Answer:
B. The membrane lets certain substances move across it freely, while others must move through a “gate”.
Explanation:
Selective permeability is a property of cellular membranes that only allows certain molecules to enter or exit the cell. This is important for the cell to maintain its internal order irrespective of the changes to the environment. For example, water, ions, glucose and carbon dioxide may need to be imported or exported from the cell depending on its metabolic activity. Similarly, signaling molecules may need to enter the cell and proteins may need to be released into the extracellular matrix. The presence of a selectively permeable membrane allows the cell to exercise control over the quantum, timing and rate of movement of these molecules.
Answer:
Density = mass/volume = 57g/4.2 mL ≈ 13.6 g/mL
Explanation:
Mass = 57 g Volume = 4.2 mL
The density of mercury is ⇒ 13.6 g/cm3.
Trust me I got it wrong and it gave me this. I just did the instruction.
Answer:
C. The enzyme changes shape and is no longer able to bind the substrate.
Explanation:
The change in heat changed the size of the enzyme. The enzyme changed size and shape which made it incapable of bonding with the substrate.
The statement which best explains why carbon is present in so many kinds of molecules is because <u>it can form four covalent bonds.
<em /></u>It isn't rare on Earth, so A is incorrect. It has valence electrons, so C is incorrect. It cannot become an ion, so D is incorrect.<u>
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