A&P Unit 3 - Cell Membrane

protein

A membrane is a collage of different __________ embedded in the fluid matrix of the lipid bilayer These determine most of the of the membrane's specific functions 2% of the molecules in plasma membrane, 50% of its weight

"Antenna" Sensory in inner ear, retina, nasal cavity, and kidney

A single, nonmotile primary cilium is like an "__________" It is located in the following: _________________

10^7 rapid bacterial

Adjacent phospholipids switch positions about ____ times per second. The lateral movements of phospholipids are _______, about 2 µm per second. A phospholipid can travel the length of a typical _________ cell in 1 sec

permeability

As a membrane solidifies, its ______________ changes

maintains fluidity by preventing tight packing

At cool temperatures, cholesterol does what to the phospholipid bilayer?

restrains the movement of phospholipids and reduces fluidity

At warm temperatures (such as 37°C), cholesterol does what to the phospholipid bilayer?

Saline layer

Chloride pumps pump Cl- into ECF, Na+ and H2O follows, and Cilia beat freely in this

9 + 2 array of microtubules Nine pairs form basal bodyAnchors cilium

Describe the microtubules that form the basal body of the cilium

Sweep substances across surface in same direction Power strokes followed by recovery strokes

Describe the movement of motile cilia

concentration gradient.

Diffusion: In the absence of other forces, a substance diffuses from where it is more concentrated to where it is less concentrated, down its __________________

diffuses

Each substance ________ down its own concentration gradient, independent of the concentration gradients of other substances.

microvilli

Extensions of membrane (1-2 mm) increase the surface area for diffusion and minimize any increase in volume.

isolating the cell's contents from the environment regulating the exchange of essential substances communicating with other cells creating attachments within and between other cells providing a surface for biochemical reactions

Functions of plasma membrane

Cilia

Hairlike processes- 7-10 mm long beat to move particles around the membrane, or to move small microscopic organisms

phospholipids covalent

Hydrophobic interactions that cause bilayer: __________ are not bonded together weaker than _________ bonds

adequate saline layer on cell surface

In cystic fibrosis, chloride pumps fail to create _________________

pancreatic ducts, respiratory tract, and genital tracts digestion of nutrients, absorption of oxygen, and transport of gametes respiratory infections 35-37

In cystic fibrosis, thick mucus plugs ________________ There is inadequate _________________ Includes chronic ____________ life expectancy of ______

population

In diffusion, the movements of individual molecules are random. However, the movement of a __________ of molecules may be directional.

normal: cilia move together in wave-like motions to transport mucus towards the mouth; the mucus contains dirt and bacteria cystic fibrosis: cilia are deformed and do not move together, causing a buildup of mucus; the mucus contains dirt and bacteria

In normal cilia lining trachea, what does the cilia do compared to cilia in the cilia lining trachea of someone with cystic fibrosis?

From side with higher water concentration to side with lower water concentration

In osmosis, how is water transported? (what concentration)

membrane proteins

In the fluid mosaic model, the __________ is a fluid-structure with a "mosaic" of various __________ embedded in or attached to a double layer (bilayer) of phospholipids.

selectively permeable

Like all biological membranes, the plasma membrane is, __________________ allowing some substances to cross more easily than others.

hydrophobic

Membrane molecules are held in place by relatively weak _____________ interactions.

"Brush Border" Milking action Actin filaments shorten Push contents into cell

Microvilli form a _____________ they have a _________ action, in which the following two things happen, _________________

transport proteins

Most _______________ are very specific. They transport some substances but not others

drift

Most of the lipids and some proteins ________ laterally in the plane of the membrane but rarely flip-flop from one phospholipid layer to the other.

Respiratory tract, uterine tubes, ventricles of the brain, efferent ductules of testes

Motile cilia are located in the following, _______________

energy

No work must be done to move substances down the concentration gradient; diffusion is a spontaneous process, needing no input of _______

cytoplasmic extracellular combine

On the ______________ side of the membrane, some membrane proteins are attached to the cytoskeleton. On the ____________ side of the membrane, some membrane proteins attach to the fibers of the extracellular matrix. These attachments ________ to give animal cells a stronger framework than the plasma membrane itself could provide.

cytoskeleton

On the cytoplasmic side of the membrane, some membrane proteins are attached to the ____________

extracellular matrix

On the extracellular side of the membrane, some membrane proteins attach to the fibers of the _____________________

nasal cavity/sinuses trachea lung middle ear infertility/fertility problems

Organs affected by cystic fibrosis what kind of problems can be caused?

amphipathic molecules

Phospholipids and most other membrane constituents are ___________________ which have both hydrophobic and hydrophilic regions

Cl-, Na+ ions and H2O

Saline layer at cell surface due to chloride pumps move ______ out of cell. _____ and _____ follow

within slowly

Some large membrane proteins drift _______ the phospholipid bilayer, although they move more ________ than the phospholipids

motor proteins, cytoskeleton cytoskeleton, extracellular matrix

Some proteins move in a very directed manner, perhaps guided or driven by ______________ attached to the ____________. Other proteins never move and are anchored to the _______________ or to the ________________.

steroid cholesterol

The _________________ is wedged between phospholipid molecules in the plasma membrane of animal cells

fluid mosaic model

The arrangement of phospholipids and proteins in biological membranes is described by the

passive transport potential energy

The diffusion of a substance across a biological membrane is ______________ because it requires no energy from the cell to make it happen. The concentration gradient itself represents _______________ and drives diffusion.

the direct activation of the intracellular effector. intermediate molecule

The drug-receptor or receptor-ligand interaction often does not result in..... Instead, often an ________________ is used as a signal to the effector.

filament, hook, basal body

The flagella is made up of 3 main parts:

faster faster long

The higher the temperature, the ________ the rate of diffusion The greater the concentration gradient, the _______ the rate of diffusion Diffusion cannot move molecules rapidly over _______ distances

less fluid less solid

The membrane with cholesterol is __________ at higher temperatures, but ___________ at lower temperatures

facilitated diffusion

The passive movement of molecules down their concentration gradient with the help of transport proteins

1. Transport of specific solutes into or out of cells 2. Enzymatic activity, sometimes catalyzing one of a number of steps of a metabolic pathway 3. Signal transduction, relaying hormonal messages to the cell 4. Cell-cell recognition, allowing other proteins to attach two adjacent cells together 5. The intercellular joining of adjacent cells with a gap or tight junctions 6. Attachment to the cytoskeleton and extracellular matrix, maintaining cell shape and stabilizing the location of certain membrane proteins

The proteins of the plasma membrane have six major functions:

synthesis, degradation amplify, dampen

The rate of __________ and ___________ of an intermediate molecule is tightly regulated to control the magnitude of response to receptor activation, and this regulation can be used to ___________ or __________ the response.

diffuse receptor-ligand

The second messenger molecule can act locally, or can _________ distally to convey the signal to a multitude of targets; and multiple second messenger systems can interact to produce complex responses to ____________ binding

integral and peripheral

There are two major populations of membrane proteins:

active enzymes and appropriate permeability

To work properly with __________________ and _________________, membranes must be about as fluid as salad oil.

Glycocalyx

Unique fuzzy coat external to the plasma membrane Carbohydrate moieties of membrane glycoproteins and glycolipids

Specific proteins facilitate the passive transport of water and selected solutes

What happens in facilitated diffusion?

kidney cells; it allows them to take up water from urine before it is excreted; 180 L

What organ cells has a high level of aquaporins and what does this allow it do to? It has been estimated that a person would have to drink ________ of water per day and excrete the same volume if the organ did not perform this function.

flagella

Whiplike structure with axoneme identical to cilium, but much longer

Glycolipids, 5%

_% of the membrane lipids Phospholipids with short carbohydrate chains on extracellular face

cholesterol, 20%

__% of the membrane lipids Holds phospholipids still and can stiffen membrane in animal membranes, it stabilizes membrane fluidity to make the bilayer strong and flexible.

Enzymes

____________ in the membrane may become inactive if their activity requires them to move within the membrane

Dynein arms ATP

_______________ "crawl" up adjacent microtubule, bending the cilia uses energy from ______

receptor-ligand, degraded

an intermediate molecule is synthesized or released in response to the _____________ interaction, and then ___________ afterwards.

aquaporin

channel protein that facilitates the diffusion of water

fluidity buffer

cholesterol acts as a "_______________" for the membrane, resisting changes in membrane fluidity as temperature changes

axoneme

core of cilia that is the structural basis for movement

second messenger

molecule inside cells that acts to transmit signals from a receptor to a target.

1. chemical messenger 2. breakdown products 3. ions 4. CAM of another cell 5. receptor 6. enzyme 7. ion channel 8. gated ion channel 9. cell-identity marker 10. cell-adhesion molecule

name these parts of this diagram that show proteins in the plasma membrane

peripheral proteins

not embedded in the lipid bilayer at all. Instead, they are loosely bound to the surface of the membrane, often to integral proteins

hook

part of a flagellum that connects filament to basal body aka the motor portion

basal body

part of a flagellum that is anchored in the cytoplasmic membrane and cell wall, it is a rotary molecular motor

filament

part of a flagellum: long, thin, helical structure extending from cell

integral proteins

penetrate the hydrophobic interior of the lipid bilayer, usually completely spanning the membrane as transmembrane proteins.

amphiphilic

phospholipids are ________ molecules arranged in a bilayer

fluid rotate

phospholipids drift and move like a _________ They drift laterally and __________

hydrophilic, hydrophobic

phospholipids have a ________________ head (polar) and a _______________ tail (non-polar)

98%, 75%

phospholipids make up ____ of molecules and ____ of membrane lipids

channel proteins

provide hydrophilic corridors for the passage of specific molecules or ions

phospholipids, steroids, proteins, and other molecules

the bilayer is a mosaic mixture of __________________

organization of cell membranes hydrophobic interactions that cause bilayer

the fluid mosaic model describes the _________________ and ________________

identical twins

the glycocalyx is unique to everyone but ___________

lipids and proteins, carbohydrates

the main macromolecules in membranes are __________ and ________, but ___________ are also important

phospholipids

the most abundant lipid in the plasma membrane

osmosis

the passive transport of water. Specifically, diffusion of water from one side of a selectively permeable membrane to the other

diffusion

the random movement of molecules of any substance to spread out in the available space

channel proteins & carrier proteins

two types of transport proteins facilitate the movement of molecules or ions across membranes

Hydrophobic molecules

type of second messenger system: DAG and phosphatidylinositols which do most of their work from the intermembrane space

soluble proteins

type of second messenger system: Jak/STAT, NF-kB, etc

ions

type of second messenger system: ionised calcium, potassium and sodium

gases

type of second messenger system: nitric oxide (NO) and carbon monoxide (CO) which diffuse easily through lipid and water alike

Hydrophilic molecules

type of second messenger system: type of second messenger system: cAMP, cGMP and IP3 - which diffuse freely in the cytosol

Hydrophobic molecules Hydrophilic molecules Ions Gases Soluble proteins

types of second messenger systems

Movement is more undulating, snakelike No power stroke or recovery stroke as in cilia

describe the movement of flagella

passive transport

diffusion of a substance across a membrane with no energy investment`

tail of sperm

example of a flagellum

Protection Cell adhesion Immunity to infection Fertilization Defense against cancer Embryonic development Transplant compatibility

functions of the glycocalyx

glycocalyx

glycolipids contribute to ____________

microvillus

has a dense bundle of cross-linked actin filaments, which serves as microvilli's structural core.

cystic fibrosis

hereditary disease causing abnormal chloride pumps

transmembrane proteins

integral proteins that span the membrane; membrane carriers through either Active transport or facilitated diffusion

the presence or absence of an electrical, chemical, or physical stimulus.

ion channels or gated channels open and close depending on?

gated channels

many ion channels function as ___________

Antiport (countertransport) Na+ is transported into the cell as H+ is transported out

membrane carriers - carries 2+ solutes in opposite directions example?

Symport (cotransport) glucose binding to symporter in the membrane this binding alters the shape of symporter, then both glucose and Na+ are transported into the cell

membrane carriers - carries 2+ solutes simultaneously in same direction example?

uniport glucose carriers in urine

membrane carriers - either active transport or facilitated diffusion - carries one solute at a time example?