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: Homeostasis
Explanation: One way that a cell maintains homeostasis is by controlling the movement of substances across the cell membrane. The lipid bilayer is selectively permeable to small, nonpolar substances. Proteins in the cell membrane include cell-surface markers, receptor proteins, enzymes, and transport proteins.
Answer: Mammals give birth to live young, whereas the birth of amphibians takes place externally. Mammals are warm-blooded, while amphibians are cold-blooded. Mammals can live in all habitats, unlike amphibians, and have muted colors. Some amphibians can regenerate their limbs.
Answer:
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Answer: Living things are placed into groups based on both structural and functional similarities. For example, bacteria are prokaryotic cells, which means they lack a true nucleus. Cytoplasm Functions. Some of these processes include protein synthesis, the first stage of cellular respiration (known as glycolysis), mitosis, and meiosis. In addition, the cytoplasm helps to move materials, such as hormones, around the cell and also dissolves cellular waste.
Explanation:
