Answer:
(a) Allow movement in only one plane/direction (that is extension or flexion)
(b) The skeletal system also produces blood cells in their bone marrow
Answer:
There are four major classes of biological macromolecules (carbohydrates, lipids, proteins, and nucleic acids); each is an important cell component and performs a wide array of functions.
Explanation:
Answer:
1. Earth's ozone layer is responsible for absorbing infrared and ultraviolet rays from the sun.
2. Changes in the composition of the atmosphere have caused gradual changes in earth's climate, causing changes in plant and animal life that contributed to mass extinctions.
3. Chemical chlorofluorocarbons (CFCs) have been banned and replaced with hydrochlorofluorocarbons (HCFCs).
4. Naturally occurring volcanic eruptions can produce large amounts of gases which contain sulfur. These gases accumulate in the atmosphere in the same way as man-made sulphuroxides.
Sorry, but after that I don't know.
Explanation:
Answer:
Mutations that activate the kinase portion of the receptor result in a receptor that is constantly phosphorylated. This causes constitutive activation of downstream signaling and the resulting cell growth and proliferation
Explanation:
The epidermal growth factor receptor (EGF receptor) is a type of receptor tyrosine kinase that recognizes and binds different ligands (including the Epidermal growth factor), which triggers its dimerization through the interaction of the extracellular domains. In humans, several mutations in genes encoding receptor tyrosine kinases have been associated with cancers. It is for that reason that mutated receptor tyrosine kinase genes are well-known oncogenes. Moreover, mutations in several receptor tyrosine kinase genes that lead to constitutive activation by phosphorylation have also been identified. In this case, it is expected that a mutation in the EGF receptor leads to constitutive phosphorylation of the mutant protein, constitutively activating downstream signaling.
