Chapter 5- Cell Membrane Structure and Function Flashcards
All____ _________ have a double layer of phospholipids.
Cell Membranes
Cell membranes are _____ mosaics or _________ with proteins within the ___________ bilayer that are constantly ________ with respect to one another.
Fluid
Patchwork
Phospholipid
Shifting
The __________ phospholipid _________ are not ______ to one another, so the movement of certain ________ and lipids is possible within the bilayer.
Individual
Molecules
Bonded
Proteins
A phospholipid consist of two different parts which are what?
A head that is polar and hydrophilic.
A pair of fatty acid tails that are non-polar and hydrophobic.
Phospholipid heads face the _____ on the _______ and inside of the plasma membrane-_________ bonds form between water and the ___________ phospholipid heads.
Water
Outside
Hydrogen
Hydrophilic
Phospholipid _____ cluster together within the bilayer because they are hydrophobic- they are ________ toward the interior of the ______ membrane.
Tails
Oriented
Plasma
What are responsible for moving substances across the plasma membrane, communicating with other cells, and identifying the cell? Grouped in 5 major categories what are they?
Proteins Enzymes Receptor Proteins Recognition Proteins Connection Proteins Transport Proteins
What are Enzymes?
Proteins that promote chemical reactions that synthesize or break apart biological molecules
_______ Proteins are proteins that allow cells to _______ to specific _________ molecules (such as hormones) carried in the _________
Recognition
Respond
Messenger
Bloodstream
Define Recognition Proteins
Glycoproteins that sever as identification tags-identifies the cells as “self”
Proteins that anchor cell membranes in various ways.
Connection Proteins
________ Proteins- proteins that span the phospholipid bilayer and ________ the movement of hydrophilic _________ across the membrane- some form channels that can be ______ or ______ to allow specific substances to ____ across the membrane.
Transport Regulate Molecules Opened Closed Pass
How substance move across membranes: Define Solute and Solvent give examples.
Solute- Substance that can be dissolved in a solvent. EX: Sugar (sugar-water)
Solvent- A fluid capable of dissolving a solute. EX: Water (sugar-water)
What is Diffusion?
A net movement to solutes from regions of high concentration to regions of low concentrations.
______ Transport- involves diffusion of substances across cell membranes down their ____________ gradients, includes ______ Diffusion,__________ Diffusion, and _______- no ______ is required.
Passive Concentration Simple Facilitated Osmosis Energy
Very small molecules with no net charge, such as water, oxygen. and carbon dioxide, con diffuse directly through the phospholipid bilayer of cell membranes. Lipid- Soluble molecules may also use this method. Give examples.
Simple Diffusion
EX: Ethyl alcohol, vitamins A,D, and E, and steroid hormones.
Process used by specific proteins to move ions and polar molecules through cell membranes- two types of proteins allow facilitated diffusion- Carrier Proteins and Channel Proteins. Aquaporins- specialized water channel proteins- selective for water molecules.
Facilitated Diffusion
The diffusion of water across a selectively permeable membrane in response to gradients of concentration, pressure, or temperature- we will focus on osmosis from a region of higher water concentration to a region of lower water concentration.
Osmosis
What am I?
A solution with equal concentrations of solute and thus equal concentrations of water.
Isotonic (iso means same)
What am I?
A solution that contains a greater concentration of solute when a membrane separates solutions with different concentrations.
Hypertonic (hyper means greater than)
What am I?
A solution that contains a lesser concentration of solute when a membrane separates solutions with different concentrations.
Hypotonic (hypo means less than)
___ _____ _____ retain their normal size in ________ solution ( they have numerous aquaporins) but in a ___________ solution, water leaves the cells by _______ causing the cells to shrivel; in a _________ solution, water enters the cells causing them to swell and eventually bust.
Red blood cells Isotonic Hypertonic Osmosis Hypotonic
What am I?
Movement of molecules into or out of a cell against a concentration gradient- during active transport, membrane proteins use cellular energy to move molecules or ions across a plasma membrane against their concentration gradients-active transport proteins are often called pumps
Active Transport
Energy requiring process that allows cells to engulf large particles or fluids- three forms: Pinocytosis, Receptor-mediated engocytosis, and Phagocytosis
Engocytosis
