Question

1. what is the primary role of the cell membrane?

a) to synthesize proteins
b) to store genetic information
c) to protect the cells internal environment
d) to facilitate cellular respiration

1. selective permeability of the cell membrane means that it:

a) allows all molecules to pass through unrestricted
b) prevents the entry of water molecules
c) allows only small, nonpolar molecules to enter
d) regulates the passage of substances based on various factors

1. which type of transport relies on the concentration gradient and does not require energy input from the cell?

a) active transport
b) passive transport
c) facilitated diffusion
d) simple diffusion

1. what type of molecules can move through the lipid bilayer of the cell membrane via simple diffusion?

a) small and nonpolar molecules
b) small and polar molecules
c) large and polar molecules
d) large and nonpolar molecules

1. facilitated diffusion involves the movement of molecules with the help of:

a) active transport pumps
b) integral membrane proteins
c) peripheral membrane proteins
d) lipid bilayer channels

Explanation:

1. The cell - membrane acts as a barrier, protecting the cell's internal environment. Protein synthesis occurs in ribosomes, genetic information is stored in DNA (usually in the nucleus), and cellular respiration involves multiple organelles like mitochondria.
2. Selective permeability means the cell - membrane regulates the passage of substances based on factors such as size, polarity, and charge.
3. Passive transport relies on the concentration gradient and does not require energy input from the cell. Active transport requires energy. Facilitated diffusion and simple diffusion are types of passive transport, but the question asks for the general type.
4. Small and non - polar molecules can move through the lipid bilayer of the cell membrane via simple diffusion due to the non - polar nature of the lipid tails.
5. Facilitated diffusion involves the movement of molecules with the help of integral membrane proteins, which can be carrier proteins or channel proteins.

Answer:

1. c) To protect the cell's internal environment
2. d) Regulates the passage of substances based on various factors
3. b) Passive transport
4. a) Small and nonpolar molecules
5. b) Integral membrane proteins