bio365s cheng exam 1

What three things can easily pass through the cell membrane?

Small hydrophobic/lipophilic molecules (O2, CO2, N2)
Small uncharged polar molecules (urea)
Cholesterol based molecules (steroid hormones)

What two things cannot easily pass through the cell membrane?

Large uncharged polar molecules (amino acids, glucose, and nucleotides)
Ions (H+, K+, Ca2+, Cl-, Mg2+, HCO3-)

What can movement be classified by?

By either energy or physical requirements

What form of transport uses energy of molecular motion and does not use ATP?

passive

What form of transport requires energy from ATP?

active

What three forms of active transport use a membrane-bound vesicle?

endocytosis, phagocytosis, and exocytosis

What does primary active transport create the concentration gradient for?

secondary active transport

What is the physical requirement for facilitated diffusion, primary, and secondary active transport?

It is mediated transport that requires a membrane protein.

What is the physical requirement for simple diffusion?

The molecule goes through the lipid bilayer.

For diffusion, is energy required?

Yes, in the form of kinetic energy

For diffusion, is ATP required?

No! No external energy

If you increase the temperature, what will happen to the rate of diffusion?

It will increase

If you increase the molecular size and weight, what will happen to the rate of diffusion?

It will decrease

If you increase the distance from the initial site, what will happen to the rate of diffusion?

It will decrease

When does diffusion stop?

when equilibrium is reached- no concentration gradient

What does diffusion across a cell membrane depend on?

-Lipid solubility of the molecule
-available surface area
-membrane thickness

What is ficks law of diffusion?

Rate = surface area x conc gradient x permeability / membrane thickness

Do channels open on both sides?

Yes

Do carriers open on both sides

No

Can channels get saturated?

No, they have no binding site

Can carriers get saturated?

Yes, they do have a binding site

What is an example of secondary active transport?

the energy stored in the Na+ gradient allows for glucose to move into the cell from low to high concentration

What are the three types of passive transport?

facilitated diffusion, diffusion, osmosis

What are the three types of active transport?

primary active transport, secondary active transport, vesicular transport

what are the 3 ways types of channel gates

voltage, mechanical (sense & movement like inner ear hair vibration to sound), ligand (ie. neurotransmitters binding)

What is osmolarity defined as?

The number of particles in a solution

Formula for osmolarity

mol x disassociation factor / L

Does tonicity describe the solution or the cell?

always the solution

What does tonicity tells us?

How the cell behaves in a solution, the nature of the solutes.

What is a functionally non-pentrating molecule?

NaCl (make the assumption that ion channels are closed)

in secondary active transport, how do you determine which molecule is actually using the energy to be transported

the molecule going AGAINST its concentration gradient

What is a completely non-penetrating molecule?

proteins (too big)

What is a freely penetrating molecule?

urea

What is a slowly penetrating molecule?

Glucose (converted to G6P upon entry)

Why is glucose a slowly penetrating molecule?

Because once glucose is moved into the cell, it is phosphorylated into glucose 6 phosphate

What is osmosis defined as?

Movement of H2O across a selectively permeable membrane towards the area of higher solute (NON permeable) concentration

What is osmolarity?

Measures # of particles in a solution
(# particles/1L solution)

What is the normal osmolarity of body fluids and the range?

300 mOsm and 280-300 mOsm

What is another word for cells shrinking?

crenate

What is another word for cells swelling?

hemolyse

What are the two isotonic solutions of the standard IV ones?

Normal Saline (0.9% NaCl)
D5 Normal Saline (5% Dextrose in Normal Saline)

What are the three hypotonic solutions of the standard IV ones?

D-5-W (5% dextrose in water)
D5 1/2 NS (5% dextrose in 0.45% NaCl)
1/2 NS (.45% NaCl)

What are the three major classes of hormones?

steroid, peptide, amine

What are amine hormones made from?

They are synthesized from either tyrosine or tryptophan

What type of connection does the posterior pituatary have to the hypothalamus?

neural connection

What type of connection does the anterior pituitary have to the hypothalamus?

vascular connection

What does somatostatin do?

it inhibits GH release

characteristics of the posterior pituatary

- down-growth or extension of hypothalamus
- neural tissue
- releases neurohormones

characteristics of the anterior pituatary

- outgrowth of roof of mouth
- true endocrine/grandular tissue
- releases classic hormones

What is the mechanical view of physiology?

The how of a biological process
Ex: the diaphragm creates pressure gradient so heart contracts to move oxygen carrying blood to the body's cells

What is the teological view of physiology?

The why of a biological process

Where is energy derived from in passive transport?

The concentration gradient

Are carriers a pump and do they have a direct connection with the ECF and ICF

No & no (pumps are like ATPases - active transporters & they are never open to both ECF or ICF at the same time like channels)

How is glucose transport different in epithelial cells (intestine and kidney cells) ?

A secondary active transporter is used in the intestinal and kidney cells , glucose concentration is high inside the cells while the Na+ concentration is low

How does glucose move in normal cells?

By facilitated diffusion, the use of the GLUT 2 and GLUT 4 carriers.

What are examples of facilitated diffusion?

The Na+ channel. and GLUT 4 carrier protein

What are examples of hypo-osmotic solutions?

distilled water, tap water

What are examples of isoosmotic solutions?

.9% NaCl, 5% dextrose in water

What are examples of hyperosmotic solutions?

3% NaCl, conc. sugar solution, sea water

Which receptors trigger signal transduction (extracellular signal to intracellular signal)?

Cell membrane receptors

What are the three positive feedback loops mentioned in class?

Milk letdown, Blood clotting, uterine contractions

Describe a simple endocrine reflex.

Insulin is released from beta cells in response to high plasma glucose. Insulin facilitates glucose uptake in adipose and muscle cells.
Receptor and integrating system are together

What is the thyroid hormone's signal transduction pathway?

TRH (hypothalamus) - TSH (anterior pituatary) - T3, T4 (thyroid gland)

List hormones that come from the hypothalamus

Dopamine
TRH(thyroid releasing hormone)
CRH
GHRH (growth hormone releasing hormone)
Somatostatin
GnRH

List hormones that come from anterior pituitary

Prolactin
TSH
ACTH
GH
FSH or LH

in a solution with a permeable membraine between 2 sides that only contain penetrating particles, how will osmosis occur?

no net movement of water

deuterium oxide (D2O) represents which fluid component: TBW, ECF, or Plasma?

TBW (60%)

Inulin, a ocmplex carbohydrate, represents which fluid component: TBW, ECF, or Plasma

ECF (1/3 of total body weight ie D2O)

evan’s blue represents which fluid component: TBW, ECF, or Plasma

plasma (1/4 of ECF)

the pressure due to H2O movement across a semipermeable membrane (towards high solute concentration - high non-penetrating particles conc.)

osmotic pressure

what is water intoxication

overconsumption of water causing blood cells to hemolyze (burst)

drinking sea water would be dangerous because

it’s hypertonic and could cause blood cells to crenate (shrink)

when an IV is given, how is blood volume affected? how is ICF affected?

blood volume (ECF) always increases! (bc adding fluid & 100% will not enter the cells) but ICF depends on tonicity (look @ [NP] to see how water will move)

chemical molecules released by neurons - short distance communication

neurotransmitters

chemical molecules released by endocrine cells into the blood for long distance communication

hormones

act like hormones but are NOT released into the blood; only to neighboring cells

paracrine

connects cells together through channels; prevents separation of cells; ions are able to flow through neighboring cells

gap junction (heart generating electrical signal; able to fire together bc gap junctions allow for ion flow)

an imitation of the normal ligand that causes the same response as typical ligand; OR receptor that imitates normal ligand receptor and initiates same response upon binding

agonists

bind with the receptor & decrease/stop it’s normal response (blocking the normal ligand from binding)

antagonist

event that causes more protein to be brought to cell membrane from cytosol (ex: insulin is released and GLUT 4 moves to cell membrane)

upregulate

evant that causes the return protein back to cytosol (ex: less glucose brought into the cell bc GLUT 4 transporters move back into cytosol)

downregulation

how do lipophilic molecules relay signal to the cell

by diffusing through the membrane and binding to receptors in the cytosol or nucleus (intraceullar receptors - steroid [ex: cortisol] or thyroid hormones, act as transcription factors)

lipophobic or lipophilic are more likely to affect protein synthesis?

lipophilic

how do lipophilic molecules travel in the blood

bound to proteins

how do lipophobic (hydrophilic) signal molecules relay signals to the cell

binding to cell membrane receptors (integral membrane proteins) and normally activate second messengers (ex: peptide hormones like insulin)

how do lipophilic molecules travel in the blood

they are dissolved in the blood (hydrophilic)

which of the following statements correctly describe the similarities btwn channels & carriers?

both are used for active and passive transport

both channels & carriers connect the ICF & ECF

both have a transport maximum

both exhibit specificity

none of the above

both exhibit specificity

how many osmoles are in your ECF if you weigh 100KG & have an osmolarity of 300mOsM

On average (physio man model) 60% of weight is from body fluid so 100kg = 100L x .6 = 60L. ECF is about 1/3 of TBW so 60 x.3 = 20L (use C= S/V) 0.300osM x 20L = 6 osmoles

how could you make the cell hyperosmotic without affecting tonicity?

add salt to the cell

add salt to the solution

add urea to the cell

add urea to the solution

add urea to the solution (since it is penetrating, it will move into the cell! in this case, via simple diffusion & cause the cell to increase in osmolarity)

which is not one of cannon’s postulates

role of autonomic nervous system

tonic activity

agonistic control

antagonistic control

agonistic control

(all contribute to homeostasis - antagonistic control used by parasymp & symp nervous system)

intracellular receptors bind what type or hormones

steroid or thyroid

cell membrane receptors bind what kind of hormones

peptide/lipophobic signals

2 main types of membrane receptors

ligand gated and G protein coupled receptors (integrin in skeletal muscle & enzyme receptor are others not emphasized in class)

name the common 2nd messengers

cAMP cGMP (photoreceptors of retina use this) IP3/DAG (contraction - release calcium from ER), Calcium

2nd messenger that promotes muscle contraction

calcium

what is normally the integrating center

the brain (hypothalamus)

difference btween local and systemic control in homeostatic response (give examples of the systems that use either of these)

local control involves cells in the same vicinity of the change initiate response (paracrine) while systemic control involves a reflex response initiated by cells that are at a distance site (nervouse & endocrine system)

changes in a variable that is regulated is

stimulus (ie. heat)

the structure that detects the stimulus

receptor (ie. stretch receptors in muscle)

if receptor is part of the integrating center, this send the input to the IC

afferent