Dental Physiology Lectures 1A, 1B, 2 And 3

Front 1

2 Key roles of membranes

Back 1

Define barrier of inside vs outside of cell

Isolate different compartments and domains in cell.

Front 2

______ serves as the interface between the cell and its environment

Back 2

plasma membrane

Front 3

How does the plasma membrane allow for interactions with other cells?

Back 3

Releases peptides and binds signals release by other cells or just physical interaction with other cells

Front 4

How is the plasma membrane in axons and dendrites diffreent to allow for propogation of electrical impulse

Back 4

selective passage of sodium/potassium

Front 5

Function of microvilli?

Back 5

Increase absorption of nutrients in epithelial cells

Front 6

Common functions of integral proteins

Back 6

receptors that transmit stimuli across membrane

or channel for ions/molecules

Front 7

Function of peripheral proteins

Supported by ____?

Back 7

bind to surface sites inside or outside the cell.

supported by proteins or lipid groups

Front 8

Lipid membrane is composed of _____

Back 8

phospholipids and cholestrol

Front 9

Function of carb chains on membrane

Back 9

Additional diversification at the cell surface (made of polymerized sugar)

Front 10

Membranes are primarily composed of _____

Back 10

lipids, proteins and carbohydrates

Front 11

______ defines the function and physiology of many cell types

Back 11

Specialization of the plasma membrane composition

Front 12

Simple lipid composition

Back 12

Glycerol connected to 2 fatty acids (sat. or unsat.)

Front 13

Membranes mostly made of _____ lipids

Back 13

complex

Front 14

Main steroid in membranes

Back 14

cholesterol

Front 15

2 common classes of phospholipids in cell membranes are ____ and ____

Back 15

phosphoglyceride and sphingolipid

Front 16

2 examples of phospholipids

Back 16

Phosphatidylcholine

Sphingomyelin

Front 17

3 features of phospholipid

Back 17

polar phosphate containing head group, glycerol backbone and hydrophobic carbon chains.

Front 18

_____ imposes order and stability on biological mebranes

Back 18

hydrophobic core/hydrophilic head arrangement

Front 19

Both ___ and ____ diffuse ____ within the membrane

Back 19

proteins and lipids diffuse laterally

Front 20

_____ is required in order for movement to occur inside the membrane

Back 20

fluidity

Front 21

Fluidity is determined by

Back 21

fatty acid composition and cholesterol content

Front 22

2 things that impact fluidity

Back 22

more cholesterol = less fluid

more unsaturated bonds = more fluid

Front 23

syntaxin is important for _____ and it ______

Back 23

synaptic transmission and vesicle fusion it is clustered in discrete membrane patches though aggregation of lipids and a negatively charged lipid called PIP2

Front 24

Common chemical modifying groups on simple lipids

Back 24

phospho group / sphingo group

Front 25

Proteins comprised of ___ amino acids which chemically combine to form _____

Back 25

20

peptide bonds

Front 26

_____ dicate the type of secondary structure that is formed

Back 26

the amino acids that make up the primary sequence

Front 27

Tertiary structure of protein

Back 27

multiple different secondary structure elements fold into single structure

Front 28

What holds together the quaternary structure of hemoglobin

Back 28

stabilizing thermodynamic forces from amino acid side chains

Front 29

Integral memebrane proteins almost always serve to ____

Back 29

transport or transmit info

Front 30

Peripheral membrane proteins bind through 2 ways

Back 30

directly to transmembrane integral proteins or directly to phospholipid bilayer

Front 31

Transmembrane proteins almost always ____ secondary structure

Why?

Back 31

alpha helix

Act like rigid poles into the membrane

Front 32

How are amino acids arranged in transmembrane alpha helicies

Back 32

Hydrophobic on outside hydrophilic on interior

Front 33

Hydrophobic with hydrophobic is _____ favorable

Back 33

thermodynamically

Front 34

In transmembrane proteins where do the N and C termini sit?

Back 34

outside the bilayer

Front 35

What is Rhodopsin?

Works how?

Back 35

Family of membrane proteins allows the flow of ions when exposed to certain light waves.

Traps retinal pigment which undergoes a chemical transition with light and pushes open a pathway for ions to flow

Front 36

How to peripheral membrane proteins associate with membrane?

Back 36

Ionic or other weak interactions

(lipid head groups or to other membrane proteins)

Front 37

Are all membrane interactions generic?

Back 37

Some are but some proteins bind to membranes with specific protein or phospholipid composition (highly specific)

Front 38

6 functions of plasma membrane proteins

Back 38

1. Ion Channels (potassium channel)

2. Transporter and pump proteins (glucose uniporter)

3. Proteins that facilitate exocytosis and endocytosis (SNARE proteins)

4. Membrane bound enzymes (acetylcholinesterase)

5. Receptor proteins for signal transduction

6. Cell adhesion proteins (Gap junc. , desmosome, tight junction)

Front 39

Sucrose:

Lactose:

Back 39

Sucrose; Glucose+Fructose

Lactose: galactose+glucose

Front 40

Membrane modifications are generally _____

Back 40

polysacharides (highly diverse in their structure and effects on membrane protein function)

Front 41

Carbs are found in biological membranes _____ attached to ______

Back 41

covalently attached to lipids and proteins

Front 42

______ is a ____ rich layer at the plasma membrane

Back 42

glycocalyx is a carb rich layer at the plasma membrane

Front 43

_____ and ____ make up the glycocalyx and are important for many types of ______

Back 43

glycoproteins and glycolipids

important for many types of cell-cell contacts

Front 44

Glycocalyx may function to ____

Back 44

protect cell from mechanical or chemical damage

Front 45

Some viruses bind to cells via _____

Back 45

carbs

Front 46

_____ protein on the surface of ____ virus binds to _____ found on cell surfaces

Binding _______

Back 46

Hemagglutinin on influenza virus binds to sialic acid, a sugar monosaccharide found on cell surfaces

binding intiates viral infection

Front 47

How is the composition of the plasma membrane all around cell?

Back 47

not uniform there is polarity

Front 48

Polarity of epithelial cell membrane

Difference between ends?

Back 48

Apical and basolateral domains

Unique protein and lipid composition

Front 49

The two domains of epithelial cell membrane separated by ____

Back 49

tight junction

Front 50

In the intestine the ____ domain faces the lumen of intestines and is involved in _____ the _____ domain is involved in ______

Back 50

the apical domain faces the lumen and is involved in bringing nutrients into the cell. The basolateral domain is involved in transporting nutrients out of the cell for distribution int he blood stream.

Front 51

The proteins that hold cells together in desmosomes are called _____ and are attached to ______(____) the role is to ______

Back 51

cadherins attached to intracellular intermediate filaments (keratin) role is hold 2 neighboring cells together (not really communicate)

Front 52

____ support gap junctions

function _____

Back 52

connexins

function to hold cells together and allow for communication between them.

Front 53

_____ are involved in tight junctions

function______

Back 53

Occludins

limit polar solutes from passing between cells. Forces solute to be processed thorugh cells.

Front 54

Small patches of membrane with distinct phospholipid composition found on cell surface called

Back 54

lipid rafts

Front 55

lipid rafts are enriched in _____

Back 55

sphingolipids and cholesterol

Front 56

Function of microdomains in membrane

Back 56

to localize proteins that must work in concert with eachother

Front 57

Caveolae

___ is known ____ is not

Back 57

Invaginations in the plasma membrane ( a subset of lipid rafts)

Much known about structure function is still intensely studied.

Front 58

Each caveolae is full of _____

Back 58

specialized signalling molecules, cholesterol and regulated lipids

Front 59

____ is an abundant protein component of the caveolae

Back 59

calveolin

Front 60

Many proteins involved in _____ and ____ are located in caveolae

Back 60

cel signaling and cell cell communication

Front 61

caveolae may be sites for _____

Back 61

the internalization of proteins from the plasma membrane into the cell (remains researched)

Front 62

Role of the secretory pathway

Back 62

Transport proteins and phospholipids to the plasma membrane

Transport proteins and other molecules to the cell surface for secretion into the extracellular space

Transport cellular components to various intracellular organelles

Front 63

Exocytosis

Back 63

(fusion) secretion of material into extracellular space

Front 64

Endocytosis

Back 64

(fission) uptake of macromolecules into the cell

Front 65

4 main organelles of the secretory pathway

Back 65

Nucleus, RER, SER, Golgi

Front 66

Blueprint for any protein starts ____

Back 66

in the nucleus and is transcripted into mRNA

Front 67

mRNA can be tranlated into proteins by ___ found ____

Back 67

ribosomes free in cytoplasm or attached to RER

Front 68

Newly translated membrane proteins _____ while soluble proteins are _____

Back 68

inserted into membrane

transported into ER lumen

Front 69

____ bring proteins and lipids from the ER to the golgi

Back 69

transport vesicles

Front 70

Golgi serves to _____

Back 70

sort , concentrate and finalize protein modifications

Front 71

from the golgi, cargo can be _____

Back 71

shuttled into lysosomes or encapsulated within transport vesiicles and targeted to final destinations

Front 72

Endosomes ______

early____

late_____

Back 72

transport membrane proteins

early: plucked off basal or apical membrane then late endosomes can go back and forth with golgi for further processing or go into lysosome

Front 73

Proteins targeted for secretion have ____

How does process work?

Back 73

signal sequence at their N Terminal end

The signal recognition particle SRP binds to the signal sequence and the ribosome. the SRP-ribosome complexes are targeted to the ER (bind to translocon which binds SRP and ribosome)

Proteins are inserted cotranslationally into the ER

Front 74

Where is the signal sequence found?

Back 74

Upon early translation, early amino acids within the primary sequence of the protein may contain the signal sequence.

Front 75

translocon

functions how?

Back 75

a channel that permits the entry of polypeptides into the ER

Soluble proteins will enter the ER lumen while membrane proteins begin to become folded as they exit the translocon and enter the Er membrane

Front 76

Cleaves the signal sequence from proteins in lumen to allow futher maturation

Back 76

signal peptidase

Front 77

Integral membrane proteins and secreted proteins enter the secretory pathway by

Back 77

cotranslational translocation at the ER

Front 78

Proteins and phospholipids are transported between the organelles of the secretory pathway via

Back 78

transport vesicles

Front 79

Transport vesicles are characterized via

Back 79

protein coat

Front 80

COPI

Back 80

Golgi to ER transport (reverse transport)

Front 81

COPII

Back 81

ER to golgi

Front 82

Clatherin

Back 82

Endocytosis at plasma membrane and post golgi trafficking

Front 83

Transport vesicle assembly (fission) 3 steps

Back 83

1: Coat proteins (COP1, COP2, ect) bind to membrane when the ADP ribosylation factor or ARF is activated by binding GTP

2. Coat proteins assemble and physically deform the membrane and start to form budding vesicles

3. Pinch off to form coated vesicle

Front 84

Coat proteins bind to membrane when ______

Back 84

ADP Ribosylation factor ARF protein (a molecular switch) is activated by binding GTP

Front 85

How do COPS direct vesicles

Back 85

highly specific SNARE proteins coat the outside of vesicles (v-snare) on the target organelle (t-snare) and they tightly bind to eachother to faciliate tight vesicular fusion. (then results in dumping of contents)

Front 86

besides SNARE proteins 2 additional families of proteins regulate membrane fusion reactions

Back 86

Rab proteins are proteins that have been found to regulate fusion reactions (activated by binding GTP)

SM-proteins are a second family of proteins that regulate SNARE-dependent membrane fusion reactions

Front 87

Rab proteins are activated by

Back 87

binding GTP

Front 88

Endocytosis _______

types ______

Back 88

Internalization of extracellular material through the formation of vesicles from the cell surface.

Pinocytosis, Receptor mediated endocytosis, Phagocytosis

Front 89

Pinocytosis

Back 89

uptake of small molecules and fluid from the extracellular space into the cell occurs through the formation of vesicles at the cell surface

NON SELECTIVE

(bud whatever is in the extracellular fluid at the time comes in)

Front 90

Receptor mediated endocytosis

Back 90

molecules are recruited into forming vesicles by protein receptors

The receptors are often found on the cell surface in clathrin coated pits

HIGHLY SELECTIVE

(when solute binds trigger pinching off of vesicles)

Front 91

Familial hypercholesteroliemia

Back 91

Individals have high serum cholesterol

have mutations in receptor for low density lipoprotein (which is internalized by receptor mediated endocytosis)

Front 92

Phagocytosis

requires ______

Back 92

the uptake of very large particles (even other cells)

dramatic changes in cell morphology

requires rearrangement of the cytoskeleton

Front 93

Departing transport vesicles are formed by ______

vesicle fusion occurs through _____

Back 93

Fission

through specific t-snare/v-snare interactions

Front 94

Functions of cytoskeleton

Back 94

holds cells together, bridges orgenelles to plasma membrane also forms highway for vesicles to be transported throughout the cell

Front 95

4 functions of cytoskeleton

Back 95

Specifies cell shape

Provides scaffolding to maintain compartmentalization

Provides scaffolding to assemble cell surface structures such as microvilli

Provides highway system for moving vesicles and organelles.

Front 96

3 major classes of cytoskeletal filaments

Back 96

Microfilaments: actin subunit

Microtubule: tubulin subunit

Intermedite filament: polypeptide strand (keratin)

Front 97

Motor proteins

Back 97

utilize energy from ATP to move along cytoskeletal filaments

Front 98

Important functions of motor proteins

Back 98

Muscle contraction

organelle and vesicle movement

Chromosome segregation

cytokinesis

Front 99

Myosin

Back 99

family of motor proteins utilize actin filaments in muscle contraction

Front 100

Dynein and kinesin

Back 100

motor proteins that move along microtubules (move in opposite directions along microtubules)

Front 101

Bidirectional motor transport along neuronal axis

Back 101

Kinesis carries escretory vesicles away from golgi complex towards axon terminal

Dyenein molecule carries debris vesicles towrds cell body

Front 102

Simple diffusion

Back 102

Diffusion across the lipid bilayer

Front 103

Passive transport

Back 103

Protein facilitated diffusion

Front 104

Activate transport

Back 104

Protein facilitated

Front 105

Simple diffusion:

Direction of net flux:

Transport protein required?:

Requires energy?:

Energy source:

Saturation?

Specificity?

Character of transported substance:

Back 105

Direction: Down electrochemical gradient

Transport protein: NO

energy: NO

Saturation: NO

Specificity: NO

Character of substance: hydrophobic

Front 106

Channel passive transport

Direction of net flux:

Transport protein required?:

Requires energy?:

Energy source:

Saturation?

Specificity?

Character of transported substance:

Back 106

Direction:Down electrochemical gradient

protein required: Yes ion channel

energy?: NO

saturation: sometimes

specific: yes

character of substance: hydrophilic (ionized polar)

Front 107

Faciliated diffusion

Direction of net flux:

Transport protein required?:

Requires energy?:

Energy source:

Saturation?

Specificity?

Character of transported substance:

Back 107

Direction: down gradient

protein required: yes carrier

energy? no

saturation: yes

specific: yes

character of substance: hydrophilic

Front 108

Primary active transport

Direction of net flux:

Transport protein required?:

Requires energy?

:Energy source:

Saturation?

Specificity?

Character of transported substance:

Back 108

Direction: up electchem gradient

protein required: yes pump

energy: yes

source: ATP or other chemical energy source

saturation: yes

specific: yes

character of transporter substance: Hydrophilic

Front 109

Secondary active transport

Direction of net flux:

Transport protein required?:

Requires energy?:

Energy source:

Saturation?

Specificity?

Character of transported substance:

Back 109

Direction: up electrochem gradient

protein required: yes pump

energy? yes

source: electrochem gradient of another solute

saturation: yes

specific: yes

character of substance: hydrophilic

Front 110

What can diffuse passivley across a pure phospholipid bilary

Back 110

water gases and some small uncharged molcules

Front 111

Ultimately the direction that the ion will go is ____

Back 111

combination of the chemical and electrical gradients (electrochemical gradients)

Front 112

Rate of net diffusion for small molecules across a membrane is described by _____

Back 112

Ficks law (concentration*permeability*area of membrane) / (sqaureroot(molecular weight)) * membrane thickness)

Front 113

_____ supply the forces that dictate the direction of ion flow

Back 113

chemical and electrical gradients

Front 114

Osmosis

Back 114

the diffusion of water from an area of low solute concentration to an area of high solute concentration

Front 115

Net osmosis lead to ____

Back 115

changes in volume

Front 116

Charged ions and solutes like to be _____

Back 116

hydrated by water molecules

Front 117

Hypotonic solution

Back 117

lower solute concentration than in the cell

Front 118

Hypertonic solution

Back 118

higher solute concentration than in the cell

Front 119

Isotonic

Back 119

Similar solute concentrations inside and outside a cell or an organism

Front 120

The change in volume due to osmosis generates

Back 120

a hydrostatic osmotic pressure

Front 121

Osmotic pressure equation

Back 121

Osmotic pressure = Gas constant*temp*change in concentration of solute

Front 122

Aquaporins

Back 122

protein channels in the plasma membrane that conduct water molecules

Front 123

Ion channels

Back 123

allow passive transport of ions across the membrane (down electrochem grad)

Front 124

Passive transport is used to move ____ ions _____ requires _____ with a ____ pathway that is _____

Back 124

used to move inorganic ions down an established electrochemical gradient requires a transport channel protein with a hydrophilic pathway that is selective for the solute

Front 125

Simple diffusion transports

Back 125

fatty acids

Front 126

Channel passive transport moves

Back 126

inorganic ions

Front 127

Faciliated diffusion passive transport moves

Back 127

organic molecules

Front 128

Primary active transport moves

Back 128

inorganic ions

Front 129

Secondary active transport moves

Back 129

Organic molecules and inorganic ions

Front 130

Uniport:

Uniporters facailitate____

Specific?

Saturation?

Back 130

a system in which one solute is transported

faciliate diffusion of molecules down their concentration gradient

Specific and can be saturated

Front 131

Glut 4

Back 131

a glucose transporter present in adipose tissue and skeletal muscle

TYPE OF UNIPORTER

Front 132

In the presence of ____ GLUT4 containing transport vesicles ______

Back 132

fuse with the plasma membrane allowing increased glucose uptake

Front 133

In type 2 diabetes ____

Back 133

cells become insulin resistant and do not effectilety transport GLUT 4 in response to insulin

Front 134

Uniporters are transport proteins that are specific to

Back 134

polar organic molecules

Front 135

energy required for uniporter?

Back 135

no direct energy (transport down concentration gradient)

Front 136

Primary active tranport

energy from?

example?

Back 136

energy from directly hydrolysis of ATP

pumps

Front 137

Secondary active transport

energy?

example?

Back 137

ATP energy is used indirectly (electrochemical gradient established by a pump protein

Cotransporter

-symporter

-antiporter

Front 138

How many known classes of ATPase?

Back 138

4

Front 139

P class pumps

Back 139

transport cations and are directly phosphorylated by ATP

Front 140

V and F class pumps

V-ATPase

F-ATPase

Back 140

proton specific they do not involve phosphoprotein intermediates

V-ATPase: transports H+ into organelles using ATP

F-ATPase: works in reverse, synthesizing ATP from H+ gradient

Front 141

ATP binding cassette (ABC)

Back 141

superfamily of pumps transport wide variety of molecules across the membrane

Front 142

How is vitamin B12 imported into cell?

Back 142

ATP binding cassette

Front 143

For the sodium potassium pump what is pumped in which direction?

Why type of pump?

Results in?

Back 143

P type pump

3 Sodium out and 2 potassium in

Results in negative charge inside the cell

Front 144

What maintains acidity of stomach

Back 144

H+/K+ ATPase (P-type) pump

Front 145

Ca2+ ATPase (P-type pump)

Back 145

Pumps Ca2+ out of cells

Pumps Ca2+ into intracellular Ca2+ store

Front 146

H+ pump (v-type)

Back 146

Maintains acidity of some organelles (endosomes and lysosomes)

Front 147

Multidrug resistance results from ____

Back 147

an ABC type pump in the plasma membrane

(tumor cell resistant to multiple chemo drugs)

It uses ATP to transport a large variety of substances out of the cell