Exam 1 - Lecture 4 8/30

Question 1

Osmolarity

Answer 1

We will use this.

Quantity of “stuff” mOsm / 1 liter of solution

Solution has a LITTLE bit less water than 1kg.

Question 2

Osmolality

Answer 2

Quantity of “stuff” mOsm / 1kgH2O

Question 3

How much mmHg is 1 mOsm?

Answer 3

19.3mmHg

Question 4

how to calculate total osmotic pressure?

Answer 4

Corrected osmo x 19.3

e.g. 281 x 19.3 = 5423

Question 5

mOsm and mEq are units of?

Answer 5

Quantity

Question 6

Weight per quantity of NaCl per the periodic table?

Answer 6

58.4g/1mol (just important to know the units for this measurement)

Question 7

Osmotic pressure: Water wants to flow ______ its concentration gradient

Answer 7

Down.

Question 8

Osmotic pressure: H2O will cross semi-permeable membrane and __________

Answer 8

Defy the force of gravity.

If there is salt only on the left side of the membrane, then water will move to the left side of the U-shaped tube.

Question 9

1 mOsm of stuff on the left side of the tube would increase the water by how many units of distance?

Answer 9

The water would rise by 19.3mm

Question 10

What is keeping all of the water from moving to the left side of the tube?

Answer 10

The weight of the water + gravity. If you did it in outer space, water would completely move over to the left side.

Question 11

Rate of facilitated diffusion is impacted by what?

Answer 11

Amount of transport proteins the body has. Once they are all saturated, diffusion speed cant increase and the speed is maxed out (Vmax)

Question 12

Rate of simple diffusion is?

Answer 12

No Vmax for simple diffusion. The speed increases linearly with concentration of substance.

Question 13

Diffusion rate can be affected by what factors?

Answer 13

Membrane (lipid) solubility: More lipid soluble the substance, faster to get across.

Size: smaller the faster

of pores/channels

Kinetic movement (heat): higher is faster

Physical pressure: blood pressure, higher is faster.

Electrical charge: if the charge of the cell is opposite of substance, draws it in faster. e.g. (-) cell drawing in Na+

Question 14

During the Na+/K+ pump, ATP is used and turned into what?

Answer 14

ADP + Pi

Question 15

What is a result of 3 Na+ leaving with 2 K+ coming in? And what happens if it stops?

Answer 15

Water follows sodium (osmotic pressure), leaving the cell. When this pump stops, cells become swollen with water. This keeps the osmolarity of the cell in check. This type of edema is extremely difficult to deal with, can only be fixed with the cell getting the appropriate ATP.

Question 16

How does sodium get into the cell?

Answer 16

Through secondary active transport, and Sodium can also leak slowly into the cell.

Question 17

Resting membrane potential: Vrm

Answer 17

Na+/K+ is a very important component of Vrm.

At rest, excitable cells are electronegative, compared to conditions outside the cell. Dictated by electrolyte gradients (Na+ 10:1, K+ 1:30)

Question 18

Vrm is denoted as?

Answer 18

-mV. A potential difference between 2 places.

inside of cell is negative in contrast to outside of cell.

Question 19

When cells are turned on, they flip:

Answer 19

Positive for a very short period of time. e.g. generate heart beat

Question 20

Proteins often carry what charge?

Answer 20

Net negative charge. Higher concentration of proteins inside than outside.

Question 21

Proteins are also an important intracellular _________.

Answer 21

Buffer