Exam 1: Chapter 4

The rate of diffusion depends on what 2 factors?

"Steepness" of concentration gradient temperature

Neurons have a resting membrane potential of ______ mv. a. -70 b. -50 c. -100

-70

The sodium-potassium exchange pump transports ___________ (number) sodium ions out of the cell for every ___________ (number) potassium ions it transports int the cell

3; 2

Exocytosis is a means by which cells release substances to the outside. This process requires the cell to expend energy in the form of _______________. Typically the secretion is packaged into ________________ which fuse with the ______________ membrane prior to release.

ATP vesicles plasma

What does a cell surface receptor do?

Bind molecules called ligands E.g., neurotransmitters released from a nerve cell that binds to a muscle cell to initiate contraction

What do identity markers do?

Communicate to other cells that they belong to the body These markers are used to distinguish healthy cells from cells to be destroyed

___________ is the viscous fluid of the cytoplasm.

Cytosol

__________ is not found in the plasma membrane. a. phospholipids b. cholesterol c. DNA d. glycoproteins

DNA

Define integral proteins.

Embedded within, and extend across the phospholipid bilayer Hydrophobic regions interact with hydrophobic interior Hydrophilic regions are exposed to aqueous environments on either side of membrane

True or False: Membrane bound organelles include ribosomes.

False

Describe membrane proteins

Float and move in fluid bilayer Performs most of membrane's functions

Describe the plasma membrane

Fluid mixture composed of equal parts lipid and protein by weight Regulates movement of most substances in and out of cell

A - Hypotonic b - Isotonic c - Hypertonic

Identify the type of solution for each of the images.

Communication - contains receptors that recognize and respond to molecular signals Electrochemical gradients - establishes and maintains an electrical charge difference across the plasma membrane Physical Barrier - phospholipid bilayer separates substances inside and outside the cell Selective Permeability - regulates entry and exit of ions, nutrients, and waste molecules through the membrane

Match the function of the plasma membrane with its mechanism of action.

A - Golgi apparatus B - mitochondrion C - nucleolus D - vesicle E - cilia

Match the letter of the cellular structure in the image with its name.

A - nucleolus B - rough ER C - golgi apparatus D - smooth ER E - peroxisome F - mitochondrion G - centriole

Match the letter with the structure.

Smooth ER - interconnected network of membrane tubules and vesicles; no ribosomes attached Rough ER - flattened intracellular network of membrane sacs called cisternae; ribosomes attached on cytoplasmic surface Golgi apparatus - stacked series of flattened, smooth membrane sacs with associated transport vesicles Mitochondria - double membrane structures with cristae

Match the membrane bound organelles with their structures.

Microtubules - move chromosomes during cell division Cilia - move fluid, mucus, and materials over the cell surface Flagellum - propels sperm cells of human male Microvilli - increase membrane surface area for increased absorption and/or secretion

Match the nonmembrane bound organelles with their function.

Isotonic - the cytosol and solution outside the cell have the same concentration of solutes Hypotonic - the solution outside the cell has a lower concentration of solutes than the cytosol Hypertonic - The solution outside the cell ha a higher concentration of solutes than the cytosol

Match the tonicity to its definition.

What do enzymes do?

May be attached to either internal or external surface of a cell Catalyze chemical reactions

Describe channel mediated facilitated diffusion

Movement of small ions through water-filled protein channels Channels specific for one ion type Important in normal function of muscle and nerve cells

The relative distributions of K+, which is more concentrated inside the cell and the Na+, which is more concentrated outside of the cell are the result of the activity of the ________. a. Na+/K+ pump b. Ca+/K+ pump c. aquaporins d. neurotransmitter

Na+/K+ pump

Define Diffusion

Net movement of a substance from area of greater concentration to area of lesser concentration Molecules and ions in constant motion due to kinetic energy If unopposed, diffusion continues until substance reaches equilibrium Molecules evenly distributed throughout a given area

Define peripheral proteins.

Not embedded in lipid bilayer Loosely attached to external or interior surfaces of membrane

What do cell adhesion proteins do?

Perform cell-to-cell attachments

What types of lipids are contained within the plasma membrane?

Phospholipids Cholesterol Glycolipids

Define membrane transport.

Process of obtaining and eliminating substance across the plasma membrane

What does a transport protein do?

Regulate movement of substances across membrane E.g., channels, carriers, and pumps, symporters, antiporters

What do anchoring sites do?

Secure cytoskeleton to plasma membrane

What functions does the plasma membrane do?

Serves as physical barrier between cell and fluid that surround it (interstitial fluid) Regulates movement into and out of a cell Establishes and maintains electrochemical gradient Functions in cell communication

Define Facilitated Diffusion

Transport process for small charged or polar solutes requires assistance from plasma membrane proteins

True or False: The phospholipid bilayer prevents the movement of most solutes.

True

Define microscopy

Using a microscope to view small-scale structures

______________ process of membrane transport requires energy and depends on the substances moving up (less to more) the concentration gradient.

active

Enzymes are proteins that act as ___________ a. adhesion molecules b. catalysts c. receptors d. cell membrane stabilizers

catalysts

The two types of facilitated diffusion are _____________ mediated diffusion and _____________ mediated diffusion.

channel carrier

Ion movement through small proteins in the membrane is an example of ___________ diffusion. a. carrier mediated b. portal mediated c. ion mediated d. channel mediated

channel mediated

What are two types of facilitated diffusion

channel mediated carrier mediated

K+ movement out of the cell is facilitated by its _____________ ____________ gradient but opposed by the __________ gradient.

chemical concentration electrical gradient

A type of steriod called ___________ is scattered within the hydrophobic regions of the phospholipid bilayer, where it strengthens the membrane and stabilizes it at extreme temperatures.

cholesterol

___________ function(s) to strengthen the plasma membrane and stabilize it at extreme temperatures. a. phospholipids b. membrane proteins c. cholesterol d. glycolipids

cholesterol

The ___________ is a general term for all cellular contents between the plasma membrane and the nucleus.

cytoplasm

The watery, syrup-like fluid of the cytoplasm is called ____________

cytosol

The three components of the cytoplasm of a cell are _____________, _______________, ________________.

cytosol, organelles, inclusions

Forms of passive transport across cell membranes include ______ ☐ pinocytosis ☐ diffusion ☐ phagocytosis ☐ osmosis ☐ inclusion

diffusion osmosis

The ________ gradient is dependent on the combination of the __________ gradient and the chemical concentration gradient.

electrochemical electrical

Some membrane proteins catalyze (speed up) the rate of metabolic reactions. These proteins are acting as _____________

enzymes

The Na+-K+ exchange pump is a special type of ion pump called an __________ pump because it moves one type of ion into a cell ______________ its concentration gradient and another type of ion out of the cell ___________ its concentration gradient.

exchange against against

True or False: All cells are able to undergo cell division and make more cells of all types.

false

True or false: the steeper the concentration gradient of a solute, the lower the osmotic pressure.

false

exocytosis is the process whereby large molecules are secreted ________ the cell. a. into b. from

from

Membrane proteins that have carbohydrates attached and are exposed to interstitial fluid are called ____. a. lipoproteins b. peripheral proteins c. enzymes d. glycoproteins

glycoproteins

Proteins with attached carbohydrate groups are __________.

glycoproteins

Osmosis is a type of diffusion in which the net movement of water across a selectively permeable membrane is from a region of _____________ water concentration to a region of ___________ water concentration.

high low

In active transport processes, materials often flow from a region of _______ concentration of the material to a region of ___________ concentration of the same material.

high ; low

The "balloon-like head" of the phospholipids are ______________ and the two "tails" are ___________. a. hydrophilic; hydrophobic b. hydrophobic; hydrophilic

hydrophilic; hydrophobic

The hydrophobic regions within the integral proteins interact with the ____________ region of the membrane.

hydrophobic

A cell containing 0.9% NaCl is placed in a solution of 5% NaCl. The solution outside the cell is __________ relative to the cell contents. a. hypotonic b. hypertonic c. isotonic

hypertonic

The term endocytosis ________. a. includes exocytosis b. refers to the disruption of cells by internal mechanisms c. includes phagocytosis and pinocytosis d. refers to the process by which cells secrete substances

includes phagocytosis and pinocytosis

What are two structural types of membrane proteins?

integral peripheral

____________ are embedded within and extend completely across the phospholipid bilayer. a. peripheral proteins b. integral proteins

integral proteins

The phospholipid bilayer ensures that the __________ remains outside the cell. a. intercellular fluid b. interstitial fluid c. cytosol d. lymph

interstitial fluid

Active transport mechanisms that move ions across a selectively permeable membrane are referred to as __________ pumps. Those that move one type of ion into the cell and another type of ion out of the cells are specifically called __________ pumps.

ion exchange

Which of the following is false regarding the cell membrane a. it contains cholesterol b. it consists of a phospholipid bilayer c. it is made primarily of cytosol d. it contains several different types of lipids

it is made primarily of cytosol

If a cell is placed into a solution of distilled water (which contains no solutes) the cell will ___________ a. lyse b. not change in volume c. crenate

lyse

A resting membrane potential is essential in the normal function of which of the following type of cells? ☐ muscle ☐ bone ☐ digestive ☐ epithelial ☐ connective tissue ☐ nerve

muscle nerve

The _________ is the cell's control center.

nucleus

Leak channels are coninuously ___________ whereas gated channels are usually ___________.

open closed

__________ processes do not require energy to move a substance in or out of the cell. a. pump b. active c. passive d. countertransport

passive

___________ process of membrane transport does not require energy and depends on moving substances down the concentration gradient. There are two types: osmosis and diffusion.

passive

What are 2 types of membrane transport?

passive active

Osmosis is a type of _________ a. active transport b. passive transport c. filtration d. pinocytosis e. phagocytosis

passive transport

A difference in solute concentration can exist between the cytosol and the interstitial fluid because the ________ prevents their movement. a. cholesterol b. phospholipid bilayer c. aquaporins d. non permeable gases

phospholipid bilayer

The bulk of the plasma membrane consists of a _________________ a. phosphate sugar backbone b. cholesterol bilayer c. phospholipid bilayer d. cell junction

phospholipid bilayer

The ___________ membrane is also called the cell membrane.

plasma

All materials that enter or leave the cell must pass across the ___________ ______________.

plasma membrane

The plasma membrane also functions in establishing and maintaining an electrochemical gradient at the plasma membrane called the __________ ______________ _______.

resting membrane potential

______________ diffusion occurs when substances move across cell membranes unaided because they are either small, nonpolar, or both.

simple

The two major cellular passive transport processes are ________ diffusion and ___________ diffusion.

simple facilitated

_________ occurs when substances move across cell membranes unaided because they are either small, nonpolar, or both. a. active transport b. bulk transport c. facilitated diffusion d. simple diffusion

simple diffusion

____________ is a passive form of transport a. exocytosis b. bulk transport c. pinocytosis d. simple diffusion e. countertransport

simple diffusion

Sodium diffusion into cells occurs ______ the loss of K+. a. after b. before c. simultaneously to d. proportionately to

simultaneously to

________ move most easily across the phospholipid bilayer. a. large, charged molecules b. non lipid soluble substances c. small and non polar solutes

small and non polar solutes

If two substances are moved across the membrane in the same direction by a carrier protein it is called a(n) ________. a. antiporter b. carrier c. symporter d. coporter e. countertransporter

symporter

The plasma membrane cannot regulate simple diffusion, rather the movement of these substances is dependent only upon _______. a. the concentration gradient b. facilitated diffusion c. bulk filtration d. osmosis

the concentration gradient

Define cytology

the study of cells microscopes are necessary

_______ proteins provide a means of regulating movement of substances across the plasma membrane. a. peripheral b. glycoproteins c. transport

transport

True or False: Obtaining nutrients and disposing of waste is a general function that all cells must perform.

true

True or False: Water molecules can pass through the phospholipid bilayer if aquaporins are present.

true

True or false: Proteins carry out most of membrane's specific functions

true

Both Na+ and K+ are pumped by the Na+/K+ pumps __________ their concentration gradients in maintaining the resting membrane potential. a. up b. down

up

Osmosis is unique as it involves the movement of _____________ and does not involve the movement of _________.

water solutes

Define simple diffusion.

• Molecules pass between phospholipid molecules • Small and nonpolar solutes • Include: respiratory gases (O2 and CO2), some fatty acids, ethanol, urea • Not regulated by plasma membrane • Movement dependent on concentration gradient • Continues to move as long as gradient exists

The rate at which different substances diffuse is not constant but is dependent upon which of the following? ☐ Temperature ☐ magnitude of the concentration gradient ☐ expenditure of cellular energy

☐ Temperature ☐ magnitude of the concentration gradient

Types of transport proteins include: ☐ carriers ☐ channels ☐ cell adhesion molecules ☐ anchoring sites ☐ pumps ☐ ligands ☐ enzymes

☐ carriers ☐ channels ☐ pumps

Select all that are found in the cell membrane? ☐ cholesterol ☐ ribosomes ☐ nucleic acids ☐ inclusions ☐ melanin ☐ glycolipids ☐ phospholipids

☐ cholesterol ☐ glycolipids ☐ phospholipids

Which of the following are considered to be membrane-bound organelles? (check all that apply) ☐ cytoskeleton ☐ mitochondria ☐ golgi apparatus ☐ ribosomes ☐ peroxisomes ☐ endoplsmic reticulum ☐ lysosomes

☐ mitochondria ☐ golgi apparatus ☐ peroxisomes ☐ endoplsmic reticulum ☐ lysosomes

Which of the following are classified as plasma membrane proteins? ☐ receptor ☐ cytoskeleton ☐ cholesterol ☐ enzymes ☐ transport protein ☐ identity markers

☐ receptor ☐ enzymes ☐ transport protein ☐ identity markers

Which statements are true regarding glycolipids? ☐ they are located only on the outer layer of the plasma membrane ☐ they may serve as enzymes ☐ they are water soluble ☐ they stabilize the cell membrane in extreme temperatures ☐ they are important for cell to cell recognition

☐ they are located only on the outer layer of the plasma membrane ☐ they are important for cell to cell recognition

Which statements are true regarding peripheral proteins? ☐ they can "float" and move about the phospholipid bilayer ☐ they are loosely attached to the cell membrane ☐ they may serve as enzymes ☐ they are often receptors for cells ☐ they are often glycoproteins ☐ they are often steroids

☐ they can "float" and move about the phospholipid bilayer ☐ they are loosely attached to the cell membrane ☐ they may serve as enzymes