Plasma Membrane Structure and Function

30 fill-in-the-blank flashcards covering the structure, components, and functions of the plasma membrane.

All cells are surrounded by the __, also known as the plasma membrane.

cell membrane

The membrane separates the cell from its __ environment.

surrounding

The plasma membrane regulates exchange of materials and removes __.

wastes

The __ Model describes proteins bobbing in a fluid phospholipid bilayer.

Fluid Mosaic

The plasma membrane is primarily a bilayer of __.

phospholipids

In animal cells, __ molecules are found between phospholipids.

cholesterol

The hydrophilic portion of a phospholipid is its __.

head (phosphate group)

Phospholipid tails are __, meaning water-fearing.

hydrophobic

Because of their properties, phospholipids self-assemble into a __.

bilayer

Proteins that span the membrane are called __ proteins.

integral

Proteins loosely attached to the membrane surface are __ proteins.

peripheral

Integral proteins help transport larger molecules like __ across the membrane.

glucose

A protein with a carbohydrate chain attached is a __.

glycoprotein

A lipid with a carbohydrate chain attached is a __.

glycolipid

The collective carbohydrate layer on the cell surface is the __.

glycocalyx

Cholesterol maintains membrane __ by preventing phospholipid tails from solidifying.

fluidity

Because it lets some substances through but not others, the membrane is __ permeable.

selectively (semi-permeable)

Nonpolar molecules like O₂ and CO₂ cross the membrane __.

rapidly / easily

Polar molecules such as __ pass only slowly through the lipid bilayer.

glucose

Ions such as Na⁺ and K⁺ move through __ proteins in the membrane.

channel

Movement that requires no cellular energy is called __ transport.

passive

Movement that uses cellular energy is called __ transport.

active

Membrane proteins that receive external signals are known as __.

receptors

The four main molecular components of the plasma membrane are phospholipids, proteins, carbohydrates, and __.

cholesterol

The hydrophilic heads of phospholipids face the __ fluid.

aqueous

Water is a __ molecule that interacts with phospholipid heads.

polar

The hydrophobic core of the bilayer blocks most __ or charged substances.

polar

Because "like dissolves like," __ molecules cross the lipid bilayer more easily.

nonpolar / lipid-soluble

Membrane proteins can attach to the cytoskeleton and __ matrix for support.

extracellular

Viruses such as HIV can hijack membrane __ to enter cells.

receptors