Question

the phospholipids in the cell membrane are packed tightly together. the outer parts of the lipid bilayer are polar and hydrophilic. the inner core of the lipid bilayer is nonpolar and hydrophobic. this structure allows only small nonpolar molecules to freely pass through the lipid bilayer. select the true statements. carbon dioxide, a small nonpolar molecule, can freely pass through the lipid bilayer. positively charged potassium ions can freely pass through the lipid bilayer. the inner core of the lipid bilayer repels polar molecules like water. the outer parts of the lipid bilayer repel polar molecules like water.

Explanation:

Step1: Recall lipid - bilayer properties

The lipid bilayer has a non - polar hydrophobic inner core and polar hydrophilic outer parts.

Step2: Analyze carbon dioxide passage

Carbon dioxide is a small non - polar molecule. Non - polar molecules can freely pass through the non - polar inner core of the lipid bilayer, so this statement is true.

Step3: Analyze potassium ion passage

Potassium ions are charged (polar) and large compared to small non - polar molecules. The non - polar inner core of the lipid bilayer repels charged and polar molecules, so potassium ions cannot freely pass through, and this statement is false.

Step4: Analyze inner core and polar molecules

The inner core of the lipid bilayer is non - polar and hydrophobic. Polar molecules like water are repelled by the non - polar inner core, so this statement is true.

Step5: Analyze outer parts and polar molecules

The outer parts of the lipid bilayer are polar and hydrophilic. They attract polar molecules like water, not repel them, so this statement is false.

Answer:

• Carbon dioxide, a small nonpolar molecule, can freely pass through the lipid bilayer. - True
• Positively charged potassium ions can freely pass through the lipid bilayer. - False
• The inner core of the lipid bilayer repels polar molecules like water. - True
• The outer parts of the lipid bilayer repel polar molecules like water. - False