Cell Membrane Structure, Transport, and Function: Phospholipids, Water Movement, and Cell Processes

What are the parts of a phospholipid?

A phospholipid consists of a phosphate head and two fatty acid tails.

What is the polar region of a phospholipid?

The phosphate head is the polar region, which is hydrophilic (water-attracting).

What is the nonpolar region of a phospholipid?

The fatty acid tails are the nonpolar region, which is hydrophobic (water-repelling).

What does selectively permeable mean?

A selectively permeable membrane allows certain substances to pass through while blocking others.

Is the cell in a hypertonic or hypotonic solution?

The cell is in a hypertonic solution if the concentration of solute outside the cell is higher than inside, causing water to move out of the cell.

In which direction will solute molecules move?

Solute molecules will move into the cell if the concentration inside is lower than outside.

In which direction will water molecules move?

Water molecules will move into the cell if it is in a hypotonic solution, and out of the cell if it is in a hypertonic solution.

Is the cell in a hypertonic or hypotonic solution with glucose?

The cell is in a hypotonic solution if the concentration of glucose is lower inside the cell than outside.

Will solutes pass into or out of the cell?

Solutes will pass into the cell if their concentration is lower inside than outside.

In which direction will water move in the glucose solution diagram?

Water will move into the cell if the extracellular fluid has a higher concentration of glucose.

What is diffusion?

Diffusion is the movement of molecules from an area of higher concentration to an area of lower concentration without the use of energy.

What is osmosis?

Osmosis is the diffusion of water across a semipermeable membrane.

What is facilitated diffusion?

Facilitated diffusion is the process of transporting substances across a membrane with the help of proteins, without using energy.

What is active transport?

Active transport is the movement of molecules against their concentration gradient, requiring energy.

How to test for glucose presence?

Use Benedict's solution; if glucose is present, the solution will change color upon heating.

Can glucose pass through dialysis tubing?

No, glucose cannot pass through dialysis tubing because it is too large; it requires facilitated diffusion.

How to test for starch presence?

Use iodine solution; if starch is present, the solution will turn blue-black.

Can starch pass through dialysis tubing?

No, starch cannot pass through dialysis tubing because it is too large.

Can water pass through dialysis tubing?

Yes, water can pass through dialysis tubing because it is small enough to diffuse through the membrane.

Why are cells small?

Cells are small to maintain a high surface area-to-volume ratio, which facilitates efficient nutrient uptake and waste removal.

What is the difference between endocytosis and exocytosis?

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