Answer:
double helix, which is made up of a nitrogenous base, a five-carbon sugar (deoxyribose), and a phosphate group. There are four nitrogenous bases in DNA, two purines (adenine and guanine) and two pyrimidines (cytosine and thymine).
Explanation:
Answer:
The correct order, from fastest to slowest, for the passage of molecules and ions through the cell membrane is oxygen, sodium ions, glucose (option D).
Explanation:
The plasma membrane is a lipid bilayer, with glycoproteins and membrane proteins, which constitutes a semi-permeable barrier to the passage of substances into and out of the cell.
The speed with which a substance can pass through the membrane depends on its chemical properties -hydrophilic substances pass through with greater difficulty than lipophilic ones- requiring in some cases specialized transport mechanisms. The different rates with which a substance passes depends on this.
- <em>Oxygen (O₂) </em><em>passes through simple diffusion, depending on a concentration gradient. It's the molecule that passes through the membrane the fastest.
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- <em>In second place, there would be the </em><em>Na⁺ ions</em><em> -charged atoms- that cross the membrane by facilitated diffusion, through specific ionic channels.
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- <em>The </em><em>glucose</em><em> molecule, being larger, requires the use of transport proteins, being its passage through the membrane slower with respect to oxygen or sodium.</em>
Undoubtedly, molecular weight and affinity for the plasma membrane are determining factors for the passage of molecules through the lipid bilayer.
Learn more:
Simple diffusion and active transport brainly.com/question/6420224
The answer would be letter B.
