Answer:
Options B, C, and D
Explanation:
The following assertions are accurate about the continental crust:
Its thickness ranges from 25 to 70 km.
It comprises various kinds of rocks.
This layer contains silicate minerals rich in sodium, potassium, aluminum, and calcium.
Answer:
C. They are carried by motor proteins using the cytoskeleton as a "roadway"
Explanation:
Vesicles hitch a ride on molecular motors such as kinesin or myosin, moving along the cytoskeleton until they reach their intended location, where they then fuse with the target membrane or organelle. Typically, vesicles progress from the ER to the cis Golgi, followed by movement from the cis to the medial Golgi, from the medial to the trans Golgi, and finally from the trans Golgi to the plasma membrane or other cellular compartments. While the predominant direction is forward, there are also vesicles that return from the Golgi to the ER, carrying proteins that should have remained in the ER (e.g., PDI) that were inadvertently enclosed in a vesicle.
D. integrins. Explanation: The extracellular matrix comprises a complex framework of proteins and carbohydrates found in the areas outside cells. Collagen proteins, modified with carbohydrates, form collagen fibers that intertwine with proteoglycan complexes consisting of polysaccharides and proteins. This structure is vital for maintaining mechanical strength and structural support for tissues. Integrins, located within the cell membranes, are essential connections between fibers in the extracellular matrix and neighboring cells. They also enable cell communication by detecting both mechanical and chemical signals from the extracellular matrix and triggering intracellular signaling pathways.
Answer:
False
Explanation:
If this were indeed accurate, it would threaten the internal balance of our cells; akin to how not all keys fit in locks, not every molecule possesses the "key" needed to transport across the phospholipid bilayer into and out of the intracellular and extracellular fluids. Typically, small hydrophobic ("water-repelling") molecules can traverse this bilayer.
The right answer is B. DNA helicase initially unwinds the double helix surrounding the +1 site.
