Ch 6, 7: Membranes Flashcards Preview

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Flashcards in Ch 6, 7: Membranes Deck (35):
1

Integral proteins

Proteins that are in contact with hydrophilic heads and hydrophobic tails in the membrane
Amino acids penetrate of entirely cross the phospholipid bilayer

2

Peripheral proteins

Proteins found on one side of the membrane
Lack exposed hydrophobic groups

3

Glycolipids

Carbohydrate-bound lipids

4

Desmosomes

Structural support
"Spot welds"
Hold the cells in place and together

5

Tight junctions

Two proteins put together at a junction
Prevents the flow of anything between cells and leakage
Keeps things moving through the cell

6

Gap junctions

Spread action potential (ions), which changes the charge
Facilitates sharing of small substances (ions)
Formed with connexons
Evens out resting potential

7

Connexons

Small membrane proteins
Put together to make a channel between two cells with gap junctions

8

Permeability

How substances move through the protein portion of the membrane

9

Protein channel

Protein on the membrane that permeated to ions
Simple diffusion
Quaternary proteins

10

Osmosis

The diffusion of water across membranes
Passive process
Solute concentration determines water amount

11

Isotonic solution

Same amount of solute compared to the intracellular fluid
Water will not move in out out

12

Hypertonic solution

High solute (low water) compared to the intracellular fluid
Water will move out of the cell
Cell will shrink

13

Hypotonic solution

Low solute (high water) compared to the intracellular fluid
Water will move inside the cell
Can cause the cell to eventually burst

14

Voltage Gated Channels

Change in ionic charge causes the channels to open
Found in excitable cells

15

Stretch Gated Channels

Channels that open only when there is a change in shape of a membrane
Mechanical

16

Phosphorylation Gated Channels

Chemical

17

Ligand Gated Channels

Channel opens the receptor when the ligand binds
Ex. neurotransmitter

18

Mediated transport

Used to transport molecules larger than ions against their gradient
Special proteins are embedded within the membrane
Highly specific and requires a conformational change
Molecule binds to the pore of the transporter

19

Facilitated diffusion

Proceeds from high to low concentration - energetically favorable
Passive transport
Requires a conformational change

20

Passive transport

.

21

Active transport

Requires the expenditure of energy
Ions are moved across the membrane against their concentration
Requires a transport

22

Uniport transporters

Moves a single type of solute
Ex. specific ion channels

23

Symport transporters

Moves two solutes in the same direction
Ex. Na+/Glucose pump

24

Antiport transporters

Moves two solutes in opposite directions
Ex. Na+/K+ pump

25

Primary active transport

Directly requires ATP
Pumps - work against concentration gradient
Only cations can pass
Ex. Na+/K+ pump

26

Secondary active transport

Indirectly requires ATP
Facilitated diffusion, made possible by active transport
Coupled transporter
Ex. Na/Glucose co-transporter

27

Na/Glucose co-transporter

Glucose moves against concentration gradient inside the cell
Movement of glucose at the expense of sodium
Na+/K+ pump uses ATP to filter out Na+
Symport
Found in cells of the digestive system and the nephron kidneys

28

Endocytosis

Brings macromolecules into the cell
Plasma membrane invaginates toward the cell interior and engulfed the macromolecule
Molecule binds to the membrane, which pinches it off inside the cell
Requires a lot of energy

29

Receptor mediated endocytosis

Hormone comes and binds to the membrane
Buds off via endocytosis
Can have an effect on the nucleus

30

Exocytosis

Materials packages in vesicles and are secreted from the cell
Vesicle membrane fuses with the plasma membrane and releases vesicle contents into the surroundings
Requires a lot of energy

31

Vesicles

A part of the plasma membrane that has been pinched off inside the cell

32

Phagocytosis

Enzymes in the cell - phagocytes
Lysosomes fuse to the vesicle and break down the contents
Release waste via exocytosis

33

Adenylyl cyclase (AC)

An effector molecule that converts ATP to cAMP
Activated by alpha subunit on G protein

34

Cyclic AMP (cAMP)

Molecule that activated protein kinase A

35

Protein Kinase A

Enzyme that phosphorylates a particular protein