Cell membrane

Question 1

What is the primary function of the cell membrane?

Answer 1

The cell membrane regulates what enters and leaves the cell, maintaining homeostasis.

Question 2

: What is the structure of the cell membrane often described as?

Answer 2

: The fluid mosaic model.

Question 3

What are the main components of the cell membrane?

Answer 3

Phospholipids, proteins, cholesterol, and carbohydrates.

Question 4

What role do phospholipids play in the cell membrane?

Answer 4

They form a bilayer that acts as a barrier to most water-soluble substances.

Question 5

How do proteins contribute to the function of the cell membrane?

Answer 5

Proteins serve as channels, carriers, and receptors, facilitating communication and transport.

Question 6

What is the significance of cholesterol in the cell membrane?

Answer 6

Cholesterol helps to stabilize the membrane’s fluidity and structure.

Question 7

What are glycoproteins and glycolipids?

Answer 7

They are carbohydrates attached to proteins and lipids, respectively, and play roles in cell recognition and signaling.

Question 8

Define passive transport.

Answer 8

Passive transport is the movement of substances across the membrane without the use of energy, typically down their concentration gradient.

Question 9

What are the types of passive transport?

Answer 9

Simple diffusion, facilitated diffusion, and osmosis.

Question 10

What is active transport?

Answer 10

Active transport is the movement of substances against their concentration gradient, requiring energy (ATP) from a low conc to high conc

Question 11

Give an example of active transport.

Answer 11

The sodium-potassium pump.

Question 12

What is the difference between endocytosis and exocytosis?

Answer 12

Endocytosis is the process of taking substances into the cell, while exocytosis is the process of expelling substances from the cell.

Question 13

What is simple diffusion?

Answer 13

Simple diffusion is the movement of small, nonpolar molecules directly through the lipid bilayer. from high to low conc

Question 14

What is facilitated diffusion?

Answer 14

Facilitated diffusion is the process where specific molecules pass through membrane channels or transport proteins down their concentration gradient.

Question 15

What is osmosis?

Answer 15

Osmosis is the diffusion of water molecules through a selectively permeable membrane from a region of high water potential to a region of low water potential

Question 16

What are isotonic solutions?

Answer 16

Isotonic solutions have equal concentrations of solutes inside and outside the cell, leading to no net movement of water.

Question 17

What happens in a hypertonic solution?

Answer 17

In a hypertonic solution, the concentration of solutes outside the cell is higher, causing water to move out and the cell to shrink.

Question 18

What occurs in a hypotonic solution?

Answer 18

In a hypotonic solution, the concentration of solutes is lower outside the cell, causing water to enter the cell and potentially leading to swelling or bursting.

Question 19

What is the function of receptor proteins?

Answer 19

Receptor proteins bind to signaling molecules (ligands) and initiate a response inside the cell.

Question 20

What is the role of channel proteins?

Answer 20

Channel proteins provide passages for specific ions or molecules to pass through the membrane.

Question 21

Define membrane potential.

Answer 21

Membrane potential is the difference in charge across a cell membrane, crucial for processes like nerve impulse transmission.

Question 22

What is the role of endocytosis?

Answer 22

Endocytosis allows cells to engulf large particles or other cells, bringing them into the cell within vesicles.

Question 23

What are the three types of endocytosis?

Answer 23

Phagocytosis (cell eating), pinocytosis (cell drinking), and receptor-mediated endocytosis.

Question 24

Describe the process of exocytosis.

Answer 24

Exocytosis involves vesicles fusing with the plasma membrane to release their contents outside the cell.

Question 25

What is the importance of membrane fluidity?

Answer 25

Membrane fluidity allows for the movement of proteins and lipids, enabling cell signaling, transport, and the fusion of membranes.

Question 26

How does temperature affect membrane fluidity?

Answer 26

Higher temperatures increase fluidity, while lower temperatures decrease it, potentially making membranes more rigid.