visible light and a system of lenses to generate magnified images of small objects
Answer:
Oncogenes result from a mutation in proto-oncogenes.
Explanation:
- Protooncogenes control the growth and division of cells.
- The proteins encoded by proto-oncogenes include growth factors, growth factor receptors, transcription factors and signal transducers.
- They contribute to the transformation process by driving cell proliferation or reducing sensitivity to cell death.
- Several types of genetic and epigenetic changes convert these proto-oncogenes to oncogenes.
- Oncogenes arise due to the changes that increases the expression of proto-oncogenes .
- Oncogenes are one of the causes of cancers.
A proto-oncogenes can turn into oncogene by following ways:
- A point mutation such as deletion, insertion and substitution in the proto-oncogene can lead to formation of oncogenes.
- Chromosomal translocation may result in activation of proto-oncogene as seen in Burkitt's lymphoma.
- Insertion of a mobile genetic material such as retrovirus changes the gene expression, but leaves their coding sequence intact.
- Activation of proto-oncogene can also occur from reduplication and amplification of DNA sequence.
Gases have no defined shape or volume.
