AP Biology - Unit 2 review

Front

What is water potential (Ψ) and how is it calculated?

Back

Water potential (Ψ) is a measure of the potential energy in water, influencing the direction of water movement. It is calculated using the formula: Ψ = Ψs + Ψp, where Ψs is the solute potential and Ψp is the pressure potential.

Front

What is the significance of the 'cis' face of the Golgi apparatus?

Back

The 'cis' face of the Golgi apparatus is the receiving side where proteins and lipids from the endoplasmic reticulum enter for processing and modification.

Front

Define hydrophobic and hydrophilic regions in cellular membranes.

Back

Hydrophobic regions are non-polar and repel water, typically composed of fatty acid tails of phospholipids. Hydrophilic regions are polar and attract water, typically composed of phosphate heads of phospholipids.

Front

What is the difference between active transport and passive transport?

Back

Active transport requires energy (ATP) to move substances against their concentration gradient, while passive transport does not require energy and moves substances along their concentration gradient.

Front

What happens to a cell with a water potential of -1.5 bars placed in a solution with a water potential of -4.0 bars?

Back

Water will flow out of the cell, as it moves from an area of higher water potential (-1.5 bars) to an area of lower water potential (-4.0 bars).

Front

What is solute potential (Ψs) and how is it calculated for a sugar solution?

Back

Solute potential (Ψs) is calculated using the formula: Ψs = -iCRT, where i is the ionization constant, C is the molar concentration, R is the pressure constant (0.0831 liter bar per mole per K), and T is the temperature in Kelvin.

Front

Explain the role of ATP in active transport mechanisms.

Back

ATP provides the energy required for active transport by phosphorylating transport proteins, enabling them to change shape and move substances across the membrane against their concentration gradient.

Front

What is the function of the trans face of the Golgi apparatus?

Back

The trans face of the Golgi apparatus is the shipping side where processed proteins and lipids are packaged into vesicles for transport to their final destinations.

Front

Describe the structure of a phospholipid and its role in cell membranes.

Back

A phospholipid consists of a hydrophilic (water-attracting) phosphate head and two hydrophobic (water-repelling) fatty acid tails. This structure allows phospholipids to form a bilayer, creating a semi-permeable membrane.

Front

What is osmosis and how does it relate to water potential?

Back

Osmosis is the diffusion of water across a selectively permeable membrane from an area of lower solute concentration to an area of higher solute concentration, influenced by water potential.