Physiology > Cell membrane > Flashcards

Cell membrane Flashcards

(36 cards)

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1
Q

Transporters: hydrophobic molecules

A
  • O2, CO2, N2, benzene
  • flow effortlessly across lipid bylayer
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2
Q

Transporters: small uncharged polar molecules

A
  • H2O, urea, glycerol
  • not as efforless, but can still cross the lipid bylayer easily
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3
Q

Transporters: Large uncharged polar molecules

A
  • glucose, sucrose
  • too big and hydrophilic to cross, require channel
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4
Q

Transporters: Ions

A
  • H+, Na+, HCO3+, etc
  • unable to cross at all without channel
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5
Q

permeability water vs glucose

A

water is 105 times more permeable than glucose

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6
Q

Plasma solute concentrations

A
  • Na: 140
  • K: 4.3
  • Cl: 105
  • HCO3-: 24
  • phosphate: 2
  • Protein: 1
  • Total Osm: 291
  • pH: 7.4
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7
Q

ECF solute concentrations

A
  • Na: 140
  • K: 4.3
  • Cl: 105
  • HCO3-: 24
  • phosphate: 2
  • protein: 0
  • Total Osm: 290
  • pH: 7.4
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8
Q

ICF solute concentrations

A
  • Na: 12
  • K: 120
  • Cl: 5
  • HCO3-: 12
  • Phosphate: 100
  • protein: high
  • Total osm: 290
  • pH: 7.2
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9
Q

uniport

A
  • channel for one solute going one direction
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10
Q

symport

A

channel for two different solutes going in same direction

ex. Na bringing glucose into capillaries from intestine

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11
Q

antiport

A

channel for two different solutes going in opposite directions

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12
Q

Nernst Equation

A

used to calculate cell potential

Veq = (61/Z) * log (Kout/Kin) mV

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13
Q

membrane potential

A

The voltage caused by the difference in concentration of ions on different sides of a cell membrane

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14
Q

depolarization

A

the interior voltage of a cell becoming less negative

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15
Q

repolarization

A

the interior of a cell becoming more negative

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16
Q

action potential

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A

when the membrane potential of a cell rapidly rises and falls

*for an action potential to happen, the membrane potential must depolarize to the critical threshold

17
Q

steps in action potential

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A
  1. Trigger raises membrane potential over threshold
  2. Na+ channels open, Na comes in, membrane potential rises
  3. Na channels close, K channels open
  4. K leaves cells, membrane potential falls, below resting
  5. K channels close, leaving only “leak” channels
18
Q

Michaelis Menten equation

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A

V= (Vmax * S)/km+S

S= substrate concentration

V = rate of reaction (enzyme productivity)

km = constant

Vmax = constant

19
Q

Km

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A

The Michaelis Menten constant which shows the concentration of the substrate when the reaction velocity is equal to one half of the maximal velocity of the reaction.

20
Q

primary active transport

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A

energy is used to bring one molecule through a channel agains the concentration gradient

Ex. 1 ATP brings 3 Na out of cell

21
Q

secondary active transport

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A

energy is used to move something against concentration gradient, but when that same thing gets back into cell, it brings another molecule.

Ex. one ATP pushes 3 Na out of cell, when Na goes back in, it brings Glucose in. In this way, energy is only used for one of the channel crossings, glucose gets in free

22
Q

aquaporins

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A

helps to transfer water across membranes when it needs to be moved more quickly.

Ex. in kidneys

23
Q

ligand

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A

a molecule that produces a signal by binding to a receptor site on a target protein

24
Q

G-Protein coupled receptors

cAMP

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A
  1. ligand connects to receptor and activates G-protein
    1. G-protein made up of Alpha, beta, and gamma
  2. GDP is released from the G- protein and replaced by GTP
  3. G protein activates Adenylyl (adenylate) cyclase.
  4. The activated Adenylate Cyclase then catalyzes ATP to become cAMP, the secondary messenger which activates the effector protein Protein Kinase-A
  5. Protein Kinase A phosphorlates specific proteins and causes desired effect
25
PK-A
effector protein | (protein kinase- A)
26
cytoplasmic/nuclear protein receptors how they work
* Some lipophilic hormones do not bind to the cell membrane but instead diffuse through and go to the nucleus. * In the nucleus, they bind to receptors associated with the DNA and regulate RNA synthesis * This process takes time to produce end effect
27
Simple transduction system
* Guanylate cyclase * effect on smooth muscle * activated in various ways * Examples: * ANP * nitric oxide
28
Complex transduction systems
* Tyrosine kinase * insulin * insulin like growth hormone * growth hormone
29
Phospholipase C Examples | (IP3)
1. Gonadotropin releasing hormone 2. thyrotropin releasing hormone 3. growth hormone releasing hormone 4. corticotropin releasing hormone 5. angiotensin II 6. Antidiuretic hormone (V1 receptor) 7. Oxytocin 8. Alpha- Andrenergic agonists Going to go carefully agains all other advice.
30
Adenylyl Cyclase (cAMP) examples
1. Adrenocorticotrophic hormone 2. leutenizing hormone 3. follicle stimulating hormone 4. ADH (V2 receptor) 5. parathyroid hormone 6. calcitonin 7. glucagon 8. B-Andrenergic agonists Autumn leaves falling and preparing christmas gifts beautifully
31
G Protein coupled recepts IP3
1. Ligand attaches to receptor on G protein 2. Alpha portion of G protein is released and activates Phospholipase C 3. Phospholipase C liberates diacycglycerol (DAG) and IP3 from membrane lipids. 4. IP3 mobilizes Ca++ from the endoplasmic reticulum 1. The Ca++ and diacycglycerol (DAG) activate protein kinase C which phosphorylates proteins and causes specific physiologic actions
32
Gualylyl cyclase
Two ways to be activated 1. give medication with NO 2. give medication that activates or is NOS (nitrous oxide synthase 1. this breaks arginine down into NO NO activates guanylyl cyclase. Guanylate cyclase converts GTP to cGMP, which is second messenger.
33
cGMP
vasodilators
34
Cytoplasmic/Nuclear Receptor (mostly steriods) examples
taking steriods can give you "roid rage" so \*insert NY accent\*... **PETTA C**an **C**urse **(d**irty..**)** * **P -** progesterone * **E -** Estradiol (estrogen) * **T -** Testosterone * **T -** Thyroid horomones (t3/t4) * **A-** Aldosterone * **C**an **-** Cortisol * **C**urse **(d**irty**) -** Calcitrol (vit D)
35
Tyrosine Kinase examples
"**Tyrone kin**dly explained that he **likes** to be '**in da sun**'.. says it helps him **grow**" "in da sun" = Insulin " likes" = IGFs (insulin-like growth factors) "grow" = Growth horomones
36
Guanalyate Cylase examples
"**A**nother **B**ad **N**ight **O**ut in **GUAM**" (all vasodialators:) * Another = ANP * Bad = BNP * Night Out = Nitric Oxide * in GUAM= sounds like **guan**alyate
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