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.
Answer:
The immune system is made up of a network of cells, tissues, and organs that work together to protect the body.
Explanation:
Fatty acids are mostly composed of chains of carbon and hydrogen. Fatty acids without double bonds are "saturated" with hydrogen. When a fatty acid has one double bond, hydrogen is released therefore the fatty acid is "monounsaturated". When a fatty acid has two or more double bonds, then the fatty acid is "polyunsaturated". Unsaturated fatty acids are usually takes in the form of oils as they are liquid in room temperature (in contrast to saturated fatty acids which are solid in room temperature). Unsaturated fatty acids are usually found in plant based fats such as oils. Therefore the answer to this question is sunflower oil.
