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:
D. they're all made up of cells
A carbohydrate composed of two covalently bonded simple sugars is called a <u>disaccharide</u>.
Carbohydrates or sugars are one of the four main categories of the macromolecules that make up living things (the other three being nucleic acids, proteins and lipids). It can either be a simple sugar (sugar monomer or monosaccharide) or a polymer of simple sugars.
Carbohydrates are composed entirely of carbon, oxygen and hydrogen atoms. Simple sugars or monosaccharides contain six carbon atoms, twelve hydrogen atoms and six oxygen atoms. When two monosaccharides bond covalently, they form a disaccharide.
Some examples of disaccharides include:
- Sucrose or table sugar - It is made up of one glucose molecule and one fructose molecule
- Lactose or milk sugar - It is made up of one glucose and one galactose molecule
- Maltose or malt sugar - It is made up of two glucose molecules.
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The student should chose a location within the office that has good ventilation and a workspace big enough to accommodate all his science materials.
What is an experiment?
An experiment can be defined as a procedure carried out under supervised conditions in order to discover an unknown effect, to test or refute a claim, or to illustrate a known law.
A science experiment should be carried out in a location within the office that has good ventilation and a workspace big enough to accommodate the required science materials. The location should be devoid of children, pets and other danger-posing objects.
In conclusion, experiments are carried out in suitable conditions and environment.
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