patho/phys exam 1 Flashcards
FUNCTIONS OF CELL MEMBRANE
what does it maintain and what does it coordinate
what kind of barrier is it
does it adhere to each other? If so, what does it form from the adhering
what 3 things does it exchange
what does it respond to changes in
what gradient does it maintain for nerves and muscles and for what kind of actvity
Homeostasis & cell survival: maintain intracellular contents of cells & coordinate activity with others - organelles should be close together
– Mechanical barrier
– Adhere together to form tissues
– Exchange nutrients (intake), wastes (CO2) & secretions
– Respond to changes in environment or signals – Maintain ionic gradient for electrical activity of… nerves & muscles have electrical activity which the ionic gradient is used for stimulation and contraction
COMPONENTS OF CELL MEMBRANE
what are the 2 kinds of lipids of the cell membrane
for the first kind of lipid, what barrier does it set and to what kind of substances
for the second kind of lipid, what 2 things does it provide to the membran e
for the first kind of lipid, what is the charge, polarity and philicity of the head and the tail
Lipids: phospholipids and cholesterol
– Barrier to passage of water-soluble substances – Provides fluidity & stability to the membrane
head (negatively charged, polar, hydrophilic)
tails (uncharged, nonpolar, hydrophobic)
COMPONENTS OF CELL MEMBRANE
what two kinds of proteins are present
- Proteins: transmembrane or one surface only
integral vs extrinsic proteins
COMPONENTS OF CELL MEMBRANE
what are the 7 functions that the proteins have
aquaporins:
– Ion ____:
– ______ molecules:
– Membrane ____: drug, NT, hormones
– _____-marker _____: Identify the specific place where the drug binds
– Membrane-____ enzymes: AchE
– Cell _____ ____ (CAMs): cell to cell adhesion, cadherins and integrins
Proteins: several types for specific functions
– Aquaporins: transport water molecules
– Ion channels:
– Carrier molecules:
– Membrane receptors: drug, NT, hormones
– Docking-marker acceptors: Identify the specific place where the drug binds
– Membrane-bound enzymes: AchE
– Cell adhesion molecules (CAMs): cell to cell adhesion, cadherins and integrins
COMPONENTS OF CELL MEMBRANE
where are carbohydrates present
what are the 2 types/what other substance can it be attached to
what is the function of carbohydrates
Carbohydrates: present on outer surface only
– Glycolipids:
– Glycoproteins:
– Function: self-identity markers
STRUCTURE OF CELL MEMBRANE
for the flud mosaic model, what is the dark and light regions
- The fluid mosaic (has other things) model: Tri-laminar structure
dark line: head
light space: tails
CELL-CELL ADHESIONS
what is the hieracrchy order from cell to organism
what is the ECM and what is it secreted by
what are the 3 specialized cell junctions
cell adhesion occurs when cells are what kind of distance away from each other
for cell adhesion, what type of system do the proteins use to adhere together
cells to tissues to organs to the system to organism
Extracellular matrix (biological glue secreted by cells)
- Specialized cell junctions:
– Desmosomes
– Tight junctions
– Gap junctions - Cell adhesion molecules:
– Occurs between cells in close proximity
– Loop and hook-shaped proteins that “velcro” together
EXTRACELLULAR MATRIX
what is it also known as and where is it present in
what is it a meshwork of
what are the 3 kinds of substances that are found
for collagen, what is it similar to, what does it provide, how much of the ECM consists of it
for elastin, what is it similar to and what can be an example of it
for fibronectin, what does it promote
AKA Interstitial fluid, present in intercellular space
Meshwork of fibrous proteins in a watery gel
– Collagen: cable-like, provides tensile strength (pulled apart w/o breaking) - makes up 50% of ECM
– Elastin: rubber-like protein, ex: lungs expand then contract
– Fibronectin: promotes cell adhesion
the cell membrane has 3 components, what are they
lipids
proteins
carbohydrates
what are the 3 kinds of lipids of the cell membrane
sphingolipids
phospholipids
cholesterol
phospholipids of the cell membrane
what are the two parts of it
what is the charge of the head group and why is it that charge
what is the charge of the tails
in H2O, how do phospholipids arrange, are there strong bonds why or why not, what does that allow for, and for what kind of cells
what is the fluid in the bilayer called
what is the fluid out of the bilayer called
can lipid soluble substances pass through
can H2O pass through the bilaer easily
phospholipid head, hydrocarbon tail
head group is charged due to the phosphate (PO4) molecule so it is negatively charged - it is hydrophilic or lipophobic
tails: uncharged so electrically neutral - it is hydrophobic or lipophilic
the phospholipid in H2O aligns into a bilayer-lipid bilayer (2 layers). It has no strong bonds which allows it to be fluid (provides fluidity) like RBCs or muscle cells that change shape which the bilayer makes possible
in the bilayer = intracellular fluid (ICF)
out of the bilayer = extracellular fluid (ECF)
lipid soluble can pass through easily
H2O soluble cannot pass through easily (hinder or inhibit)
cholesterol of the cell membrane
is the head group polar or nonpolar, what about the tail
where does it orient
what does it prevent of the phospholipids and thus prevents what from happening. What else does it provide
where do we get cholesterol from, if we not get from there where can out body synthesize it
where is cholesterol only found in and not some where else
head group - polar so water-loving or hydrophilic or lipophobic
tail - nonpolar, lipophilic or hydrophobic
orients between phospholipids
prevents tight packing of phospholipids and thus prevents crystallization and increases fluidity. Also provides stability to the membrane
gets cholesterol from diet. If you do not get it from the diet, the liver will synthesize it
cholesterol is only in animal cells and not in plant cells
sphingolipids of the cell membrane
how are they different from phospholipids and thus what can they form, what is contained there
where can this be found
similar to phospholipids but have longer fatty acid tails so they form lipid rafts that contain receptors for cell signaling
found in a cave-like structure of cell membrane
proteins of the cell membrane
where in the cell membrane do transmembrane proteins pass through and thus what kind of regions does it have, what is another name for transmembrane proteins
what is the name of the proteins located on one side of the membrane, what kind of regions does it have
what is another kind of integral or intrinsic proteins, how do they look
Transmembrane proteins: pass directly through the membrane - and have polar and non-polar regions. AKA integral or intrinsic proteins
extrinsic or peripheral proteins: have mostly polar regions - located on one side of the membrane
another kind of integral or intrinsic protein are on one side of the membrane connected by a strong bond indicated by a squiggly line
transmembrane proteins have both hydrophilic and hydrophobic regions
true
false
true
aquaporins
what are they
what are they made of and what do they allow the movement of from where
water pores
composed of proteins and allow movement of H2O through membrane from outside to inside and vice versa
channels
what are they for
what do they only allow the movement for
what must the size of the ion be
what are leak channels and do they close
what are gated channels and are they regulated, if so by what kind of molecule and what kind of drug
can they be open or closed to let what kind of molecules through
what are they specific for
for ions
allow movement of ions only
ion size: <0.8 nm diameter
leak channels: always open so ions can move freely
gated channels: regulated by neurotransmitters and drugs like CCB
- can be open or closed only to let certain ions through
specific for certain ions: Na, K, Cl, Ca
- Na cannot go through K channels and etc
carriers
what does it transport
what can it transport and at what size
is it specific or nonspecific
- can the amino acid transporter transport both glycine and glucose
what ions do thyroid cells use
transports proteins
glucose, amino acids
transport H2O soluble substances >0.8 nm diameter
specific - transport 1 substance at a time or a closely regulated substance
- ex: amino acid carrier can transport glycine, alanine but not glucose
thyroid cells use iodine
carbohydrates
what kind of molecules are they
what can they be attached to and what would those molecules be called
what is markers identification needed for
if this goes wrong what does it lead to
sugar molecules
can be proteins or lipids
attached to protein: glycoprotein
attached to lipid: glycolipid
markers identification - needed for embryonic development
if wrong then leads to cancer
EXTRACELLULAR MATRIX
Secreted by cells, important for their functioning
- Pathway for the diffusion of water-soluble substances
- Regulates behavior and functions of the cells:
– Amount & composition of ECM varies with cell type - Can become highly specialized for specific functions:
– Examples: cartilage, tendons, hardness of bones & teeth etc. - all of these are ECM that are specialized
DESMOSOMES/ADHERING JUNCTIONS
cells are connected by “Spot rivets” which are composed of:
* Plaque
* Glycoprotein filaments
* Keratin filaments
* Present in skin, heart, uterus and any other organ that needs to stretch
TIGHT/IMPERMEABLE JUNCTIONS
Cells adhere firmly, seals formed at kiss sites by junctional proteins
- Found b/w epithelial cells, separate 2 compartments of diverse chemical compositions e.g., intestines, kidneys
- Passage of materials takes place through cells, not between cells, via channels and carriers
GAP/COMMUNICATING JUNCTIONS
Gaps/tunnels between cells
- Connexons: six subunits in a hollow tube-like structure, 2 connexons join together
- Only small particles pass, like ions!
- Present in electrically active
cardiac/smooth muscle - Enables synchronized action
- Metabolic/communication link
MEMBRANE TRANSPORT
Essential for homeostasis: nutrients in, wastes out
- Plasma membrane is selectively permeable
- Factors affecting membrane permeability:
– Lipid solubility: can cross through the membrane
– Particle size: < 0.8 nm - can cross membrane thru channels, > 0.8 nm will use carriers - Forces are required for membrane transport
– Passive force: no energy expenditure by cells for transport, no energy required
– Active force: energy (ATP) expenditure by cells for transport
permeable: substance can cross
impermeable: substance cannot cross
water solubility is also needed because
1- The phospholipid head is polar
2- blood is aqueous and will transport water soluble substance
MEMBRANE TRANSPORT
unassisted: no channels or carriers involved
- diffusion
- osmosis
- movement along an electrical gradient
assisted
- vesicular transport
- carrier mediated
vesicular transport
- endocytosis
- exocytosis
carrier mediated
- facilitated diffusion
- active transport
active transport
- primary active transport
- secondary active transport
caveolae: membrane transport and signal transduction - sphingolipids rafts found in caveolae
