The distinguishing feature of a prokaryotic cell is that it has no nucleus or internal membranes, so unlike eukaryotic cells they contain no membrane bound organelles. - google
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. hyperthyroidism
Explanation:
Hyperthyroidism is a condition that occurs when the thyroid gland in our body secretes too much of the thyroxin hormone. Thyroid gland is a butterfly shaped gland that is located in our neck and it produces the hormone called thyroxin. Excess production of thyroxin leads to a condition named hyperthyroidism.
A person's metabolism increases when he or she is suffering from hyperthyroidism. One's weight is lost but the appetite increases. Other symptoms are extreme fatigue, irritability, heart palpitations, sweating and puffy eyes.
Thus in the context, Ms. Jones is suspect to have hyperthyroidism as she she is showing all the above symptoms.
Answer:
D more active metabolically
Explanation:
As a result of their surface area to volume ratio, smaller living cells are more active metabolically as transport through the cell organelles occur faster
Answer:
Explanation:
The Julia butterfly (or dryas iulia) isn't trying to cheer up the turtle, it is actually a symbiotic relationship between the two creatures. The butterflies undertake the process of lachryphagy, or 'tear feeding' as a way of gaining much needed nutrition.