AP Bio Review: Cell membrane, Transport

Front

What is water potential?

Back

Water potential is the measure of the potential energy in water, influencing the direction of water movement. It is calculated as the sum of solute potential and pressure potential.

Front

How do you calculate water potential?

Back

Water potential (Ψ) = Solute potential (Ψs) + Pressure potential (Ψp).

Front

What is solute potential?

Back

Solute potential is the measure of the effect of solute concentration on the overall water potential of a solution, typically expressed in megapascals (MPa).

Front

What is pressure potential?

Back

Pressure potential is the physical pressure exerted on a solution, which can affect the movement of water in and out of cells.

Front

What is passive transport?

Back

Passive transport is the movement of substances across a cell membrane without the use of energy, moving from areas of high concentration to low concentration.

Front

What is active transport?

Back

Active transport is the movement of substances against their concentration gradient, requiring energy (usually in the form of ATP).

Front

Describe the structure of a phospholipid.

Back

A phospholipid consists of a hydrophilic (water-attracting) 'head' and two hydrophobic (water-repelling) 'tails', forming a bilayer in cell membranes.

Front

What is the role of the sodium-potassium pump?

Back

The sodium-potassium pump actively transports sodium ions out of the cell and potassium ions into the cell, crucial for maintaining cellular homeostasis.

Front

What is the endosymbiotic theory?

Back

The endosymbiotic theory suggests that certain organelles in eukaryotic cells, like mitochondria and chloroplasts, originated from free-living prokaryotes that were engulfed by ancestral eukaryotic cells.

Front

What evidence supports the endosymbiotic theory?

Back

Evidence includes the presence of DNA in mitochondria and chloroplasts that is similar to prokaryotic DNA, and the double membrane structure of these organelles.