ch 3- the plasma membrane

Question 1

plasma membrane

Answer 1

the phospholipid bilayer and embedded proteins which separate the intracellular environment from the extracellular environment. Also known as cell membrane

Question 2

intracellular

Answer 2

inside a cell

Question 3

extra cellular

Answer 3

outside a cell

Question 4

selective permeability

Answer 4

a property of cell membranes that ensures only specific substances pass across them. Also known as semipermeable

Question 5

phospholipid

Answer 5

the main molecule of which membranes are composed. They have a phosphate head and two fatty acid tails

Question 6

phospholipid bilayer

Answer 6

a double layer of amphiphilic molecules that forms the primary component of cell membranes

Question 7

phosphate head

Answer 7

the hydrophilic subunit of a phospholipid and is negatively charged and polar

Question 8

fatty acid tail

Answer 8

the hydrophobic lipid subunit of a phospholipid, no charge and non polar

Question 9

hydrophilic

Answer 9

having a tendency to be attracted to and dissolve in water

Question 10

polar

Answer 10

describes a molecule with both a positive end and negative end. These tend to be hydrophilic

Question 11

hydrophobic

Answer 11

having a tendency to repel and be insoluble in water

Question 12

non polar

Answer 12

describes a molecule without a clearly positive or negative end. These tend to
be hydrophobic

Question 13

amphipathic

Answer 13

describes molecules with both hydrophilic and hydrophobic components.
Also known as amphiphilic

Question 14

protein

Answer 14

a class of biomacromolecule made of amino acid monomers folded into a
3D shape, consisting of carbon, hydrogen, oxygen, nitrogen, and sometimes sulphur

Question 15

carbohydrate

Answer 15

a class of biomacromolecule made from monosaccharide monomers consisting of carbon, hydrogen, and oxygen. Also known as saccharides or sugars

Question 16

cholesterol

Answer 16

a steroid-alcohol that regulates fluidity in plasma membranes

Question 17

integral protein

Answer 17

a protein that is permanently secured to the plasma membrane

Question 18

transmembrane protein

Answer 18

an integral protein that spans the entire plasma membrane

Question 19

peripheral protein

Answer 19

a protein temporarily attached to the plasma membrane

Question 20

cytoskeleton

Answer 20

the microscopic web of protein filaments in the cytoplasm. It provides structure and support, and transports products around the cell

Question 21

glycolipid

Answer 21

a phospholipid bound to a carbohydrate

Question 22

glycoprotein

Answer 22

a protein bound to a carbohydrate

Question 23

function of proteins

Answer 23

transport, catalysis, communication and adhesion

Question 24

function of carbs

Answer 24

cell-cell communication, signalling, recognition, adhesion

Question 25

cholesterol

Answer 25

regulates fluidity of the membrane, higher temperature the cholesterol keeps them bound together and at lower temperature, it disrupts the fatty acid tails, stopping phospholipids from becoming a solid boundary

Question 26

fluid mosaic model

Answer 26

the theory of how the plasma membrane is structured

Question 27

saturated

Answer 27

a fatty acid chain with only single bonds between carbon atoms

Question 28

unsaturated

Answer 28

a fatty acid chain with at least one double or triple bond between carbon atoms

Question 29

cytosol

Answer 29

the aqueous fluid that surrounds the organelles inside a cell

Question 30

passive transport

Answer 30

the movement of molecules through a semipermeable membrane and down the concentration gradient, without an input of energy

Question 31

active transport

Answer 31

movement of molecules across a semipermeable membrane that requires energy

Question 32

diffusion

Answer 32

the passive movement of molecules from areas of high concentration to areas of low concentration (down the concentration gradient)

Question 33

concentration gradient

Answer 33

the difference in solute concentration between two adjacent areas

Question 34

kinetic energy

Answer 34

the energy a particle or body possesses due to motion

Question 35

solute

Answer 35

a substance dissolved in the solvent

Question 36

solvent

Answer 36

a liquid in which a solute is dissolved, forming a solution

Question 37

facilitated diffusion

Answer 37

a type of passive transport where molecules move through a phospholipid bilayer with the aid of a membrane protein

Question 38

protein channel

Answer 38

a transmembrane protein pore in a phospholipid bilayer that selectively enables transport of large or polar molecules

Question 39

carrier protein

Answer 39

a membrane protein that undergoes conformtional change to transport molecules across a membrane

Question 40

conformational change

Answer 40

a change in the three-dimensional shape of macromolecules such as proteins

Question 41

osmosis

Answer 41

the passive transport of a solvent (typically water) through a semipermeable membrane from a region of low solute (high solvent) to a region of high solute (low solvent)

Question 42

tonicity

Answer 42

a measure of the relative concentration of solutes on either side of a semipermeable membrane, described as hypertonic, hypotonic, or isotonic

Question 43

hypertonic

Answer 43

describes a solution with a higher solute concentration when compared to another solution

Question 44

isotonic

Answer 44

describes a solution with the same solute concentration as another solution

Question 45

hypotonic

Answer 45

describes a solution with a lower solute concentration when compared to another solution

Question 46

turgid

Answer 46

describes plant cells that are swollen and firm from water uptake

Question 47

plasmolysed

Answer 47

describes plant cells with weak and sagging plasma membranes from water loss

Question 48

lyse

Answer 48

to cause a cell plasma membrane to burst or break

Question 49

protein mediated active transport

Answer 49

a type of active transport which involves using membrane proteins to move molecules across a membrane against their concentration gradient. Also known as active transport

Question 50

bulk transport

Answer 50

a type of active transport that uses vesicles to move large molecules or groups of molecules into or out of the cell. Also known as cytosis

Question 51

protein pump

Answer 51

a polypeptide that transports molecules across a membrane against its concentration gradient with the aid of ATP

Question 52

adenosine triphosphate

Answer 52

a high energy molecule that, when broken down, provides energy for cellular processes

Question 53

carrier protein

Answer 53

a membrane- based protein that undergoes conformational change to transport molecules across a membrane

Question 54

conformational change

Answer 54

a change in the three-dimensional shape of macromolecules such as proteins

Question 55

exocytosis

Answer 55

a type of bulk transport that moves large substances out of the cell

Question 55

osmosis

Answer 55

the passive transport of a solvent (typically water) through a semipermeable membrane from a region of low solute (high solvent) to a region of high solute (low solvent)

Question 55

vesicle

Answer 55

a small membrane-bound sac that transports or stores substances within a cell

Question 56

endocytosis

Answer 56

a type of bulk transport that moves large substances into the cell

Question 57

secretory products

Answer 57

the substances inside a vesicle that are being transported out of the cell

Question 58

phagocytosis

Answer 58

endocytosis of solid material or food particles

Question 59

pinocytosis

Answer 59

endocytosis of liquid or dissolved substances