Chapter 5 biology

The cell maintains a favorable internal environment due to the selective ____ of the plasma membrane.

Permeability

Which of the following regions serve as likely binding sites for peripheral membrane proteins

Polar head groups of phospholipids; hydrophilic regions of integral membrane proteins

Transmembrane proteins participate in many cellular processes. What are examples of these

Transport, cell recognition, energy transduction, cell signaling

What would happen if an animal cell is placed in pure water (which contains no solutes)?

Water will move into the cell from the outside

Transporter proteins transport solutes across the membrane via ______.

a conformational change triggered by solute binding

Most transmembrane segments of integral membrane proteins are folded into what type of secondary structure

alpha helix

The cell membrane is referred to as a mosaic because it is a mixture of what types of molecules

carbohydrates, lipids, proteins

What type of proteins form an open passageway for facilitated diffusion of ions or molecules across the membrane?

channels

Proteins that assist in the movement of substances across membranes can be classified into two types based on how they move solutes across a membrane: and

channels and transporters

What is the short, rigid molecule produced by animal cells that is involved in membrane fluidity?

cholesterol

The plasma membrane of a cell is considered to be

selectively permeable

Water is considered to be a ______ that dissolves ______ molecules.

solvent; hydrophilic solute

When the concentration of solutes on both sides of the plasma membrane are equal, the two solutions are said to be

isotonic

The presence of a double bond in a phospholipid tail makes the membrane more fluid because ______.

it prevents phospholipids from packing tightly

Most phospholipids move freely within a semifluid membrane ____

laterally along the plane of the membrane in 2 dimensions

Most phospholipids move freely within a semifluid membrane

laterally along the plane of the membrane in two dimensions

The movement of charged ions through the Na+/K+-ATPase pump creates a net charge difference because ______.

one cycle of pumping results in the net export of one positive charge

Animal cell in a hypotonic solution

osmotic lysis

Plant cell in a hypertonic solution

plasmolysis

Which of the following types of transport involves pumping ions against a gradient using ATP as a source of energy

primary active transport

Movement of ions and large molecules into and out of the cell is mediated by membrane ______.

proteins

The Na+/K+-ATPase hydrolyzes ATP after the binding of _

three Na+

Which of the following are pumped by the Na+/K+-ATPase?

three Na+ out of the cell two K+ into the cell

The Na+/K+-ATPase pumps ______ Na+ ions out of the cell and ______ K+ ions into the cell.

three, two

A term that describes a situation in which the concentration of a solute is higher on one side of a membrane than the other is ______.

transmembrane gradient

a segment of amino acids is inserted into the phospholipid bilayer

transmembrane protein

Where would peripheral (or extrinsic) membrane proteins likely reside with respect to the plasma membrane?

-on the outside of the inner leaflet, facing the cytoplasm -on the outside of the outer leaflet, facing the outside of the cell

Isotonic refers to a consequence of osmosis in which the solute concentrations are ______.

Equal inside and outside of the cell

What two processes are coupled across animal cell membranes?

Export of Na+ and import of k+ ions

The Na+/K+-ATPase produces an electrical gradient across the membrane because one cycle of pumping results in the NET ______ positive charge

Export of one

Channel proteins are transmembrane proteins that are used for what?

Facilitated diffusion

T or f the lipid anchored proteins are loosely associated with membrane proteins

False

Some molecules are known to move laterally in the plane of the membrane as such we can say the membrane is

Fluid

Peripheral membrane proteins can be removed from integral proteins by changing ph or salt concentration because they are bound to integral proteins which types of bonds

Hydrogen and ionic

What type of interactions are typically involved in peripheral proteins binding to biological membranes

Hydrogen, ionic

Phospholipid bilayers are an effective barrier to many charged or polar solutes because of their _____interior region.

Hydrophilic

The solute concentration outside a cell is higher than the Colette concentration inside the cell

Hypertonic

The solute concentration outside the cell is lower than the solute concentration inside the cell

Hypotonic solution

Lipids with shorter tails contribute ___ plasma membrane fluidity.

Increased

Which of the following statements is correct about a biological membrane that is fluid

Individual molecules can move within the membrane.

A membrane protein that has a portion integrated into the hydrophobic region of the membrane is called a _____ membrane protein

Integral

A membrane protein that has a portion integrated into the hydrophobic region of the membrane is called a ____membrane protein

Integral

Identify functions of the selectively permeable plasma membrane

Maintain a proper supply of essential molecules such as glucose and amino acids, remove wast products from within the cell. Maintain a proper balance of ions within the cell

Which of the following statements are consistent with the fluid mosaic model

Many membrane proteins move within the plane of the membrane, membranes are mainly composed of proteins and phospholipids, phospholipids can move within the plane of the membrane

Why is it more appropriate to describe membranes as semi fluid rather than fluid?

Molecules more laterally within the membrane leaflet; phospholipids usually move in two dimensions

The Na+/K+-ATPase pump establishes and maintains a gradient that ensures which of the following conditions?

Na+ is higher outside the cell than inside, and K+ is higher inside the cell than outside

A transmembrane segments of integral membrane proteins are ____ and interact with the ___ of the phospholipid bilayer

Non polar; hydrophobic tails

The fatty acid tails of phospholipids are ___ and are found in the ___ foo the phospholipid bilayer

Non polar;interior

Membrane proteins that span both leaflets of the lipid bilateral have transmembrane segments that are composed of ______ amino acids

Nonpolar

Cells take up so much water that they burst

Osmotic lysis

Which of the following best describes the process of active transport?

Particles moving across a membrane against a concentration gradient.

Proteins that are non covalently bound to the hydrophilic regions of integral membrane proteins or to the polar head groups of lipids are called ___ membrane proteins

Peripheral

Proteins that are non-covalently bound to the hydrophilic regions of integral membrane proteins or to the polar head groups of lipids are called ___ membrane proteins

Peripheral

Proteins that associate with he plasma membrane through non covalent interactions with phospholipids or transmembrane proteins are called ______ membrane proteins

Peripheral

Noncovalent associations form with phospholipids other membrane proteins

Peripheral membrane protein

What is osmosis?

Diffusion of water from an area of low solute concentration to an area of high solute concentration

Sequence the steps involved in the actions of the Na+/K+-ATPase pump. Start with the binding of Na+ at the top.

3 Na+ bond from cytosol, ATP is hydrolyzed, and ADP is released P is bound to the pump, switching it to the E2 configuration 3 Na+ are released outside the cell 2 K+ bind from outside the cell Phosphate is released and the pump switches to the E1 configuration 2 K+ are released into the cytosol

In order to move a solute from areas of low concentration to areas of high concentration ______ is required.

An input of energy

The Na+/K+-ATPase pump is considered a(n) ______ because it binds both Na+ and K+ and

Antiporter

Cholesterol in a membrane has which of the following effects

At a high temperature, it makes the membrane less fluid; at a low temperature, it makes the membrane more fluid.

The sodium/potassium-ATPase transports Na+ and K+ ions against their gradients using the energy from ____hydrolysis

Atp

Why is the Na+/K+-ATPase pump considered an antiporter?

Because it moves two substances in opposite directions.

Why is the phospholipid bilayer an effective barrier to hydrophilic or polar molecules?

Because of the hydrophobic interior of the bilayer

Why are transmembrane proteins able to span the hydrophobic portion of the bilayer

Because these proteins have stretches of non polar amino acids

Transporter proteins bind their solutes in a hydrophilic pocket and then undergo a(n) ___change that switches the exposure of the pocket from one side of the membrane to the other.

Conformational

How is a lipid-anchored protein attached to the membrane?

Covalently bound to an amino acid side chain within the protein

Water exits the cell causing it to shrivel up

Cremation

What type of interactions are typically involved in peripheral proteins binding to biological membranes

Ionic bonds and hydrogen bonds

No change or addition change in cell volume

Isotonic

The solute concentration outside a cell is equal to the solute concentration inside the cell

Isotonic

What demonstrates that a protein is an intergral membrane protein

It cannot be released from the membrane unless the membrane is treated with a detergent or organic solvent

The presence of a double bond in a phospholipid tail makes the membrane more fluid because____

It prevents phospholipids from packing tightly

In the 1940s, studies of animal cells suggested that the import of ______ is coupled to the export of _____

K+, Na+

The double bonds in unsaturated lipids create ____ in the acyl tails making it more difficult for neighboring lipids to interact

Kinks

Which of the following is a valid conclusion of the Frye and Edidin experiment?

Lateral protein movements within the membrane are temperature-dependent.

A lipid molecule is covalently attached to an amino acids side chain of the membrane protein

Lipid anchored protein

A membrane protein with a lipid covalently bound to an amino acid side chain within the protein is known as a

Lipid anchored protein

Integral membrane proteins include which of the following

Lipid anchored proteins, transmembrane proteins

Integral membrane proteins include which of the following

Lipid-anchored proteins, transmembrane proteins

Transport involving a pump that uses energy from ATP to transport solutes against a gradient is called ____active transport.

Primary

Which of the following movements of a phospholipid are energetically favorable within that bilayer?

Rotational movements and lateral movements

All cells are surrounded by a(n) ____permeable plasma membrane, meaning that the membrane allows the passage of some molecules and ions but not others.

Selectively

Why do shorter tails make membranes more fluid?

Shorter tails interact less with each other.

In a solution, the ions that are dissolved are called the ___molecules, and the liquid in which they are dissolved is called the _____

Solute; solvent

The Frye and Eddie experiment demonstrated that lateral protein movement within the membrane is affected by ____

Temperature

Cellular membranes are described as fluid why

Their lipids and proteins can move relative to each other

When the concentration of a solute is higher on one side of membrane than the other, a(n) ______ gradient is established

concentration

Animal cell in a hypertonic solution

crenation

An unsaturated lipid contains

double bonds

Select the processes used by eukaryotic cells to transport large molecules such as proteins and polysaccharides.

endocytosis and exocytosis

According to the ___ model, membrane proteins and lipids are able to move relative to one another within the plasma membrane

fluid mosaic

What property of biological membranes describes the ability of individual molecules to move within the membrane?

fluidity

Phospholipids have a ____ head region that will interact with aqueous environments

hydrophilic

Movements that keep the phospholipid fatty acid tail within the ____ region of the bilayer are energetically favorable

hydrophobic

A membrane protein that has a portion integrated into the hydrophobic region of the membrane is called a(n) ______ membrane protein

integral

What are the categories of proteins that assist in the movement of molecules and ions across membranes?

transporters and channels

When a double bond is present in the fatty acid tail of a phospholipid, the lipid is said to be

unsaturated