Water and Movement Across the Membrane Flashcards Preview

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Flashcards in Water and Movement Across the Membrane Deck (32):
1

What does amphipathic mean?

- A molecule containing an area of hydrophobic and of hydrophilic nature

2

How do water soluble molecules arrange themselves in solution?

- Water- water H bonding of the water is replaced by
- Water- solute bonding

3

What do water soluble molecules arrange themselves like this?

- Water-solute hydrogen bonding is more favourable

4

How do uncharged molecules arrange themselves in water?

In such a way that will bring the least amount of disruption to the water-water bonds

5

What are uncharged molecules said to form in solution?

Cages

6

What do phospholipids form to minimise water disruption?

- Micelles
- Bilayers

7

What are buffers?

Solutions of weak acids that dissociate to form a conjugate acid-base

8

What 3 things aid diffusion?

- Large surface area
- High permeability
- High conc. gradient

9

What 3 properties do molecules need to have to diffuse across the membrane?

- Small
- Uncharged
- Lipophobic

10

What 2 elements can cross the membrane easily?

- N2
- O2
Because they are small and uncharged (symmetry)

11

What two waste compounds can easily cross the membrane?

- Urea
- CO2

12

What are the 2 classes of membrane proteins?

- Integral
- Peripheral

13

4 types of integral proteins?

- Channels
- Carriers
- Enzymes
- Receptors

14

What happens to the plasma membrane if integral proteins are removed?

It is disrupted

15

Relative "amphipathicness" of integral and peripheral proteins

Integral = amphipathic
Peripheral = not

16

Where are peripheral proteins found?

Inner side of the membrane

17

What do peripheral proteins tend to be?

Enzymes

18

What do peripheral proteins play a key role in?

Cell shape and motility

19

What is an example of a peripheral protein that is important for cell shape and motility (hint: the gene for its coding is lost in duchennes dystrophy)

Dystrophin

20

Name two cells and their membrane protein percentage to show how different membranes can be

- Schwann cells (18%)
- Mitochondria (75%)

21

What protein does water use to enter/exit the cell?

Aquaporin

22

What are the 2 types of gated channels

- Voltage gated
- Ligand gated

23

How does voltage changes cause voltage gated channels to open??

- It acts on charged regions of the protein
- Causes a conformational change

24

Define osmolarity

- Number of osmoles of solute per litre of solution

25

Define osmolality

- Number of osmoles of solute per kg of solvent

26

Osmolarity of 1M of glucose?

1 osmol/L

27

Osmolarity of 1M of NaCl

2osmol/L

28

What determines the tonicity?

Conc of non penetrating solutes on 2 sides of the membrane

29

What happens if the ECF has a higher tonicity than the ICF?

- Cell is hypotonic
- Cell will swell as water enter

30

What happens if the ECF has a lower tonicity than the ICF?

- Cell is hypertonic
- Cell will shrink as water leaves

31

What is an isosmotic solution?

Equal number of both penetration and non penetrating solutes on either side of the membrane

32

Isotonic?

Equal number of non penetrating solutes on each side