Chapter 7: Membrane Structure and Function

Question 0

integral proteins

Answer 0

transmembrane proteins that completely span the hydrophobic interior of the bilayer

Question 1

phospholipid bilayer

Answer 1

large part of fluid mosaic model

hydrophobic and hydrophilic interactions hold membrane together

most lipids and some proteins can drift randomly in the bilayer (some are attached to the cytoskeleton)

Question 2

peripheral proteins

Answer 2

loosely bonded to the surface of the membrane and some are attached to the extra cellular matrix

Question 3

oligosaccharides

Answer 3

short sugar chains attached to the membrane

15 sugar units long

Question 4

oligo

Answer 4

short (Greek)

Question 5

glycolipid

Answer 5

sugar chains bonded directly to the membrane (phospholipid layer)

Question 6

glycoprotein

Answer 6

sugar chain directly bonded to a protein

Question 7

oligosaccharide usages

Answer 7

markers that distinguish one cell from another

vary from species to species and distinguish blood types using varying oligosaccharides

Question 8

blood types

Answer 8

O, A, B, AB

Question 9

6 functions of proteins in membrane

Answer 9

1) Transport
2) Enzymatic activity
3) Signal transduction
4) Cell-cell recognition
5) Intercellular joining
6) Attachment to the cytoskeleton and extra cellular matrix (ECM)

Question 10

cholesterol in the membrane

Answer 10

steroid or lipid in the membrane that reduces membrane fluidity

reduce phospholipid movement by stabilizing the membrane

Question 11

kinks in phospholipid tails

Answer 11

where double bonds (unsaturated bonds) are located

Question 12

why do unsaturated bonds increase fluidity?

Answer 12

more porous, spaced farther apart (see diagram)

Question 13

saturated bonds

Answer 13

single bonds that make membrane more viscous

heads close together, tails straight

Question 14

passive transport

Answer 14

does NOT require adenosine triphosphate

moves with concentration gradient

Question 15

diffusion

Answer 15

when any substance moves from an area of higher concentration to an area of lesser concentration without the use of energy

Question 16

concentration gradient

Answer 16

when there is an area of high and low concentration

Question 17

no equilibrium is when

Answer 17

diffusion is still occurring. when diffusion is done, there is no high/low concentration

Question 18

equilibrium

Answer 18

when a substance is equally spaced throughout a container

Question 19

osmosis

Answer 19

the diffusion of water across a selectively permeable membrane

Question 20

isotonic environment

Answer 20

having the same amount of water and dissolved diluted as the cell

75% water 25% solutes in
75% water 25% solutes out

Question 21

hypertonic environment

Answer 21

having less water and more dissolved solutes as the cell

75% h2o 25% solutes in
        (more dilute)
     (lose water, cell shrinks---->)
70% water 30% solutes out
        (more stuff)

Question 22

hypotonic environment

Answer 22

having more water and less dissolved solutes as the cell

75% h2o 25% solutes in
     (less h2o)
    (gains water, cell swells ---->)
80% h2o 20% solutes out
     (more h2o)

Question 23

ocean water is

Answer 23

isotonic to most marine invertebrates

Question 24

extracellular fluid is

Answer 24

isotonic in land dwelling animals

Question 25

fresh water invertebrates live in a

Answer 25

hypotonic environment

Question 26

osmoregulation

Answer 26

the control of water balance using adaptations

Question 27

example of osmoregulation

Answer 27

paramecium (hypotonic (fresh water))

Question 28

example of osmoregulators in paramecium

Answer 28

contractile vacuole pellicle

Question 29

pellicle

Answer 29

intricate cell membrane that slows water gain into the organism (less permeable than average cell membrane) ex of osmoregulators in paramecium

Question 30

turgor pressure

Answer 30

in plant cell; (turgid environment) when a plant cell is turgid, this is a healthy condition in the plant- it's gained enough water where the cell membrane is pushed against the cell wall

Question 31

turgor pressure helps plants:

Answer 31

support; keeps them straight

Question 32

flaccid

Answer 32

low turgor pressure- limp

Question 33

plasmolysis

Answer 33

when cell is actively losing water

Question 34

herbaceous plants

Answer 34

soft plants (will wilt)

Question 35

woody plants

Answer 35

not enough water ----> dies

Question 36

lyse

Answer 36

(in animal cell) cell gains too much water that it breaks open

Question 37

facilitated diffusion

Answer 37

flows WITH concentration gradient many polar molecules and ions are impeded by the lipid layer so they must be transported with the help of transport proteins. these transport proteins are specialized for the solute

Question 38

main molecule moved by facilitated diffusion

Answer 38

glucose

Question 39

main example of solute with specialized transport proteins

Answer 39

glucose

Question 40

gated channels

Answer 40

stimulus causes these to open or close (electrical or chemical)

Question 41

ex of gated channels

Answer 41

nerve cell (neurotransmitter used to open a gated channel that allows sodium into the cell)

Question 42

active transport

Answer 42

any cellular transport that requires cellular energy and moves AGAINST the concentration gradient

Question 43

sodium-potassium pump

Answer 43

ATP transfers it's terminal (last) phosphate directly to the transport protein. this changes the protein's conformation and translocation the solute

Question 44

how sodium-potassium pump works

Answer 44

sodium is being pushed out of the cell against it's concentration gradient (10% more sodium outside than inside the cell). potassium is being pushed inside the cell against it's concentration gradient (10% more K inside than outside)

Question 45

Na to K ratio in sodium potassium pump

Answer 45

3 Na for every 2 K

Question 46

endocytosis

Answer 46

when materials are moving into the cell

Question 47

phagocytosis

Answer 47

*form of endocytosis (type of AT)* when a cell engulfs food by wrapping pseudopods around it and forming a food vacuole (cell eating)

Question 48

pinocytosis

Answer 48

*form of endocytosis (type of AT)* a pocket forms in the cell membrane trapping extracellular fluids and it's contents. the vesicles pinches off and enters the cell (cell drinking)

Question 49

receptor - mediated endocytosis

Answer 49

*form of endocytosis (type of AT)* receptor proteins in the cell membrane are clustered in regions of the membrane called coated pits. the cell is collecting a desired substance called a ligand. the ligands bind to these receptors and are pulled into the cell forming vesicles (called coated vesicles)

Question 50

exocytosis

Answer 50

cell removing materials the vesicles fuses with the cell membrane and dumps it's contents outside of the cell

Question 51

ex of exocytosis

Answer 51

pancreas secreting insulin