Answer:
Mitochondrial proteins enter the organelle through channels formed by membrane proteins present in its inner and outer membranes.
Explanation:
All the biological membranes have lipid bilayer with the non-polar core that does not allow entry of charged and large substances. Mitochondrial proteins are synthesized in the cytosol and the unfolded proteins bind to the chaperons that deliver them to the receptors present in the outer mitochondrial membrane.
The receptor moves the protein to the membrane channels formed by integral membrane proteins of inner and outer mitochondrial membranes. The proteins enter the intermembrane space and are targeted to the inner membrane through channels while chaperons are left outside only.
Answer:
The article revealed the fact that Black inventors have always played an active role in inventing new things in America. In the 18th and 19th centuries they were denied the right to patent their inventions because of their status as slaves. This has changed for the better in present times as many Black inventors are being granted patent rights.
Explanation:
The article, "America’s always had black inventors – even when the patent system explicitly excluded them", by Shontavia Johnson, explained the active role that Black Americans, both free and slaves played in inventing things in the United Slaves. The article explained that although the patent rights signed into the constitution in 1787 was written in a neutral tone, it did not change the fact that black inventors were actually denied patent rights.
This segregation affected people like Henry Boyd, Ned, Benjamin Montgomery among others. In recent times, this segregation has significantly been curbed as many Black inventors are now owners of patents. An example is Lonnie Johnson, inventor of the Water Gun and owner of more than 80 patents.
Answer:
c) allowing an organism to adjust to changes in environmental conditions
Explanation:
A stimulus can be defined as any change in the external or internal environment that produces a corresponding response in the organism. These responses enable the organism to maintain an internal equilibrium (homeostasis). Gene expression in prokaryotes, which are the simplest forms of life, is highly regulated by environmental stimuli. Some examples of stimuli known to regulate gene expression patterns in prokaryotic organisms are light, water, pressure, temperature, etc.
Answer:
The correct answer will be option-
1. UV light strikes the skin and converts a steroid molecule into an inactive form of vitamin D.
2. Inactive vitamin D is transported to the liver where it is modified.
3. Vitamin D is activated under the influence of PTH.
4. Inactive, chemically altered vitamin D is transported to the kidneys.
Explanation:
Vitamin D is a fat-soluble metabolite which helps maintain the health of the bone by maintaining the calcium homeostasis.
The vitamin D is synthesized mainly in the liver and kidney from the biologically inactive precursor of vitamin D called ergocalciferol and Cholecalciferol.
The inactive vitamin is synthesized in the skin when the skin is exposed to UV rays. The UV rays convert the 7-dehydrocholesterol, a steroid molecule to Vitamin D3, This inactive vitamin is then transported to the liver where it is converted to 25-hydroxyvitamin D.
This vitamin D form is further metabolized in the kidney controlled and regulated by the Parathyroid glands.
