Flashcards- Ch 7 Cell Membrane Structure

Front

Function of the cell membrane

Back

The cell membrane is often referred to as "the edge of life" because it defines the boundary of the cell and regulates the movement of substances in and out.

Front

Membrane functions

Back

- Allow some substances to leave or enter the cell - Maintain internal and external cell environments - Display cell antigens/markers - Hold receptors for large molecules - Seal, fuse, and remain flexible as the cell changes shape

Front

describe the structure of phospholipids.

Back

Phospholipids have a glycerol backbone attached to a phosphate group and 2 fatty acid chains. Phospholipids are amphipathic, meaning they have both hydrophobic and hydrophilic ends.

Front

Identify hydrophobic and hydrophilic regions of a phospholipid.

Back

The glycerol and phosphate group are hydrophilic (polar); the lipid tails are hydrophobic (nonpolar)

Front

Result of phospholipid structure in water

Back

Cell membrane forms spontaneously as a lipid bilayer.

Front

Function of protein channels in lipid bilayer

Back

Protein channels penetrate the lipid bilayer to prevent complete impermeability. Allow specific molecules that are too large or too polar to cross the membrane.

Front

Role of hydrophobic amino acids in proteins

Back

Hydrophobic amino acids allow proteins to embed themselves in the phospholipid tail region of the plasma membrane since the membrane is hydrophobic there.

Front

Lipid bilayer membranes are permeable to:

Back

IN GENERAL:

- Other lipids - Nonpolar molecules
- Small polar molecules

SPECIFIC EXAMPLES of some of these molecules are in parentheses:

- Nonpolar molecules (e.g., O₂, CO₂)
- Small polar molecules (e.g., H₂O)

Front

Lipid bilayer membranes are impermeable to:

Back

IN GENERAL:

- Ions
- Large polar molecules

SPECIFIC EXAMPLES of some of these molecules are in parentheses:

- Ions (e.g., Na⁺, K⁺, Cl⁻)
- Large polar molecules (e.g., sugars C₆H₁₂O₆, proteins)

Front

3 main types of globular proteins embedded within the cell membrane

Back

1. Integral Protein: permanently attached 2. Transmembrane Protein: an integral protein that crosses the entire membrane 3. Peripheral Protein: not permanently attached